Effects of waking-auditory stimulation on human sleep architecture

Evidence suggests that sleep architecture is affected by endogenous homeostatic mechanisms as well as by behavioral and sensory demands during the prior wakefulness. Regarding the auditory system, sensory deprivation has shown to drastically modify the sleep structure, stressing the relevance of such sensory system for sleep organization. Changes in sleep architecture following prolonged auditory stimulation during prior wakefulness would provide additional support to this hypothesis. In the present study, auditory stimulation was administered over a 6 h period prior to sleep. Sleep parameters obtained from visual scoring were quantified across the total sleep period, for each sleep cycle, and for the two halves of the night, separately. Results showed that 6 h of waking-auditory stimulation were followed by an increase in the duration of slow wave sleep, a shortening of the latency between slow wave sleep periods, and a longer sleep onset latency as compared with the baseline night. In contrast, REM sleep parameters were unaffected by the pre-sleep auditory stimulation. These results indicate that sleep architecture depends on auditory demands during the prior wakefulness, suggesting that the local neural activation underlying auditory stimulation may trigger brain control mechanisms selectively involved in both the slow wave sleep maintenance and organization.