Using a Novel Conflict Paradigm to Understand the Role of the Medial Temporal Lobe in Approach-avoidance Conflict Decision-making and Outcome Uncertainty

The anterior hippocampus (aHPC) has been implicated in processing approach-avoidance (AA) conflict. Previous paradigms have utilized stimuli that comprise of spatial or context features and elicit both conflict and uncertainty. Therefore, it is unclear whether the aHPC is recruited when decontextualized objects are used and to which specific type of information the hippocampus is sensitive. To address these questions, the current study used a novel paradigm to directly compare the effects of conflict and uncertainty on AA behaviour while participants underwent functional magnetic resonance imaging (fMRI). Participants’ behavioral responding was driven by conflict as opposed to uncertainty and high AA conflict was associated with perirhinal cortex but not aHPC activity, which is consistent with the notion of stimulus specificity within the medial temporal lobe. Importantly, there was no interaction between conflict and uncertainty suggesting that medial temporal lobe involvement during AA decision-making is driven by conflict rather than uncertainty.M.A