Hypothalamic stimulation as a reinforcer of discrimination learning.

Abstract

Electrical stimulation of the posterior hypothalamus was used as the reward In a self-paced brightness discrimination problem. Rate of responding in this task, as in ope rant bar-pressing situations, is a positive function of both current and pulse frequency. Manipulation of these 2 stimulus parameters failed, however, to produce corresponding effects on discrimination learning. Whereas stimulus current had no influence upon the acquisition of the brightness habit, pulse frequency and rate of discrimination learning were found to be inversely related. It is concluded that rate of responding maintained by rewarding hypothalamic stimulation fails to predict the effects of that stimulation as a relnforcer in discrimination learning.