Investigating Cerebellar Activity During Freely-Moving Social Behavior in Mice

Effortless social interactions like a handshake or a conversation belie a bewilderingly complex process of learning and adaptation. Even simple interactions require us to recognize cues like facial expressions, body language, and intent, then modify our behavior to replicate rewarding outcomes and avoid negative ones. Such social behaviors are not innate but learned through experience. There has been a nascent but growing appreciation for the cerebellum’s role in this social learning. However, information processing by the cerebellum during social behavior remains poorly understood. This study employed calcium imaging and optogenetics to investigate cerebellar social processing by recording and manipulating cerebellar neural activity during naturalistic social behavior in mice. Single-cell imaging of cerebellar Purkinje cells (PCs) revealed that a substantial subset of neurons exhibited decreased activity at the onset of social behaviors. Furthermore, optogenetic manipulation of PCs during social interactions demonstrated that compared to controls, inhibition of cerebellar activity increased aggressive behavior, whereas excitation suppressed it. These circuit-level insights into the cerebellar mechanisms underlying social interactions are important for understanding the etiology of autism spectrum disorder and other neuropsychiatric social impairments and may lead to more effective diagnosis and intervention of these disorders.