Results of Time Series Analysis on Spontaneous Motor Activity in Mice

Abstract

To obtain information on the physiology of mice, the amount of spontaneous motor activity was measured in these animals. Then, its periodic rhythm was examined by time series analysis.Spontaneous motor activity was measured chronologically in three groups of mice by means of three apparatuses, Animex (group A), Wheel (group W), and Photo-Cell (group P), respectively. When its amount was subjected to correlogram analysis, the spontaneous motor activity formed the vibratory wave of a circular model consisting of several fluctuations of periodic variation. This vibratory wave composed of a large wave with its peak at 24 hours of the dark phase, regardless of the apparatus used, and such a small wave with its peak at 12 hours of the light phase as shown in groups A and P. These peaks appeared repeatedly in 24 hours and were considered to present a diurnal rhythm. Moreover, a small wave was observed in groups A and W. It seemed to appear at 24 hours' intervals at about the time of transition into the dark or into the light phase.Periodic components were examined by power spectrum analysis. The highest spectrum was observed in groups A and P at about 4 hours and in group W at about 2 hours. Small spectra were noticed in groups A and P at about 2 and 6 hours and in group W at about 6 and 8 hours.It was interpreted that in the spontaneous motor activity of mice such vibratory waves as induced at there periodic times were synthesized and united into a diurnal rhythm.From the results mentioned above it was concluded that a simultaneous use of correlogram analysis and power spectrum analysis was an effective means for time series analysis on spontaneous motor activity in mice.