Our laboratory has developed a unique methodology for studying structure/function relationships in the brain by studying people with acute or evolving left hemisphere stroke initially within 24 hours of onset of stroke symptoms with advanced MRI -- diffusion-weighted imaging (DWI), perfusion weighted imaging (PWI) -- and with batteries of language tasks, and then longitudinally with both imaging and language tests to identify changes in language that correlate with changes in blood flow in the brain. This work has led to interesting insights into both the anatomy of the neural networks that support language and how these networks change over time. The networks are sometimes restored to their normal structure in response to restored blood flow and sometimes reorganize, such that new areas assume the function of the damaged areas during the first year of recovery. In our current work we aim to combine our unique methodology of studying the neural bases of language (evaluating changes in blood flow with concurrent changes in language performance) with both task-related and resting state functional connectivity MRI (rsfcMRI) to investigate the neural basis of recovery of naming, spelling, lexical-semantics (word meaning), and sentence comprehension over the first year after stroke. We believe that by combining careful analysis of the changes in cerebral blood flow (in response to stroke or stroke treatment) with the changes in the brain activation (measured by the hemodynamic response), changes in resting state connectivity (measured by correlations in the hemodynamic response in various areas at rest), and changes in anatomical connectivity, we will develop a better understanding of the course of language recovery over the first year after stroke.
The overall goal of this work is to better understand how people who have language impairments caused by stroke improve during the first year. We know from our previous research on blood flow imaging that some of their improvement is due to restoring blood flow to parts of the brain that are important for language, while functional imaging research shows that some recovery is due to reorganization of language circuitry. We are now combining blood flow imaging with functional imaging to develop a complete picture of recovery, to develop new treatments for language problems due to stroke in the future.
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