CONICET | Buscador de Institutos y Recursos Humanos

When a subject is exposed to successive different learning experiences, the novelty of the second experience can interfere the consolidation of memory of the first one. Novelty usually induces a quick habituation, reflected by the rapid decrease of responding to the new environment or situation. In this sense, the exposition of mice to the nose-poke habituation task (NPH, second learning task) after training on the inhibitory avoidance task (IA, first learning task), impaired retention performance on the IA, indicating an interference caused by the second learning situation.What is the reason for this interference? To gain more insight on this question, in the present work we used the muscarinic antagonist scopolamine (SCOP), a drug already known to cause anterograde, but not retrograde amnesia at low doses. The dose of 0.5 mg/kg of SCOP given immediately after training on the IA task, did not affect retention performance, suggesting that consolidation of the IA is not affected. The same dose given 20 min before training on the NPH task, impaired performance, suggesting that it blocks acquisition of the NPH. When mice was trained in the IA task, received SCOP immediately after it, and 20 min later was exposed to the NPH task, retention performance on the IA was not impaired. These results could be suggesting that the blockade of the acquisition of the second task might be the critical step causing the anterograde amnesia induced by the novel learning situation.

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