Mismatch negativity and P300 to behaviorally perceptible and imperceptible temporal contrasts

The purpose of this study was to specify whether electrophysiological indices of behavioral discrimination of auditory duration could be demonstrated. Mismatch negativities and P300s were recorded to perceptible and imperceptible stimuli in 23 normal-hearing young adults. Behaviorally perceptible and imperceptible stimuli were demonstrated by measuring difference limens in a standard psychophysical procedure in a subset of participants (n = 8). Perceptibility was further demonstrated using a standard clinical pattern-perception test and modified-duration pattern tests created for this study. Mismatch negativities and P300s were recorded with an oddball paradigm using stimuli identical to those used in behavioral testing. All participants exhibited P300s in the perceptible contrast, while responses were absent for the imperceptible contrast. Mismatch negativities were found for 18 and 5 of 23 participants to the perceptible and imperceptible contrasts, respectively. The mismatch negativity did not correspond with behavioral discrimination and, as such, one could question its clinical feasibility. The P300 more accurately reflected behavioral discrimination performance in the current paradigm.