We collapsed the data across the three speeds and performed regression of firing learn more rate (or normalized firing rate) versus each variable. A regression slope and correlation coefficient of one for any particular

variable would indicate that the neuron encodes the value of that variable unambiguously. For the variable of elapsed time, we obtained an average regression slope of 0.90 and correlation coefficient of 0.79 in both monkeys. Slopes and correlations were somewhat smaller for distance (slope = 0.62 and 0.61; r = 0.75 and 0.71) and for speed (slope = 0.67 and 0.66; r = 0.65 and 0.62). Thus, the neural responses as a group could encode any of the three variables but were best related to elapsed time. For a learned movement to be effective, it not only needs to have the correct trajectory but must also

be produced at the desired time. We have provided evidence that the FEFSEM is involved in regulating the timing of learned pursuit eye movements. We show that when driven by a temporally precise instructive stimulus, learned changes in firing rate are preferentially expressed in neurons that respond best at the time of the instructive stimulus Wnt inhibitor during prelearning step-ramp pursuit. Our results suggest that the FEFSEM may be a site where the timing of sensory errors is processed during learning and integrated into appropriate, learned motor commands. We provide several lines of evidence that the learned responses of neurons in

the FEFSEM are related selectively to learning and are not secondary to the altered eye movement. Comparing the changes in firing rate resulting from two different instruction times showed that the magnitude of the learned neural response depended more unless on the temporal properties of the instructive stimulus than on the size of the learned eye movement. Our analysis of the learned changes in eye velocity and firing rate across single trials revealed a dissociation between the magnitudes of the behavioral and neural responses. Finally, for the same neuron, the change in firing rate associated with a visually-driven eye velocity was often quite different from the change in firing rate produced by learning, even though the visually-evoked eye velocity mimicked the learned eye velocity closely.