Perseverative stereotypic behavior of Epac2 KO mice in a reward-based decision making task

Abstract

Successfully navigating dynamic environments requires balancing the decision to stay at an optimal choice with that to switch to an alternative to acquire new knowledge. However, the genetic factors and cellular activity shaping this "stay or switch" action decision remains largely unidentified. Here we find that mice carrying a deletion of the exchange protein directly activated by cAMP 2 (Epac2) gene, a putative autism locus, exhibit perseverative "stay" behavior in a dynamic foraging task. Anatomical analysis found that the loss of Epac2 resulted in a significant decrease in the density of PV-expressing interneurons in the ventrolateral orbitofrontal cortex (OFC) and dorsal striatum (dSTR). Further, in vitro whole cell patch clamp recordings of PV⁺ GABAergic interneurons in the dSTR revealed altered neural activity in Epac2 KO mice in response to dopamine. Our findings highlight a potential role of Epac2 in structural changes and neural responses of PV-expressing GABAergic interneurons in the ventrolateral OFC and dSTR during value-based reinforcement learning and link Epac2 function to abnormal decision-making processes and perseverative behaviors seen in autism.

Keywords: Epac2; Fast-spiking interneurons; Orbitofrontal cortex; Parvablumin-expressing GABAergic interneurons; Stay-switch decision-making; Striatum.