Is cholinergic activity of the striatum involved in the acquisition of positively-motivated behaviors?

Cholinergic activity of the caudate-putamen (CPU) is crucial for the acquisition of aversively-reinforced behaviors (active and passive avoidance). To determine whether this activity is also involved in the acquisition of a positively-rewarded behavior, in the present experimental series the effects of scopolamine applications to the antero-dorsal or postero-dorsal aspects of the striatum on auto-shaping were assessed. The auto-shaping procedure that was used allowed rats to learn to bar press at their own rate. It was found that scopolamine injection into either region of the CPU produced a marked retardation in the acquisition of the conditioned behavior. These results indicate that cholinergic activity of the striatum is critically involved in the early phases of positively-reinforced learning.