Fig. 6.

D1-type receptor activation and D2-type receptor suppression ameliorate dopamine depletion-induced task-switching inflexibility. (A) In both the RDT–VCT and VCT–RDT switching paradigms, pretreatment with the D1-type agonist SKF81297 or the D2-type antagonist sulpiride restored the increased total number of trials needed to reach the criterion caused by dopamine lesion in the NAc. (B–D) The effects of the drugs are also reflected in the number of perseverative errors (B) and regressive errors (C) committed but not in the number of never-reinforced errors (D). In A–D, sham and lesion groups as shown in Fig. 3 E–H are included here for comparisons. *P < 0.05; **P < 0.01; ***P < 0.001, unpaired t test. Data are presented as mean ± SEM.