Animal preference for method of obtaining reinforcing brain stimulation.

Abstract

Rats with electrodes in septal and posterior hypothalamic areas were given the choice of obtaining stimulation via lever pressing (self-stimulation) or at a fixed rate with no response required (free stimulation). Results indicate that at hypothalamic intensities up to and including those which support maximal lever pressing rates, there is an equal preference for the 2 methods. However, at very high intensities, which produce motoric side effects, Ss exhibit a clear preference for control over the stimulus. Results with septal stimulation were similar, but compared with hypothalamic placements, free stimulation was preferred less. These preference tests demonstrate that over a wide range of intensities, the reinforcing value of brain stimulation is little changed when control is taken from S.