ERP correlates of response inhibition to elemental and configural stimuli in a negative patterning task

Objective: The present experiment examined the ERP correlates of response inhibition to elemental and configural Nogo stimuli in a Go/Nogo task. Design and Methods: Event-related potentials (ERPs) were recorded while 8 subjects completed a visual Go/Nogo task. Nogo stimuli required the inhibition of a response to stimuli that differed from Go stimuli (A+, B+) either on the basis of each of two physical features (elemental Nogo stimuli; CD−) or on the basis of the conjunction of features represented in the Go stimuli (configural Nogo stimuli; AB−). Behavioural data and ERP component measures (amplitude and latency) were analysed using analysis of variance. Results: An enhanced N2 component and an enhanced fronto-centrally distributed P3 component were elicited following elemental Nogo stimuli relative to Go stimuli, consistent with a number of studies examining ERPs during Go/Nogo tasks. In contrast, an enhanced late frontal negative/parietal positive slow wave was elicited following configural Nogo stimuli relative to Go stimuli. Conclusions: These results cast doubt on the interpretation of the N2 enhancement as reflecting response inhibition processes per se. The pattern of results was interpreted as providing support for the unique cue model of learning rather than the configural model of learning and was discussed in the context of a recent model of executive functioning.