Sleep and wake in rhythmic versus arrhythmic chronotypes of a microphthalmic species of African mole rat (Fukomys mechowii).

TitleSleep and wake in rhythmic versus arrhythmic chronotypes of a microphthalmic species of African mole rat (Fukomys mechowii).
Publication TypeJournal Article
Year of Publication2011
AuthorsBhagwandin, A, Gravett N, Lyamin OI, Oosthuizen MK, Bennett NC, Siegel JM, Manger PR
JournalBrain, behavior and evolution
Volume78
Issue2
Pagination162-83
Date Published2011
ISSN1421-9743
KeywordsAdaptation, Physiological, Animals, Circadian Rhythm, Electroencephalography, Electromyography, Male, Mole Rats, Ocular Physiological Processes, sleep, Sleep, REM, Time Perception, Wakefulness, Zambia
Abstract

The giant Zambian mole rat (Fukomys mechowii) is a subterranean Afrotropical rodent noted for its regressed visual system and unusual patterns of circadian rhythmicity--within this species some individuals exhibit distinct regular circadian patterns of locomotor activity while others have arrhythmic circadian patterns. The current study was aimed at understanding whether differences in circadian chronotypes in this species affect the patterns and proportions of the different phases of the sleep-wake cycle. Physiological parameters of sleep (electroencephalogram and electromyogram) and behaviour (video recording) were recorded continuously for 72 h from 6 mole rats (3 rhythmic and 3 arrhythmic) using a telemetric system and a low-light CCTV camera connected to a DVD recorder. The results indicate that the arrhythmic individuals spend more time in waking with a longer average duration of a waking episode, less time in non-rapid eye movement (NREM) with a shorter average duration of an NREM episode though a greater NREM sleep intensity, and similar sleep cycle lengths. The time spent in rapid eye movement (REM) and the average duration of an REM episode were similar between the chronotypes.

DOI10.1111/j.1365-2869.2012.01023.x
Alternate JournalBrain Behav. Evol.