APOMORPHINE PRODUCES AN ACUTE DOSE-DEPENDENT THERAPEUTIC EFFECT ON NEGLECT PRODUCED BY UNILATERAL DESTRUCTION OF THE POSTERIOR PARIETAL CORTEX IN RATS

The neglect syndrome is a complex and devastating neurological disorde r typically induced by unilateral destruction of one of three regions of the neocortex: the inferior parietal lobule, the dorsolateral prefr ontal cortex or the cingulate cortex. Previous studies of neglect usin g a rodent model have indicated that disruption of dopaminergic mechan isms may underlie neglect. However, the pharmacological results were o btained using a rodent prefrontal model of the syndrome (medial agranu lar cortex), whereas the majority of cases of neglect in humans are pr oduced by unilateral destruction of the posterior parietal cortex (inf erior parietal lobule). The present study examined the effects of admi nistration of the dopamine receptor agonist apomorphine on neglect ind uced by unilateral destruction of the posterior parietal cortex (PPC) in rats. The results indicated that administration of apomorphine prod uced a significant dose-dependent decrease in the severity of neglect. The results support the contention that neglect induced by cortical d amage may be produced by a disruption of dopaminergic mechanisms, and that the PPC may be one component of a cortical system for directed at tention.