VII International Conference Aspects of Neuroscience, Warsaw, Poland (November 24-26)
Successful performance in cognitive tasks relies on the deployment of cognitive control mechanisms including non-specific regulation of motor threshold and modulation of attentional processes specific to the task. Failure of each of the two mechanisms may lead to different kind of responses, post-response adaptations and, importantly, distinctive behavior correlates. In particular, slow correct and erroneous responses could be associated with attentional lapses and high levels of uncertainty; whereas fast responses are probably associated with low levels of uncertainty, with occasional errors caused by a failure to withhold action impulses. In the present study, we aimed to ask whether modulations of oscillatory activity indicate two different types of responses. We recorded EEG while subjects performed auditory version of two-choice condensation task, which is highly demanding for sustained attention, but implies no inhibition of prepotent responses. We found enhanced frontal midline theta (FMT) power in the pre-response time window on both correct and erroneous responses. Error-related FMT power increase was observed in post-response and post-feedback time windows. Frontal beta band oscillatory activity was enhanced exclusively after positive feedback presentation. Trial-by-trial correlation analysis between the FMT power and the response time (RT) revealed: (1) positive correlation before the response for both correct and erroneous trials, (2) negative correlation after the erroneous responses. Post-feedback frontal beta-band power positively correlated with the RT. Thus, slower errors were characterized by higher FMT power before the response and higher frontal beta power after positive feedback presentation, suggesting stronger cognitive effort and intensive feedback processing of more informative feedback, respectively, in the situation of high uncertainty. On the contrary, higher FMT power after error commission was associated with lower RT’s, implying instantaneous internal error detection in the case of low outcome uncertainty. Taken together, our results suggest that single-trial RT may serve as a valid measure for distinguishing slow trials with high levels of decision uncertainty due to attentional lapses and fast erroneous trials with preserved attentional processes and motor threshold failures. The study was implemented in the framework of The Basic Research Program at the National Research University Higher School of Economics in 2017.
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.