Functional recruitment and connectivity of the cerebellum supports the emergence of Theory of Mind in early childhood

There is accumulating evidence that the human cerebellum is heavily implicated in adult social cognition. Yet, its involvement in the development of Theory of Mind (ToM), a hallmark of social cognition, remains elusive. In a functional MRI study involving children with emerging ToM abilities (N=41, age range: 3-12 years) and adults (N=78), we showed that children with ToM abilities activated cerebellar Crus I-II in response to ToM events during a movie-watching task, similar to adults. This activation was absent in children lacking ToM abilities. Functional connectivity profiles between cerebellar and cerebral ToM regions differed as a function of childrens ToM abilities. Notably, task-driven connectivity shifted from upstream to downstream connections between cerebellar and cerebral ToM regions from childhood to adulthood. Greater dependence on connections emerging from the cerebellum early in life suggests an important role of the cerebellum in establishing the cognitive processes underlying ToM in childhood and thus for the undisrupted development of social cognition.