Cortical, thalamic, and hypothalamic responses to cooling and warming the skin in awake humans: a positron-emission tomography study.
Thermoregulatory mechanisms are remarkably efficient, ensuring minimal temperature variation within the core of the human body under physiological conditions. Diverse afferent and efferent neural pathways contribute to the monitoring of core and skin temperature, generation of heat, and control of thermal exchange with the external environment. We have investigated the cortical, thalamic, and hypothalamic responses to cooling and warming by using positron-emission tomography activation imaging of subjects clad in a water-perfused suit, which enabled rapid change of their skin-surface temperature. Human brain regions that respond to changes in skin temperature have been identified in the somatosensory cortex, insula, anterior cingulate, thalamus, and hypothalamus, with evidence that the hypothalamic response codes for the direction of temperature change. We conclude that signals from thermosensors in the skin providing crucial afferent information to the brain are integrated with signals from central thermosensors, resulting in thermoregulatory responses that maintain core temperature within a remarkably narrow range.
Egan
Gary F
GF
Howard Florey Institute and Centre for Neuroscience, University of Melbourne, Melbourne, Victoria 3010, Australia. g.egan@hfi.unimelb.edu.au
Johnson
John
J
Farrell
Michael
M
McAllen
Robin
R
Zamarripa
Frank
F
McKinley
Michael J
MJ
Lancaster
Jack
J
Denton
Derek
D
Fox
Peter T
PT
D000328:Adult; D000344:Afferent Pathways / Q000502:physiology; D001833:Body Temperature Regulation / Q000502:physiology*; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000502:physiology*; D004525:Efferent Pathways / Q000502:physiology; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007031:Hypothalamus / Q000000981:diagnostic imaging / Q000502:physiology*; D008297:Male; D049268:Positron-Emission Tomography; D012881:Skin Temperature / Q000502:physiology*; D013788:Thalamus / Q000000981:diagnostic imaging / Q000502:physiology*