Fluctuation of locomotor activity.

<p>Illustrative examples of locomotor activity data (local variance with window size 60 s) of a (<b>a</b>) WT, (<b>b</b>) <i>mPer2^Brdm1</i>, (<b>c</b>) <i>Clock/Clock</i>, and (<b>d</b>) <i>Bmal1⁻</i>^/− mouse over 3 consecutive days (left panels). The middle panels are magnifications of the left panels with 4-h periods during subjective daytime. The overall average of non-zero activity levels is used as a threshold (horizontal dotted line), and the period during which the levels are continuously below or above the threshold is coded as a resting (open bar in bottom panels) or active (closed bar) period, respectively. Because body weight varies across individuals, activity levels in the vertical axis (nVar) are normalized by the mean variance of each record. The right panels are the moduli of CWT of locomotor activity shown in the left panels. Values of moduli are color coded according to their magnitude (blue indicates a low and red a large value), and the ordinates are represented on a logarithmic scale.