Evidence of maintenance tagging in the hippocampus for the persistence of long-lasting memory storage.

TOMAIOULO M; KATCHE C; VIOLA H; MEDINA JH

Neural Plasticity

Hindawi

Año: 2015

The synaptic tagging and capture (STC) hypothesis provides a compelling explanation for synaptic specificity and facilitation of long-term potentiation. Its implication on long-term memory (LTM) formation led to postulate the behavioral tagging mechanism. Here we show that a maintenance tagging process may operate in the hippocampus late after acquisition for the persistence of long-lasting memory storage. The proposed maintenance tagging has several characteristics: 1) The tag is transient and time-dependent; 2) It sets in a late critical time window after an aversive training which induces a short-lasting LTM; 3) Exposing rats to a novel environment specifically within this tag time-window enables the consolidation to a long-lasting LTM; 4) A familiar environment exploration was not effective; 5) The effect of novelty on the promotion of memory persistence requires dopamine D1/D5 receptors and Arc expression in the dorsal hippocampus. The present results can be explained by a broader version of the behavioral tagging hypothesis, and highlight the idea that the durability of a memory trace depends either on late tag mechanisms induced by a training session and on events experienced close in time to this tag.