AbstractsPsychology

Coordination between networks of brain regions is important for optimal cognitive performance, especially in attention demanding tasks. With the event-related optical signal (EROS; a measure of changes in optical scattering due to neuronal activity) we can characterize rapidly evolving network processes by examining the millisecond-scale temporal correlation of activity in distinct regions during the preparatory period of a response-mode switching task. Participants received a pre-cue indicating whether to respond vocally or manually. They then saw or heard the letter ???L??? or ???R???, indicating a ???left??? or ???right??? response to be implemented with the appropriate response modality. We employed lagged cross-correlations to characterize the dynamic connectivity of preparatory processes. Our results confirmed coupling of frontal and parietal cortices, and the trial-dependent relationship of the right frontal cortex with response preparation areas. The frontal-to-modality-specific cortex cross-correlations revealed a pattern in which first irrelevant regions were deactivated and then relevant regions were activated. These results provide a window into the sub-second-scale network interactions that flexibly tune to task demands.