Influence of adaptation to altitude hypoxia on the behavior of rats in a conflict situation.

Adaptation to altitude hypoxia under conditions of conflict between thirst and defensive motivation was studied. The subjects adapted to altitude hypoxia made three times more attempts to drink from a water bowl despite receiving an intense shock. Adaptation to altitude hypoxia increased the stability of an initiated drinking reaction over intense shock. In adapted animals that began to drink, the drinking response changed to defensive behavior with twice the shock intensity as in control animals. In the absence of conflict, there was no difference in the satisfaction of the thirst and the defensive motivation in animals adapted to hypoxia and in controls. Hence, the effect of adaptation to hypoxia consists in making the animals more capable of inhibiting the responses to defensive motivation under conditions where it is necessary to satisfy another vital motivation.