Human vigilance and auditory evoked responses

摘要: Abstract 1. In seven normal subjects vigilance fluctuations and related changes in the auditory evoked response were quantitatively analysed during rest lasting 10 min (eyes open) or 80 closed) a soundproof room. Vigilance was visually determined from EEG on basis of sensitive classification. Responses by slowly repeated clicks summated selectively according to level 2 sec immediately prior each stimulus. 2. During session decreased noticeably all whether eyes kept open closed. With closed decrease rapid most cases reached real sleep. After this initial fall increased again remained, with smaller oscillations, at certain intermediate stages. 3. The click-evoked large stable alert state. decreasing progressive amplitude reduction three prominent components (N1a, N1b, P2b) observed. At stage B2 these had approximately 25% their original size O. transition sleep characterized marked increase N2 slight growth P2a. P1 did not change over whole range. 4. No latency shifts focus noticed. There was, however, posterior shift 5. loss is interpreted as decline activity brain functions which are essential for maintenance an efficient subject-environment relation.