Hyperthermia impairs retrieval of an overtrained spatial task in the Morris water maze.
Fifteen rats were trained to learn the location of a spatially fixed platform hidden in a Morris water maze (40 +/- 2 degrees C). Then retention of the spatial task was assessed immediately after raising core body temperature (Tc) to 42 or 40 degrees C or stabilizing at 37 degrees C (the normothermic control). The hyperthermic treatment order was counterbalanced according to a Latin-square design. Hyperthermia at 42 degrees C Tc significantly impaired spatial performance. Hyperthermic animals were cooled to normothermia (Tc = 37 degrees C) and spatial performance was tested again approximately 30 min later. Cooling resulted in a complete recovery of spatial performance. These results demonstrate that hyperthermia-induced amnesia can be obtained on an overtrained spatial-mapping strategy and cooling to normothermia initiates recovery of spatial performance.
Rauch
T M
TM
U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts 01760.
Welch
D I
DI
Gallego
L
L
D000818:Animals; D001833:Body Temperature Regulation; D004193:Discrimination Learning / Q000502:physiology*; D008297:Male; D008568:Memory; D011939:Mental Recall / Q000502:physiology*; D009949:Orientation / Q000502:physiology*; D010056:Overlearning / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012153:Retention, Psychology / Q000502:physiology