[Circadian cycles of wakefulness and rest in Rana temporaria frogs].

In the diurnal activity of the frog R. temporaria, rest and awakefulness stages were investigated. Resting stage was differentiated into daily and nocturnal phases. During daily rest, plastic tone in neck muscles was registered. During this phase, the head might be subjected to unnatural position which is maintained for a certain period. The heart rate was minimal, respiration could not be recorded. During nocturnal rest, in contrast to daily one, the animal changed its positon when touched at the head and kept itself in this positon. Cardiac contractions exhibited evident rhythmicity. Sleep episodes were rare and occasional; they were accompanied by eye closing and relaxation of the body.