Signaling of Predictive and Feedback Information in Purkinje Cell Simple Spike Activity

Computational theories require that controlling movements involves both predicting the consequences of a motor command and continuously monitoring for errors. In this view, sensory prediction errors, defined as the discrepancy between the predicted consequences of motor commands and the sensory feedback, are crucial for online movement control and motor learning. The cerebellum has been implicated in these computations. New results demonstrate that the simple spike discharge of Purkinje cells signals effector kinematics and performance errors. Each motor parameter is encoded by a pair of signals, one leading and one lagging the actual movement. These dual-firing representations are consistent with the predictive and feedback signals needed to generate sensory prediction errors. Furthermore, the encoding of kinematics and performance errors in the simple spike discharge suggests the cerebellum acquires forward internal models of both effectors and task-specific parameters.