Cortico-cerebellar connectivity changes underlie the emergence of Theory of Mind in early childhood

COEX 

The neurobiological basis of social cognition is well-established in the cerebral cortex, but recent work in adult populations has shown that the cerebellum is also heavily involved in social cognitive processing. However, the role of the cerebellum in the early-life development of social cognition remains elusive, despite clinical evidence linking early-life cerebellar disruptions with social cognitive deficits in autism and schizophrenia. In the current study, we investigated the functional contribution of the cerebellum to Theory of Mind (ToM) in young children (N = 41, age range: 3-12 years) and compared it to its role in adult ToM (N = 78). We found evidence of functional reorganisation of cerebro-cerebellar connectivity as a function of ToM, with growing connections between the posterior cerebellum and ToM regions of the cerebral cortex as children developed ToM abilities. Further, dynamic causal modelling (DCM) during a movie-watching task revealed forward connections from the posterior cerebellum to the cerebral ToM network in children with emerging ToM abilities, whereas adults showed inverse connections from the cerebral ToM network to the posterior cerebellum. This suggests a developmental gradient from forward to inverse cerebro-cerebellar connectivity for ToM: forward connections from the cerebellum may support the construction of social schemas early in life and be gradually replaced by inverse cerebro-cerebellar connections, which may support automatic use of these schemas later in life.