Brain temperature as related to gross motor activity in the unanesthetized chicken

It is concluded that brain temperature and gross motor activity are only loosely coupled to each other, and that especially the circadian rhythm of temperature does not depend on a concurrent rhythm of activity.

Abstract

Brain temperature was recorded, together with activity, continuously for up to 8 days at various depths of the tissue in awake, but moderately restrained chicken. The animals were kept in a small round arena with a movable floor and exposed to either a light-dark cycle or constant dim illumination. In entrained as well as in free running rhythms, the circadian rise of temperature preceded onset of activity by several hours. Circadian rhythms of brain temperature were clearly expressed in animals showing no activity rhythm. Short bursts of activity were positively correlated with increases in temperature during the time of circadian low temperatures (sleep) but not during high temperatures (wakefulness). It is concluded that brain temperature and gross motor activity are only loosely coupled to each other, and that especially the circadian rhythm of temperature does not depend on a concurrent rhythm of activity.