Neural Communication Patterns Underlying Conflict Detection, Resolution, and Adaptation

In an ever-changing environment, selecting appropriate responses in conflicting situations is essential for biological survival and social success and requires cognitive control, which is mediated by dorsomedial prefrontal cortex (DMPFC) and dorsolateral prefrontal cortex (DLPFC). How these brain regions communicate during conflict processing (detection, resolution, and adaptation), however, is still unknown. The Stroop task provides a well-established paradigm to investigate the cognitive mechanisms mediating such response conflict. Here, we explore the oscillatory patterns within and between the DMPFC and DLPFC in human epilepsy patients with intracranial EEG electrodes during an auditory Stroop experiment. Data from the DLPFC were obtained from 12 patients. Thereof four patients had additional DMPFC electrodes available for interaction analyses. Our results show that an early theta (4-8 Hz) modulated enhancement of DLPFC gamma-band (30-100 Hz) activity constituted a prerequisite for later successful conflict processing. Subsequent conflict detection was reflected in a DMPFC theta power increase that causally entrained DLPFC theta activity (DMPFC to DLPFC). Conflict resolution was thereafter completed by coupling of DLPFC gamma power to DMPFC theta oscillations. Finally, conflict adaptation was related to increased postresponse DLPFC gamma-band activity and to theta coupling in the reverse direction (DLPFC to DMPFC). These results draw a detailed picture on how two regions in the prefrontal cortex communicate to resolve cognitive conflicts. In conclusion, our data show that conflict detection, control, and adaptation are supported by a sequence of processes that use the interplay of theta and gamma oscillations within and between DMPFC and DLPFC.