Decay time of the auditory sensory memory trace during wakefulness and REM sleep.
In a repetitive auditory stimulus sequence, deviant infrequent tones typically elicit a component of auditory event-related potentials termed mismatch negativity (MMN). The elicitation of MMN is assumed to reflect the existence of a memory trace of the standard stimulus that has a decay time of about 10 s and is strengthened by repetition of the standards. The main aim of the present study was to test the decay time of the sensory memory trace during rapid-eye movement (REM) sleep vs. wakefulness, as indexed by the MMN. Subjects were presented 10 tone trains, separated by 3, 6, or 9 s of silence, during waking and REM sleep. Each train consisted of 9 standards of 1000 Hz and 1 deviant of 2000 Hz that occurred at position 1, 2, 4, or 6. The waking deviants elicited a frontocentral negativity with a scalp topography equivalent to the MMN component. During REM sleep, the negative component showed the same scalp distribution only for the 3-s intertrain interval (ITI). In this brain state, the MMN amplitude was smaller and decreased with prolongation of the ITI. These results suggest a weaker sensory memory trace formation and a premature decay time of such a memory trace during REM sleep as compared with wakefulness.
Laboratory of Sleep and Cognition, Seville, Spain. suesevilla@interbook.net
M
M
Atienza
J L
JL
Cantero
C M
CM
Gómez
D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005260:Female; D006309:Hearing / Q000502:physiology*; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D012895:Sleep, REM / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology*