Abstract
Rats, implanted with chronic electrodes at the postero-lateral part of the hypothalamus, were allowed to self-regulate the train duration of electrical rewarding brain stimulation in two different surroundings, i.e. home cage and strange cage. The total time of self-stimulation, the number of bar pressings, as well as the mean duration of bar pressing were automatically recorded. Results show that the total time of self-stimulation and the number of bar pressings increase in the strange cage while the mean duration of bar pressing decreases. It is assumed that the environment of a strange cage offers fewer positive properties than the environment of the home cage because self-stimulation behavior is higher in the strange cage.