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Updated: Dec 25, 2025

Measuring Neural Mechanisms Underlying Sleep-Dependent Memory Consolidation During Naps in Early Childhood
Published on: October 2, 2019
Does upper-body elevation affect sleepiness and memories of hypnagogic images after short daytime naps?
Kenta Nozoe1, Kazuhiko Fukuda2, Takamasa Kogure3
1Sleep Research Institute, Edogawa University, 474 Komagi, Nagareyama-shi, Chiba 270-0198, Japan.
Abstract:
The present study aimed to examine the effects of a somatosensory stimulus on sleepiness and memories of hypnagogic imagery during short daytime naps. Participants experienced two daytime nap conditions: (1) a somatosensory stimulus was created by raising the upper part of the bed 20 min after turning off the light and (2) a somatosensory stimulus was not created; the angle of the upper part of the bed remained flat. Approximately 20 min and 30 s after turning off the light, participants were awakened and questioned regarding their subjective sleepiness and the presence or absence of hypnagogic imagery. Results showed that subjective sleepiness following the nap was reduced only in the raised condition, and hypnagogic imagery in the raised condition was lower than that in the flat condition. These findings may provide insight on developing new techniques for improving subjective conditions after awakening.
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