Social behavioral deficits in NF1 emerge from peripheral chemosensory neuron dysfunction.

Neurofibromatosis type 1 (NF1) is a neurodevelopmental disorder commonly associated with social and communicative disabilities. The cellular and circuit mechanisms by which loss of neurofibromin 1 (Nf1) function results in social deficits are unknown. Here, we identify social behavioral dysregulation with loss of Nf1 in Drosophila. These deficits map to primary dysfunction of a small group of peripheral sensory neurons, rather than central brain circuits. Specifically, Nf1 regulation of Ras signaling in adult, Ppk23+ chemosensory cells is required for normal social behaviors in flies. Loss of Nf1 results in attenuated ppk23+ neuronal activity in response to pheromonal cues, and circuit-specific manipulation of Nf1 expression or neuronal activity in ppk23+ neurons rescues social deficits. Unexpectedly, this disrupted sensory processing gives rise to persistent changes in behavior lasting beyond the social interaction, indicating a sustained effect of an acute sensory misperception. Together our data identify a specific circuit mechanism through which Nf1 acts to regulate social behaviors, and suggest social deficits in NF1 arise from propagation of sensory misinformation.