Evoked potential attenuation in the two-tone paradigm.
The recovery cycle and two variants of the habituation hypothesis invoked to explain the N1-P2 amplitude attenuation of evoked potentials (EPs) to the second tone in two-tone series, were investigated. Paired stimuli were presented with a constant 360 ms inter-stimulus interval (ISI), but with different, fixed inter-pair intervals (IPIs) of 800, 1 000 and 1 200 ms in addition to a variable IPI averaging 1 000 ms. Amplitude reduction of the second tone EP was present for only the 1 000 and the 1 200 ms IPI series. These data contradict the specific predictions of all three hypotheses, although one prediction of the recovery cycle hypothesis was supported, stating that for a given relation of IPI to ISI the second tone attenuation effect disappears. To account for all findings in this experiment, an alternative explanation is advanced incorporating the concept of recovery cycle and involving the effects of rhythmic stimulation, whereby tone pairs are processed as units whose perceptual cohesiveness determines the distribution of response resources to each tone.
D000328:Adult; D001921:Brain / Q000502:physiology*; D005072:Evoked Potentials, Auditory; D005260:Female; D006185:Habituation, Psychophysiologic / Q000502:physiology*; D006801:Humans; D008297:Male; D011571:Psychoacoustics; D011930:Reaction Time / Q000502:physiology