Effect of a unilateral lesion of nigrostriatal dopaminergic neurons on oral bouts induced by the infusion ofm-CPP into the left subthalamic nucleus (STh). Data are expressed as the mean ± SEM number of oral bouts per 60 min (n = 6–8). Doses ofm-CPP (0, 0.2, 0.5, and 1 μg in 0.1 μl of NaCl 0.9%) were administered over 4 weeks in a counterbalanced order with a 1 week drug-free period between drug administrations. The nigrostriatal lesion did not modify m-CPP-induced oral bouts (two-way ANOVA; see Results). *p < 0.05 and **p < 0.01 (compared with vehicle injection, Dunnett's test following significant one-way ANOVA, see Results).