Memory recovery in amnestic animals is one of the most poorly studied processes. In this paper, we examine the role of
protein synthesis and a reminder in the mechanisms of
amnesia and memory recovery in grape snails trained to conditioned food aversion.
Amnesia was induced by the impairment of memory reconsolidation using
NMDA (
N-methyl d-aspartate)
glutamate receptor antagonists. In an early stage of
amnesia (day 3),
injections of
protein synthesis inhibitors into animals combined with a reminder by a conditioned stimulus (CS) led to the recovery of aversive reactions to its presentation. Two types of changes in reactions to CS were revealed. In most animals, a persistent recovery of memory retrieval was found that lasted for at least 10 days. In other snails, aversive responses to CS persisted for 24 h. Isolated
injections of inhibitors,
injections of inhibitors and a reminder by the learning environment (without presenting a CS), usage of a differentiating stimulus instead of a CS, or inhibitor
injections after the reminder did not affect the development of
amnesia. The administration of
protein synthesis inhibitors and a reminder in the late period after
amnesia induction (10 days) did not affect its development or caused a short-term memory recovery. We suggest that
amnesia is an active process that develops over time. The reminder induces the reactivation of the
amnesia process dependent on
protein synthesis, while the administration of
protein synthesis inhibitors leads to the impairment of
amnesia reactivation and recovery of the state formed before
amnesia induction (i.e., recovery of conditioned food aversion memory).