Coordinated cerebellar-midbrain activity for predictive signaling during fear learning in mice
Learning from experience to assess threat is crucial for survival and mental health. This function is known to involve several midbrain areas, notably the ventrolateral periaqueductal grey (vlPAG) and dorsal raphe nuclei (DRN). Recently it has been shown that fear learning involves projections from the cerebellar fastigial nucleus (FN) to the vlPAG. Here, we show using simultaneous single-unit recordings during fear conditioning that a subset of vlPAG/DRN and FN neurons acquire responses to conditioned cues following learning. Strikingly, these populations exhibit firing covariance and directional functional interactions consistent with their collaboration to the response to cues predicting threat. We also demonstrated the reciprocal monosynaptic connectivity between vlPAG/DRN and FN supporting the interactions between these structures. Together, our findings demonstrate shared dynamical activity within a network integrating midbrain and cerebellar computations during fear learning.