The effects of sleep loss in animals

Marcella Oonk

Sleep deprivation (SD) in humans represents a challenge to our physiology and behavior. Experimental studies on SD are important and animal models may offer opportunities to take us beyond the knowledge we have from human studies. In this thesis several animal models are validated and behavior is tested in the context of sleep loss. The two-trial Y-maze provides a simple test of spatial recognition memory. Six hours of gentle handling-induced SD (GH-SD; ZT 0-6) in mice, after the acquisition trial, did not affect memory performance in the recall trial, 6 h post-acquisition, compared to undisturbed mice. Thus, short-duration SD does not affect memory consolidation in mice, as measured on the two-trial Y-maze. The rat psychomotor vigilance task (rPVT) is a rat analog of the human PVT (hPVT), a sustained attention task. Twenty-four hours of GH-SD impaired global rPVT task performance compared to baseline performance. In addition, rats displayed characteristic performance decrements across the 30 min task duration. However, SD did not amplify this decrement. These data are in accordance with human literature on performance impairments measured by the hPVT, although several task parameters require adjustment to improve the external validity. Sleep deprivation in animals, like GH-SD, is enforced through the use of inescapable and often aversive stimuli. Intracranial self-stimulation (ICSS) is considered a voluntary and rewarding behavior. Similarly, non-contingent stimulation (NCS) involves rewarding, albeit imposed, stimulation. Six hours of ICSS or NCS successfully induced wakefulness, followed by an increase in NREMS and REMS similar to GH-SD. However, the increase in EEG SWA during NREMS was attenuated following ICSS compared to GH-SD and NCS. These results indicate that ICSS and NCS are capable of inducing SD. The different ICSS-induced sleep phenotype, compared to GH-SD and NCS, could indicate that controllability and adversity differentially affects rebound sleep. In conclusion, the studies presented herein suggest that the two-trial Y-maze is not a sensitive model for studying the effects of short-duration SD on memory consolidation. The rPVT shows good validity for studying long-duration SD. ICSS may provide a new model for studying sleep and SD-related consequences.

The effects of sleep loss in animals

Files and links (1)

Abstract

Metrics

Details