Circadian studies of the spontaneous rotational behavior of the gerbil

Abstract

Normal unoperated gerbils rotate or turn in circles spontaneously (i.e., without lesions or drugs). Two experiments were conducted to determine possible circadian patterns of spontaneous rotation. In Experiment 1, one hour testing indicated that rotational behavior during the light and dark portions of the diurnal cycle are not different. In Experiment 2, continuous monitoring of rotation for 6-day sessions revealed that gerbils maintain a steady baseline level of rotation throughout the diurnal cycle, unlike rats which spontaneously rotate only at night. Two-thirds of gerbils tested rotated in one direction during an initial phase of testing and then switched the direction of preferred rotation for the remainder of the test session. These shifts in direction of rotation by some gerbils may reflect the influence of arousal on lateralized behavior. Thus, the spontaneous rotational behavior of gerbils is characterized both by a distinct lack of circadian fluctuation and directional variability.