Sc. Kissinger et Dc. Riccio, STIMULUS CONDITIONS INFLUENCING THE DEVELOPMENT OF TOLERANCE TO REPEATED COLD-EXPOSURE IN RATS, Animal learning & behavior, 23(1), 1995, pp. 9-16
Tolerance to an environmental cold challenge in rats is eliminated whe
n cold exposure occurs in a context different from the adaptation cont
ext, indicating that learning mechanisms play a role in; thermoregulat
ion (Riccio, MacArdy, and Kissinger, 1991). This finding, analogous to
outcomes obtained with drug tolerance; was investigated in the presen
t study. Experiment 1 demonstrated that a change in both proximal and
distal contextual cues disrupts an established cold adaptation, an out
come consistent with the view that associative processes contribute to
the tolerance. In Experiment 2, although cold tolerance persisted ove
r a 7-day retention interval, the disruption of tolerance by a shift i
n context was attenuated with the delay of testing. This finding sugge
sts that the precise stimulus attributes of the context were forgotten
over the interval. Experiment 3 demonstrated that cold-tolerance disr
uption is due to the actual change in context and not to novelty of th
e test context. Experiment 4 showed that changing the context associat
ed with each cold exposure impaired the development of tolerance. The
results of these experiments provide additional evidence that cold tol
erance is regulated at least partially by associative learning process
es.