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This study was carried out in order to further test the hypothesis that the occurrence of REM sleep in the rat in the form of episodes separated by long intervals (single REM sleep episodes) and by short intervals (sequential REM sleep episodes) is differently influenced by changes in both sleep and ambient related processes. Rats were studied during the(More)
Both circulation and breathing show basic differences in regulation between synchronized sleep and desynchronized sleep. Closed-loop operations of automatic control mechanisms during synchronized sleep ensure an efficient and steady regulation of such functions as in wakefulness, although at a lower level of energy expenditure. In contrast, a change in the(More)
The behavioral state-dependent changes in the hypothalamic temperature of homeotherms reflect extracerebral adjustments in circulatory variables to influence the temperature and flow of the arterial blood cooling the brain. There are different mechanisms for brain cooling, i.e. systemic and selective brain cooling, which are affected by the changes in body(More)
STUDY OBJECTIVES Exposure to low ambient temperature (Ta) depresses REM sleep (REMS) occurrence. In this study, both short and long-term homeostatic aspects of REMS regulation were analyzed during cold exposure and during subsequent recovery at Ta 24 degrees C. DESIGN EEG activity, hypothalamic temperature, and motor activity were studied during a 24-h(More)
The effects of the rhythmical delivery of an auditory stimulus (1000 Hz, from 50 to 100 dB, 20 ms, every 20 s) on the pattern of rapid eye movement (REM) sleep occurrence was studied in the rat. The stimulation was simultaneously carried out on pairs of rats over 5 consecutive days (10-h recording sessions), during which a tone of increasing intensity (50,(More)
The present research studied the mechanisms underlying the increase in brain temperature during REM sleep in the unrestrained rabbit carrying chronically implanted electrodes, thermistors and common carotid artery occluders. During the ultradian wake-sleep cycle at constant ambient temperature (25+/-2 degrees C), we recorded: (i) the ear pinna temperature(More)
The influence of changes in heat loss at specific heat exchangers, appraised by recording ear skin temperature (Ts), on the hypothalamic temperature (Thy) rise during desynchronized sleep (DS) was studied in unrestrained cats at different ambient temperatures (Ta). The correlations of initial and final Thy changes (delta iThy and delta fThy) with initial(More)
The thermal influence of dorsal cervical and interscapular brown adipose tissue (ISBAT) on pontine and preoptic-hypothalamic temperatures was studied in unrestrained adult male rats across the non-rapid eye movement sleep (NREM) and rapid eye movement sleep (REM) sleep states. The animals had chronically implanted electrodes and thermistors for(More)