Anais da Academia Brasileira de Ciências | |
The transition from memory retrieval to extinction | |
Martín Cammarota2  Daniela M. Barros1  Mónica R.m. Vianna2  Lia R.m. Bevilaqua2  Adriana Coitinho2  Germán Szapiro1  Luciana A. Izquierdo2  Jorge H. Medina1  Iván Izquierdo2  | |
[1] ,Universidade Federal Do Rio Grande Do Sul Departamento de Bioquímica ICSPorto Alegre RS ,Brasil | |
关键词: memory; retrieval; extinction; reconsolidation; inhibitory avoidance; memória; expressão; extinção; reconsolidação; esquiva inibitória; | |
DOI : 10.1590/S0001-37652004000300011 | |
来源: SciELO | |
【 摘 要 】
Memory is measured by measuring retrieval. Retrieval is often triggered by the conditioned stimulus (CS); however, as known since Pavlov, presentation of the CS alone generates extinction. One-trial avoidance (IA) is a much used conditioned fear paradigm in which the CS is the safe part of a training apparatus, the unconditioned stimulus (US) is a footshock and the conditioned response is to stay in the safe area. In IA, retrieval is measured without the US, as latency to step-down from the safe area (i.e., a platform). Extinction is installed at the moment of the first unreinforced test session, as clearly shown by the fact that many drugs, including PKA, ERK and protein synthesis inhibitors as well as NMDA receptor antagonists, hinder extinction when infused into the hippocampus or the basolateral amygdala at the moment of the first test session but not later. Some, but not all the molecular systems required for extinction are also activated by retrieval, further endorsing the hypothesis that although retrieval is behaviorally and biochemically necessary for the generation of extinction, this last process constitutes a new learning secondary to the unreinforced expression of the original trace.
【 授权许可】
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