The Structural Connectome
The connectome, or the massive array of neural connections in our brain, controls not only information transfer, but also brain function, cognition, and behavior. Recently, the use of Diffusion Tensor Imaging (DTI) has yielded groundbreaking insights in the field of brain tractotraphy. DTI has allowed researchers to map the human brain connectome, in vivo and non-invasively, for the first time. However, DTI-based tractography, which is prone to error and fails to provide information about signal transfer efficiency, still provides only a limited assessment of the connectome. In collaboration with Professor Peter Basser of the NIH, our lab has developed two new Magnetic Resonance Imagine (MRI)-based methods, AxCaliber and CHARMED, which are capable of estimating axonal density and diameter for each fiber path in the brain. In combination with graph theory analyses, these methods allow for new, highly accurate measurements of the connectome. With these techniques in hand, we are currently investigating how the structure of the connectome, as weighted by axonal diameter properties, differs between healthy and diseased brains (e.g. multiple sclerosis).