Recent research suggests that yawning is an adaptive behavior that functions to promote brain thermoregulation among homeotherms. To explore the relationship between brain temperature and yawning we implanted thermocoupled probes in the frontal cortex of rats to measure brain temperature before, during and after yawning. Temperature recordings indicate that yawns and stretches occurred during increases in brain temperature, with brain temperatures being restored to baseline following the execution of each of these behaviors. The circulatory changes that accompany yawning and stretching may explain some of the thermal similarities surrounding these events. These results suggest that yawning and stretching may serve to maintain brain thermal homeostasis.
Keywords: yawning, stretching, thermoregulation, brain cooling, brain temperature
Citation: Shoup-Knox ML, Gallup AC, Gallup GG Jr. and McNay EC (2010) Yawning and stretching predict brain temperature changes in rats: support for the thermoregulatory hypothesis. Front. Evol. Neurosci. 2:108. doi: 10.3389/fnevo.2010.00108
Received: 18 March 2010;
Paper pending published: 18 June 2010;
Accepted: 18 August 2010; Published online: 24 September 2010
Edited by:Jesse Bering, Queens University, Ireland
Reviewed by:Cheryl S. Lynch, University of Louisiana, USA.
Copyright: © 2010 Shoup-Knox, Gallup, Gallup Jr. and McNay. This is an open-access article subject to an exclusive license agreement between the authors and the Frontiers Research Foundation, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are credited.
*Correspondence: Melanie L. Shoup-Knox, Evolution and Human Behavior Laboratory, Biopsychology, Department of Psychology, 1400 Washington Avenue, Albany, NY 12222, USA. e-mail: email@example.com