Dopaminergic stimulation in unilateral neglect

Objective - To explore the hypothesis that dopaminergic circuits play a part in the premotor components of the unilateral neglect syndrome, the effects of acute dopaminergic stimulation in patients with neglect were studied. Methods - Two tasks were evaluated before and after subcutaneous administration of apomorphine and placebo: a circle crossing test and a test of target exploration (a modified version of the bell test), performed both in perceptual (counting) and in perceptual-motor (pointing) conditions. Subjects - Four patients with left neglect. Results - After dopaminergic stimulation, a significant improvement was found compared with placebo administration and baseline evaluation, in the performance of the two tests. Three of the patients had a more marked improvement in the perceptual-motor condition (pointing) of the task than the perceptual condition (counting). Conclusions - The findings suggest that dopaminergic neuronal networks may mediate, in different ways, both perceptive and premotor components of the unilateral neglect syndrome.