The relationship between traumatic brain injury-induced changes in brain temperature and behavioral and anatomical outcome.

Alteration of brain temperature, experimentally induced or spontaneous, has been shown to affect the symptoms resulting from a variety of cerebral insults. This study examined the effect of traumatic brain injury (TBI) on brain and body temperature in rats and the relationship between TBI-induced temperature changes, neuropathology, and behavioral recovery. Anesthesia, surgery and TBI all caused changes in brain and body temperatures. The level of brain (but not body) temperature at the time of TBI was positively correlated with the severity of hippocampal and thalamic pathology. In contrast, the measured levels of both brain and body temperatures after TBI were not related to behavioral or neuroanatomical outcome. Interestingly, the increase in brain (but not body) temperature from the time of TBI to 5 to 10 minutes after termination of anesthesia was negatively correlated with behavioral and anatomical outcome. Simply stated, the more rapidly brain temperature returned toward normal, the better the rats' behavioral and anatomical outcome. This rate of return toward normal brain temperature is not interpreted as causally related to outcome but rather as an index of the severity of brain injury.