Muscarinic antagonism during consolidation disrupts long-term memory expression without affecting memory storage

SUÁREZ LD; CAFFARO P; BARREIRO KA; BLAKE MG; DELORENZI A

Huerta Grande, Córdoba

Congreso; XXVII Congreso Anual de la Sociedad Argentina de Investigación en Neurociencias; 2012

Sociedad Argentina de Investigación en Neurociencias

Until now, most works on induced amnesia in animal models interpreted deficits in memory expression as deficits in the storage or retrieval of memory. We proposed that during consolidation, acquired information is evaluated and that during this process it is decided whether the new memory is going to be expressed or not in the long-term. A protocol to test whether a non-expressed memory trace is indeed an intact functional memory that can be retrieved -even when is not expressed- is to prove that this memory is able to enter in reconsolidation. For this purpose, a reminder is presented followed by a facilitatory treatment that changes long-term memory expression. Very acute controls for memory reconsolidation are needed to discard another effects related to reminder presentation, as summation of new memories. We found that the amnesic effect of pre- and post-training scopolamine (SCP, a competitive muscarinic receptor blocker) injections can be reversed by improving memory reconsolidation. This reversion depends not only in the presentation of a reminder, but also this reminder must be able to trigger reconsolidation, thus ruling out summation effects. On the contrary, higher doses of SCP or sulfazalazine (that induces amnesia by reducing the entrance to the nucleus of NF-B transcription factor) induce amnesias that can not be reverted by this protocol, thus showing that storage of memory or the formation of retrieval links could have been disrupted by those treatments.