Self-stimulation of the sulcal prefrontal cortex in the rat: direct evidence for ascending dopaminergic mediation.

Intracranial self-stimulation (ICSS) of the prefrontal cortex dorsal to the rhinal sulcus in rats has been abolished by means of injections of 6-hydroxydopamine (6-OHDA) (4 micrograms/2 microliters) into the ascending trajectory of the A10 mesocortical dopaminergic fibers ipsilateral to the stimulation electrodes. Similar injections made contralateral to the stimulation electrodes produced a transient attenuation of this self-stimulation. All cases of such lesions were confirmed with the use of Vibratome histochemical fluorescence examination of each of the dopamine projection areas in the forebrain.