Thermal stress modulates temporal patterns of responding on a multiple DRL-FR schedule.
To investigate temporal changes in behavior induced by moderate cold temperatures, rats performing on a multiple differential-reinforcement-of-low-rate (DRL) fixed-ratio (FR) schedule were exposed to ambient temperatures of 2, 8, 16, and 24 degrees C. DRL response rates markedly increased with decreasing cold temperatures, while FR response rates remained unchanged. In addition, as ambient temperatures decreased, the interresponse time (IRT) distribution of DRL responses shifted toward shorter times and short IRT bursts increased. Compared with cold effects, exposure to 38 degrees C heat induced decreases in both DRL and FR response rates which were associated with increases in long IRTs. Decreases in reinforcement frequency was associated only with the DRL schedule in cold, and with both DRL and FR schedules during heat exposures. The distinct effects of cold and heat on both DRL and FR responding suggest that the increases in DRL response rates and shifts in IRT distribution are unique to cold, and are not due to general effects of nonspecific thermal change in the ambient environment.
Thomas
J R
JR
Behavioral Neuroscience Division, Naval Medical Research Institute, Bethesda, MD 20889-5055.
Ahlers
S T
ST
Shurtleff
D
D
D000818:Animals; D001070:Appetitive Behavior / Q000502:physiology; D001143:Arousal / Q000502:physiology*; D001833:Body Temperature Regulation / Q000502:physiology*; D003080:Cold Temperature / Q000009:adverse effects; D006358:Hot Temperature / Q000009:adverse effects; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D011603:Psychophysiology; D051381:Rats; D012055:Reinforcement Schedule; D013823:Thermoreceptors / Q000502:physiology; D013998:Time Perception / Q000502:physiology*