Studies examining adaptation to thermoregulatory challenges have shown
that tolerance to hypothermia is mediated, in part, by associative (P
avlovian) learning mechanisms. This study examined whether acquired to
lerance to deep body cooling (hypothermia) could be extinguished by co
nditions in which presentations of the environmental cues were present
ed in the absence of hypothermia treatment. The results of Experiment
1 indicate that five extinction exposures in which the context was pre
sented alone were not sufficient to extinguish established hypothermia
tolerance in rats. Experiment 2 demonstrated that tripling the number
of daily extinction exposures from 5 to 15 also did not disrupt adapt
ation to cold, and further demonstrated that the presentation of a cha
llenge condition (heat exposure) over the 15-day extinction phase of t
he experiment had no effect on established cold tolerance. Furthermore
, Experiment 2 confirmed associative control of tolerance by demonstra
ting a context shift effect in resistance to cold. The lack of an exti
nction effect in these two experiments suggests that the environmental
context may be acting as an occasion setter.