ИСТИНА

Response commission in cognitive tasks comprises a complex set of mechanisms including decision making and action execution. Decision-making processes in multi-choice tasks involve sensory evidence integration and action selection, that are strongly related to the activity of the intraparietal cortical areas. Action execution is regulated within motor areas that may implement response initiation and inhibition. Failures within one or the other of the two systems may lead to qualitatively different kinds of errors that differ in the response time. Presumably, fast errors, with response latency shorter than average response latency on correct trials, are caused by inability to inhibit irrelevant prepotent responses, while slow errors, with response latency longer than average response latency on correct trials, result from disruptions forming the decision variable. Errors can be detected and appropriate corrective adaptations can be initiated in top-down fashion by performance monitoring systems, with errors detected either internally (following error commission), or externally (following negative feedback presentation). We recorded EEG while participants performed the auditory version of the condensation task with high cognitive demand. In order to detect modulations of oscillatory activity and functional connectivity patterns between areas, we used spectral power measures and weighted phase-locking index, which is a measure of stability of phase difference between signals recorded from two electrodes. We observed alpha power suppression in the pre-response time window with the minimum at the left parietal electrodes, which presumably reflects generation of a decision variable after sensory evidence integration. Midfrontal theta power and phase coupling between midfrontal and left parietal regions increased after negative feedback presentation, associated with performance monitoring and top-down adjustments of the decision variable in the intraparietal cortical areas. Moreover, functional coupling was more pronounced for subjects who tended to commit slower errors, compared to correct responses. This finding suggests that functional connectivity patterns differ depending on the type of error committed. That is, in the case of slow errors, which resulted from failures in decision-making processes, negative feedback elicited robust functional connectivity, that might be used in top-down influence on decision-making systems.