Coupled inverse and forward models in the cerebellum

Speaker : Javier Francisco Medina

Professor & Brown Foundation Chair in Neuroscience

Department of Neuroscience

Baylor College of Medicine

 

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RECURRENT CEREBELLAR CIRCUITS FOR GENERATING ACTIONS AND PREDICTING THEIR SENSORY CONSEQUENCES

Previous analyses of motor-related responses in the cerebellum have helped define how signals are processed along the feedforward stream that links Purkinje cells to neurons in the downstream cerebellar nuclei. In contrast, there is a lack of information about the contribution of feedback signals flowing in the reverse direction, even though recent anatomical and functional studies have demonstrated the existence of such recurrence and suggest that it may play an important role in gain control and pattern completion of learned movements. Here, we examined how feedback signals contribute to the motor-related responses of Purkinje cells using a combination of in vivo electrophysiology and optogenetic experiments in mice performing a Pavlovian eyeblink conditioning task. Our experiments reveal that the neural dynamics of Purkinje cells are controlled by recurrent circuits that link the function of two different cerebellar modules together: the output of one module serves as the motor command for a specific action (i.e. the inverse model), which is sent via fast recurrent pathways to Purkinje cells in surrounding modules responsible for predicting the sensory consequences of that action (i.e. the forward model). This inter-modular recurrent architecture provides a neural substrate for implementing a key operational principle of control theory based on coupling the function of internal models together, allowing the cerebellum to generate accurate motor commands very quickly without having to wait for slow proprioceptive sensory feedback signals.

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10AM : Talk "Coupled inverse and forward models in the cerebellum"
11AM : Discussion