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Bulletin of Experimental Biology and Medicine, Vol. 157, No. 1, May, 2014
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PHYSIOLOGY
Induction of Latent Memory for Conditioned Food Aversion and Its Transformation into Active State Dependon Translation and Transcription Processes
S. V. Solntseva and V. P. Nikitin
Translated from Byulleten Eksperimentalnoi Biologii i Meditsiny, Vol. 1 57, No. 1, pp. 4-8, January, 2014 Original article submitted December 17, 2012
Mechanisms of induction and retrieval of latent (hidden) memory for conditioned food aversion were investigated in snails. After initial training (single combination of a food stimulus with electric shock), aversive reactions to presentation of the conditioned food stimulus were not revealed. Repeated presentation of the stimuli in 12 days after the rst combination was followed by the appearance of aversive food reactions that persisted for at least 14 days. Injections of inhibitors of protein (cycloheximide) or RNA (-amanitin) synthesis immediately after the rst or second combined presentation of the stimuli disturbed skill performance. We hypothesized that single combination of food and reinforcing stimuli led to translation- and transcription-dependent induction of latent conditioned food aversion memory. Transformation of this memory into an active state after repeated presentation of the stimulus combination also depends on the synthesis of new proteins and RNA.
Key Words: latent memory; protein and RNA synthesis inhibitors; conditioned food aversion; snail
Long-term memory formation proceeds through its consolidation, which depends on protein and mRNA synthesis [4,9]. However, it is increasingly evident that reorganization of long-term memory (integration with other types of memory, enhancement, attenuation, distortion, and even complete erasure) can take place during a long period after completion of its consolidation [4,15]. A possible scenario of memory formation and reorganization is the so-called latent or hidden memory, described in animals and humans [3,6,8,10-12]. It is believed that memory exists in an active (actual) ready for implementation form and in a passive
(or latent) form, not ready for immediate reproduction. Latent memory can be formed under certain training conditions, as a result of amnesic exposure, or natural forgetting. In addition, latent memory can be induced even in the absence of overt learning: the phenomenon of latent (hidden) training. Studies in mammals and mollusks have demonstrated that induction of latent memory depends on protein synthesis [11]. Reminder or re-training is used for...