Enhanced inter-site coherence reflects post-feedback adjustments in situations of high outcome uncertainty
Flexible goal-directed behavior in cognitive tasks relies on multiple task-specific processes, as well as on functioning of the monitoring system. In multiple-choice tasks, the task-specific processes include sensory evidence integration and action selection that partially occur in the lateral intraparietal area (LIP). The performance monitoring system is located in the medial frontal regions of the cortex. Activation of this system is associated with increased frontal midline theta (FMT) power, and increased theta coherence between midfrontal areas and the task-specific areas. One of the situations that require the increase of cognitive control is receiving a negative feedback after an erroneous response. There are two possible types of errors. One of them originates from failures in task-specific processes and is associated with increased response times with high outcome uncertainty; the other is related to failures of non-specific motor inhibition and is characterized by decreased response times with low levels of outcome uncertainty. In the present study, we aimed to investigate whether post-feedback activity of the performance monitoring system depends on the type of committed errors. We recorded EEG while subjects performed an auditory version of the two-choice condensation task, in which both types of errors described above could occur. In the time window between the stimulus and the response, we observed significant decrease of alpha power in the left central-parietal sites (compared to the baseline), which presumably reflects the task-specific activation of the LIP area. Higher frontal midline theta (FMT) power and theta-band coherence with left parietal electrodes were observed after negative feedback, compared to positive one, reflecting error detection by medial frontal structures and their interaction with the LIP aimed to prevent future errors, respectively. Furthermore, the difference in theta coherence and the mean response time ratio between erroneous and correct responses were positively correlated, i.e. subjects that tended to commit slow errors demonstrated stronger increase of theta coherence after negative feedback. These findings support the idea that slow errors are associated with high outcome uncertainty, and the feedback information in this case is used to a greater degree in the processes aimed at performing post-error adaptations.