Local serial correlation in behavioral states in the mouse

In the mouse, Mus musculus, local (ultradian) serial correlation (LSC) within the sleep and wakefulness states varies significantly as a function of circadian phase. The amplitude of the correlation function is greatest during the active phase of the mouse's diurnal cycle. Additionally, mean LSC (averaged across circadian phase) is significantly positive and monotonically decreasing for a broad range of short lags (1-23 minutes). Thus there is no evidence of positive, periodically occurring peaks in the correlation function separated by patches of small or negative correlations that is characteristic of a rhythmic process of fixed period. These findings challenge the concept that an ultradian oscillator plays a significant role in the temporal control of sleep-wake state. (Author)