LOCALIZED INJECTIONS OF VARIOUS COMPOUNDS EFFECTING NEUROTRANSMITTER ACTIVITY IN THE MAMMILLARY COMPLEX ENHANCE (T-MAZE) AVOIDANCE RETENTION

The mammillary complex is implicated in the amnesic syndrome associate d clinically with Korsakoff's syndrome, Alzheimer's disease and experi mentally with lesions in animals. There is however no direct evidence that the mammillary bodies are involved in long term memory processing . Mice were partially trained on a footshock avoidance task. Immediate ly after training drugs were injected into the mammillary complex, Ret ention was tested 1 week later by continuing training until each mouse made five avoidance responses in six trials. The results indicated th at muscarine, nicotine, dopamine, glutamine and adrenoceptor agonists as well as GABA and 5-HT receptor antagonists and neuropeptide Y impro ved retention test performance relative to the control. Injection of t he same drugs 1 mm above the injection site for the mammillary complex failed to significantly improve retention test performance, It is con cluded that the mammillary complex, with its important connections to other areas of the limbic system, is involved in memory processing eve nts that occur shortly after training,