Studies on evoked potentials to click and somatosensory stimulation in the waking state and during sleep in man.

Abstract

SummaryThe changes of evoked potentials by a click and somatosensory stimulus in the waking state and during various stages of sleep were studied in 18 normal subjects by using the averaging method.The results obtained were as follows:1) Evoked potentials by a click recorded from the scalp consisted of five components (positive of 28 msec. negative of 40 msec. positive of 90 msec. negative of llO msec. and positive of 180 msec. respectively) in the waking state.2) Evoked potentials by somatosensory stimulation consisted of a triphasic wave of short latencies (17 msec. positive, 22 msec. negative and 30 msec. positive) and late components of 50 msec. negative, 90 msec. positive, 110 msec. negative and 180 msec. positive respectively in the waking state.3) The response of short latencies to somatosensory stimulation considered as primary response remained unchanged, while the late components to both somatosensory and click stimulation considered as secondary response changed markedly during various stages of sleep.4) In activated sleep, components of long latencies were deprgyed completely and the responses did not resemble those in any other stages of sleep.5) There was a relationship between the changes of forms of an evoked response to sensory stimulus and the changes of the basic activities of the scalp EEG in various stages of sleep.6) There was a similarity in the relatively long‐lasting evoked potentials during sleep in the different sensory modalities.