Numerous works show a circadian rhythm of activity in several species of animals; the ultradian rhythms have not received much interest. This study investigated whether the circadian motor activity rhythm would be synchronized to two non-24h light cycles and explored the effects of these light-dark cycles on different ultradian rhythms. We used a radar-doppler detection system. Inbred strains of mice BALB/C and C57BL/6 were exposed to a 24LD cycle and then to a shorter (10.5:10.5 LD) or longer (14:14 LD) cycle. Time series corresponding to observation periods of seven days were analysed by Discrete Fourier Transform and Chi-Square periodogram. BALB/C synchronized to T21 and T28 cycles, whereas C57BL/6 did not. In both strains the motor activity showed ultradian components. Some ultradian rhythm was affected from the synchronization of the circadian rhythm to the non-24h light cycles. The relation of the compound structure of the circadian and ultradian rhythms is discussed.
Circadian and ultradian motor activity rhythms under 21h and 28h lighting cycles
PASQUALI, Vittorio;
2009-01-01
Abstract
Numerous works show a circadian rhythm of activity in several species of animals; the ultradian rhythms have not received much interest. This study investigated whether the circadian motor activity rhythm would be synchronized to two non-24h light cycles and explored the effects of these light-dark cycles on different ultradian rhythms. We used a radar-doppler detection system. Inbred strains of mice BALB/C and C57BL/6 were exposed to a 24LD cycle and then to a shorter (10.5:10.5 LD) or longer (14:14 LD) cycle. Time series corresponding to observation periods of seven days were analysed by Discrete Fourier Transform and Chi-Square periodogram. BALB/C synchronized to T21 and T28 cycles, whereas C57BL/6 did not. In both strains the motor activity showed ultradian components. Some ultradian rhythm was affected from the synchronization of the circadian rhythm to the non-24h light cycles. The relation of the compound structure of the circadian and ultradian rhythms is discussed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
