Jack Harmer¹, Richard Bowtell¹, and Susan Francis^1
1SPMMRC, The University of Nottingham, Nottingham, Nottinghamshire, United Kingdom

Spontaneous, low frequency fluctuations in connected networks have been identified in T2*-weighted gradient-echo (GE) BOLD data. Here, we use a dual GE-SE-EPI sequence at 7T to identify functional connectivity maps in SE and GE BOLD data using ICA analysis. We assess the correlation of signal fluctuations in the SE and GE time-series, showing a higher correlation in the DMN than in global grey matter. We calculate the ratio of the changes in relaxation rates underlying the signal fluctuations, δR2*/δR2, to be 1.910.30 in grey matter, in good agreement with the value of ~2.1 found for task-induced changes in motor cortex.

Henning Matthias Reimann¹, Jan Hentschel¹, Babette Wagenhaus¹, Andreas Pohlmann¹, and Thoralf Niendorf^1,2
1Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück-Center for Molecular Medicine (MDC), Berlin, Germany, ²Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max-Delbrück-Center, Berlin, Germany

Only little is known about the temperature perception and regulation mechanisms in mammals. The combination of fMRI and genetic modifications in rodents has great potential to help elucidating the role of the various proteins involved in the underlying pathways. Here we demonstrate the successful adaptation of an MR-optimized thermo-stimulation system to mice fMRI, which is of particular interest considering the numerous transgenic strains used in biomedical research of thermal perception. Moreover this report is the first that demonstrates fMRI activations for cold stimuli in mice. Signal-to-noise ratio was enhanced by using a cryogenic RF probe. Based on the concepts and results reported here we anticipate to extend our fMRI explorations into temperature perception and regulation mechanisms in mice with the ultimate goal to characterize the cold sensing transient receptor potential channel TRPM8.

Yen-Liang Liu^1,2, Yun-An Huang¹, In-Tsang Lin¹, Hong-Chang Yang³, and Jyh-Horng Chen^1,2
1Interdisciplinary MRI/MRS Lab, Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan, ²Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan, ³Department of Physics, National Taiwan University, Taipei, Taiwan

A 4cm high-temperature superconducting (HTS) radio-frequency (RF) coil platform was applied on the fMRI study in a 7T MRI system. Not only the image SNR but also the functional SNR were improved due to reduced thermal noise. Compared to a similar home-made copper RF coil, this study obtained an approximate twice SNR gain in both fast spin echo and echo planar imaging (EPI) sequences. The time-series analysis of the resting state fMRI study showed that not only the functional SNR was raised but also the functional connectivity was improved.

Aaron Benjamin Simon¹, and Richard Buxton^2
1Department of Bioengineering, University of California San Diego, La Jolla, CA, United States, ²Department of Radiology, University of California San Diego, La Jolla, CA, United States

We analyzed a novel method of quantitatively measuring CBF fluctuations during complex behavior without knowledge of stimulus dynamics, based on the combined measurement of BOLD and CBF time series. We hypothesized that projection of the ASL time series onto the BOLD time series would separate ASL fluctuations due to CBF from those due to noise. This method was tested on data from a visual stimulus experiment and was found to significantly remove noise from the ASL data, although it produced a small underestimate of CBF fluctuations due to the presence of noise in the BOLD signal.

Ling Mei^1,2, Xiaojing Long*¹, Qian Huang², Haibo Yu³, Yanjun Diao^1,3, Wanzhang Yang⁴, and Bensheng Qiu*^1,5
1Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China,²Department of Electronic and Information Engineering, South China University of Technology, Guangzhou, Guangdong, China, ³Shenzhen Hospital of TCM Affiliated Guangzhou University of TCM, Shenzhen, Guangdong, China, ⁴Shenzhen Nanshan Hospital, Shenzhen, Guangdong, China, ⁵Department of Radiology, University of Washington School of Medicine, Seattle, WA, United States

Three types of metal acupuncture needles were evaluated with respect to MR imaging artifact and RF-induced heating effect. The gold needle generated little artifact, and the Austenitic stainless steel needle produced moderate artifacts in both phantom and in-vivo experiments. However, the traditional stainless steel needle produced huge artifacts. The temperature of the three needles in the phantom have no significant change during a long time MR scanning. In conclusion, gold and Austenitic stainless steel acupuncture needles are MR compatible and safe, which can be used for systemic research on the ancient acupuncture using a modern and powerful MR imaging modality.

Jascha Zapp¹, Sebastian Schmitter², and Lothar R Schad^1
1Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany, ²Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, United States

Acoustic scanner noise causes an unwanted BOLD signal in the auditory cortex during fMRI and also poses a safety issue. Conventional EPI produces high sound pressure level (SPL) due to fast switching of trapezoidal gradients. The aim of this work is to present an enhanced sinusoidal EPI (sEPI) with PAT for reduced SPL. We provide a comprehensive comparison of SPL measurements between sEPI and conventional EPI for their most feasible configurations. The sEPI PAT sequence provides a reduction in SPL of up to 11.1dB and 5.1dB compared to EPI PAT at 3T for matrix sizes of 64x64 and 128x128pixels, respectively.

Stefan Posse^1,2, and Elena Ackley^1
1Neurology, University of New Mexico, Albuquerque, NM, United States, ²Electrical and Computer Engineering, Physics and Astronomy, University of New Mexico, Albuquerque, NM, United States

We introduce high-speed multi-echo EVI with 241 ms temporal resolution and investigate the BOLD contrast characteristics of parametric EVI images during visual and motor tasks. Average T2* values in cortical areas ranged from 30-60 ms, consistent with multi-echo EPI. First and second echo images, T2* maps and weighted echo average maps showed strong BOLD activation in visual and motor cortex and supplementary motor area. The S0 maps showed much smaller activation, predominantly in large blood vessels, consistent with localized in-flow effects. Multi-echo multi-slab EVI enables rapid mapping of T2* and sensitive detection of brain activation and in-flow effects.

Pei-Hsin Wu¹, Hsiao-Wen Chung^1,2, Ming-Long Wu^3,4, Tzu-Chao Chuang⁵, and Tzu-Cheng Chao^3,4
1Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan, ²Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan, ³Department of Computer Science and Information Engineering, National Cheng Kung University, Tainan, Taiwan, ⁴Institute of Medical Informatics, National Cheng Kung University, Tainan, Taiwan, ⁵Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan

Previous study demonstrates that optimization of image contrast for morphological depiction using DESS imaging. The sensitivity of DESS signals to functional brain activations, however, has not been explored. In this study, we report the preliminary results from phantom and human experiments to investigate the relationship between functional contrast and the imaging parameters for S+ and S- images, respectively.

Mark Chiew^1,2, and Simon J Graham^1,3
1Medical Biophysics, University of Toronto, Toronto, Ontario, Canada, ²Rotman Research Institute, Toronto, Ontario, Canada, ³Imaging Research, Sunnybrook Research Institute, Toronto, Ontario, Canada

We present a novel method for fast acquisition of densely-sampled multi-echo fMRI data over a restricted field of view. The DSI (Direct SENSE Imaging) technique employs a modified STEAM localization method for selective excitation of a small number of voxels, and uses direct sensitivity encoding for spatial separation of measured signals. The readout requires no imaging gradients as no Fourier encoding is performed, and the received signals contain both T2 and T2* contrast. This method is proposed as a promising alternative to whole-brain approaches for fast imaging in targeted, ROI-based fMRI.

Steven D. Beyea^1,2, Dan Holland³, Careesa Liu¹, Xiaowei Song¹, Ryan C.N. D'Arcy^1,4, Tynan Stevens^1,5, Andy Sederman³, Lynn Gladden³, and Chris V. Bowen^1,2
1Institute for Biodiagnostics (Atlantic), National Research Council Canada, Halifax, Nova Scotia, Canada, ²Physics & Radiology, Dalhousie University, Halifax, Nova Scotia, Canada, ³Department of Chemical Engineering & Biotechnology, University of Cambridge, Cambridge, United Kingdom, ⁴Neuroscience & Radiology, Dalhousie University, Halifax, Nova Scotia, Canada, ⁵Physics, Dalhousie University, Halifax, Nova Scotia, Canada

Compressed Sensing (CS) reconstruction of variable density spiral fMRI acquisitions are evaluated. CS is shown to improve fMRI sensitivity relative to conventional density compensated re-gridding. Using CS, it was demonstrated that, even when using a matched TR, it is possible to obtain data using a 28% under-sampled 1-shot acquisition which exhibits no loss in fMRI sensitivity compared to a uniformly sampled 2-shot acquisition.

Nguyen Van Le¹, Thanh Hai Nguyen¹, Xiaoyi Yu¹, Zhongnan Fang¹, and Jin Hyung Lee^1,2
1Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, Califorinia, United States, ²Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, California, United States

ofMRI is a powerful new technology that enables precise control of brain circuit elements while monitoring its causal output. To bring ofMRI to it’s full potential, it is essential to achieve high-spatial resolution with minimal distortions. To this end, we combined compressed sensing (CS) reconstruction with under-sampled ultra-high-resolution b-SSFP fMRI, and fast spiral readout. Under-sampling was performed by random selection of 1 in 3 spiral interleaves. The CS object function was designed to optimize data consistency and L1 norm minimization in spatial and temporal dimensions. The results demonstrate achievement of high-quality high-resolution images with precise temporal dynamics necessary for fMRI.

Hans Weber¹, Daniel Gallichan¹, Jakob Assländer¹, Jürgen Hennig¹, and Maxim Zaitsev^1
1Department of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany

The ExLoc concept enables excitation and geometrically matched spatial encoding of curved slices with variable curvature, orientation and position. This allows a better adaptation of the slice geometry to the anatomy under investigation. In this study we apply the ExLoc concept to echo planar imaging and present preliminary results from a curved slice fMRI experiment.

Lirong Yan¹, Emily Kilroy¹, and Danny JJ Wang^1
1Neurology, University of California, Los Angeles, Los Angeles, California, United States

Perfusion fMRI using arterial spin labeling (ASL) is advantageous for quantifying perfusion both at rest and during task activation. However, it is limited by low temporal resolution and sensitivity. With pseudo-continuous ASL (pCASL) with background suppressed (BS) 3D GRASE, the temporal resolution and sensitivity of perfusion fMRI can be improved by skipping control acquisitions without compromising the quantification of cerebral blood flow. In this study, a flexible framework of perfusion fMRI was introduced by using asymmetric label and control acquisitions in pCASL with BS 3D GRASE which was validated using visual cortex stimulation.

Trong-Kha Truong¹, and Nan-kuei Chen^1
1Brain Imaging and Analysis Center, Duke University, Durham, NC, United States

Spiral imaging is vulnerable to spatial and temporal variations of the static magnetic field (B₀) caused by susceptibility effects, subject motion, physiological noise, and/or system instabilities, resulting in image blurring. Previously proposed deblurring methods rely on separately acquired B₀ maps, which increases the scan time and precludes the correction of temporal B₀ variations. Here, we propose a novel k-space energy spectrum analysis method that can inherently and dynamically generate a B₀ map from SENSE spiral k-space data at each time point, without requiring any additional data acquisition or pulse sequence modification, and demonstrate its effectiveness in resting-state fMRI experiments.

Benedikt Andreas Poser¹, and V Andrew Stenger^1
1UH-QMC Neuroscience and MR Research Program, University of Hawaii, Honolulu, Hawaii, United States

BOLD fMRI usually employs EPI, which suffers from distortions caused by field inhomogeneity. Most correction methods rely on some form of reference data acquired at the start. Subject motion during the scan may invalidate this reference as distortion changes with head position. Ability to dynamically update correction parameters may therefore be beneficial. We show that dynamic correction can achieved using IDEA EPI, originally intended for Nyquist ghost compensation. Two images are simultaneously sampled under the positive and negative readout gradients. Their ΔTE of one echospacing (0.5–0.9ms) allows fieldmaps to be calculated from each volume. Phantom and in vivo examples are shown and compared to conventional fieldmap correction.

Linqing Li¹, Christine Law¹, Yazhuo Kong¹, Michael Kelly¹, Jamie Near¹, and Peter Jezzard^1
1FMRIB, Clinical Neurology Department, University of Oxford, Oxford, United Kingdom

We propose the employment of DANTE prepared multislice EPI (DANTE-EPI) for whole brain BOLD signal measurement. Based on the flow suppression feature of DANTE, we hypothesize that the intravascular BOLD signal will be largely suppressed and thus the venous blood contamination reduced. As such, the BOLD signal from DANTE-EPI may be more accurately located to the site of neuronal activity.

Robert V. Mulkern¹, Mukund Balasubramanian¹, Dimitrios Mitsouras², and Stephen Haker^2
1Department of Radiology, Children's Hospital Boston, Boston, Massachusetts, United States, ²Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts, United States

Reversible relaxation processes resulting from inherent frequency distributions have been incorporated into SSFP signal analyses to separately examine how changes in either reversible or irreversible transverse relaxation affect SSFP based fMRI signal intensities. The analytic expressions obtained for Lorentzian, Gaussian and square distributions were derived using a single sum series expansion previously unnoted which allowed for a closed form solution for the Lorentzian and rapidly converging solutions for Gaussian and square distributions. The expressions should be useful for allowing detailed investigations of mechanisms affecting SSFP based fMRI studies in either transition band or passband modes.

Jürgen Finsterbusch^1,2
1Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, ²Neuroimage Nord, University Medical Centers Hamburg-Kiel-Lübeck, Hamburg-Kiel-Lübeck, Germany

Magnetic field inhomogeneities and susceptibility differences cause geometric distortions in echo-planar imaging that are related to the phase modulation induced during the echo train. Here, an approach involving additional blip gradient pulses in the phase and readout direction (“yz-shimming”) is presented that aims to compensate these unwanted phase modulations and, thus, corrects for the geometric distortions. Its feasibility is demonstrated in a phantom and the human spinal cord in vivo.

Sebastian Domsch¹, and Lothar R. Schad^1
1Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany

The orbitofrontal cortex (OFC), important for decision-making and reward processing, is affected by susceptibility gradients (SG) causing signal drop outs and image distortions in fMRI using EPI. In subcortical brain areas, BOLD sensitivity (BS) depends critically on echo time (TE). In this work, optimal TE for single EPI slices are calculated via BS simulations considering local T2star and SG values to maximize BS in the OFC. It shows that optimal TEs increase in foot-head direction from about 20ms to 40ms for AC-PC section orientation. Further, the results show good consistency over all subjects.

Jürgen Finsterbusch^1,2
1Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, ²Neuroimage Nord, University Medical Centers Hamburg-Kiel-Lübeck, Hamburg-Kiel-Lübeck, Germany

With spatially 2D-selective RF excitations rectangular profiles can be excited which can be used to acquire inner fields-of-view without phase-encoding aliasing. Thus, geometric distortions in echo-planar imaging that are caused by magnetic field and susceptibility inhomogeneities, can be reduced for small target regions. In the present study, two approaches are investigated that either involve a FID sequence or a spin-echo-based acquisitions with an echo train shift. The feasibility of both approaches to acquire high-resolution T2*-weighted echo-planar images of inner fields-of-view with minimum distortions is shown. Furthermore, their applicability to functional neuroimaging is demonstrated.

Seong Dae Yun¹, Martina Reske¹, Kaveh Vahedipour¹, Tracy Warbrick¹, and N. Jon Shah^1,2
1Institute of Neuroscience and Medicine - 4, Forschungszentrum Jülich, Jülich, Germany, ²JARA - Faculty of Medicine, RWTH Aachen University, Aachen, Germany

EPI is in widespread use in MR studies acquiring time series data due to its capability of achieving a relatively high temporal resolution. However, the fact that EPI acquires echoes with evolving time delays makes it prone to severe image distortions. To overcome this issue, EPIK (EPI with Keyhole) accelerated using GRAPPA was tested at 3T. This EPIK variant offers a higher temporal resolution and robustness against field inhomogeneities when compared to interleaved EPI and single-shot EPI, respectively. The performance of the method was validated with human functional MRI measurements as well as MRI simulation results using JEMRIS.

Renaud Lopes¹, Aurelien Monnet¹, and Xavier Leclerc^1
1CHRU Lille, Neuroradiology service, Lille, Nord, France

In this study, we assess the potential impact of 32-channel head coil on the results of a fMRI paradigm with 3D PRESTO-SENSE sequence. fMRI results obtained with 32-channel head coil were compared to those obtained with 8-channel head coil. Model-based and data-driven analyses were used in order to compare the statistical power of activity detection for each coil. In this study, it was demonstrated that 3D PRESTO-SENSE with 32-channel head coil can be used for fMRI studies. Higher fMRI sensitivity was found compared to the same sequence with 8-channel head coil.

Kevin Wen-Kai Tsai¹, Thomas Witzel², Wei-Jui Kuo³, and Fa-Hsuan Lin^1,2
1Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan, Taiwan, ²Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, ³Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan, Taiwan

Functional MRI experiments using EPI should tune the echo time (TE) to local T2* value in order to optimize the BOLD signal sensitivity. Since the T2* values are different across the whole brain, acquisitions using one single TE may not be optimal. Using experimental data, we demonstrate that, the InI can use different TEs across acquisitions to improve the sensitivity of detecting BOLD signal and obtain hemodynamic response estimates of 100 ms temporal sampling, reasonable spatial resolution, and whole-brain coverage.

Hai Zheng¹, Lei Sheu^2,3, Tiejun Zhao⁴, Yongxian Qian⁵, Tamer Ibrahim^1,5, Howard Aizenstein^1,2, and Fernando Boada^1,5
1Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States, ²Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, United States, ³Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States, ⁴Siemens Medical Solutions USA, Pittsburgh, Pennsylvania, United States, ⁵Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States

T2* weighted BOLD fMRI in ultra high field (UHF) is hampered by susceptibility-induced signal loss between air cavities and brain tissues. In this article, we proposed a new RF pulse design strategy, dubbed as PTX 3DTRF, by combing 3DTRF method and PTX technique to simultaneously and precisely recover multi-slice signal loss and improve BOLD signal. Significant improvement in UHF human study can be observed when the proposed methods are applied. Robustness and reproducibility are proved by scanning multiple subjects (N=5) and multiple times on one subject (two of the five subjects were scanned twice, respectively).

Ariane Fillmer¹, Milan Scheidegger^1,2, Peter Boesiger¹, and Anke Henning^1
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, ZH, Switzerland, ²Clinic of Affective Disorders and General Psychiatry, University Hospital of Psychiatry Zurich, Zurich, ZH, Switzerland

To make use of the full capacity of fMRI applications in ultra-high field strengths, an excellent B0 shimming is inevitable. Usually these applications suffer from major distortions and signal drop-outs in the frontal cortex area. This work presents a modified approach of B0 shimming, which enables the restoration of signal in the frontal cortex and therefore renders fMRI applications in the frontal cortex possible.

Jerzy Bodurka¹, Vadim Zotev¹, Raquel Phillips¹, and Han Yuan^1
1Laureate Institute for Brain Research, Tulsa, Oklahoma, United States

We describe the system we implemented on commercial MRI and EEG equipment in which we achieved integration of concurrent real-time fMRI (rtfMRI) and electroencephalography (EEG) data for the purpose of simultaneous rtfMRI-EEG neurofeedback. This first-of-its-kind real-time simultaneous fMRI and EEG multimodal neurofeedback (rtfMRI-EEG-mnf) approach allows research participants to receive information about their cerebral electrophysiological and hemodynamic activity in real-time and to then use this information to volitionally self-regulate neural responses. This system can be used in the development of novel cognitive neuroscience research paradigms and novel enhanced cognitive therapeutic approaches for major psychiatric disorders.

Li-Ming Hsu¹, Kuan-Hung Cho², Cyril Poupon³, Denis Le Bihan³, and Ching-Po Lin^1,4
1Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan, ²Instrumentation Resource Center, National Yang-Ming University, Taipei, Taiwan, ³NeuroSpin, IFR 49 CEA Saclay, Gif-sur-Yvette, France, ⁴Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan

To optimize the diffusion-fMRI at different b-values by considering the signal performance compared with BOLD-fMRI during visual stimulation. The results show that the DfMRI at b-value = 1,200 s/mm² should be a better choice than b-value = 600 and 1,800 s/mm². DfMRI could provides the chance to approach the neuron activation than hemodynamic response.

Valur Olafsson¹, Jia Guo¹, Chi Wah Wong¹, Prantik Kundu², Souheil Inati³, Wen-Ming Luh³, Vinai Roopchansingh³, Noah Brenowitz², Peter Bandettini^2,3, Eric Wong¹, and Thomas Liu^1
1UCSD Center for Functional MRI, La Jolla, CA, United States, ²Section on Functional Imaging Methods, NIMH, Bethesda, MD, United States, ³Functional MRI Facility, NIMH, Bethesda, MD, United States

Motion and physiological noise confounds are key factors that limit the sensitivity of resting-state functional connectivity MRI (fcMRI) measures. The acquisition of multiple echoes has been shown to be effective for automatically identifying and removing these confounds. However, the acquisition of multiple echoes requires additional readout time and leads to a decrease in temporal resolution. To address this issue, we have used a simultaneous multislice excitation strategy to compensate for the extra readout time and achieve whole brain coverage with 3 echoes, 2 mm isotropic resolution, and a TR of 2 seconds.

Zhongnan Fang¹, and Jin Hyung Lee^1,2
1Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, California, United States, ²Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, California, United States

Here we present a novel real-time optogenetic functional magnetic resonance imaging (ofMRI) method. ofMRI is a novel technology, which enables systematic analysis of brain circuits by using optogenetic stimulation as input, and fMRI readout as output. Real-time ofMRI (rt-ofMRI) aims to provide real-time brain circuit analysis capabilities using ofMRI. Our goal is to acquire, reconstruct, motion correct, and analyze ofMRI images in real-time. This approach enables high-throughput ofMRI studies with live activation feedback on image quality, motion characteristics, and optogenetic stimulation response. It prevents long offline processing and facilitates interactive experiment parameter selection (e.g. stimulation frequency, isoflurane level, etc.).

Eddy Solomon¹, Nadya Pyatigorskaya², Peter Bendel¹, Denis Le Bihan², Luisa Ciobanu², and Lucio Frydman^1
1Weizmann Institute of Science, Rehovot, Israel, ²Neurospin, CEA, Saclay, France

This presentation examines the origin of the function-derived activation detected by SPEN fMRI, with a series of preclinical high (7T) and ultra-high (17.2T) magnetic field studies. Artifact-free images of a rat’s head with good resolution in all areas and localized activation maps were obtained in a single scan using a variety of SPEN sequences. Our data shows that, besides the normal T2*-weighted BOLD contribution which arises in non-refocused sequences, fMRI SPEN signals contains a strong component caused by apparent T1-related inflow effects. This contribution can be modulated by varying the scanning repetition rate; measurements at 7T support this finding.

Nitzan Tirosh¹, and Uri Nevo^1
1Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel

Isolated and viable spinal cords of newborn rats were used to investigate whether the changes in DWI signal during neuronal activation originate from biophysical mechanisms linked to neuronal activity or related to vascular effects. DW images were acquired with three diffusion times and along three diffusion directions during three physiological phases: Spontaneous activity, chemically induced enhanced activity and return to baseline activity. Reduction of 18-27% in the average ADC was observed during elevated neuronal activity. These results suggest that electrical activity affects water displacement in neurons and these changes are not an MR artifact due to a vascular effect.

Dmitry S. Novikov¹, Marco Reisert², and Valerij G. Kiselev^2
1Radiology, NYU School of Medicine, New York, NY, United States, ²Radiology, University Medical Center Freiburg, Germany

NMR diffusion measurements are confounded by heterogeneous microscopic magnetic susceptibility. It is known that apparent diffusion coefficient (ADC) is smaller in this case than the genuine diffusivity when diffusion is slow. We discover a more general effect: ADC over- or underestimates the genuine diffusivity when diffusion is fast depending on the pulse sequence. Our theory agrees with Monte Carlo simulations in computer-generated capillary network. The ~5% change in the simulated ADC quantitatively explains the observed DWI signal changes both in hypercapnia and under neuronal activation, suggesting that BOLD effect is sufficient for rationalizing the “diffusion fMRI” phenomenon.

Padmavathi Sundaram¹, Darren Orbach¹, Robert Mulkern¹, Mukund Balasubramanian¹, and William Wells^2
1Radiology, Children's Hospital Boston, Harvard Medical School, Boston, MA, United States, ²Radiology, Brigam and Women's Hospital, Harvard Medical School, Boston, MA, United States

In past work, we imaged epileptiform events using gradient-echo EPI and found fast MR phase changes that suggested 183 nT local magnetic fields inside neuronal tissue. Here we attempt to determine whether these fields are compatible with electrophysiology in epilepsy. Nature and strengths of magnetic fields inside the brain are largely unknown. All empirical measurements are done using MEG and are of magnetic fields outside the brain.

Daniel L Shefchik¹, Andrew S Nencka¹, Andrzej Jesmanowicz¹, and James S Hyde^1
1Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States

Tissue segmentation for functional MRI studies is normally performed with FreeSurfer, which utilizes T1 weighted anatomical images to provide tissue separation maps. The anatomical separation maps have a different image warping than EPI images and can lead to incorrect image registration. A different tissue separation method utilizes the GREASE-II sequence to produce T1, T2, and T2’ relaxivity maps in the same EPI space as functional studies. The three EPI relaxivity maps produce CSF, gray and white matter maps by using their mean relaxivity values. Tissue maps are combined to view the Partial volume effect throughout the brains gray matter.

Sebastian Baecke¹, Michael Luehrs¹, Ralf Luetzkendorf¹, and Johannes Bernarding^1
1Biometrics and Medical Informatics, Otto-von-Guericke University, Magdeburg, Sachsen-Anhalt, Germany

We have developed an adaptive hyper-scanning software system, that combine two (or more) MR scanner in real time. The activation of the two volunteers can be analysed in real time and used on a brain-computer interface for controlling various paradigms. The biggest advantage here is the direct feedback to the subjects which may then influence their own brain activity and thus the development and optimization of their own strategies to increase their neural response. Here we present the first results of a feasibility study for social interaction connecting a 3T and 7T MR scanners.

Sebastian Domsch¹, Andreas Lemke¹, Sebastian Weingärtner¹, and Lothar R. Schad^1
1Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany

UNFOLD to increase sampling rates in fMRI to detect transient BOLD signal modulations requires temporal filtering before statistical mapping in the time domain is carried out. Low-pass filtering and zero-filling has been proposed. Both strategies are non-optimal since low-pass filtering degrades temporal resolution and zero-filling leads to serial correlations (non-white noise) known to bias linear modeling of neuronal responses. We propose a more sophisticated temporal filtering strategy intrinsically avoiding non-white noise to increase statistical inference.

Jarle Ladstein¹, Hallvard Røe Evensmoen², Asta Kristine Håberg², Anders Kristoffersen³, Dominic Holland⁴, Anders M Dale^4,5, and Pål Erik Goa^3
1MI Lab and Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway, ²Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway, ³Clinic of Radiology, St. Olavs University Hospital, Trondheim, Norway, ⁴Department of Neurosciences, The University of California, San Diego, United States, ⁵Department of Radiology, The University of California, San Diego, United States

Geometric distortions in functional EPI scans cause local misregistration between functional and anatomical images. This can decrease the power of functional group level analysis in regions with much distortion. To evaluate the effect of applying a distortion correction to the functional data, 25 subjects were scanned during a special encoding paradigme and the data analyzed both with and without applying a correction estimated from reverse gradient scans. In regions of interest in the entorhinal cortex the degree of distortion was high and using distortion corrected data had a positive effect in terms of increased activation volume and peak z-volume.

Emilie Vallée¹, Live Eikenes², Anders Kristoffersen³, and Asta K Håberg^2,3
1MI Lab, Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway, ²Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway, ³MI Lab, Department of Medical Imaging, St. Olavs Hospital, Trondheim, Norway

Diffusion functional MRI has been proposed as a method that detects true neuronal activity as changes in the grey matter diffusion properties. Due to the high level of noise present in the data, the origin of the diffusion signal remains uncertain. Data was analyzed using a response function modeling the diffusion process (DRF) and the vascular process (HRF). Though the average time-course from DRF analysis showed a 3s earlier and steeper rise than the one from HRF analysis (= BOLD signal), noise measurements suggested that the observed shift was caused by correlated noise (physiological and artefactual) present in the data.

Günther Grabner Grabner^1,2, Benedikt Andreas Poser², Siegfried Trattnig¹, and Markus Barth^2
1Department of Radiology, Medical University Vienna, Vienna, Vienna, Austria, ²Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands

Due to the availability of high field scanners and novel imaging methods, high resolution, whole brain fMRI becomes feasible. However, for performing fMRI group analyses spatial smoothing is necessary to account for inter-individual anatomical variation. Here, we investigate the possibility to build a high resolution, group specific anatomical template (model) directly from the functional T2* weighted data acquired at 7 Tesla. The purpose of this model is two fold; first, spatial smoothing can be kept at a low level and second, misregistration between distorted functional and anatomical data is avoided.

Waqas Majeed^1,2, Feng Wang^1,2, Robert M Friedman³, Chaohui Tang^1,2, and Malcolm J Avison^1,2
1Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University, Nashville, TN, United States, ²Department of Radiology, Vanderbilt University, Nashville, TN, United States, ³Department of Psychology, Vanderbilt University, Nashville, TN, United States

In this study, we describe an approach for detecting weak and focal activity patterns in fMRI data. High resolution cerebral blood volume weighted images were acquired from squirrel monkeys during tactile stimulation of digits 1 and 3. The data were preprocessed to enhance effective contrast-to-noise ratio, and the model order was estimated in a data-driven fashion (based upon stability of the principal modes). Activation patterns associated with stimulation of individual digits were successfully detected using ICA. In future, we intend to use this approach to investigate the presence of local functional connectivity networks within the somatosensory cortex of squirrel monkeys.

Imali Thanuja Hettiarachchi¹, Shady Mohamed¹, and Saeid Nahavandi^1
1Centre for Intelligent Systems Research, Deakin University, Geelong, VIC, Australia

This work demonstrates a novel Bayesian learning approach for model based analysis of Functional Magnetic Resonance (fMRI) data. We use a physiologically inspired hemodynamic model and investigate a method to simultaneously infer the neural activity together with hidden state and the physiological parameter of the model. This joint estimation problem is still an open topic. In our work we use a Particle Filter accompanied with a kernel smoothing approach to address this problem within a general filtering framework. Simulation results show that the proposed method is a consistent approach and has a good potential to be enhanced for further fMRI data analysis.

Yao-Wen Chang¹, and Teng-Yi Huang^1
1Dept. of EE, National Taiwan University of Science and Technology, Taipei city, Taiwan

This study investigated the multifocal fmri method for retinotopy mapping. Different from the previous studies employing m-sequence, we utilized a correlation approach to create stimulus series. This approach can be used to comprise the hemodynamic response function of BOLD effect in the generated series. In our preliminary result, we were able to acquire local signals in V1 from each of the 60 stimulated regions.

Glyn S Spencer¹, Karen J Mullinger¹, Andrew Peters¹, and Richard Bowtell^1
1SPMMRC, School of Physics and Astronomy, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom

The EEG gradient artefact (GA) is formed from a linear superposition of individual artefacts generated by the orthogonal gradients. Variations in position of the head and/or EEG leads scale the relative weighting of the artefact contribution from the different gradient channels. Here we verify this concept and use it to introduce a novel GA correction method, which is based on a gradient model fit (GMF). Our results show that GMF performs better than conventional GA correction methods at high frequency when subject movement occurs, potentially providing a more robust method for GA correction when investigating gamma (30-150Hz) frequency neuronal activity.

Molly Gallogly Bright¹, and Kevin Murphy^1
1CUBRIC, School of Psychology, Cardiff University, Cardiff, United Kingdom

FMRI data reflect noise sources in addition to neuronal activation, and their relative contributions depend on the echo time (TE). Short TE data may contain information related to motion and physiology, and could potentially correct BOLD-weighted fMRI data for these confounds. We used a dual-echo sequence to simultaneously record fMRI data at short and BOLD-weighted TEs, introducing head nodding, breathing challenges, and visual stimulation to characterize their effects on both datasets. Significant correlations were observed between short TE data and “noise” regressors. Using short TE data to correct BOLD-weighted data (replacing motion correction regressors) increased the significance of activation maps.

Jeremy F Maglandd¹, and Anna Rose Childress^2
1Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, ²Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, United States

It is generally assumed that facial movements occur randomly throughout the fMRI scan. However, since humans use facial movements to express emotion, task-correlated movement cannot be ruled out. Eight healthy volunteers were instructed to move systematically during fMRI examinations, with various types of movements of the eyes (open/close, squint), face (smile/frown, clench jaw), and body. Standard fMRI analyses were performed to identify ‘false activations’. The facial movements resulted in several brain regions having high statistical significance. Jaw clenching yielded the characteristic false activation in the region surrounding the temporal muscles. These data may be used to characterize the potential confounding effects of systematic movements during an fMRI exam.

Joong Il Kim^1,2, Haewon Nam³, Jeong Hoon Ko², and Hae-Jeong Park^1,2
1BK21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea, ²Department of Diagnostic Radiology, Nuclear Medicine and Research Institute of Radiological Science, Seoul, Korea, ³Medical Research Institute, Ewha Womans University, Seoul, Korea

Motion during long-acquisition interleaved EPI sequence was detected using both discontinuity measure defined by the authors and realignment parameters. Retrospective correction of motion artifact was achieved by sub-volume utilization, which takes advantage of the interleaved characteristics of the acquired sequences. Discontinuity measure and realignment parameter respectively detected inter-volume and intra-volume motion, and thereby complemented each other. The proposed method is especially useful in long-acquisition studies where motion can severely affect image quality..

Rasim Boyacioglu¹, and Markus Barth^1
1Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands

Phase-constrained inverse imaging (pcInI) combines inverse imaging (InI) and phase-constrained reconstruction. Performance of pcInI is assessed with a moving dots functional paradigm. A phase regressor is obtained for each coil channel and used as confound regressors in the analysis (either individually or after averaging). On group average, cluster size and maximum z-scores increase 52% and 10% (average regressor) and 534% and 36% (individual regressors) with respect to the case with no regressors.

Christina Triantafyllou^1,2, Jonathan R Polimeni², Jennifer A McNab², Thomas Witzel², and Lawrence L Wald^2,3
1A.A. Martinos Imaging Center, McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, United States, ²A.A. Martinos Center for Biomedical Imaging, Department of Radiology, MGH, Charlestown, MA, United States, ³Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, United States

In this study, we compare two different acquisitions; Accelerated (GRAPPA) single-shot and non-accelerated mutli-shot EPI with matched effective echo spacing. Our findings demonstrate that in both thermal and physiological noise dominated acquisitions, when the temporal sampling interval is matched, by temporally smoothing the single-shot time-series, the single-shot accelerated time-series result in higher tSNR. But if the fixed duration scan can afford reduced temporal resolution (sampling interval not matched), then the slower multi-shot strategy provides slightly higher tSNR than the distortion matched single-shot acquisition.

Jonathan R. Polimeni¹, Christina Triantafyllou^1,2, and Lawrence L. Wald^1,3
1Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, Charlestown, MA, United States, ²A. A. Martinos Imaging Center, McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, United States, ³Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States

The original model for relating image SNR to temporal SNR demonstrated that physiological noise scales linearly with signal level, providing a quantitative relationship between image SNR and temporal SNR. Recently it has been demonstrated that fMRI data acquired with multi-channel array coils deviates from the standard model and the deviation appears to increase with element count. Here we consider the effects of physiological noise correlations across coil channels. Extending the physiological noise model to include a physiological covariance matrix can explain the observed deviation of the data from the Kruger model and provides an interpretation of the recently proposed models.

Chisato Suzuki¹, Kenichi Ueno¹, R. Allen Waggoner², and Kang Cheng^1,2
1fMRI Support Unit, RIKEN-Brain Science Institute, Wako-shi, Saitama, Japan, ²Laboratory for Cognitive Brain Mapping, RIKEN-Brain Science Institute, Wako-shi, Saitama, Japan

Cardiac artifacts are a major contributor to noise in BOLD studies of deep brain structures. The aim of this study was to evaluate the effect of this artifact with MPRAGE and EPI images. By reordering the k-space data based on the cardiac cycle timing, we revealed signal components synchronized to cardiac pulses. In contrast to EPI data that showed widely distributed artifacts in and around the brainstem, no heartbeat-synchronized signal was found in T1W data. These results suggest that rather than physical motion the main component of the artifacts is from sources such as CSF flow and the vessel pulsation.

Rob H.N. Tijssen^1,22, and Karla L. Miller^1
1FMRIB Centre, Oxford University, Oxford, United Kingdom, ²University Medical Center Utrecht, Utrecht, Netherlands

Recent renewed interest in 3D acquisition methods for FMRI poses the question whether retrospective corrections are better performed in image space (RETROICOR or k-space (RETROKCOR). As 3D acquisitions typically use multi-shot readouts in which the data are combined over a period of several seconds one could argue that a k-space based correction is more appropriate. It was found, however, that RETROICOR performs equally well compared to RETROKCOR suggesting that a single cardiac/respiratory phase for the entire volume is sufficient to generate suitable nuisance regressors for an effective correction of the data.

Maryam Falahpour^1,2, Hazem Refai², and Jerzy Bodurka^1
1Laureate Institute for Brain Research, Tulsa, Oklahoma, United States, ²Electrical and Computer Engineering, University of Oklahoma, Tulsa, Oklahoma, United States

It has been consistently shown that physiological noise contribution in BOLD fMRI data is significantly greater in gray matter than in white matter and with evidence of the largest noise in CSF. Here, we investigate brain-tissue-specific physiological noise spatial distributions, along with further investigations for CSF compartments noise level. T1-based tissue segmentation has been used for generating appropriate masks. We showed that the physiological noise in CSF compartments is highly spatially dependent. It is higher for inferior and superior axial slices where it has more overlap with GM and brain vasculature, and lowest in the slices containing ventricles.

Jacco A de Zwart¹, Peter van Gelderen¹, Zhongming Liu¹, and Jeff H Duyn^1
1Advanced MRI section, LFMI, NINDS, National Institutes of Health, Bethesda, MD, United States

BOLD fMRI experiments of spontaneous brain activity in humans have found inter-hemispheric correlation between homologous regions, and suggested involvement of a direct callosal connection. We studied spontaneous activity in human Lateral Geniculate Nuclei (LGN), with no direct commissural connections. High-resolution 7 T fMRI was performed during visual stimulation and rest. Correlation analysis was performed between left and right LGN, and left and right visual cortex. Substantial specific left-right LGN correlation was found, which was not merely driven by visual cortex, or the result of global fluctuations. Strong signal coherence was thus found not indicative of a direct neuronal connection.

Wen-Ju Pan¹, Matthew Magnuson¹, Garth Thompson¹, and Shella Keilholz^1
1Biomedical Engineering, Emory University/Georgia Institute of Technology, Atlanta, GA, United States

The power density distribution in BOLD fluctuations of intrinsic brain activity may be a potential index of neural excitability. The present study examined resting state activity in an animal model and demonstrated a spatially-varying BOLD power distribution across brain regions under light anesthesia. Variations were observed across cortical areas, but much larger differences were present between cortical and subcortical regions.

Hsin-Long Hsieh^1,2, Pin-Yu Chen², Jhih-Wei He¹, Yao-Chia Shih^1,2, Fu-Shan Jaw¹, and Wen-Yih Isaac Tseng^2
1Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan, Taiwan, ²Center for Optoelectronic Biomedicine, National Taiwan Univerity College of Medicine, Taipei, Taiwan, Taiwan

Independent component analysis (ICA) has recently been employed in the detection of the resting-state networks (RSNs) which are consistent and highly reproducible across healthy subjects. However, the identification of RSNs often involves visual inspection and/or correlating spatial maps derived from ICA with templates or seed-based results. To avoid bias caused by investigators, we employed a more objective and template-free approach to select and classify components derived from ICA as RSNs based on the component's time course correlation. Our proposed method adds value to the data-driven approach in defining RSNs, and is potentially useful in the connectome research.

Daniel L Shefchik¹, Andrew S Nencka¹, Andrzej Jesmanowicz¹, Edgar A DeYoe¹, and James S Hyde^1
1Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States

Preliminary data show that a T1 to T2 ratio map can be used to generate a seed region for fcMRI analysis. The acquisition of T1 and T2 maps in the same EPI space as fcMRI data allows a direct, one-to-one relationship between the ratio map and the functional data for a precise definition of the regions of interest. fcMRI analysis based upon seeds from mCytoarchitecture removes the need for functional scout scans from fcMRI studies, while avoiding potential confounds associated with template-based seed determination or independent component analysis.

Gang Chen¹, Guangyu Chen¹, Chunming Xie¹, B. Douglas Ward¹, Wenjun Li¹, Piero Antuono², and Shi-Jiang Li^1
1Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States, ²Neurology, Medical College of Wisconsin, Milwaukee, WI, United States

In resting-state functional MRI studies, the efficacy of the global signal regression method remains questionable. We demonstrate that the accuracy of the estimated global signal is determined by the level of global noise. A method to quantify global noise levels was then introduced. We show that a criteria to determine the necessity for global signal regression can be found based on the method.

Kayako Matsuo¹, Yung-Chin Hsu², and Wen-Yih I Tseng^1
1National Taiwan University College of Medicine, Taipei, Taiwan, ²Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Taipei, Taiwan

We examined an interaction between the low pass filtering (LPF) and the first degree autocorrelation (AR(1)) on SPM8 platform using resting state fMRI. We set 2 different procedures for the same data: with or without an LPF at 0.1Hz. Time courses were extracted from 3 cognitive mode network (CMN) regions as well as 3 default mode network (DMN) regions. We set 2 different GLMs for both of LPF and no LPF data: with or without AR(1). The LPF and the AR(1) acted in an opposite way with each other; specifically, the LPF enhanced DMN activity, whereas the AR(1) decreased.

Zhihao Li¹, Behnaz Yousefi¹, Gopikrishna Deshpande^2,3, and Xiaoping Hu^1
1Biomedical Engineering, Emory University & Georgia Institute of Technology, Atlanta, GA, United States, ²Electrical and Computer Engineering, Auburn University, Auburn, AL, United States, ³Psychology, Auburn University, Auburn, AL, United States

Granger causality analysis of fMRI data suffers from spatial variability of the hemodynamic response. The present study attempted to correct this variance by signal latency values derived from breath holding. With fMRI data acquired during face perception, our correction showed improved effective connectivity from the primary visual cortex to the fusiform face area. The present results demonstrated the utility of breath holding based signal latency correction for Granger causality analysis.

Chia-Jung Yeh¹, Yu-Sheng Tseng¹, Teng-Yi Huang¹, and Shang-Yueh Tsai^2,3
1Dept. of EE, National Taiwan University of Science and Technology, Taipei, Taiwan, ²Graduate Institute of Applied Physics, National Chengchi University, Taipei, Taiwan,³Reasearch Center for Mind, Brain and Learning, National Chengchi University, Taipei, Taiwan

The rest-state fMRI (rsfMRI) detects the dynamic neuronal activity using a long series of BOLD imaging and measures the “connectivity” of brain functional areas using either correlation analysis or independent component analysis. However, in our experience, rsfMRI sometimes shows unstable results even if we preformed study using the same imaging protocols and data analysis methods. In this study, we proposed to use reweighted L1 regression, a form of robust regression, to find the “outliers” of the rsfMRI time series in the default-mode network (DMN) and developed a grading method for rsfMRI datasets.

Jose Angel Pineda-Pardo^1,2, Elena Molina¹, Ana Beatriz Solana¹, Kenia Martinez³, Roberto Colom³, Javier Martin Buldu⁴, Juan Antonio Hernandez Tamames¹, and Francisco del Pozo Guerrero^2
1Laboratory of Neuroimaging, Center for Biomedical Technology - Universidad Politecnica de Madrid and Universidad Rey Juan Carlos, Pozuelo de Alarcon, Madrid, Spain,²Laboratory of Biosignal and Brain Connectivity Analysis, Center for Biomedical Technology - UPM, Pozuelo de Alarcon, Madrid, Spain, ³Universidad Autonoma de Madrid, Spain,⁴Laboratory of Biological Networks, Center for Biomedical Technology - UPM, Pozuelo de Alarcon, Madrid, Spain

In this work we present a new comparative approach aiming to find differences between structural connectivity and resting state functional connectivity (SC-rsFC) networks focusing in the organization of their connections. We compare weights distribution, normalized graph metrics, links orientation, and Rentian scaling in order to find out how rsFC differs from SC network. Structural connectivity was obtained by means of a graph based tractography method instead of usual deterministic tractography. We found out that rsFC network was less spatially optimized than SC in terms of Rentian scaling and normalized graph metrics. We also observed different tendencies in the links orientations when the weights distributions of the networks are compared.

Molly Gallogly Bright¹, and Kevin Murphy^1
1CUBRIC, School of Psychology, Cardiff University, Cardiff, United Kingdom

Characterization of resting state networks may provide insight into clinical populations. However, patients often exhibit increased motion artifacts, obscuring resting state correlations. Short echo time (TE) fMRI data reflect several noise sources, and may assist in mapping correlated networks in these scenarios. We used a dual-echo sequence to acquire fMRI data at very short (~3ms) and BOLD-weighted TEs. Cued head motion was introduced to simulate noncompliant patient behavior. The short TE data were used as voxelwise noise regressors to correct the BOLD-weighted data. This correction recovered seed correlation maps of the default mode network in data with gross motion artifacts.

K Gopinath^1,2, W Ringe³, L Ouyang², K Carter³, L Butler², B Thapa-Chhetry², A Goyal², P Gandhi², H Dinse⁴, R Haley⁵, and R Briggs^2,5
1Department of Radiology & Imaging Sciences, Emory University, Atlanta, GA, United States, ²Department of Radiology, UT Southwestern Medical Center, Dallas, TX, United States, ³Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX, United States, ⁴Institut für Neuroinformatik, Ruhr-University, Bochum, Germany,⁵Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, United States

Resting-state functional connectivity networks are influenced by the conditions under which fcMRI is conducted. Previous reports have demonstrated increased striatal functional connectivity to somatosensory and attention networks during minimally perceptible transcutaneous electrical stimulation (TENS-Lo), compared to eyes open resting (REST) conditions. In this study the functional connectivity to somatosensory and attention networks were assessed during strongly perceptible (but not painful) TENS (TENS-Hi), as well as REST conditions. During TENS_Hi dorsal striatal functional connectivity to somatosensory and attention networks was significantly weaker compared to REST. Combined with previous reports from TENS-Lo, results indicate a need for systematic graded TENS fcMRI studies.

Zhifeng Liang¹, Jean King¹, and Nanyin Zhang^1
1Psychiatry, University of Massachusetts Medical School, Worcester, MA, United States

Anticorrelated resting-state functional connectivity (RSFC) has yet been observed without the commonly used preprocessing step of global signal correction. In this study we reported robust anticorrelated RSFC that is independent of preprocessing procedures within a well documented frontolimbic circuit between the infralimbic cortex and amygdala. The finding of this study makes it possible to uncover the neurophysiologic basis of anticorrelated RSFC when combining with other techniques such as neuron recording.

Zhifeng Liang¹, Jean King¹, and Nanyin Zhang^1
1Psychiatry, University of Massachusetts Medical School, Worcester, MA, United States

Intrinsic connectional architecture of the brain is a crucial element in understanding the governing principle of brain organization. However, this research topic is significantly underexplored in animals. By utilizing an awake animal imaging model in this study we explored the intrinsic connectional architecture of the rat brain. Our data suggested that the rat brain network exhibited typical features of small-worldness and strong community structures as shown in the human brain The results of this work provided a functional ‘atlas’ of the rat brain at both intra- and inter-region levels. More importantly, the current work revealed that functional networks in rats are organized in a non-trivial manner and conserved fundamental topological properties as the human brain.

Adam Q Bauer¹, Brian R White¹, Abraham Z Snyder¹, Bradley L Schlaggar¹, Jin-Moo Lee², and Joseph P Culver^1
1Radiology, Washington University in Saint Louis, Saint Louis, MO, United States, ²Neurology, Washington University in Saint Louis, Saint Louis, MO, United States

We combined resting-state functional connectivity mapping with optical intrinsic signal imaging (fcOIS). We demonstrate functional connectivity in mice through highly detailed fcOIS mapping of resting-state networks across most of the cerebral cortex. Synthesis of multiple network connectivity patterns through iterative parcellation and clustering provides a comprehensive map of the functional neuroarchitecture and demonstrates identification of the major functional regions of the mouse cerebral cortex.

Peter Herman¹, Robert N. S. Sachdev², Basavaraju G. Sanganahalli¹, Hal Blumenfeld^2,3, David A. McCormick², and Fahmeed Hyder^1,4
1Department of Diagnostic Radiology, Yale University, New Haven, Connecticut, United States, ²Department of Neurobiology, Yale University, New Haven, Connecticut, United States, ³Department of Neurology, Yale University, New Haven, Connecticut, United States, ⁴Department of Biomedical Engineering, Yale UNiversity, New Haven, Connecticut, United States

A long-standing hypothesis is that tasks or stimuli that evoke neural activity also trigger cerebral blood flow (CBF). Here we examined whether spontaneously occurring cortical fluctuations triggered changes in local blood flow in head-fixed awake and anesthetized rodents. While the linear correlations were rarely significant, using a convolution model of neurovascular coupling we found non-linear correlation between the neural and hemodynamic signals. The calculated transfer functions were significantly different in awake and anesthetized states. In particular the intensity of neurovascular signals decreases with deeper anesthesia and, the response time of the neurovascular coupling slows down.

Catie Chang¹, Coraline D. Metzger², Gary H. Glover³, and Martin Walter^2
1Advanced MRI section, NINDS, National Institutes of Health, Bethesda, MD, United States, ²Department of Psychiatry, Otto-von-Guericke University, Magdeburg, Germany,³Department of Radiology, Stanford University, Stanford, CA, United States

It was previously observed that functional connectivity exhibits dynamic changes over the course of a resting-state fMRI scan. The origins and relevance of such fluctuations, however, are not clear. Here, we examine whether heart rate variability, an index of psycho-physiological state, covaries with changes in the seed-based functional connectivity maps of regions involved in salience processing (dACC, amygdala). Significant effects were found in multiple cortical and subcortical regions, including thalamus, brainstem, basal ganglia, and insula, suggesting that fluctuations in autonomic or emotional processes may constitute one source of spontaneous connectivity variation.

Elena Molina¹, Susana Borromeo¹, Guillermo Luna¹, Jose Angel Pineda-Pardo¹, Ana Beatriz Solana¹, Cristina Gómez², Adolfo Toledano³, and Juan Antonio Hernández-Tamames^1
1Neuroimaging Lab., Center for Biomedical Technology - Universidad Politécnica de Madrid and Universidad Rey Juan Carlos, Pozuelo de Alarcón, Madrid, Spain, ²CC. Salud Universidad Rey Juan Carlos, Móstoles, Madrid, Spain, ³Servicio Otorrino Fundación Hospital de Alcorcón, Alcorcón, Madrid, Spain

In this work, we describe hubs organization within the olfactory network with Functional Magnetic Resonance Imaging (fMRI). Granger causality analyses were applied in preselected regions of interest (ROIs) involved in olfactory tasks. We found differences between healthy subjects and patients with different types of anosmia: viral, idiopathic and traumatic. The study of the hubs organization conducted us to an accurate description of the strength of the nodes within the olfactory network and which of them are impaired in different anosmic pathologies.

Lirong Yan¹, Yong Fan², and Danny JJ Wang^1
1Neurology, UCLA, Los Angeles, CA, United States, ²Institute of Automation, Chinese Academy of Sciences, Beijing, China

Resting-state functional connectivity (RSFC) analysis of ASL perfusion fMRI may improve the understanding of the biophysical mechanism of resting connectivity, and may provide a quantitative alternative to resting state BOLD fMRI. In this study, pseudo-continuous ASL (pCASL) with 3D background suppressed (BS) GRASE readout was used to detect RSFC arising from spontaneous perfusion fluctuations. By comparison with a standard resting-state BOLD fMRI scan and a pCASL GRASE scan with compromised BS, the present study shows that the default mode network can be reliably detected in resting-state perfusion image series without BOLD contamination.

Delong Zhang¹, Bo Liu^2,3, Jun Chen^2,3, Xiaoling Peng¹, Xian Liu^2,3, and Ruiwang Huang^1
1Center for Studies of Psychological Application, Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University, Guangzhou, China,²Department of Radiology, Guangdong Province Hospital of Traditional Chinese Medicine, Guangzhou, China, ³Department of Radiology, Guangzhou University of Traditional Chinese Medicine, Guangzhou, China

Here we used support vector machines (SVM) method to predict the Vascular Dementia (VaD), one of the most common types of dementia, from the functional brain scans according to the whole-brain functional networks, and compared the detection efficiency at different frequency bandwidths, slow-5 (0.01~0.27 Hz), slow-4 (0.027~0.073 Hz), and whole band (0.01~0.073 Hz). The result suggested that whole-brain functional connectivity contain adequate information about neurobiological changes in VaD patients, and the detection efficiency related to the slow-5 was more prominent. These contribute to the understanding of VaD and may facilitate discovery of biomarkers for the diagnosis of individual VaD patient.

Silvia Mangia¹, Federico De Martino^1,2, Anjali Kumar³, Amir Moheet³, Pete Kollasch¹, Lynn Eberly⁴, and Elizabeth Seaquist^3
1CMRR - Dept. of Radiology, University of Minnesota, Minneapolis, Minnesota, United States, ²Department of Cognitive Neuroscience, University of Maastricht, Maastricht, Netherlands, ³Dept. of Medicine, University of Minnesota, Minneapolis, Minnesota, United States, ⁴Div. of Biostatistics, University of Minnesota, Minneapolis, Minnesota, United States

We measured the brain default mode network (DMN) in six subjects with type 1 diabetes (T1DM) and hypoglycemia unawareness and in seven healthy controls with similar age and body-mass-index, by using resting-state fMRI while blood glucose levels were controlled by hyperinsulinemic clamps. Decreased functional connectivity of some DMN regions was observed in T1DM subjects as compared to controls in euglycemia. Furthermore, whereas the prefrontal cortex had basically no functional connectivity to the other areas of the DMN during hypoglycemia in controls, such response was largely reduced in T1DM unaware patients, likely reflecting differences their perception of the stress of hypoglycemia.

Ai Wern Chung¹, James W. Dodd², Rebecca A. Charlton³, Paul W. Jones², and Thomas R. Barrick^1
1Stroke and Dementia Research Centre, St George's University of London, London, London, United Kingdom, ²Division of Clinical Science, St George's University of London, London, United Kingdom, ³Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, United States

Chronic obstructive pulmonary disease (COPD) is a heterogeneous condition increasingly recognised to be a multi-system disorder associated with a wide range of extra pulmonary comorbidities such as heart disease. Brain pathology and cognitive dysfunction is a potential systemic occurrence in COPD. Using functional MRI, we sought to identify differences in the underlying functional connectivity between stable COPD patients and controls, under the resting-state condition. We found wide-spread decrease in resting-state functional connectivity across the brain including the default mode and pre-frontal networks, suggesting global differences between patients and controls.

Hsiao-Ying Wey^1,2, Jinqi Li², and Timothy Q Duong^2,3
1Department of Radiology, A. A. Martinos Center for Biomedical Imaging, MGH/Harvard Medical School, Charlestown, MA, United States, ²Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States, ³Department of Radiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States

Recent advances in resting-state functional connectivity highlight its potential utility in clinical populations. In this study, we aimed to systematically investigate the effects of different basal oxygenation and blood flow conditions on fc measurements in non-human primate. Our results showed that cerebral connectivity, when compared to normal air condition, was reduced under hypercapnia and hyperoxia but remained comparable under hypoxia. These findings could have strong implications when applying resting-state fMRI in disease states in which baseline oxygenation and blood flow are markedly altered.

Kaundinya Gopinath^1,2, Aman Goyal², Richard Briggs², and K Sathian^3
1Department of Radiology & Imaging Sciences, Emory University, Atlanta, GA, United States, ²Department of Radiology, UT Southwestern Medical Center, Dallas, TX, United States, ³Department of Neurology, Emory University, Atlanta, GA, United States

A number of areas in the human occipitotemporal cortex are specialized for processing particular types of sensory stimuli. Among these areas are the lateral occipital complex (LOC), an object-selective area and the extrastriate body area (EBA), a body part-selective area. This study used seed-based and graph theory approaches to test whether these areas connect to distinct resting-state networks. LOC and EBA exhibited different functional connectivity patterns. LOC interacted more with motor regions and lateral frontoparietal regions involved in processing external stimuli. In contrast EBA interacted more with somatic sensorimotor regions and DMN regions involved in self-referential processing.

Si Kang Lew¹, Fatima Nasrallah¹, Amanda Low¹, and Kai Hsiang Chuang^1
1MRI Group, Singapore Bioimaging Consortium, Singapore, Singapore, Singapore

Previous study on medetomidine showed dosage dependent suppression of functional connectivity without changing BOLD activation. We used electrophysiology measurements including somatosensory evoked potential (SEP) and resting electroencephalography (EEG) to understand the underlying neural correlate. The neurovascular coupling was investigated in the primary somatosensory cortex (S1) using forepaw stimulation. The SEP shows similar response under different medetomidine doses and correlated well with BOLD activation. The coherence of resting EEG between the bilateral S1 didn’t change except for gamma band. The link between BOLD fluctuation and EEG synchrony has yet to be determined.

Fatima Ali Nasrallah¹, Amanda Simin¹, Chen Kaina¹, and Kai-Hsiang Chuang^1
1MRI Group, Singapore Bioimaging Consortium, Singapore, Singapore, Singapore

Receptor targeted pharmaceuticals are applied to modulate neurotransmission to investigate the neural correlate of resting state functional connectivity. The á2 adrenergic receptor agonist, Medetomidine, and antagonist, Atipamezole, were used to understand the role of the adrenergic system in modulating functional connectivity. Activation of the á2 receptor caused a dosage dependant loss of interhemispheric connectivity compared to deactivation of the receptor by the antagonist which resulted in an increase in functional connectivity. This study provides an insight into the underlying basis of functional connectivity.

Sreenath Pruthviraj Kyathanahally¹, Oleg Mykolajovych Pustovyy², Paul Waggoner³, Ronald Beyers¹, John Schumacher⁴, Jay Barrett⁵, Edward E Morrison², Robert L Gillette⁴, Thomas S Denney^1,6, Vitaly J Vodyanoy⁵, and Gopikrishna Deshpande^1,6
1AU MRI Research center,Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama, United States, ²Department of Anatomy,Physiology & Pharmacology, Auburn University, Auburn, Alabama, United States, ³Canine Detection Research Institute, Auburn University, Auburn, Alabama, United States, ⁴Department of Clinical Sciences, Auburn University, Auburn, Alabama, United States, ⁵College of Veterinary Medicine, Auburn University, Auburn, Alabama, United States, ⁶Department of Psychology, Auburn University, Auburn, Alabama, United States

The Default mode network (DMN) has been observed in humans and monkeys, but not in rodents. In order to investigate the evolutionary hierarchy of the DMN, we obtained resting state fMRI data in dogs and performed independent component analysis (ICA). Dogs, being lower than humans/monkeys, but higher than rodents in evolution, showed localized correlations in the posterior cingulate region in one ICA component while in the medial frontal regions in another ICA component. This shows that there is anterior-posterior dissociation and localized synchrony in DMN in dogs, which is a strikingly similar result to the one obtained in young children.

Zhongming Liu¹, Jacco A de Zwart¹, Bing Yao¹, Peter van Gelderen¹, Li-Wei Kuo¹, and Jeff H Duyn^1
1Advanced MRI Section, LFMI, NINDS, National Institutes of Health, Bethesda, Maryland, United States

Simultaneous EEG-fMRI data were analyzed to reveal the thalamocortical networks associated with the modulation of cortical alpha (8-12Hz) EEG. The occipital alpha rhythm was found to be negatively correlated with the BOLD signals at both the visual cortex and the visual thalamus but positively at the anterior dorsal nuclei, which was neither structurally nor functionally connected with the visual cortex. Negative thalamic BOLD-alpha correlation was mostly found at Pulvinar, as confirmed by comparison with reference locations defined through functional localizer with visual stimulation as well as high-resolution anatomical images with gradient echo phase contrast at 7T.

Deng Mao¹, Kuang-Chi Tung¹, Peiying Liu¹, Yong He², Jinhui Wang², and Hanzhang Lu^1
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States, ²State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China

A number of evidences have suggested that the resting brain can be modulated by recent experience. However, few reports have demonstrated the feasibility to measure brain changes after merely minutes of use. Here, we used a 20-min memory encoding task to stimulate the brain, and collected fcMRI data (under resting state) before and after the task. We compared resting brain networks between these two time points and demonstrated that fcMRI brain networks can be modified in the acute phase using a memory task. Finally, we correlated the extent of connectivity change with the behavioral data of memory scores across individuals.

Claudia Huerta¹, Jinqi Li¹, Hsiao-Ying Wey², and Timothy Q Duong^1
1UTHSCSA, San Antonio, TX, United States, ²Martinos Center for Biomedical Imaging, Charlestown, Massachussetts, United States

The hypothalamus plays a pivot role in the regulation of satiety and hunger. This study optimized imaging parameters to ensure reliable detection and stability of EPI signals from the hypothalamic and applied rsfMRI to identify hypothalamic network regulating hunger and satiety in healthy lean subjects. We identified common and different activated structures before and after food ingestion, some are established and some appeared novel. Future studies will focus on validation, extend this approach to study hypothalamic connectivity in obese subjects to attempt to undercover pathological neural mechanisms regulating satiety.

Russell Wade Chan^1,2, Iris Y. Zhou^1,2, Leon C. Ho^1,2, and Ed X. Wu^1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China, ²Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China

This study explores the effects of pregnancy on resting-state functional connectivity in the rat brain. The results show that pregnancy alters the strength and spatial distribution of the fcMRI signals. Specifically, the effects of pregnancy at G17 increase the spontaneous fluctuations in fcMRI signal in the caudate putamen, hippocampus and thalamus; whereas the spontaneous fluctuations in fcMRI signal were similar in the motor cortex for the pregnant and non-pregnant group. The longitudinal effects of pregnancy, as well as, the effects on other functional networks are to be explored.

Xinyuan Miao¹, Thomas Zeffiro², Jing Chen¹, Xiaohong Joe Zhou³, and Yan Zhuo^1
1Institute of Biophysics, Chinese Academy of Sciences, Beijing, Beijing, China, ²Neural Systems Group, Massachusetts General Hospital, ³Department of Radiology and Center for MR Research, University of Illinois Medical Center, United States

n this resting state study, we examined the effect of the menstrual cycle on six major functional brain networks as well as the hippocampus and amygdala, regions which may play an important role in spatial cognition and emotion processing throughout the menstrual cycle. We utilized 160 meta-analysis derived ROIs to parcellate the cortex and cerebellum into six networks: cingulo-opercular, frontoparietal, default mode, sensorimotor, occipital, and cerebellar. It was observed that the inter-regional correlations among some of these networks as well as the hippocampus and amygdala were differentially modulated during phases of the menstrual cycle.

Chris Tailby^1,2, David F Abbott^1,3, and Graeme D Jackson^1,3
1Brain Research Institute, Florey Neuroscience Institutes, Melbourne, Victoria, Australia, ²Psychological Sciences, University of Melbourne, Melbourne, Victoria, Australia,³Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia

Previous work demonstrated that resting state functional connectivity (RSFC) measured in an individual can vary with prior cognitive state. The analysis of large multicentre data sets using RSFC is becoming increasingly widespread. It is therefore important to determine whether the dependence of RSFC on a given prior cognitive state is consistent across individuals, as this would have the potential to bias large multicentre RSFC analyses. By comparing, across 25 healthy participants, RSFC maps obtained following performance of two cognitive tasks we show that RSFC networks vary heterogeneously across subjects. Such effects can produce weak effects at the group level.

Roberto Goya-Maldonado¹, Brice Fernandez^1,2, Victor Spoormaker¹, and Michael Czisch^1
1MPI of Psychiatry, Munich, BY, Germany, ²GE Healthcare, Global Applied Science Laboratory, Munich, Germany

Functional connectivity (fc) analysis allows monitoring specific regional brain changes in activation along time. The susceptibility artifacts commonly present during the acquisition of fMRI with GRE-EPI can drastically limit the investigation of the emotional circuitry. We tested the applicability of SE-EPI for fc analysis at 3T. The seeds placed in the emotional circuitry presented robust and anatomically reliable connectivity patterns in the differential contrast SE>GRE. This suggests a potential benefit to be further explored in functional studies addressing the affective system.

Yin Jiang¹, Yue Zhang², Jing Wang², Jing Fang², Jisheng Han¹, Xiaoping Hu³, Cailian Cui¹, and Jue Zhang^2
1Neuroscience Research Institute and Department of Neurobiology, Peking University, beijing, China, ²Biomedical Engineering, Peking University, beijing, China, ³Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States

Acupuncture has been worldwide used to against many disorders. However, the neural mechanism underlying acupuncture is still unclear. Many studies have investigated to the sustained effects using short-time acupuncture (no more than 6 min) for healthy subjects, which may be not long enough to satisfy the treatment effects. This is the first study, to our knowledge, to investigate small-world properties of brain functional networks modulated by long-time acupuncture(30 minutes). A tendency of increasing local efficiency was demonstrated in TEAS(transcutaneous electric acupoint stimulation) when compared with MTEAS(minimal TEAS),which suggest higher fault-tolerance for brain network after long-time acupuncture.

Stephen D Mayhew¹, Nicholas Hylands-White², Camillo Porcaro³, and Andrew P Bagshaw^1
1Birmingham University Imaging Centre, School of Psychology, University of Birmingham, Birmingham, West Mids, United Kingdom, ²Pain Management Group, Faculty of Health, Birmingham City University, Birmingham, United Kingdom, ³Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom

Here we define pain regions of interest (ROIs) from brain areas exhibiting a very significant BOLD response to thermal stimulation: ACC, SII and anterior insula. We compare the strength of functional connectivity between these ROIs during rest with the mean amplitude of the BOLD response in these ROIs during the stimulation runs. We observed that subjects who had greater resting connectivity between pain-responsive regions had a larger BOLD response to thermal pain stimulation. This work provides a novel demonstration that part of the inter-subject variability in evoked BOLD responses is explained by the intrinsic resting properties of the pain network.

Silke Kreitz¹, Marina Sergejeva¹, and Andreas Hess^1
1Institute of Experimental and Clinical Pharmacology and Toxicology, FAU Erlangen-Nuremberg, Erlangen, Germany

The investigation of the neural basis of pain perception using modern neuroimaging techniques, such as functional MRI, has shown that nociceptive stimuli commonly elicit activity within a wide range of brain structures. In this study, we used functional MRI and graph theoretical network analysis methods to investigate the connectivity between mouse brain structures that are activated by thermal nociceptive and non nociceptive stimuli. The resulting stimulus specific interregional connectivity networks demonstrate the rebuilding of connections between brain structures during nocicpetive processing and give us a deeper insight into the functionality of the brain under pain.

Qihong Zou^1,2, Thomas J. Ross², Hong Gu², Xiujuan Geng², Xi-Nian Zuo³, Elliot L. Hong⁴, Jia-Hong Gao^1,5, Elliot A. Stein², Yu-Feng Zang^6,7, and Yihong Yang^2
1MRI Research Center and Beijing City Key Lab for Medical Physics and Engineering, Peking University, Beijing, Beijing, China, ²Neuroimaging Research Branch, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, United States, ³Institute of Psychology, Chinese Academy of Sciences, Beijing, Beijing, China, ⁴Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, United States, ⁵Brain Research Imaging Center, University of Chicago, Chicago, IL, United States, ⁶Center for Cognition and Brain Disorders and The Affiliated Hospital, Hangzhou Normal University, Hangzhou, Zhejiang, China, ⁷State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, Beijing

There is no consensus whether spontaneous activity predicts task activation, and it is unknown whether rest-task relationship is dependent on task load. Here, we investigate these issues on forty subjects with a resting-state scan and following N-back verbal working memory task scans. We show that fALFF during resting state can predict activation during working memory task. We further demonstrate that such rest-task correlations are modulated by cognitive load of working memory task. These findings suggest that resting-state activity facilitate specific brain circuit engagement for performing a cognitive task, and that resting-state activity can load dependently predict task-induced brain responses.

Qihong Zou^1,2, Hong Gu², Jiongjiong Wang³, Jia-Hong Gao^1,4, and Yihong Yang^2
1MRI Research Center and Beijing City Key Lab for Medical Physics and Engineering, Peking University, Beijing, Beijing, China, ²Neuroimaging Research Branch, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, United States, ³Department of Neurology, University of California Los Angeles, Los Angeles, CA, United States, ⁴Brain Research Imaging Center, University of Chicago, Chicago, IL, United States

Brain activation and deactivation induced by N-back working memory tasks and load effects have been investigated using PET and BOLD fMRI. However, mechanisms of BOLD fMRI are not completely understood and PET requires injection of radioactive tracers. Here, a pCASL technique was used to quantify CBF, a well understood index reflective of cerebral metabolism. We showed activation in fronto-parietal cortices and deactivation in PCC and MPFC during working memory tasks. Most of the activated/deactivated brain regions showed approximately linear relationship between CBF and task loads. These results demonstrate feasibility of ASL techniques to quantify brain activity during high cognitive tasks.

Shilpi Modi¹, Janani Rajagopalan², Pawan Kumar¹, Rajendra P Tripathi¹, Subash Khushu¹, and Manas K Mandal^2
1Institute of Nuclear Medicine and Allied Sciences (INMAS), Delhi, Delhi, India, ²Defence Institute of Psychological Research, Delhi, Delhi, India

An fMRI paradigm was designed to obtain the neural correlates of camouflage detection with real life photographs. The study accentuates on the comparative study between Field-dependent and Field-independent individuals in accordance to their neural correlates derived upon camouflage detection. A widespread activation of the dorsal stream of visual processing was obtained with a greater activation in field dependent subjects as compared to the field independent ones suggesting a greater effort required by them for task performance. However, additional recruitment of superior parietal, thalamic and cerebellar regions in field independent subjects might explain their capability to better perform the task.

Deepika Bagga¹, Namita Singh¹, Shilpi Modi¹, Mohan Lal Garg², Debajyoti Bhattacharyya³, Prabhjot Kaur¹, and Subash Khushu^1
1NMR Research Centre, Institute of Nuclear Medicine and Allied Sciences (INMAS), Delhi, Delhi, India, ²Department of Biophysics, Punjab University, Chandigarh, Punjab, India,³Base Hospital, Army Medical Corps, Delhi, Delhi, India

Neuropsychological findings suggest a deficit in abstract reasoning abilities in alcohol dependents. However, this deficit has not been studied so far using BOLD fMRI. We attempted to address this issue by carrying out an fMRI study on alcohol dependents and controls for an abstract reasoning task. Alcoholics showed a greater activation in the fronto-parieto-temporal network implicated in abstract reasoning suggesting a compensatory mechanism to meet the task performance comparable to controls.

Laura Parisi¹, Maria A. Rocca¹, Letizia Leocani², Roberto Gatti³, Carlotta Castellani², Monica Rossi³, Andrea Falini⁴, Giancarlo Comi⁵, and Massimo Filippi^1
1Neuroimaging Research Unit, Institute of Experimental Neurology, San Raffaele Scientific Institute and Vita-Salute San Raffaele University, Milan, Italy, Italy, ²Dept. of Clinical Neurophysiology, San Raffaele Scientific Institute and Vita-Salute San Raffaele University, Milan, Italy, Italy, ³Rehabilitation Department, San Raffaele Scientific Institute and Vita-Salute San Raffaele University, Milan, Italy, Italy, ⁴Department of Neuroradiology, San Raffaele Scientific Institute and Vita-Salute San Raffaele University, Milan, Italy, Italy, ⁵Department of Neurology, San Raffaele Scientific Institute and Vita-Salute San Raffaele University, Milan, Italy, Italy

Using functional magnetic resonance imaging (fMRI), we investigated brain motor networks involved in interlimb coordination in 14 young high-level professional fencers in comparison to 15 matched young, untrained subjects while performing three different motor tasks (bimanual anti-phase, right hand-foot in-phase and right hand-foot anti-phase movements). Both single motor task analysis and voxel-wise analysis of functional connectivity with the motor cortex showed an optimization of the recruitment of the brain regions underlying interlimb coordination in fencers in comparison to controls, suggesting that specific intensive motor training can modulate neural plasticity of cerebro-cerebellar-basal ganglia loops and their functional connectivities.

Ajchamon Thammachai¹, Suwit Saekho^2,3, Nuanlaor Thawinchai⁴, Taipesrinivasti Bhakdikul⁵, Uten Yarach², Sranut Chunpenmongkol², and Witaya Sungkarat^6
1program in Forensic Science, Graduate school, Chiang Mai University, Chiang Mai, 50200, Thailand, ²Radiological Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Thailand, ³Biomedical Engineering Center, Chiang Mai University, Thailand, ⁴Physical Therapy, Faculty of Associated Medical Sciences, Chiang Mai University, Thailand, ⁵Faculty of Law, Chiang Mai University, Thailand, ⁶Radiology, Mahidol University, Thailand

Deceptive detection using Functional magnetic resonance imaging (fMRI) is an exciting tool. The Peak of Tension Test (POT) can provoke deceptions about criminal details. We propose a new method to identify deception using the POT along with the fMRI by comparing the differences in brain activities between deception and truth telling in both POT and Relevant questions (R). The results demonstrated that right inferior frontal gyrus was more activated in the POT. Left inferior and middle frontal gyri were more activated during deception than those telling the truth.

Peter Brotchie^1,2, Shaun Seixas³, Shoane Ip⁴, Mathew Hughes³, and Graeme Jackson^4
1MRI, Geelong Hospital, Geelong, Victoria, Australia, ²Radiology, University of Melbourne, Melbourne, Victoria, Australia, ³Brain and Psychological Research Centre, Swinburne University of Technology, Melbourne, Victoria, Australia, ⁴Melbourne Brain Centre, Brain Research Institute, Melbourne, Victoria, Australia

Posterior parietal cortex (PPC) has long been known to be involved in spatial processing, forming a key element of the “where” pathway in visual processing. However, its role in navigation has not been well documented with functional imaging studies. In this study we have looked at the role of PPC in navigation using a delayed response paradigm to assess the persistent activity that is known to be present in the neurons of the posterior parietal cortex (PPC) in delayed response tasks. In order to detect orientation specific activity, we used repetition suppression of the subect’s orientation with respect to a virtual environment. We found increased activity predominantly in area PFm of the left PPC that was orientation specific, but present only when the subject was planning a change in orientation. The findings indicate a specialised region in PPC that plans for upcoming changes in orientation.

Frank P. Schulte^1,2, Stefan Maderwald², Nicole C. Kraemer³, and Matthias Brand^1,2
1General Psychology: Cognition, University Duisburg-Essen, Duisburg, Germany, ²Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany, ³Social Psychology: Media and Communication, University Duisburg-Essen, Duisburg, Germany

Media psychology suggests that watching sad movies does not only include sad aspects, but also positive messages, and elicits “bittersweet” feelings. Using 7T-fMRI, we examined neural activity during the presentation of positive, negative and bittersweet movies. Data from 10 female participants shows activation differences in the left orbitofrontal cortex (BA 47,11), indicating that this region is crucially involved in integrating the sweet and the bitter component of bittersweet movies. We found no activation differences within key brain structures of the limbic system, indicating that the different presented films seem to have induced equally strong emotional experiences.

Ikuhiro Kida¹, Yoshinobu Iguchi¹, and Yoko Hoshi^1
1Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, Japan

We employed parametric mediation analysis to identify the functional circuits mediating emotion response. Unpleasant pictures induced activity in sub-cortical regions, including the amygdala, as well as in cortical regions, particularly the right inferior frontal gyrus. Parametric mediation analysis of fMRI signals in the activated region revealed that, although the right ventrolateral prefrontal cortex (VLPFC), BA47, contained no mediators for valence, the region was a mediator for all other predictors. These results suggest that the right VLPFC plays a key role in emotion generation and cognition through the convergence of emotion processing on this region from other cortical and sub-cortical regions.

Kuang-Chi Tung¹, Jinsoo Uh¹, and Hanzhang Lu^1
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States

Resting brain encodes footprint of training effect. The spatial pattern of increase in the amount of spontaneous activity and functional connectivity are strikingly different, based on the amount of neural activity involved during the training. Our present findings show that in two-hand training, consolidation of training effect took place in frontal lobe and mid-brain regions such as hypothalamus and basal nuclei, whereas in one-hand training, it took place primarily in the motor and somatosensory areas.

Dietmar Cordes¹, Grit Herzmann², Rajesh Nandy³, and Tim Curran^2
1University of Colorado, Denver, CO, United States, ²University of Colorado, Boulder, CO, United States, ³University of California, Los Angeles, CA, United States

In this study, a new method is proposed for optimization of contrast detection power by including probabilistic behavioral information, based on pilot data, in the genetic algorithm. As a particular application, a recognition memory task is studied and the design matrix optimized for contrasts involving the familiarity of individual items and the recollection of the items' qualitative information. Optimization of contrast efficiency is a complicated issue, especially for recognition memory tasks, because subjects’ responses are not deterministic but probabilistic. Contrast efficiencies are not predictable unless behavioral responses are included in the design optimization.

Jason G Parker^1,2, Jonathan Sackett³, Phani Kidambi², Lacey Sickinger¹, and Cemil Kirbas^1,4
1Innovation Center, Kettering Health Network, Kettering, OH - Ohio, United States, ²Biomedical, Industrial, and Human Factors Engineering, Wright State University, Dayton, OH - Ohio, United States, ³Siemens Medical Solutions USA, Malvern, PA, United States, ⁴Psychiatry, Wright State University, Dayton, OH - Ohio, United States

The magnitude and extent by which humans can control brain function remains poorly understood. The purpose of this work was to determine if humans receiving neurofeedback on two brain regions simultaneously were less effective at learning brain control than those receiving feedback from a single region. Ten subjects (2 groups of 5) were imaged during single- and dual-ROI feedback. Performance was quantified as the mean % signal changed weighted by the HRF. No significant differences were found between the two methods, possibly indicating humans can learn to control multiple brain regions at once.

Toshiharu Nakai¹, Naoki Kamiya¹, Makoto Miyakoshi², and Kayako Matsuo^3
1Neuroimaging & Informatics, NCGG, Ohbu, Aichi, Japan, ²JSPS, Tokyo, Japan, ³NTU, Taipei, Taiwan

The correlation between the BOLD based aging index (BAI) and MMSE score change two years later was evaluated. It was indicated that age-related augmentation of brain activation observed in early stage of the elderly group (60-75 year old) may be associated with the potential risk of converting to MCI, when BAI was evaluated using a visuo-motor task, while BAI obtained by checker board stimuli did not correlate with MMSE score change. BAI may represent two different types of demand at neuro-physiological and neuronal circuit level, which can be discriminated by the cognitive contents of the tasks.

Claudia Huerta¹, and Timothy Q Duong^1
1UTHSCSA, San Antonio, TX, United States

The aim of the present study was to determine the concurrence in the brain regions activated in response to multimodal food cue stimuli in healthy normal weight adults. Activation likelihood estimation meta-analysis was performed for: i) visual food cues, contrasted between food and nonfood pictures, ii) taste food cues, contrasted between food and tasteless solution, and iii) olfactory food cues contrasted between food/pleasant and nonfood/unpleasant odors. Different neural systems were observed to be associated with each modality but the insula was commonly engaged across the different presentations of food cues.we have identified and compared the neural systems involved in different food cue presentations in healthy normal weight adults. These findings have the potential to improve our understanding of food perception, advance research in neurophysiology and neuropathology of hunger and craving, and help develop novel therapeutic strategies targeting obesity.

Kayako Matsuo¹, S.H. Annabel Chen², Chih-Min Liu³, Chen-Chung Liu³, Hai-Go Hwu³, and Wen-Yih I Tseng^1
1National Taiwan University College of Medicine, Taipei, Taiwan, ²Division of Psychology, Nanyang Technological University, Singapore, ³Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan

We investigated influences of various covariates on a verbal working memory (VWM) fMRI employing 18 each of schizophrenia and control participants. Six covariates of age, gender, response time (RT), accuracy rate, handedness score, and education year had all no significant differences between the two subject groups. Covariates by the behavioral data (RT and accuracy) specifically showed positive correlations with the DMN activation, which reflect the self-regulating mechanism during the low load condition. The inclusion of covariates into the design matrix was effective to obtain the “true� contrast effects even when the comparison groups were “matched� beforehand.

Uttam Kumar¹, and C L Khetrapal^1
1CBMR, Center of Biomedical Magnetic Resonance, Lucknow, Uttar Pradesh, India

Functional Magnetic Resonance Imaging technique has been employed to study the expression and interpretation of negation in Hindi language. Hindi is subject-object-verb (SOV) language and has a long tradition of grammar and literature. To account the effect of semantic and syntactic features on neural network the study was undertaken where native Hindi reader performed the sentence judgment task (target-Probe) in affirmative and negative sentences. The result shows involvement of common as well as distinct regions for affirmative and negative sentences.

Mark Chiew^1,2, Stephen M LaConte^3,4, and Simon J Graham^1,5
1Medical Biophysics, University of Toronto, Toronto, Ontario, Canada, ²Rotman Research Institute, Toronto, Ontario, Canada, ³Virginia Tech Carilion Research Institute, Virginia Tech, Roanoke, Virginia, United States, ⁴Virginia Tech – Wake Forest University School of Biomedical Engineering and Sciences, Virginia Tech, Blacksburg, Virginia, United States, ⁵Imaging Research, Sunnybrook Research Institute, Toronto, Ontario, Canada

Functional MRI neurofeedback (fMRI NF) enables subjects to regulate their brain activity by viewing and manipulating their fMRI signals in real-time. Here we present an fMRI NF study of brain activity in the left and right primary motor (M1) ROIs associated with kinesthetic motor imagery, analyzed offline using partial least squares methods. Using a differential feedback measure (left M1 - right M1 and vice versa), we found subjects were more successful at suppressing activity in the ipsilateral M1 than up-regulating activity in the contralateral M1, and that task success was correlated with expression of task-positive network regions.

Tomokazu Murase¹, Masahiro Umeda², Yuko Kawai², Yasuharu Watanabe², Toshihiro Higuchi³, and Chuzo Tanaka^3
1Department of Neurosurgery, Meiji University of integrative Medicine, Nantan-shi, Kyoto, Japan, ²Department of informatics, Meiji University of integrative Medicine,³Department of Neurosurgery, Meiji University of integrative Medicine

We examined the correlation between the selected ICs and some hypothetical GLMs and predicted the temporal delay in brain activation induced by acupuncture. The fMRI data were analyzed using Tensor-ICA, and IC-related cerebral activity with each stimulation was selected to the activation area by referring to previous studies. Acupuncture stimulation for a duration of 15 s resulted in little cerebral activity; however, a duration of 30 s resulted in great cerebral activity in the predictable area. In conclusion, we found that changes in BOLD signals caused by acupuncture stimulation lasted for around 15 s after the stimulation.

Jennifer M Walz¹, Jordan Muraskin¹, Robin I Goldman¹, Truman R Brown², and Paul Sajda^1
1Biomedical Engineering, Columbia University, New York, NY, United States, ²Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, United States

We previously demonstrated that single-trial variability (STV) of EEG components recorded simultaneously with 1.5T fMRI can yield task-relevant BOLD activations that are unobservable using traditional fMRI analysis methods. A higher field MR system provides greater SNR of the fMRI BOLD signal, but reduces the SNR of the EEG due to increased magnitude of gradient, BCG, and motion artifacts. We have demonstrated the feasibility of our EEG-fMRI STV analysis methods in the more challenging environment of the higher-field 3T scanner, and we have surpassed our previous results in EEG discrimination performance, cluster size, and max z-score.

Amir M Abduljalil¹, Chima Oluigbo¹, Xiangyu Yang¹, Ali Rezai¹, Dustin Cunningham¹, Seongjin Choi¹, and Michael V Knopp^1
1The Ohio State University, Columbus, Ohio, United States

In Task based fMRI, the detectable activation is expected to diminish as the task continues over one minute. In this study, a comparison was made between a scan of the subject at rest and a scan of the same subject performing a task for the entire duration. The calculated functional maps were generated from multiple sections of the time series data in a sliding window manner. A consistent differentiation was observed in the independent components and seed-based functional maps between the resting scans and the scans under extended period of stimulation.

Xiaoyu Sun¹, Jianli Wang¹, Christopher W Weitekamp¹, Megha Patel¹, Jeffrey Vesek¹, and Qing X Yang^1,2
1Radiology, Pennsylvania State University College of Medicine, Hershey, PA, United States, ²Neurosurgery, Pennsylvania State University College of Medicine, Hershey, PA, United States

The odor perception is intimately coupled with sniffing, and both functions are processed in the primary olfactory cortex (POC). A variety of studies on mammalian olfactory systems have shown the spatial distribution of the olfactory components in the olfactory system. However, It is difficult to differentiate odorant perception from sniffing in human primary olfactory cortex using fMRI. In this study, we demonstrated that the BOLD signals in the POC from odorant stimulation can be separated and quantified from those by sniffing, which opens up opportunities for investigating mechanisms of olfactory deficits in several neurodegenerative diseases.

Jianli Wang¹, Xiaoyu Sun¹, Zackary Herse¹, Megha Patel¹, Sarah Ryan¹, Jeffrey Vesek¹, and Qing X Yang^1,2
1Radiology, Penn State College of Medicine, Hershey, PA, United States, ²Neurosurgery, Penn State College of Medicine, Hershey, PA, United States

As the brain’s BOLD signal responding to odorant stimulation is strongly modulated by habituation and respiration, quantitative assessment of olfactory deficits in the brain using fMRI is complex. A thorough understanding of the dynamic behavior of the BOLD signal due to habituation in the central olfactory system is essential for clinical applications of olfactory fMRI. Published fMRI studies on human olfactory habituation have been limited. In this study, we characterized the dynamic behavior of the BOLD signal in human primary olfactory cortex and related structures when subjected to odor habituation.

David Matthew Carpenter¹, Edmund Wong¹, Jessica Roman¹, and Cheuk Ying Tang^1,2
1Radiology, Mount Sinai School of Medicine, New York, New York, United States, ²Psychiatry, Mount Sinai School of Medicine, New York, New York, United States

Here we used the random fluctuations of the resting state brain and capitalized on the hemodynamic delay of BOLD fMRI to investigate what primes the brain for best performance: preceding blood oxygenation levels or preceding neuronal activity. The results show correlation between response time (at T=0) and blood oxygen levels of the default network (BOLD at T=0) but not with neuronal activity of the network (BOLD at T=2sec). Subjects’ performance was correlated to the oxygen level and not the neuronal activity immediately preceding level of activity.

Maolin Qiu¹, Ramachandran Ramani², and R. Todd Constable^1
1Diagnostic Radiology, Yale University, New Haven, CT, United States, ²Anesthesiology, Yale University, New Haven, CT, United States

The anesthetic effects of different agents on CBF have been investigated in recent years, however, variability in results among the studies exists. We use pulsed arterial spin labeling (PASL) MRI, with the similar experiment protocols, to assess the regional CBF changes in healthy human volunteers induced by sevoflurane and propofol. Our results showed, in the presence of an anesthetic, the observed regional CBF is the interplay among local neuronal activity that contributes to the regional changes in CBF via the neurovascular coupling, the distributions of the neuroceptors as the molecular targets of the agent, the neurophysiology of the brain, i.e., the subsystems of the brain that the anesthetic progressively suppressed, and the vascular structure of the brain.

Jinqi Li¹, Michael Riedel², Karl Li³, Claudia Ivette Huerta², Hsiao-Ying Wey⁴, Jacob L Eisenrich³, and Timothy Q Duong^2
1Research Imaging Institute, San Antonio, Texas, United States, ²Research Imaging Institute, ³Medical School, UT Health Sience Center, ⁴Harvard University, United States

fMRI studies were done on four healthy subjects who performed static handgrip. Two fMRI analyses were performed using FSL: 1) block-correlation of rest versus handgrip, and 2) linear-correlation with HR. Stronger activations in insula, thalamus and anterior cingulate, which were highly accepted as central command areas, in block –correlation analysis largely disappeared in HR correlation analysis. We concluded that the commonly identified activation of thalamus and insular cortex, anterior cingulated are likely to be involved in performing the visual feedback tasks, but unlikely to be the predominant central command networks that drive HR or BP increases during exercise.

Manus Donahue^1,2, Charlotte Stagg², Jacinta O'Shea², Peter Jezzard², Leif Ostergaard³, Bradley MacIntosh^2,4, Heidi Johansen-Berg², and Jakob Blicher^3
1Vanderbilt University, Nashville, TN, United States, ²FMRIB Centre, Oxford University, Oxford, Oxfordshire, United Kingdom, ³Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark, ⁴Medical Biophysics, University of Toronto, Toronto, Ontario, Canada

The aim of this work is to apply a multi-modal, noninvasive fMRI approach to better quantify hemodynamic compensation mechanisms during stroke recovery (n=22). Despite robust BOLD, CBF-weighted and CBV-weighted reactivity changes in healthy subjects, in stroke patients with motor impairment, BOLD-fMRI yielded no significant (P>0.05) average changes, despite significant (P<0.01) changes in CBF and CBV. Therefore in chronic stroke, neuronal activity can lead to measurable changes in CBF and CBV in expected cortical areas despite an absent BOLD-fMRI response. Thus, multi-modal fMRI may be better suited than BOLD-fMRI for interrogating cortical reorganization under circumstance of impaired neurovascular coupling.

Toshiharu Nakai¹, Ichiro Takashima², Makoto Miyakoshi³, Shintaro Ninomiya⁴, Ayuko Tanaka⁵, Kayako Matsuo⁶, and Junichi Hasegawa^4
1Neuroimaging & Informatics, NCGG, Ohbu, Aichi, Japan, ²AIST, Tsukuba, Ibaragi, Japan, ³JSPS, Tokyo, Japan, ⁴Chukyo University, Toyota, Aichi, Japan, ⁵NCGG, Ohbu, Aichi, Japan, ⁶NTU, Taipei, Taiwan

The relationship between the BOLD contrast in the primary motor area and the motor performance quantified by motion-capture analysis using conventional CCD camera and color markers compatible with MRI was investigated. Significant difference of the correlation gradient corrected by the mean amplitude of the movements determined was detected depending on the preciseness of the movements (p<0.05). It was suggested that the correlation between the BOLD signal and motor performance is potentially biased by movement amplitude instability.

Xiaolin Liu¹, Barney D Ward¹, Shi-Jiang Li¹, and Anthony G Hudetz^2
1Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States, ²Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States

In this study, we examined whether the loss of consciousness in deep propofol sedation is more related to a direct action of the propofol on corticocortical functional connections or a disruption of thalamocortical interactions, of particular interest, the nonspecific thalamic network. We found that although the nonspecific functional connectivity was significantly diminished as the level of consciousness was reduced, functional connectivity between the cortical network nodes were not statistically altered during deep sedation and the subsequent recovery. These preliminary findings suggest that propofol-induced reduction in the level of consciousness is reflected by changes of the nonspecific thalamocortical connectivity rather than by changes of the corticocortical connections.

David F. Abbott^1,2, Susan M. Palmer³, Essie Low³, Graeme D. Jackson^1,2, and Leeanne M. Carey^3,4
1Brain Research Institute, Florey Neuroscience Institutes, Melbourne, Victoria, Australia, ²Department of Medicine, The University of Melbourne, Melbourne, Victoria, Australia, ³National Stroke Research Institute, Florey Neuroscience Institutes, Melbourne, Victoria, Australia, ⁴LaTrobe University, Bundoora, Victoria, Australia

We used fMRI to explore the relative lateralisation of brain activity associated with controlled tactile stimulation of the fingertips of the left or right hand, in thirteen healthy subjects. An adaptive and largely threshold independent method of objectively determining laterality was adapted for this study to permit statistical comparison of the laterality of activity associated with dominant-hand compared to laterality of activity associated with non-dominant-hand stimuli. We found that subjects are more strongly lateralised in secondary somatosensory cortex for sensory stimuli of their dominant right-hand than for similar stimuli applied to their non-dominant left hand.

Rebecca D. Ray¹, Michelle Johnson², and Christopher Pawela^3
1Plastic Surgery, Medical College of Wisconsin, Milwaukee, WI, United States, ²Physical Medicine and Rehabilitation, Medical College of Wisconsin, Milwaukee, WI, United States,³Plastic Surgery and Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States

Can specific hand movements be mapped onto unique brain regions? This study investigates the common and different representations of individual hand movements (grasp, index finger flexion and extension, finger spread and thumb raise). Participants wore MRI compatible sensor gloves to measure finger flexure and the orientation (pitch and roll) of the user’s hand as they controlled a small black dot. Several key regions are common to these tasks. There are also activated regions unique to each task. Understanding how motor tasks map onto specific neural regions allows investigators to study plasticity following nerve damage and other disorders of the nervous system.

Prasanna Karunanayaka¹, Chris Weitekamp1¹, Kathleen Gates², Jianli Wang¹, Paul Eslinger³, Peter Molenaar², and Quing Yang^1
1Radiology, Penn State University, Hershey, PA, United States, ²Human Development and Family Studies, Penn State University, University Park, PA, United States,³Neurology, Penn State University, Hershey, PA, United States

Using fMRI data, we present a novel approach capable of revealing the olfactory network that subserve a four-strength fMRI paradigm. The method entails combining unified Structural Equation Modeling (uSEM) and group independent component analysis (ICA) to investigate the underlying olfactory network structure. A significant finding of this study is the identification of primary as well as secondary networks that subserve olfactory processing. Thus, the approach presented and described in this paper highlights the advantage of analyzing olfaction in terms of cognitive modules based on underlying network structure(s).

Sunil K. Valaparla^1,2, Hsiao-Ying (Monica) Wey^1,2, William E. Rogers¹, Jinqi Li¹, Geoffrey D Clarke², and Timothy Q. Duong^1,2
1Research Imaging Institute, University of Texas Health Science Center San Antonio, San Antonio, Texas, United States, ²Radiology, University of Texas Health Science Center San Antonio, San Antonio, Texas, United States

High resolution mapping of somatotopy remains an active area of research. In this study, we: i) designed and constructed a MRI-compatible stimulator working on magneto-mechanical principles that is applicable for a wide-range of stimulation frequencies, ii) implemented high-resolution fMRI studies with 1.5 mm isotropic resolution to map human finger somatosensory cortex (S1), iii) mapped out the tuning curve as a function of stimulation frequency, and iv) applied the optimal conditions to map finger somatotopy.

Vadim Zotev¹, Raquel Phillips¹, Han Yuan¹, Wayne Drevets¹, and Jerzy Bodurka^1
1Laureate Institute for Brain Research, Tulsa, OK, United States

We have employed novel integration of real-time functional magnetic resonance imaging (rtfMRI) and encephalography (EEG) to provide simultaneous rtfMRI-EEG multimodal neurofeedback for regulation of both hemodynamic and electrophysiological activity of the human brain. We demonstrated, for the first time, that healthy participants can learn to simultaneously regulate their frontal high-beta EEG asymmetry and left amygdala fMRI activation using retrieval of positive autobiographical memories along with rtfMRI-EEG neurofeedback. This proof-of-concept study opens up possibilities for development of novel cognitive neuroscience research paradigms and enhanced cognitive therapeutic approaches for major neuropsychiatric disorders.

Rupeng Li¹, Nicholas Flugstad², Xiping Liu³, Christopher Pawela^1,2, Ji-Geng Yan², Hani S Matloub², and James S Hyde^1
1Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States, ²Plastic Surgery, Medical College of Wisconsin, Milwaukee, WI, United States, ³Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States

Cortical and subcortical pathways accouting for phrenic nerve function were discovered with the combination of BOLD fMRI and fcMRI for the first time.It helps with further investigation of respiratory system control and provide physiological basis for this nerve to be used as donor for peripheral nerve injury repair.

Aileen Schroeter¹, Joanes Grandjean¹, Aline Seuwen¹, Bechara Saab², and Markus Rudin^1,3
1Institute for Biomedical Engineering, University and ETH, Zürich, Switzerland, ²Institute for Brain Research, University and ETH, Zürich, Switzerland, ³Institute of Pharmacology and Toxicology, University, Zürich, Switzerland

FMRI has been widely used to assess changes in brain activity evoked by innocuous and noxious stimuli. In our laboratory, the application of established sensory stimulation paradigms to isoflurane-anesthetized mice yields consistent bilateral BOLD signal changes in the brain. This observation stands in contrast to the majority of fMRI studies reporting predominantly contralateral brain responses during unilateral innocuous and mild noxious paw stimulation in healthy rats and mice. The presented study deals with the characterization and clarification of the bilateral BOLD signal change in the mouse brain and should yield to more insight into interhemispheric processing of unilateral peripheral stimuli.

Bianca Gonzales Cerqueira¹, Qiang Shen¹, Fang Du¹, Glenn M. Toney², and Timothy Q. Duong^1
1Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States, ²Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States

Osmoregulation is an essential function in mammals. This study uses BOLD fMRI to investigate rat brain activation in response to a 200µl bolus injection of hypertonic saline into the right internal carotid. Activated areas are cingulate cortex, somatosensory cortex, fornix, periaqueductal gray, field CA3 of hippocampus, hypothalamic paraventricular nucleus, insula, median preoptic nucleus, and organsum vasculosum laminae terminalis. We found novel sites of activation as well as established areas that are consistent with osmoregulatory circuits reported in electrophysiological, histological, and lesion studies. Our ultimate goal is to identify and validate new sites for targeting treatment of salt-sensitive forms of hypertension.

Nicholas A Flugstad¹, Jack B Stephenson¹, Rupeng Li², Ji-Geng Yan¹, Christopher Pawela², Hani S Matloub¹, and James S Hyde^2
1Plastic Surgery, Medical College of Wisconsin, Milwaukee, WI, United States, ²Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States

9.4T fMRI was done in a controlled rat survival model after total brachial plexus avulsion and cross C7 nerve tranfer. fMRI scans at 0, 3, 5, and 7 months after repair demonstrated remodeling of the sensory cortex of the rat forepaw. Over time, the signal migrated from the ipsilateral sensory cortex to the contralateral sensory cortex. This represents trans-hemispheric cortical remodelling and restoration of native somatotopy. After cross C7 nerve trnsfer, the rat brain seems to be capable of higher level reorganization in order to restore sensory input to its native anatomical location in the cortex.

Shiliang Huang¹, Fang Du¹, Yen-Yu I Shih¹, Qiang Shen¹, Ai-Ling Lin¹, Shao-Hua Yang², and Timothy Q Duong^1
1Reseach Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States, ²Department of Pharmacology and Neuroscience, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX, United States

Methylene blue (MB) is FDA-approved to treat methemoglobinemia and cyanide poisoning and it has recently been shown to be neuroprotective in stroke, Alzheimer and Parkinson diseases in preclinical and clinical studies. MB enhances ATP production by acting as an electron donor in the mitochondrial electron transport chain. It also reduces free radical production under metabolically stressed conditions. This study used MRI to investigate the effects of MB on hemodynamic and metabolic parameters. We found that MB increases basal BF, hypercapnia-induced and forepaw-stimulation fMRI responses and oxygen consumption during forepaw stimulation. These results support the positive benefits of MB for treatments.

Nellie Byun^1,2, Ayan Ghoshal^1,3, Nathaniel D. Kelm^2,4, Robert L. Barry^2,5, Wellington Pham^2,5, Carrie K. Jones^1,3, John C. Gore^2,5, and P. Jeffrey Conn^1,3
1Vanderbilt Center for Neuroscience Drug Discovery, Nashville, TN, United States, ²Vanderbilt University Institute of Imaging Science, Nashville, TN, United States,³Pharmacology, Vanderbilt University Medical Center, Nashville, TN, United States, ⁴Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, ⁵Radiology & Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States

Previous preclinical studies have demonstrated the potential of compounds that target the metabotropic glutamate receptor subtype 5 (mGluR5) for the treatment of schizophrenia. Like typical and atypical antipsychotic drugs, the novel selective mGluR5 potentiator VU0360172 suppressed amphetamine-induced hyperlocomotion in rodents. Here we used VU0360172 and pharmacologic MRI (phMRI) to determine specific regions of mGluR5-mediated modulation of amphetamine-induced brain activation as well as the effects of VU0360172 alone.

Tobias C Wood¹, Denise Duricki², Lawrence Moon², Camilla Simmons¹, Michel Mesquita¹, Steven Williams¹, and Diana Cash^1
1Department of Neuroimaging, King's College London, London, United Kingdom, ²Wolfson Centre for Age Related Diseases, King's College London

We present a longitudinal fMRI study of focal stroke recovery in adult rats under Alpha-Chloralose anesthetic using forepaw stimulation. Spontaneous plasticity was observed, confirming this protocol is suitable for use with repeated imaging experiments.

Joanes Grandjean¹, and Markus Rudin^1,2
1Institute for Biomedical Engineering, ETH and University, Zürich, Switzerland, ²Institute of Pharmacology and Toxicology, University of Zürich, Switzerland

Resting-state fMRI in mice has been limited due to small voxel-size, leading to low SNR. It would allow studying mechanisms underlying resting-state fMRI, and provide a translational platform. In this study, we measured the amplitudes of low-frequency fluctuation (ALFF) of the fMRI signal during resting-state and nicotine infusion in mice and showed the organization of ALFFs in the mouse brain. Nicotine infusion increased low frequencies in the frontal cortex, and decreased medium frequencies in the sensory/motor cortex. Analysis of the ALFFs may be used to study resting-state fMRI in mice and frequency distribution can be altered following an intervention.

Basil Künnecke¹, Andreas Bruns¹, Eric Prinssen¹, Jean-Luc Moreau¹, Joseph G Wettstein¹, Markus von Kienlin¹, and Céline Risterucci^1
1CNS Research, F. Hoffmann-La Roche Ltd, Basel, Switzerland

Preclinical pharmacological fMRI (phMRI) has been successfully used to elucidate the effects of psychoactive drugs on regional cerebral activity, but comparative meta-analyses of study ensembles are largely missing. The present work provides such a systematic and quantitative analysis of perfusion-based phMRI data obtained upon interventions with an extensive set of neuroactive reference compounds impacting on the domains of anxiety and depression. Neural activity patterns detected by phMRI were subjected to principal component analysis in order to yield specific signatures for the drugs’ modes-of-action and objective measures of dose-effect and treatment duration-effect relationships.

Ikuhiro Kida¹, Yoshinobu Iguchi¹, and Yoko Hoshi^1
1Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, Japan

The neuronal mechanisms underlying taste discrimination and perception in cortical and subcortical regions remain unclear. We performed blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging at 7 T to clarify the neuronal network in the cortical and subcortical regions for taste discrimination. Sucrose and NaCl stimulation increased and decreased the BOLD signals, respectively, in the insular cortex and regions like the caudate-putamen and nucleus accumbens core. This suggests that the activated regions differed but overlapped for taste discrimination. The correlation between the signals in such regions may be related to positive and negative emotional and affective processes, including food preferences.

Guang Li¹, Yen-Yu I. Shih², Bryan H. De La Garza², Jeffrey W. Kiel^3,4, and Timothy Q. Duong^2
1Radiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States, ²Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States, ³Ophthalmology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States, ⁴Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States

Autoregulation of ocular blood flow (BF) with respect to changing blood pressure (BP) is important to retinal health. Autoregulation dysfunction has been implicated in many retinal diseases such as glaucoma. This study investigated changes in BF and blood-oxygen-level-dependence (BOLD) MRI of the retinal and choroidal vasculatures in the retina with respect to increased blood pressure (BP), which is induced by transient partial occlusion of the descending aorta. We found that BF in both of the retinal and choroidal vasculatures was tightly regulated. This approach sets the stage for study of retinal diseases in which autoregulation may be perturbed.

Pei-Ching Chang¹, Sara Pollema¹, Maria Virginia Centeno¹, Daniele Procissi², Marwan Baliki¹, Marco Martina¹, and A. Vania Apkarian^1
1Departments of Physiology, Northwestern University, Chicago, IL, United States, ²Departments of Radiology, Northwestern University, Chicago, IL, United States

In this study, we combined rs-fMRI and receptors expression to evaluate the mechanisms of transition from an acute peripheral nerve injury to chronic neuropathic pain. We showed that enhanced functional connectivity in NAc with prefrontal regions in the neuropathic pain animals, consistent with increased PFC-NAc connectivity we observed in chronic pain patients. Furthermore, significant correlation between functional connectivity and receptors expression was observed in the neuropathic pain animals. This is the first demonstration of a link between human and animal fMRI for transition to chronic pain, and the first evidence relating changes in receptors expression and functional connectivity.

Diana Cash¹, Camilla Simmons¹, Alanna C Easton², David J Lythgoe¹, Steven CR Williams¹, and Michel SB Mesquita^1
1Neuroimaging, King's College London, London, United Kingdom, ²Neuroscience, King's College London, London, United Kingdom

Forepaw sensory stimulation at 0.5 and 3 Hz in anaesthetized rats was characterized for BOLD fMRI, neural activity and regional glucose uptake. Electrical activity was greater at lower frequency whereas metabolic activity was greater at higher frequency. An expected increase in BOLD in forepaw cortex was detected at 3Hz, but a widespread negative BOLD signal was detected at 0.5Hz, suggesting the lack of neurovascular coupling at this slow stimulation rate.

Wen-Ju Pan¹, Garth Thompson¹, Matthew Magnuson¹, and Shella Keilholz^1
1Biomedical Engineering, Emory University/Georgia Institute of Technology, Atlanta, GA, United States

BOLD fluctuations typically exhibit high power only in the low frequencies (<0.1). The mechanism of the frequency cutoff has been rarely investigated. By simultaneous intracortical DC recording and fMRI, the DC/BOLD coherences were demonstrated within a frequency range of high BOLD power, and can be modulated by vasoactive properties in a rat model.

Feng Wang¹, Robert Friedman¹, Chaohui Tang¹, and Malcolm Avison^1
1Vanderbilt University, Nashville, TN, United States

To examine the role of dorsal column (DC) and spinothalamic (ST) spinal cord afferents to primary somatosensory (SI) cortex, we compared the cortical and thalamic topography and stimulus response properties associated with vibrotactile (VS) and electrocutaneous stimulation (ES) of single digits in anesthetized squirrel monkeys. VS, which activates only the DC inputs and ES, which activates both DC and ST afferents, elicited similar stimulus responses in area 3b, but very different responses in areas 1 and 3a.

Yi-Hua Hsu^1,2, Chiao-Chi V Chen², Yen-Yu I Shih³, and Chen Chang^1,2
1Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan, Taiwan, ²Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, Taiwan, ³Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States

Vasoactive neurotransmitters are a direct cause of negative fMRI signals. Dopamine, for instance, can be vasoconstrictive. The dopaminergic system mainly involves a long projection from the substantia nigra to the striatum. The coupling of the fMRI signals with a long vasoactive pathway raises the issue whether the negative fMRI response represents remote rather than local neuronal activity. To clarify, a local anesthetic was used to block the local or remote site of the pathway during induction of the negative fMRI signals. The results indicate that the negative fMRI signals are directly coupled to remote neuronal activation without involving local neurons.

Joe S. Cheng^1,2, Patrick P. Gao^1,2, Condon Lau^1,2, Jevin W. Zhang^1,2, Matthew M. Cheung^1,2, Iris Y. Zhou^1,2, and Ed X. Wu^1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China, ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China

Amplitude modulations (AMs) are an essential cue for recognizing and categorizing behaviorally relevant sound and broad tends concerning the coding of AMs parameters use electrophysiology techniques[1-3].

Hanbing Lu¹, Leiming Wang¹, William W Rea¹, Elliot A Stein¹, and Yihong Yang^1
1National Institute on Drug Abuse, NIH, Baltimore, MD, United States

Spontaneous fluctuations in the resting state fMRI time course have been shown to exhibit structured spatial and temporal patterns. However, the underlying mechanisms are still poorly understood. The goal of this study is to investigate how tasks modulate ongoing spontaneous fluctuations.

Condon Lau^1,2, Jevin W. Zhang^1,2, Joe S. Cheng^1,2, Kyle K. Xing^1,2, Iris Y. Zhou^1,2, Matthew M. Cheung^1,2, and Ed X. Wu^1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, Hong Kong SAR, China, ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, Hong Kong SAR, China

Interaural level differences (ILDs) are important features for sound localization. Sound arrives at the ears with different sound pressure levels (SPLs) depending on the azimuth of the source. fMRI with seven ILD settings spanning ±18dB (higher SPL in left ear is positive) is used to examine a rat model of subcortical ILD processing. Results show the inferior colliculus and dorsal lateral lemniscus contralateral to the higher SPL ear respond with larger signal change. This asymmetry is not apparent in the cochlear nucleus and superior olivary complex. These findings demonstrate fMRI is an effective tool for examining subcortical ILD processing.

Nathalie Just¹, and Rolf Gruetter^1,2
1LIFMET, CIBM/EPFL, Lausanne, Switzerland, ²Department of Radiology, Universities of Lausanne and Geneva, Switzerland

BOLD fMRI investigations in rodents are useful to understand and interpret the underlying physiological and molecular mechanisms of brain activation. Neurons of the whisker barrel system in the rodent primary somatosensory cortex are known to encode external events in time and space and thus offer an excellent model to study BOLD activation processes. In the present study, we proposed to investigate the BOLD contrast mechanisms initiated during sustained trigeminal nerve (TGN) stimulation in the rat since different stimulation durations could potentially result in different activation maps themselves resulting from the recruitment of different neuronal, vascular or metabolic mechanisms.

Yi Zhang^1,2, Oscar San Emeterio Nateras¹, Qi Peng¹, and Timothy Duong^1,2
1Radiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States, ²Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States

The human retina is supplied by two (retinal and choroidal) separate vasculatures and their integrity is vital for maintaining normal retinal structure and function. This study demonstrates a novel BOLD fMRI application in the human retina with laminar specificity, made possible by stable eye fixation and bSSFP acquisition. Inversion-recovery bSSFP with reversed partial-Fourier readout was used to suppress the vitreous and to achieve strong BOLD-sensitivity without distortion. bSSFP fMRI reveals differential BOLD responses to hyperoxia in retinal and choroidal vasculatures. This approach could provide useful physiological information of the retina in healthy and diseased states, and complement existing imaging techniques.

Bryan H DeLaGarza¹, Eric R Muir¹, William E Rogers¹, and Timothy Q Duong^1
1Research Imaging Institute, Ophthalmology/Radiology, Univ of Texas Health Science Center at San Antonio, San Antonio, TX, United States

This study reports a novel application of BOLD fMRI of visual stimulation in the rat retina at 11.7 Tesla. Visual stimuli employed diffuse achromatic light flickering at 8 Hz. Higher magnetic field was used to improve signal-to-noise ratio, spatial resolution (110x110x1000 microns) and BOLD contrast sensitivity. This approach can be used to evaluate functional changes in the rat retinas where many retinal disease models are readily available. BOLD fMRI of the retina provides unique clinically relevant data and has the potential to complement existing retinal imaging techniques.

Varsha Jain¹, Jeremy Magland¹, Michael Langham¹, and Felix W Wehrli^1
1Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States

Measuring oxygen saturation (SvO2) in large blood vessels can provide important information about oxygen delivery and its consumption. Quantification of blood’s T2 value can be utilized to determine SvO2.We propose a fast method for blood T2 quantification via computing the complex difference of velocity-encoded projections.Average resting state SvO2 measurements in superior sagittal sinus,straight sinus, left and right internal jugular veins in the three subjects were 65±3 %, 70±1%, 68±3% and 69±3%, respectively, in agreement with previous reports. Additionally, in concurrence with the known vasoldilatory effect of hypercapnia SvO2 levels increased by ~10%HbO2. Potential clinical applications extend to the study of pathological conditions affecting cerebral metabolism, for example, neurodegenerative conditions such as Alzheimer’s dementia.

Deqiang Qiu¹, Thomas Christen¹, Wendy W Ni¹, Greg Zaharchuk¹, and Michael E Moseley^1
1Radiology, Stanford University, Stanford, CA, United States

Ultra Small Paramagnetic Iron Oxide (USPIO) contrast agents have a strong T2* effect, which allows steady-state high-resolution quantitative Cerebral Blood Volume mapping (CBV) as well as enhanced sensitivity for fMRI based on CBV changes. We characterized the half-life of an FDA-approved USPIO compound ferumoxytol (AMAG Pharmaceuticals, Inc., Cambridge, MA) in humans. The R2* values of the brain before and after contrast injection as well as at follow-up sessions were obtained. The half-life of the contrast agent was estimated to range from 12.1 hours to 22.6 hours, longer than that measured in animal studies.

Steffen Norbert Krieger¹, Robert Trampel¹, Markus Streicher¹, and Robert Turner^1
1Neurophysics, Max Plank Institute for Human Cognitive and Brain Sciences, Leipzig, Saxonia, Germany

Due to its good localization to neuronal activity, fMRI studies have begun to utilize changes of cerebral blood volume (CBV). However, if cerebral vessels are considered to be impermeable, the contents of the skull incompressible, and the skull itself inextensible, task-related and hypercapnia-related changes of CBV could produce intolerable changes of intracranial pressure. We propose that much of the change in CBV is facilitated by exchange of water between capillaries and surrounding tissue. To explore this idea we developed a novel hemodynamic boundary-value model and found approximate solutions. A macroscopic experimental model provides biophysical insight.

Dimo Ivanov¹, Laurentius Huber¹, Stefan Kabisch^1,2, Markus Streicher¹, Haiko Schloegl^1,2, Ilona Henseler¹, Elisabeth Roggenhofer¹, Wolfgang Heinke³, and Robert Turner^1
1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, ²Department of Medicine, University Hospital Leipzig, Leipzig, Germany, ³Department of Anesthesiology and Intensive Care Therapy, University Hospital Leipzig, Leipzig, Germany

 

Nicholas P Blockley¹, and Richard B Buxton^1
1Center for Functional MRI, University of California San Diego, La Jolla, California, United States

Measurement of the BOLD response to hyperoxia has been proposed as a way to measure venous cerebral blood volume. We simulated two methods of achieving this aim with a detailed BOLD signal model, testing each for sensitivity to intersubject variations in haematocrit and baseline oxygen extraction. The first was the original method of normalising the tissue signal response to hyperoxia by the signal response of a large vein. The second was a new method based only on the tissue signal response. Compared with the original approach, this new method was found to be much less sensitive to intersubject variability.

Paula L. Croal¹, Emma L. Hall¹, Ian D. Driver¹, Penny A. Gowland¹, and Susan T. Francis^1
1Sir Peter Mansfield MR Centre, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom

Local CBF (LCBF) is currently thought to increase on cortical activation to meet an increased demand in oxidative metabolism. However, animal literature suggests that this increase is dominated by a change in the vascular reactivity, as the LCBF response is higher with hyperoxia. This study measures the LCBF response in the human motor cortex on hyperoxia using LL-FAIR-ASL. A trend was seen, with hyperoxia increasing the LCBF response and reducing transit times to a greater extent than normoxia. This finding raises questions as to whether the role of functional hyperaemia is driven by changes in metabolic demand or vasculature reactivity.

Stefan Alexandru Carp¹, Woo Hyun Shim¹, Jeong Kon Kim¹, and Young Ro Kim^1
1Massachusetts General Hospital, Charlestown, MA, United States

Hypercapnic (CO2) calibration is necessary to be able to measure relative changes in the cerebral metabolic rate of oxygen (CMRO2) during evoked fMRI responses. The underlying assumption is that there are no metabolic changes associated with CO2 inhalation. In this work we administered several levels of CO2 (2.5, 5 and 7.5%) to anesthetized rats and compared relative CMRO2 values between these levels. We observe that when calibrating with the 2.5% to 5% transition, 7.5% CO2 appears to result in lower cerebral oxygen demand. This may be a result of BOLD signal contamination due to venous volume changes.

Yuji Shen¹, and Ida M Pu^2
1Brain Research Imaging Centre, University of Edinburgh, Edinburgh, Scotland, United Kingdom, ²Department of Computing, Goldsmiths, University of London, London, United Kingdom

Hypercapnia and hyperoxia-induced BOLD contrasts were employed to measure the mean venous vessel size in human brain in response to hypercapnia and hyperoxia. A combined GE and SE sequence was used to acquire GE and SE signals simultaneously. The experimental paradigm consisted of two 3-minute blocks of breathing 6% CO2 or 100% O2 interleaved with three 2-minute blocks of breathing room air. The vessel size index q = ÄR2*/ÄR2 was calculated and then converted to the vessel radius. It was found that the mean venous vessel radii were larger in hypercapnia than in hyperoxia in both grey and white matter.

Martin Krämer¹, Andreas Deistung¹, Thies H Jochimsen², and Jürgen R Reichenbach^1
1Medical Physics Group, Department of Diagnostic and Interventional Radiology I, Jena University Hospital, Jena, Germany, ²Klinik und Poliklinik für Nuklearmedizin, Universitätsmedizin Leipzig, Leipzig, Germany

Vessel size imaging at 3T requires sensitive mapping of the transverse gradient-echo and spin-echo relaxation rates. To realize hypercapnia-induced vessel size imaging at lower clinical field strength we demonstrate that the PROPELLER-EPI technique can be applied for this purpose. Results shown from our in-vivo study at 3T are then compared to a previous single-shot EPI study performed at 7T.

Zachary M Smith¹, Ethan Li¹, and David J Dubowitz^1
1Center for Functional MRI, University of California San Diego, La Jolla, California, United States

Hypobaric hypoxia is accompanied by an increase in cerebral O₂ metabolism. During acute hypoxia this CMRO₂ rise can be paritally mitigated by maintaining arterial CO₂ at its normoxic level. We investigated if acetazolamide (a carbonic anhydrase inhibitor that increases CO₂ in the cerebral tissues) modulated this CMRO₂ increase during sustained hypoxia. CMRO₂ was measured using ASL and TRUST at 3T in human volunteers during normoxia, and following 2-days sustained hypoxia with or without treatment with acetazolamide. Following acetazolamide, the hypoxia-induced rise in CMRO₂ was reduced. These data provide evidence for a CO₂ dependence of the CMRO₂ rise during sustained hypobaric hypoxia.

Zachary M Smith¹, Ethan Li¹, and David J Dubowitz^1
1Center for Functional MRI, University of California San Diego, La Jolla, California, United States

Cerebral blood flow (CBF) and pulmonary ventilation both increase with hypercapnia or hypoxia. We investigated 1) the CBF reactivity to isolated hypoxia and isolated hypercapnia, 2) reactivity to both stimuli in combination and 3) impact of prolonged hypoxic acclimatization on CBF response. Results were compared with ventilation reactivity. Following 7-days hypoxic acclimatization ventilatory reactivity to hypoxia increased, whereas CBF reactivity diminished. For combined hypoxic/hypercapnic stimuli, CBF shows an additive increase in sensitivity, whereas ventilation shows a multiplicative increase. However, after hypoxic acclimatization, the response in both CBF and ventilation is multiplicative. These differences in CBF and ventilatory sensitivity may provide insights into the mechanisms of hypoxic and CO₂ modulation of CBF.

Farshad Moradi¹, and Richard B Buxton^1
1Radiology, Univeristy of California, San Diego, San Diego, California, United States

After prolonged stimulation, the flow and metabolic activity in the visual cortex undergo significantly reduction. However, the BOLD signal did not show a significant adaptation due to the changes in neurovascular coupling opposing the effect of flow adaptation. Our results demonstrate that the coupling between flow and neural activity not only depends on attention and contrast, but also on structure of the stimulus (continuous versus intermittent presentation) and sensory adaptation.

Kevin Murphy¹, Ashley D Harris¹, and Richard G Wise^1
1CUBRIC, School of Psychology, Cardiff University, Cardiff, United Kingdom

By administering CO2 at two different levels, we show that calibrated BOLD techniques perform similarly in baseline conditions and at altered baseline CBF levels that simulate drug or disease effects on baseline brain physiology. We combined the hypercapnic challenge and task scans of calibrated BOLD techniques into a single acquisition. A 4mmHg increase in CO2 at baseline and elevated CBF levels yields similar estimates of task-related CMRO2 change. Verifying the performance of calibrated approaches at modified CBF levels renders calibrated BOLD techniques more pertinent to a clinical setting.

Yi-Ching Lynn Ho¹, Jakob Udby Blicher¹, Christopher Bailey¹, Torben Ellegaard Lund¹, Jamie Near², Kim Vang³, Arne Møller³, and Leif Østergaard^1
1Center for Functionally Integrative Neuroscience (CFIN), Aarhus University, Aarhus, Denmark, ²FMRIB, Oxford University, Oxford, United Kingdom, ³PET Center, Aarhus University, Aarhus, Denmark

The influence of baseline GABA on hemodynamics is a current topic of interest, with a few studies showing correlations of GABA with BOLD and hemodynamic metrics, e.g. baseline CBF. In our study, we found that the GABA-BOLD correlations appear to depend on the area under investigation. Furthermore, in areas showing significant correlations, parallel changes in PET-CBF do not seem to contribute to the relationship. A simple, linear, mechanistic relationship between GABA concentrations and hemodynamics may not exist.

Marta Bianciardi^1,2, Peter van Gelderen¹, and Jeff H Duyn^1
1Advanced MRI Section, LFMI, NINDS, National Institutes of Health, Bethesda, MD, United States, ²A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States

Resonance frequency shifts observed from phase signals in gradient echo fMRI may provide information complementary to magnitude signals. However, because of confounding effects of instrumental and physiological noise, these signals are difficult to detect and rarely used. We demonstrate that optimized pre-processing improves detection of task-evoked and spontaneous changes in phase signals over large areas of the cortex. Comparison with magnitude data suggests that the observed phase signal originate from neuronal activity and represent susceptibility changes in pial and intracortical veins. They therefore provide complementary information to magnitude signals.

Yun-Hsuan Lin¹, Kai-Ling Lu¹, Chin-Tien Lu¹, Yi-Jui Liu², and Fu-Nien Wang^1
1Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan, ²Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan

Absolute quantification of phMRI could benefit inter-subject comparison and longitudinal follow-up. In this study, we combined a modified Vascular-Space Occupancy (VASO) method and the phMRI technique to acquire high-resolution multi-slice absolute quantification of cerebral blood volume (CBV), and applied for methamphetamine (mAMPH) challenged phMRI on a rat model. We used single slice IR-RARE sequence to calculate absolute CBV by the VASO method with Gd-DTPA administration. Short TR as 1600ms was used to reduced the tissue interference. Then, multislice relative CBV maps calculated by the pre- and post-MION images were converted to absolute values according to the overlapped slice.

Xiaoqi Wang¹, Alexander L Sukstanskii², and Dmitriy A Yablonskiy^1,2
1Department of Physics, Washington University in St. Louis, St. Louis, Missouri, United States, ²Department of Radiology, Washington University in St. Louis, St. Louis, Missouri, United States

Recently introduced qBOLD technique allows quantitative estimate of brain tissue hemodynamic parameters such as deoxygenated blood volume and oxygen extraction fraction. The technique is based on a two extravascular compartment model of MR signal (intra- and extra-cellular) in the presence of blood vessel network and a gradient echo sampling of spin echo (GESSE) sequence for data acquisition. At the same time numerous publications treat BOLD signal in the framework of a single compartment model which can introduce bias if quantitative results are needed. In this work we present direct experimental evidence supporting two extravascular compartments contribution to the BOLD signal.

Marta Bianciardi^1,2, Peter van Gelderen¹, and Jeff H Duyn^1
1Advanced MRI Section, LFMI, NINDS, National Institutes of Health, Bethesda, MD, United States, ²A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States

Blood fractional oxygen saturation is an indicator of oxygen delivery and metabolism, and may be used to report tissue viability and function. Current methods that estimate the blood fractional oxygen saturation rely on the use of sophisticated fMRI sequences and modeling. We demonstrate the feasibility of estimating the functional change in blood fractional oxygen saturation in large veins during task performance by analyzing the phase signal in gradient-echo fMRI. With activation, fractional oxygen saturation in the sagittal sinus was found to increase by 0.05 which is close to literature estimates.

Xin Yu¹, Benjamin Porter¹, Stephen Dodd¹, Afonso Silva¹, and Alan Koretsky^1
1NINDS, NIH, Bethesda, MD, United States

Direct characterization of the intracortical changes in vascular elements eliciting BOLD and CBV remains challenging. We measured BOLD and iron oxide based CBV in layer IV/V of the barrel cortex after whisker pad stimulation at high temporal (100msec) and spatial resolutions (150 x150µm) using EPI and fast gradient-echo MRI. Low intensity EPI voxels corresponded to activated BOLD voxels and were attributed to venules. Voxels activated using BOLD were non-overlapping with CBV voxels. Fast activations (<500msec) and distinct locations from BOLD voxels led us to attribute these CBV voxels primarily to penetrating arterioles known to vasodilate during increased neural activity.

Toru Yamamoto¹, and Hiroharu Kubota^2
1Faculty of Health Sciences, Hokkaido University, Sapporo, Hokkaido, Japan, ²Graduate School of Health Sciences, Hokkaido University, Sapporo, Hokkaido, Japan

Conventional fMRI involving gradient-echo EPI is mainly influenced by the magnetic distortion around the draining vein from the activation area. This distortion depends on the angle between the draining vein and the static magnetic field in MRI (ƒÆ). To investigate how the activation area is influenced by the angle between the draining vein and the static magnetic field, we performed the same fMRI study for different head positions in an RF coil by tilting the volunteer�fs head. We found that the activation area, especially the position of the largest signal increase, shifted superiorly along the draining vein when ƒÆ increased.

Paula L. Croal¹, Ian D. Driver¹, Emma L. Hall¹, Susan T. Francis¹, and Penny A. Gowland^1
1Sir Peter Mansfield MR Centre, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom

The linearity of R2* with blood oxygenation is a critical assumption in most models of the BOLD signal, and in the measurement of venous cerebral blood volume (vCBV) using hyperoxia. We used isocapnic hyperoxic to test the linearity of R2* in grey matter across a dynamic range of precisely targeted PETO2 levels. A strong linear relationship was found between oxygenation and R2*, allowing calculation of GM vCBV (1.97%). The advantage of this method over previous methods of measuring vCBV using hyperoxia is that it does not assume that the relaxivity of the oxygen is the same in the vein and tissue.

Katja Neumann¹, Myung-Ho In¹, and Oliver Speck^1
1Biomedical Magnetic Resonance, Otto-von-Guericke-University, Magdeburg, Germany

Functional magnetic resonance (fMRI) phase images of motor and visual stimulation and a breath hold condition obtained at 7 Tesla were processed using a stable phase preserving reconstruction method and analyzed using general linear model and independent component analysis. Phase changes upon activations have shown a comparable sensitivity as magnitude data. Temporally correlated magnitude and phase time courses of independent components were observed for motor stimulation; temporally anti-correlated time courses were observed for independent components of visual stimulation data. fMRI phase images may provide complementary information about spatial localization of brain activation and may also increase the detection sensitivity.