Ventral Hippocampus and NAc Core, but not Shell activity is required for well-learned instrumental memory destabilization

While there is increasing evidence that instrumental memories undergo destabilization and reconsolidation, little is known about the underlying neural mechanisms of these processes. Here, we focussed on instrumental memory destabilization, and the functional involvement therein of the nucleus accumbens core and shell regions, as well as the ventral hippocampus. In male rats, and using a previously established destabilization reminder procedure, we infused the GABA receptor agonists baclofen/muscimol at the time of memory reminder. We found infusions into the core but not shell impaired well-learned instrumental memory destabilization, protecting against MK-801-induced reconsolidation impairment. Moreover, infusion of baclofen/muscimol into the ventral hippocampus resulted in the same protective effect. These results suggest that the NAc core, but not the shell or vHPC, is involved in the destabilization of well-learned instrumental memory, potentially through a vHPC-NAc core projection.