Scopolamine deficits in negative patterning discrimination: evidence for a role of the central cholinergic system in retention but not acquisition of non-spatial configural association learning.

The effects of scopolamine (0.1 mg/kg s.c. and 0.6 mg/kg s.c.) were assessed on the acquisition and retention of a negative patterning discrimination task in rats. At 0.1 mg/kg scopolamine did not affect either acquisition or retention of the task. At 0.6 mg/kg scopolamine did not affect acquisition but did impair retention of the task. This impairment is likely to be centrally mediated as N-methyl scopolamine (0.6 mg/kg s.c.) did not affect retention. Lack of effect of scopolamine on acquisition of the task indicates that the central cholinergic system is not a necessary substrate of the acquisition of non-spatial configural associations. The scopolamine-induced deficit in retention of the task, suggests that there may, however, be a central cholinergic involvement in the retention/retrieval of this type of learning.