The interaction of acetylcholinergic and serotonergic neural systems on performance in a continuous non-matching to sample task.

The interactions of cholinergic and serotonergic neural systems were investigated in a working memory, continuous non-matching-to-sample task in an operant chamber. Each rat was injected (i.p.) with scopolamine and/or methysergide. The serotonergic system was destroyed by p-chloroamphetamine (PCA) injection. Scopolamine, but not PCA, impaired response accuracy. The effects of methysergide and scopolamine together were not different from scopolamine alone. Scopolamine had a significantly smaller effect on choice accuracy in PCA-treated than in untreated rats.