An involvement of acetylcholine in object discrimination learning and memory in the marmoset.

Five marmosets (Callithrix jacchus) were tested, using a Wisconsin General Test Apparatus, on a series of junk object visual discrimination tasks, including new learning, 24-hr reversal and 24-hr retention. The effects of administering the cholinergic receptor blocking agent, scopolamine either just before or immediately after the new learning task, or just before the 24-hr reversal and retention tasks, were assessed. Results suggest that scopolamine impairs new learning and impairs the encoding of new information in long term memory. Some evidence of a mild retrieval deficit under scopolamine was also seen, while state-dependent effects were not apparent.