Reconsolidation allows fear memory to be updated to a less aversive level through the incorporation of appetitive information.

The capacity to adapt to new situations is one of the most important features of memory. When retrieved, memories may undergo a labile state that is sensitive to modification. This process, called reconsolidation, can lead to memory updating through the integration of new information into a previously consolidated memory background. Thus reconsolidation provides the opportunity to modify an undesired fear memory by updating its emotional valence to a less aversive level. Here we evaluated whether a fear memory can be reinterpreted by the concomitant presentation of an appetitive stimulus during its reactivation, hindering fear expression. We found that memory reactivation in the presence of appetitive stimuli resulted in the suppression of a fear response. In addition, fear expression was not amenable to reinstatement, spontaneous recovery, or rapid reacquisition. Such effect was prevented by either systemic injection of nimodipine or intra-hippocampal infusion of ifenprodil, indicating that memory updating was mediated by a reconsolidation mechanism relying on hippocampal neuronal plasticity. Taken together, this study shows that reconsolidation allows for a 're-signification' of unwanted fear memories through the incorporation of appetitive information. It brings a new promising cognitive approach to treat fear-related disorders.