Eeg delta power and auditory arousal in rested and sleep-deprived
rabbits.
Opp, Mark R., Linda A. Toth, and Elizabeth A. Tolley.
Department of Psychiatry and Behavioral Sciences, University of
Texas Medical Branch, Galveston, TX, Department of Infectious
Disease, Comparative Medicine Division, St. Jude Children's Research
Hospital, Memphis, TN, Department of Preventative Medicine, Division
of Biostatistics and Epidemiology, University of Tennessee, Memphis,
TN
APStracts 3:0334R, 1996.
Slow wave activity in the electroencephalogram is thought to reflect
the depth or intensity of sleep. This hypothesis is primarily derived
from studies of rats or humans. However, some characteristics of
sleep of rabbits differ from those of rats or humans. To determine
whether slow-wave activity (power density in the delta frequency band
of 0.5 - 5.0 Hz) correlates with arousability in rabbits, we
presented auditory stimuli (72 - 90 dB) to control or sleep-deprived
animals during slow wave sleep. The resulting behavioral responses,
defined by changes in eye state and body posture, and the latency to
return to sleep were used as measures of arousability. Behavioral
responsiveness to auditory stimuli increased with increasing stimulus
intensity in both control and sleep-deprived animals. Overall,
however, sleep-deprived animals exhibited fewer postural changes and
eye openings than did control rabbits. Sleep-deprived rabbits also
more rapidly returned to sleep after the stimulus presentation than
did control animals. Latency to return to sleep was correlated with
delta power prior to stiumulus presentation, but behavioral
responsiveness was not. These data suggest that in this rabbit model,
delta power may not be predictive of behavioral arousability, but may
reflect sleep propensity.
Received 30 May 1996; accepted in final form 8 August 1996.
APS Manuscript Number R301-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 September 1996