Behavioral, molecular and neurobiological processes underlying memory retrieval

Memory retrieval can modify existing memories by incorporating new information rather than disrupting them. Using contextual fear conditioning in mice, this dissertation examined behavioral and neurobiological mechanisms underlying retrieval-induced changes. Retrieval was more sensitive to enhancement than acquisition, and extinction after either produced similar effects. Outcomes varied by exposure duration, with strong reactivation enhancing fear and longer or very brief exposures promoting response loss. Region-specific interventions revealed prelimbic and infralimbic cortex roles in fear enhancement and reduction, respectively. Findings suggest retrieval engages multiple processes, informing strategies to treat maladaptive memories such as trauma and addiction.