Briese E
Brain Res. 1985 Oct 21;345(2):389-93. doi: 10.1016/0006-8993(85)91023-6.
Rats placed in thermally graded enclosures cyclically selected ambient temperatures about 195 degrees out of phase with the circadian variations of their hypothalamic temperature. This finding cannot be explained by the generally accepted assumption that body temperature circadian rhythm is due to a cyclic shift of the set-point temperature.