HABITUATION AND THE HUMAN EVOKED-POTENTIAL

Habituation of human scalp-recorded cerebral evoked potentials was studied in response to auditory and visual repetitive stimuli of different intensities. Changes in magnitudes of evoked potentials with stimulus repetition were examined according to the parametric characteristics of habituation, generalization and dishabituation. Tests of the predictions of 2 theories of habituation were made regarding the degree and direction of intensity generalization of habituation. Both auditory and visual evoked potentials exhibited decrements in response magnitudes across the repetitive stimuli consistent with the parametric criteria of habituation. Early evoked potential peak components showed a pattern of intensity generalization of habituation consistent with the predictions of the dual-process theory of habituation. Intensity generalization of late evoked potential peak components occurred in a mannor more consistent with the predictions of the stimulus comparator theory of habituation. Further evidence was provided that evoked potentials can be used as electrophysiological indexes of plasticity in humans.