How voicing, place and manner of articulation differently modulate event-related potentials associated with response inhibition

The experimental investigation of response inhibition and the neuropsychological assessment of impulsivity are classically conducted with Go/Nogo tasks, where the participant presses a key for standard (Go) stimuli and withholds the response for deviant (Nogo) ones. However, auditory Go/Nogo tasks frequently fail to elicit the typical ERP correlates of response inhibition (N2, P3). We elaborated an auditory Go/Nogo experiment with speech stimuli (VCV) and sufficient difficulty level (Go and Nogo stimuli differed by one phonetic feature only) to strongly involve response inhibition. An N2 wave – the earlier correlate of inhibition – was recorded in 15 healthy adults. This result encourages the use of auditory Go/Nogo tasks to assess impulsivity, which results in decreased N2 amplitude. Additionally, a substantial P3 was observed as a secondary correlate of inhibition. Its amplitude was clearly modulated by the perceptual salience of the phonetic difference: P3 was highest for manner of articulation, then voicing, and it was smallest for place differences. ERP indices of the right-hemisphere involvement in voicing processing are also reported. This auditory Go/Nogo task therefore appears useful as a clinical tool for impulsivity assessment and an experimental way to address phonetic issues.