Cerebellin-2positive (Cbln2⁺) Neurons in the Parafascicular Thalamic Nucleus Regulate Self-Grooming Behavior

Self-grooming represents a stereotyped repetitive behavior which is commonly observed in various neuropsychiatric disorders. Deep brain stimulation (DBS) targeting the centromedian / parafascicular complex (CM/PF) has been shown to alleviate obsessive-compulsive disorder/behavior (OCD/OCB) symptoms in human. However, little is known about the neural circuits of the PF that are involved in the regulation of self-grooming behavior in rodents. Here, we report thatcerebellin-2positive (Cbln2⁺) neurons in PF bidirectionally encode self-grooming. Chemogenetic activation ofCbln2⁺PF neurons significantly reduces both physiological and pathological self-grooming, and chemogenetic inhibition ofCbln2⁺PF neurons increases physiological self-grooming. Moreover, activating synaptic excitatory inputs toCbln2⁺PF neurons inhibits self-grooming, while synaptic inhibitory inputs enhance it.Cbln2⁺PF neurons independently transmit neural signals to the dorsal and ventral striatum. Activation of PF-dorsal striatum and PF-ventral striatum pathways both inhibit self-grooming behavior. Together, these data reveal thatCbln2⁺PF neurons are integral components of a brain network involved in self-grooming behavior.