Abstract
The authors have devised an apparatus for monitoring the spontaneous locomotor activity of rats, with which the patterns of locomotor activity under the condition of light-dark cycle (light period: twelve hours from 6 a.m., dark period: the other half of the day) were analysed. In addition, changes in locomotor activities due to forced exercise (swimming) were recorded. The results obtained were as follows: 1. The patterns of locomotor activities in rats recorded by the monitor showed the same patterns as reported already by other researchers. The authors believe that this new apparatus can be used practically as a locomotor activity monitor. 2. Due to exhaustive exercise by swimming, changes of the ultradian rhythm in rats were observed. 3. By loading of swimming, locomotor activities in rats decreased significantly, especially in the dark period. These results suggest that this newly devised apparatus is useful as a locomotor activity monitor, and that the fatigue in rats caused by physical load can be shown as the change in locomotor activities.
