Response latency of conditioned avoidance responses during generalization experiments in self-stimulated rats.

Rats exhibiting steady self-stimulation behavior were trained to avoid a footshock after presentation of a unique brain rewarding stimulation of the postero-lateral part of the hypothalamus. Fifty percent of the animals tested were able to learn this conditioning paradigm. An hypothesis based upon modified internal physiological state elicited by the hypothalamic stimulation is discussed to explain the remaining half of the sample which failed to be conditioned. In the conditioned rats it seems that the time-dependent variable, the latency of response, can be used as a valid index for other experiments in which it is wished to study the internal decision process used to discriminate different hypothalamic stimulations in terms of their rewarding value.