Prestimulus Frontal Midline Theta Reflects Increased Cognitive Control During Spontaneous Lapses Of Attention

Performance errors are well studied under conditions of increased demands for motor inhibition; within this framework, errors are considered to be manifestations of motor conflicts between mutually exclusive responses to stimuli presented. However, tasks that require prolonged exertion of sustained attention and complex stimulus-response mapping may involve somewhat different internal causes of performance errors related to fluctuation in cognitive control; this aspect has not been previously addressed in literature. Specifically, it has not been studied whether performance errors can result from conflicts with spontaneous internally generated task-unrelated processes. In the present study, modulation of prestimulus brain activity in relation to spontaneous performance errors was studied during the auditory condensation task. Frontal midline theta (FMT) power, which is an indicator of cognitive control system activation, was found to be significantly higher before incorrect responses than before correct ones. Relative increase in FMT power before incorrect responses was positively correlated with Strength of excitation (STI questionnaire) and negatively correlated with the percentage of errors and with correct-to-error response time ratio. These findings allow us to suggest that the increase in the prestimulus FMT power before incorrect responses under the condensation task was at least partly related to the adjustment of the cognitive control system and conflict regulation. We speculate that the conflict may arise from interference between task-related and task-unrelated processes such as mind wandering