Thalamic integration of basal ganglia and cerebellar circuits during motor learning

The ability to control movement and learn new motor skills is one of the fundamental functions of the brain. The basal ganglia (BG) and the cerebellum (CB) are two key brain regions involved in controlling movement, and neuronal plasticity within these two regions is crucial for acquiring new motor skills. However, how these regions interact to produce a cohesive unified motor output remains elusive. Here, we discovered that a subset of neurons in the motor thalamus receive converging synaptic inputs from both BG and CB. By performing multi-site fiber photometry in mice learning motor tasks, we found that motor thalamus neurons integrate BG and CB signals and show distinct movement-related activity. Lastly, we found a critical role of these thalamic neurons and their BG and CB inputs in motor learning and control. These results identify the thalamic convergence of BG and CB and its crucial role in integrating movement signals. HighlightsO_LIIndividual neurons in motor thalamus receive converging synaptic input from SNr and DCN projections. C_LIO_LIThalamic neurons with SNr and DCN input are concentrated at the border between VM and VAL thalamic nuclei. C_LIO_LIThalamic neurons functionally integrate SNr and DCN activity and adapt with motor learning. C_LIO_LIThalamic neurons and their inputs from SNr and DCN are critical for learning and executing motor tasks. C_LI