Ventral hippocampus and NAc core, but not shell activity is required for well-learned instrumental memory...

While there is increasing evidence that instrumental memories undergo destabilisation and reconsolidation, little is known about the underlying neural mechanisms of these processes. Here, we focussed on instrumental memory destabilisation, 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 destabilisation 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 destabilisation, 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 and vHPC, but not the shell, is involved in the destabilisation of well-learned instrumental memory, potentially through a vHPC-NAc core projection.