Sleep homeostasis in infant rats.
Homeostatic regulation is a defining characteristic of sleep but has rarely been examined in infants. This study presents an automated method of sleep deprivation in which 5-day-old rats were shocked whenever the nuchal muscle became atonic. The intensity of shock was always set at the minimal level required to maintain arousal. Deprived pups exhibited rapid increases in sleep pressure, as evidenced by increased attempts to enter sleep and subsequent increases in sensory threshold; this increased sensory threshold was not due to sensory adaptation of peripheral receptors. In addition, myoclonic twitching was suppressed during the 30-min deprivation period, leading to rebound twitching during recovery sleep. These results provide the earliest demonstration of the homeostatic regulation of sleep in an altricial mammal.
Blumberg
Mark S
MS
Program in Behavioral and Cognitive Neuroscience, Department of Psychology, University of Iowa, Iowa City, IA 52242, USA. mark-blumberg@uiowa.edu
Middlemis-Brown
Jessica E
JE
Johnson
Eric D
ED
D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001522:Behavior, Animal; D004307:Dose-Response Relationship, Radiation; D004576:Electromyography / Q000379:methods; D004597:Electroshock / Q000009:adverse effects; D005260:Female; D006706:Homeostasis / Q000502:physiology*; D008297:Male; D009207:Myoclonus / Q000209:etiology / Q000503:physiopathology; D009714:Nucleus Accumbens / Q000502:physiology / Q000528:radiation effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012684:Sensory Thresholds; D012890:Sleep / Q000502:physiology*; D012892:Sleep Deprivation / Q000503:physiopathology; D013997:Time Factors