Electrophysiological correlates of attention, inhibition, sensitivity and bias in a continuous performance task

Objective: The aim was to verify the occurrence of proposed electrophysiological correlates of attention, inhibition, sensitivity and bias in a continuous performance task and to support their functional interpretation by using a manipulation intended to enhance subjects' response bias.Methods: Electroencephalographic activity was recorded during administration of a transformed version of the AX continuous performance task in which cues signaled response alternatives.Results: The previously reported parietal P3, NoGo–N2, NoGo–P3 and contingent negative variation were replicated. Besides, the frontal selection positivity and the lateralized readiness potential were demonstrated. With increasing Go-probability, the parietal P3 to the cue increased without changes in other cue-related correlates. In addition, reaction times decreased, non-parametric measures of sensitivity and bias decreased, the NoGo–N2 increased, and the parietal Go–P3 decreased.Conclusions: The proposed electrophysiological correlates were identified. Sub-threshold LRPs suggested a central inhibition mechanism. Cue-related correlates revealed that anticipation of a high-probability Go-stimulus involves attention rather than bias. This implies that the increased NoGo–N2 reflected an increase in conflict rather than an increase in inhibition.Significance: Electrophysiological measures can greatly enhance our understanding of normal and abnormal information processing during continuous performance and related tasks.