An electrophysiological and behavioural study of self-stimulation in the orbitofrontal cortex of the rhesus monkey.

It was found that neurons in the posterior orbitofrontal cortex, area 13, of the rhesus monkey were activated from self-stimulation electrodes (in 142 of 168 possible instances), and that neurons in the anterior orbitofrontal areas were much less likely to be activated from the self-stimulation electrodes (in only 28 of 177 possible instances). This activation of neurons in the posterior orbitofrontal cortex was found mainly from self-stimulation sites in the nucleus accumbens septi, lateral hypothalamus, and the orbitofrontal cortex itself. In a second investigation the orbitofrontal cortex was mapped for self-stimulation, and it was found that self-stimulation occurred in the posterior orbitofrontal area. These results implicate the posterior or caudal orbitofrontal cortex, mainly area 13, but not the more anterior orbitofrontal areas, in self-stimulation.