Intracranial self-stimulation: mapping against the lateral boundaries of the dopaminergic cells of the substantia nigra.

The lateral boundaries of the substantia nigra, zona compacta, were mapped for intracranial self-stimulation in rats. The boundaries of the positive region for self-stimulation were found to correspond to the boundaries of the dopaminergic cell layer. These data strengthen the view that rewarding stimulation in this system activates the tegmental dopaminergic cells or, more likely, their immediate afferents.