Learning new motor behavior is aided by error signals that occur in association with each attempted behavior. Although sensory error inputs are known to be essential for guiding motor learning, the nature and source of error signals are incompletely understood. Therefore, we applied micro-electrical stimulation in the pretectal nucleus of the optic tract (NOT), which encodes retinal error information during smooth pursuit and sends signals to the cerebellum through the inferior olive. Here we would argue that artificial error information (simulated retinal motion) produced by NOT stimulation could provide instructive signals for visually guided motor learning.
The cerebellar cortex is usually offered up as the prime example of a well-worked out circuit; its basic neuronal organization consists of a well understood and conserved circuitry that is repeated throughout the entire structure. Yet mysteries still abound about the computations that are performed within its layers, and how these computations contribute to sensation and behavior. Until recently, the center piece of popular models dealing with cerebellar function has been the excitatory pathways travelling through the cerebellar cortex. For these models the remaining elements of the circuit, inhibitory interneurons, play mostly a regulatory or supporting role, secondary to that of the excitatory pathways. However, evidence is accumulating to suggest that inhibitory interneurons in the cerebellar cortex are key in cerebellar processing, carrying out many of the computations attributed to this structure. Here we review recent work on the physiology of cerebellar cortex interneurons, and the role that these interneurons play in cerebellar function.