A memorytrace built in conjunction with a stressor is privileged: Reconsolidation-resistant memories in the crab neohelice

DELORENZI A; MAZA F; MOLINA V; BLOISSE L; FERNANDEZ LARROSA; GONZALEZ HEIDI SOLEDAD

Congreso; Society for Neuroscience 2018; 2019

The dynamics of memory processes are conserved throughout evolution, a feature based on the hypothesis of a common origin of the high-order memory centers in bilateral animals. Reconsolidation is just one example where, for instance, in crabs and humans both expressed or unexpressed memories can enter reconsolidation only if a surprise is presented during reactivation sessions. Our view is that, during reconsolidation, endogenous neuromodulators determine the probability of the memory to guide behavior by decreasing or increasing its behavioral expression, disturbing neither its persistence nor its capacity to be reactivated. The possibility to interfere long-term memory expression during reconsolidation has been proposed as a potential clinical approach to treat traumatic memories. However, several pieces of evidence in humans and rodents show that both robust fear memories or stressful events applied before acquisition promote reconsolidation-resistant memories, i.e., memories that are resistant to the interfering effect of drugs on memory reconsolidation. Is the induction of reconsolidation-resistant memories part of the dynamics of memory processes conserved throughout evolution? In the semiterrestrial crab Neohelice, memory reconsolidation is triggered by a short reminder without reinforcement since the onset of reconsolidation depends on errors in outcome prediction. Here, we showed that an increase in the salience of the aversive stimulus boosts memory strength; nonetheless, the proteins synthesis inhibitor cycloheximide still disrupted the reconsolidation process. However, crabs stressed by a water-deprivation episode before a strong training session build up a memory that was reconsolidation-resistant. We tested whether these reconsolidation-resistant effects can be challenged by changing the parametric conditions of memory-reactivation sessions; multiple (three) memory reactivations without reinforcement were not able to trigger the labilization-reconsolidation of this apparent resistant memory. Overall, the presentfindings suggest that reconsolidation-resistant memories can be another feature of the dynamics of memory processes conserved throughout evolution. Memories built in conjunction with stressors are privileged. Consequently, its ability to guide behavior should not be put at risk after each memory reactivation episode.