Vertex potentials evoked during auditory signal detection: Relation to decision criteria

Abstract

Vertex potentials were recorded from eight Ss performing in an auditory threshold detection task with rating scale responses. The amplitudes and latencies of both the N1 and the late positive (P3) components were found to vary systematically with the criterion level of the decision. These changes in the waveshape of the N1 component were comparable to those produced by varying the signal intensity in a passive condition, but the late positive component in the active task was not similarly related to the passively evoked P2 component. It was suggested that the N1 and P3 components represent distinctive aspects of the decision process, with N 1 signifying the quantity of signal information received and P3 reflecting the certainty of the decision based upon that information.