Dynamics of brain networks during reading
Cox, Steven J
Doctor of Philosophy
We recorded electrocorticographic (ECoG) data from 15 patients with intractable epilepsy during a word completion task to precisely describe the spatiotemporal brain dynamics underlying word reading. Using a novel technique of analyzing grouped ECoG, cortical regions distributed throughout the left hemisphere were identified as significantly active versus baseline during our word stem completion task. Regions of activity spread from fusiform to frontal regions, including pars opercularis, pars triangularis, and pre, post, and subcentral gyri during the time period approaching articulation onset. The ECoG data recorded from electrodes within these regions were fit into linear multivariate autoregressive models, which precisely reveal the time, frequency, and magnitude of information flow between localized brain regions. Grouped network dynamics were quantified with two metrics of evaluating statistical significance of post-stimulus interactions compared to baseline. Results from both methods reveal bidirectional exchanges between frontal regions with fusiform, supporting theories which incorporate top-down and bottom-up processing during single word reading.
electrophysiology; multivariate autoregressive models; effective connectivity