Similarity in evoked responses does not imply similarity in macroscopic network states across tasks
Javier Rasero, Amy Sentis, Timothy Verstynen, Carnegie Mellon University, United States; Richard Betzel, Indiana University Bloomington, United States; Thomas Kraynak, Peter Gianaros, University of Pittsburgh, United States
Posters 2 Poster
Pacific Ballroom H-O
Fri, 26 Aug, 19:30 - 21:30 Pacific Time (UTC -7)
There is an ongoing debate as to whether cognitive processes arise from a group of functionally specialized brain modules (modularism) or as the result of distributed nonlinear processes (dynamical systems theory). The former predicts that tasks that recruit similar brain areas should be equally similar in their connectivity profile. The latter allows for differential connectivity, even when the areas recruited are largely the same. Here we evaluated both views by comparing region-wise activation patterns and connectivity profiles from a large sample of healthy subjects (N=242) that performed two executive control tasks known to recruit nearly identical brain areas, the color-word Stroop task and the Multi-Source Interference Task (MSIT). Using a measure of instantaneous connectivity, based on edge time series, we estimated the task-related networks that differed between incongruent and congruent conditions. At both group and subject level, the two tasks were much more different in their connectivity than in their activation. Our results are consistent with the perspective of the brain as a dynamical system, suggesting that task representations should be understood at both node and edge (connectivity) levels.