0199 CHARACTERIZING SLEEP, CIRCADIAN RHYTHMS, AND EYE CLOSURE IN ACOMYS CAHIRINUS (CAIRO SPINY MOUSE)

Abstract

In order to better understand the functions and origins of sleep, sleep should be studied across a variety of species. We aim to characterize sleep and wake in Acomys cahirinus, the Cairo spiny mouse. Few studies on the circadian activity of this species are available and nothing is known of their sleep behavior. Therefore, we have begun to characterize sleep, circadian rhythms, and eye closure for this species (A. cahirinus) in greater detail and alongside the well-studied house mouse (Mus musculus). Sleep and wake states were determined using a piezoelectric system for individually housed mice for 7 days under 12:12 LD condition. Four infrared cameras were set up around the cage to monitor activity patterns of A. cahirinus in light and dark conditions. Starting with one mouse, two more were added to the cage every four days ending with a total of five to study the effect of group housing on activity. Then, mice were surgically instrumented for tethered electroencephalogram (EEG) recording. To research eye closure of A. cahirinus, we set up a light flashing experiment to challenge the eye. We found A. cahirinus and M. musculus to be primarily nocturnal, but with distinct behavioral patterns. The activity of A. cahirinus sharply increases at dark onset, but surprisingly, decreases sharply just one hour later. A. cahirinus is more active in the first half of the night than the second half in both single and group housing. Based on EEG analysis, A. cahirinus sleeps more than Mus during both day and night. The proportion of REM is significantly higher (nearly tripled). The proportion of wakefulness is more in the first half of the night. We also found that A. cahirinus do not close their eyes during sleep periods of the day or night, even with lights flashing. A. cahirinus has different sleep and circadian behavior than the standard laboratory nocturnal mouse. They sleep more than Mus during both daytime and night time. REM percentage is significantly higher. NSF and OISE (IOS-1353713), NIH grant NS083218, Kentucky Cabinet for Economic Development.