IFIBYNE   05513
INSTITUTO DE FISIOLOGIA, BIOLOGIA MOLECULAR Y NEUROCIENCIAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Scopolamine interferes with memory expression without disrupting long-term storage
Autor/es:
. LUIS DANIEL SUÁREZ1; PEDRO CAFFARO, KARINA A. BARREIRO MARIANO G. BLAKE Y ALEJANDRO DELORENZI
Lugar:
New Orleans, Louisiana
Reunión:
Congreso; 42nd Annual Meeting of the Society for Neurosciences –; 2012
Institución organizadora:
Society for Neurosciences –
Resumen:
  Not every acquired experience builds a memory that can be expressed in the long term. Until now, most works on induced amnesia in animal models interpreted deficits in memory expression as deficits in the storage or retrieval of memory. However, evidence in the crab Chasmagnathus and in humans has shown that memory traces can be retrieved even in the absence of behavioral expression. We proposed that during consolidation, acquired information is evaluated and that is during this process that it is decided whether the new memory is going to be expressed or not in the long-term. A typical 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, a reminder is presented, followed by a facilitatory treatment that changes memory expression, so the intact memory can be tested in a second testing session. Very acute controls for memory reconsolidation are needed, so another effects related to reminder presentation (as summation of new memories) can be discarded. In the Context-Signal Memory model in Chasmagnathus, a Visual Danger Stimulus (VDS) is associated with the training context. This model is particularly well suitable for studies on reconsolidation because the constraints of a reminder to induce reconsolidation were described. A short non-reinforced re-exposure to the training context labilizes the memory, while a presentation of the VDS after the same re-exposure time impedes the labilization of memory. It is know that this memory, as in many vertebrate models, can be blocked by pre- or post-training scopolamine (SCP, a competitive muscarinic receptor blocker) injections. In this work, we studied whether the amnesic effect of pre- and post-training SCP can be reversed by a reminder presentation followed by a water shortage stress. We found that SCP-induced amnesia can be reverted by this stressor. 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. Therefore, amnesia induced by SCP administration can not be explained by blockade of acquisition, storage deficits or an impediment for retrieval. Muscarinic receptors should be involved in the modulation of long-term memory expression. On the contrary, higher doses of SCP or sulfazalazine (that induces amnesia by reducing the entrance to the nucleus of NF-κB 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.