Cntnap2loss drives striatal neuron hyperexcitability and behavioral inflexibility

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by two major diagnostic criteria - persistent deficits in social communication and interaction, and the presence of restricted, repetitive patterns of behavior (RRBs). Evidence from both human and animal model studies of ASD suggest that alteration of striatal circuits, which mediate motor learning, action selection, and habit formation, may contribute to the manifestation of RRBs.CNTNAP2is a syndromic ASD risk gene, and loss of function ofCntnap2in mice is associated with RRBs. How loss ofCntnap2impacts striatal neuron function is largely unknown. In this study, we utilizedCntnap2^-/-mice to test whether altered striatal neuron activity contributes to aberrant motor behaviors relevant to ASD. We find thatCntnap2^-/-mice exhibit increased cortical drive of striatal projection neurons (SPNs), with the most pronounced effects in direct pathway SPNs. This enhanced drive is likely due to increased intrinsic excitability of SPNs, which make them more responsive to cortical inputs. We also find thatCntnap2^-/-mice exhibit spontaneous repetitive behaviors, increased motor routine learning, and cognitive inflexibility. Increased corticostriatal drive, in particular of the direct pathway, may contribute to the acquisition of repetitive, inflexible behaviors inCntnap2mice.