<p>There are two major classes of theories about the basal ganglia. The first class hypothesizes</p><p>that the basal ganglia are the site where cortical sensorimotor and dopaminergic reward</p><p>information interact to potentiate and select actions. These theories predict that content</p><p>specificity of information emerges from within the basal ganglia. The second class of</p><p>theories posits that information is manipulated within the basal ganglia through processes</p><p>such as dimensionality reduction. These theories are primarily based on the fact that there</p><p>is a large reduction in the number of neurons from the input to the output stages of the basal</p><p>ganglia. These theories posit that there are changes in the coding properties of neurons</p><p>rather than the emergence of content specificity.</p><p>In this talk, I will present a set of studies where we analyzed the eye movement system of</p><p>monkeys to compare single-neuron activity in the basal ganglia with activity in the</p><p>cerebellum and the frontal cortex. We used tasks that manipulated both eye movements</p><p>and expected rewards. We found that rather than coding specific sensorimotor or reward</p><p>parameters, the basal ganglia were unique in how they coded these parameters, both in</p><p>terms of the signal-to-noise ratio of responses and in the variety of their temporal patterns.</p><p>These results strongly suggest that the basal ganglia play a role in manipulating rather than</p><p>generating reward and sensorimotor signals.</p>