Infradian Modulation of Circadian Rhythm in Small Mammals and Birds under Constant Light

The study examined the infradian rhythms in total motor activity and the periods of freerunning circadian rhythm in male C57BL/6 mice and European greenfinch Chloris chloris exposed to constant light. In birds and mice, the motor activity was characterized with inphase 4-day-long rhythm. The periods of free-running circadian rhythms in birds and mice were 23 and 25 h, respectively, and they were modulated with 4-day-long periodicity. The maximal...