Analysis of hypothalamic self-stimulation with stimulation of fixed duration

Correlation between the frequency of bar pressing and the frequency of hypothalamic self-stimulation of fixed duration was studied in cats during changes in strength of the stimulating current. Strong direct correlation was found between the frequency of bar pressing and the frequency of self-stimulation, whereas strong negative correlation was found between the frequency of pressing and the animal's "work effectiveness." It is suggested that the strongest motivation arises in the presence of an optimal strength of self-stimulation, giving rise to maximal frequency of bar pressing.