ERP analysis of reafferent information processing during the performance of an arithmetical task

Reafferent information processing accomplished by distributed cerebral systems was studied by analysing concomitant event-related potentials (ERPs) elicited by weak electrical stimulation of the skin of the hand. The subjects were instructed to interpret this stimulus as feedback information indicating whether their solution of an arithmetical task was correct or not. ERPs elicited by positive or negative feedback signals showed striking differences. ERPs were also influenced by the subject's confidence in the correctness of the solution, while probability of stimulus occurrence was less important in the design. Neurophysiological implications of ERP-disclosed influences on feedback processing are discussed.