Connectivity fingerprints for brain function


February 25, 2014 - 12:00pm
William James Hall 765
About the Speaker
Zeynep Saygin (MIT)

A fundamental assumption in neuroscience is that a region’s connections to the rest of the brain determine that region’s function.  However, beyond primary cortices, the relationship between connectivity and function is much less clear, especially in the human brain: are function and extrinsic connectivity tightly coupled at a fine spatial grain across the adult human brain?  And is connectivity the causal driver of brain function in development? 

I will present experiments that directly test the relationship between neural responses and extrinsic connectivity by using a novel approach combining fMRI and diffusion-weighted imaging (DWI) in individual subjects.  First, I will demonstrate that the degree of face-selectivity of each voxel in the fusiform gyrus of individual subjects can be predicted from that voxel’s connections to the rest of the brain (its unique connectivity fingerprint), as measured through both DWI and resting functional data.  I will also extend this work to the rest of the brain, and determine whether connectivity also predicts neural responses to other high-level visual representations (faces, bodies, objects, and scenes) in each individual’s brain.  Next, I will explore the causal role of connectivity in functional development, and ask whether early-developing connectivity can predict future reading ability in kindergarteners.  I will end by describing an ongoing set of experiments that tests whether connectivity fingerprints for neural function are already present in children, even prior to any relevant experience (such as reading), and whether a child's connectivity fingerprints can predict the same child's neural responses at a later age. 

These experiments address fundamental questions about the relationship between function and structure in the adult human brain, and about the developmental origins of the functional organization of the adult brain.  Further, the ability to infer functional brain maps from connectivity in individuals may be particularly useful for populations who cannot be functionally scanned (e.g. comatose individuals).  This research could also enable earlier diagnosis and intervention in neurodevelopmental disorders, since connectivity can be acquired in sleeping infants (even before the relevant behavior exists or can be measured).  Finally, by establishing homologies across species based on connectivity fingerprints, this approach will be useful for better understanding the evolution of the human brain.