Dynamics of EEG slow-wave activity and core body temperature in human sleep after exposure to bright light.
In seven subjects sleep was recorded after a single 3-hour (2100-0000 hours) exposure to either bright light (BL, approx. 2,500 lux) or dim light (DL, approx. 6 lux) in a crossover design. The latency to sleep onset was increased after BL. Whereas rectal temperature before onset and during the first 4 hours of sleep was higher after BL than after DL, the time course of electroencephalographic (EEG) slow-wave activity (SWA, EEG power density in the range of 0.75-4.5 Hz) in nonrapid eye movement sleep (NREMS) differed only slightly between the conditions. After BL, SWA tended to be lower than after DL in the first NREMS-REMS cycle and was higher in the fourth cycle at the time when the rectal temperature did not differ. The differences in SWA may have been due to a minor sleep-disturbing aftereffect of BL, which was followed by a rebound. The data are not in support of a close relationship between SWA and core body temperature.
Cajochen
C
C
Institute of Pharmacology, University of Zürich, Switzerland.
Dijk
D J
DJ
Borbély
A A
AA
D000328:Adult; D000704:Analysis of Variance; D001831:Body Temperature / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D012890:Sleep / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology