An analysis of the behavior elicited by stimulation of the dorsal pons in rat

Dorsal pontine intracranial self-stimulation (ICSS) sites were electrically stimulated in rats. Only stimulation-induced oral behavior and not locomotor behavior was observed. The predominant elicited behavior was a fragmentary type of forepaw grooming. In some cases the stimulation-induced forepaw grooming was changed to drinking by the forced presentation of a drinking spout in the perioral region. Neither the dorsal pontine stimulation-induced oral behavior nor the ICSS was disrupted by six-hydroxydopamine lesions of ascending noradrenergic projections from locus coeruleus to widespread forebrain areas. It is suggested that the mesencephalic nucleus of the trigeminal nerve, with its connections to the motor trigeminal nucleus, may mediate dorsal pontine stimulation-induced behavior and ICSS.