Normal Developing Brain

Monday 12 May 2014

Dan Wu¹, Ilan Gobius², Linda J Richards², Susumu Mori³, and Jiangyang Zhang^3
1Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States, ²Queensland brain Institute, The University of Queensland, Brisbane, Queensland, Australia, ³Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States

Diffusion MRI is an ideal tool to characterize the microstructures in the embryonic mouse brain, and high resolution is key to delineate these fine structures. Using a 3D diffusion-weighted gradient and spin echo sequence, we were able to acquire HARDI data of the embryonic mouse brains at 30 to 45 µm isotropic resolution and 30 diffusion directions. The high-resolution data from embryonic day 10.5 (E10.5) to E15.5 (n=5 per stage) revealed the dynamic changes in the early gray and white matter structures with unprecedented details.

Vincent Jerome Schmithorst¹, Jessica Wisnowski¹, and Ashok Panigrahy^1
1Radiology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States

We investigated possible sex differences in structural and functional network topology in healthy neonates using DTI and intrinsic-connectivity fMRI, respectively. While structural network topology is similar, females show greater modularity due to a more developed frontal interhemispheric subnetwork. Functionally, females show more developed frontal and fronto-temporo-parietal interhemispheric subnetworks, resulting in greater modularity, efficiency, and small-worldness. Results show that at least some brain sex differences arise during prenatal development. Moreover, these differences may account for the greater risk of white matter injury and poorer neurocognitive outcomes in males following perinatal stressors such as preterm birth or congenital heart disease.

Laura Biagi¹, Sofia Allegra Crespi^2,3, Michela Tosetti¹, and Maria Concetta Morrone^1,4
1IRCCS Stella Maris Foundation, Calambrone, Pisa, Italy, ²Department of Psychology, Vita-Salute San Raffaele University, Milan, Italy, ³CERMAC and Neuroradiology Unit, San Raffaele Hospital, Milan, Italy, ⁴Department of Translational Research on New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy

There is little information about the developmental timelines of the cortical areas comprising the neural network that analyses visual motion. We measured at 1.5T cortical bold response in 11 full-term awake 7-weeks-old infants, contrasting coherent flow motion to blank or random noise. Areas MT and V6 respond well to motion at 7 weeks. Correlation analysis suggests weak connectivity between V1 and MT in young infants, but a stronger functional connectivity between the cuneus/MT and V6. The fast development and immature connectivity between V1 and MT points to a possible alternative V1-independent input to MT.

Hong Zhang^1,2, Xuna Zhao³, Jinyuan Zhou², and Yun Peng^4
1Imaging Center,Beijing Children’s Hospital, Capital Medical University, Beijing, China, ²Neurosection, Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, United States, ³Peking University, Beijing, China, ⁴Beijing Children’s Hospital, Capital Medical University, Beijing, China

MT-MRI is sensitive to a semi-solid macromolecular phase in tissue, and APT-MRI is sensitive to the amide protons of mobile proteins and peptides, both accomplishing detection using the water signal. We detected brain development patterns in normal children using MT and APT imaging at 3T. Our preliminary results showed that MTRasym(3.5ppm) decreased exponentially and MTR increased exponentially with age, with the most significant changes occurring within the first 2 years of life. MT and APT imaging may be useful to assess the progress of myelination.

Douglas C Dean¹, Jonathan O'Muircheartaigh^1,2, Holly Dirks¹, Nicole Waskiewicz¹, Lindsay Walker¹, and Sean C.L. Deoni^1
1School of Engineering, Brown University, Providence, RI, United States, ²Neuroimaging, King's College London, Institute of Psychiatry, United Kingdom

Quantitative MRI affords a unique opportunity to map the dynamic patterns of neurodevelopment and provide insight into the relationships between brain maturation and emerging cognition. Longitudinal developmental trajectories of quantitative T1, T2, and the myelin water fraction (VFM) from 103 typically developing children are presented and characterized using non-linear mixed effects modeling. We furthermore examine the relationships between changes in these quantitative parameters and measures of cognition. Our results reflect the coincident development of myelinated white matter and cognitive ability; providing an important step for understanding the typical patterns of normative white matter maturation and its relationship to emerging function.

Lirong Yan¹, Emily Kilroy², Mayank Jog¹, and Danny JJ Wang^1
1University of California Los Angeles, Los Angeles, CA, United States, ²University of Southern California, Los Angeles, CA, United States

Due to the lack of assays of baseline function and absolute quantification of task-induced effect size, it is hard to interpret developmental BOLD fMRI findings. In this study, a concurrent ASL/BOLD fMRI paradigm of working memory tasks was employed to investigate the relationship between CBF and BOLD responses in 57 children and adolescents aged 7 to 17. Our results showed that while the percentage of BOLD response increases with age, both baseline CBF and absolute task-induced CBF decrease with age, suggesting more efficient use of oxygen of the brain during development.

Marta Re¹, Vaibhav Diwadkar², and Paolo Brambilla^1
1RUBIN, ICBN, University of Udine and University of Verona, Udine, Italy, ²Dept of Psychiatry & Behavioral Neurosciences, Wayne State University SOM, Detroit, MI, United States

Emotion processing and the ability to decode facial expressions is crucial for normal emotional development but the evolution of these processes and of the neural systems associated with this over the adolescence remains unclear. Moreover, understanding cognitive top-down effects during affective processing is of relevance as these mechanisms may modulate the response of the face processing network. In this study, by means of an fMRI task, we evaluated differential top-down effects on the modulation of the face processing network and founded an affected response of the fusiform gyrus in adolescents.

Nils Daniel Forkert¹, Zhaoying Han¹, Matthew Daniel Li¹, Roland Bammer¹, and Kristen Yeom^1
1Department of Radiology, Stanford University, Stanford, CA, United States

The extraction of diffusion and perfusion parameters from MRI is of high clinical utility in various neurological diseases. However, adult normal values cannot be applied directly to pediatric patients due to age-dependent parameter changes. The aim of this work is to investigate the age-dependent change of ADC and CBF values in healthy children over the entire pediatric age range by applying an atlas-based analysis of ASL and ADC datasets in different brain regions. Overall, logarithmic relations between age and ADC as well as CBF values were found, which may help to identify neuropathological conditions of childhood in future.

Zach Eaton-Rosen¹, Andrew Melbourne¹, Eliza Orasanu¹, Alan Bainbridge², Giles S. Kendall³, Nicola J. Robertson³, Neil Marlow³, and Sebastien Ourselin^1
1CMIC, UCL, London, United Kingdom, ²Medical Physics, UCH, London, United Kingdom, ³Academic Neonatology, EGA UCL Institute for Women's Health, London, United Kingdom

During normal cortical development, there is a period of high fractional anisotropy (FA) measured in the cortex as revealed by diffusion tensor imaging. In a longitudinal study of a preterm neonatal population, we fitted the NODDI model to multi-shell diffusion MR and separated the FA into contributions from orientation dispersion (ODI) and from the volume fraction of the intra-cellular component (vic). We found that the decrease in FA is predominantly attributable to increased ODI rather than changing vic. Establishing biomarkers of cortical maturation from diffusion-weighted data will aid in developing measures of cognitive outcome in this at-risk population.

Malek I Makki¹ and Cornelia Hagmann^2
1MRI Research, University Children Hospital of Zurich, Zurich, Switzerland, ²Neonatalogy, University Hospital of Zurich, Zurich, Switzerland

Using fiber tracking we draw a topographic map of the interhemispheric-cortices pathways in healthy neonates by segmenting the corpus callosum in 5 substructures: genu, rostral body, body, isthmus and splenium. The connectivity of the genu and rostrum to premotor cortex, the body to the motor cortex as well as the splenium to occipital and temporal occipital lobes were more developed in girls compared to boys (significantly lower mean and radial diffusions in girls). The isthmus connectivity to the superior temporal and posterior parietal is similar in both groups and is the last substructure to develop (lowest anisotropy, and axial diffusion).