In vivo Quantitative Magnetic Resonance Imaging of Myelin Plasticity

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Quantitative Magnetic Resonance Imaging of Myelin Plasticity The brain is a highly plastic organ, it has the lifelong ability to alter its structure and function in response to experience. While the neuroscience community has long focused on neuronal and synaptic plasticity, it is now clear that myelin is also an important structural pillar of brain plasticity. Myelin is a lipid-rich sheath wrapped around axons, and is adapted to achieve and maintain the rapid conduction and synchronous timing of information in the brain. Recent studies have started to identify the mechanisms that regulate adaptive myelination. There is now a critical need for translational tools to bridge the gap between these mechanisms identified in rodent models and their impact on human behaviour. Magnetic resonance imaging (MRI) is a powerful non-invasive tool that can be used to investigate the spatio-temporal dynamics of brain microstructure in vivo. Several quantitative MRI measures have been proposed as in vivo biomarkers of myelin content, but their specificity if often questioned. The goal of this research program is to develop a translational quantitative MRI framework to study myelin plasticity in vivo in mice and humans. I have previously developed quantitative MRI acquisition and analysis techniques to map myelin content in vivo and post mortem. I have applied these techniques to study the normal variation in cortical myelin content in healthy adults, the relationship between cortical myelin maps and functional brain networks, and to improve the detection of demyelinated cortical lesions in multiple sclerosis. My group will build upon this expertise to address important limitations of current quantitative MRI techniques in order to study subtle adaptive changes in myelination due to experience. The program includes the development of novel MRI acquisition techniques, biophysical models of myelin content in the white and grey matter, and validation of the sensitivity and specificity of these MR contrasts mechanisms in mouse models of adaptive myelination. My research program will enable future research on myelin plasticity, such as the impact of age and environment on our capacity for adaptive myelination in the different areas and myelinated networks of the brain. It will facilitate knowledge translation between labs investigating myelin plasticity in mouse models and humans. Given the multi-disciplinary expertise housed at the MNI, and our collaborations with other MRI groups in Montreal and internationally, we are uniquely positioned to train the next generation of neuroimaging scientists and make significant contributions to the exciting new field of myelin plasticity via advanced imaging tools.