Selection for Action: The Medial Frontal Cortex Is an Executive Hub for Stimulus and Response Selection

摘要

This EEG study investigates the electrophysiological activityunderlying processes of stimulus and response selection, andtheir executive orchestration via long-range functional connectivityunder conflict condition, in order to shed more light onhow these brain dynamics shape individual behavioral performance.Participants (n = 91) performed a modified flankertask, in which bilateral visual stimulation and a bimanual responsepattern were employed to isolate the stimulus and responseselection-related lateralized activity. First, we identifiedconflict-related markers of task-relevant processes; most importantly,the stimulus and response selection were evidencedby contra–ipsilateral differences in visual and motor activity,respectively, and executive control was evidenced bymodulationsof midfrontal activity. Second, we identified conflict-relatedfunctional connectivity between midfrontal and other taskrelevantareas. The results showed that interregional phase synchronizationin theta band was centered at the midfrontal site,interpreted here as a “hub” of executive communication.Importantly, the theta functional connectivity was more robustunder the condition of increased demands for stimulus and responseselection, including connectivity between the medialfrontal cortex and the lateral frontal and motor areas, as wellas cross-frequency theta–alpha coupling between the medialfrontal cortex and contralateral visual areas. Third, we showedthat individual differences in the measured conflict-related EEGactivity, particularly the midfrontal N2, theta power, and globaltheta connectivity, predict the behavioral efficiency in conflictresolution.