he Role and Dynamic of Strengthening in the Reconsolidation Process in a Human Declarative Memory: What Decides the Fate of Recent and Older Memories?

CECILIA FORCATO; RODRIGO FERNANDEZ; MARIA EUGENIA PEDREIRA

Munich

Congreso; 45th European Brain and Behavior Society meeting; 2013

Aims: Consolidated memories pass from stable to labile state after specific reminders are presented. Then, memories are susceptible to amnesic agents again, followed by a re-stabilization phase: the reconsolidation process. One of the functions proposed for this process is the strengthening of the original memory. We have previously demonstrated this function in a declarative memory in humans. Here, we delve more deeply into the strengthening-function associated with reconsolidation by answering the following questions (Q). Q1) Does strengthening maintain the memory available for longer periods of time (memory persistence)? Q2) Does strengthening modify the effect of an amnesic agent? Q3) Does this function depend on the age of the memory? Methods: The paradigm consisted of learning five pairs of nonsense cue-response syllables (List 1). Reactivation-reconsolidation was triggering by presenting a specific reminder (cue-reminder). In all the experiments subjects acquired the List 1 on Day 1. Q1) On Day 2, subjects differed in the number or presence or absence of reminders. All subjects underwent testing on Day 7. Q2) On Day 2, subjects received one or two presentations of the cue-reminder; some of them received the List 2 (a second learning used as an amnesic agent). All subjects underwent testing on Day 3. Q3) On Day 7, subjects could receive one cue reminder; others two- or four cue reminders. All subjects were tested on Day 8. Results: Q1) One labilization-reconsolidation process was enough to strengthen a memory that was evaluated 5 days after its re-stabilization. Q2) Repeated labilization-reconsolidations rendered memories more resistant to interference. Q3) Strengthening appeared to depend on the age of the memory. Forgetting could be the process that weakens this effect. Conclusions: This study examined strengthening in various experimental scenarios, shedding light onto the role of reconsolidation in the fate of declarative memories in humans.