Discontinuous long-train stimulation in the anterior striatum in monkeys induces abnormal behavioral states.

The striatum has been identified as a new target for therapeutic deep brain stimulation in the treatment of neurological and psychiatric disorders. The nonhuman primate model offers opportunities for detailed mapping of the behavioral effects of stimulation within the striatum. We recently showed that dysfunction in the dorsal and ventral striatum was able to produce a specific pattern of abnormal movements and behavioral states. In the present study, electrical stimulation of monkey striatum evoked abnormal movements and behavioral states depending not only on the location of stimulation sites but also on the parameters of stimulation. Abnormal movements were induced by stimulation of sites in the anterior associative and posterior sensorimotor striatum. Short-train stimulation evoked myoclonic-like movements and long-train stimulation produced sustained dystonic-like and complex abnormal movements. Long-train stimulation of the anterior part of the striatum, corresponding to the associative-limbic territory, induced 3 abnormal behavioral states--hyperactivity, hypoactivity, and stereotyped behaviors. Short-train stimulation was less effective in producing these effects. No significant effects were observed with the continuous mode of stimulation. Our results show that discontinuous long-train stimulation of the anterior associative and limbic parts of the striatum is the most effective mode of stimulation to produce these behavioral states.