The panic of losing your car in the carpark captures the importance of associative recognition memory, i.e. the ability to identify something as familiar, along with where and when it was last seen. However, the neuronal networks underpinning this memory are only just being identified. Effectively modelled through object-in-place (OIP) tasks, associative recognition memory can be represented by the time mice spend exploring novel compared to familiar objects and configurations. During learning, active neurons are recruited into neuronal ensembles making an engram, the neural representation of memories. Interneurons, especially parvalbumin- (PV+) and somatostatin-expressing (SOM+), are essential in regulating network activity and memory formation, but their contributions to an associative recognition memory engram is little understood. Using TRAP technology, engram cells expressing TdTomato (TdTom+) within the prelimbic (PrL) and infralimbic (IL) cortices were tagged, visualized and characterised using immunohistochemistry following an OiP task and control tasks (familiar and novel arena). Specifically, the number of TdTom+ cells, PV+ and SOM+ cells, and the overlap between TdTom+/PV+ or TdTom+/SOM+, were quantified and compared across conditions using ANOVA. Preliminary results indicate that mice in familiar and novel arenas, and OIP tasks display average overlaps versus chance values of 279, 401.7 and 240 respectively in the PrL, and 1248.6, 1417.8 and 28506.3 in the IL. Therefore, PV cells are engaged at a higher level in the novel arena in the PrL, and in OIP tasks within the IL. Thus, PV cells are incorporated into engrams in distinct PFC regions in a task dependent manner.