After 250 ms, however, the majority of cells (n = 40, 85%) accurately reflected the response values predicted by the steady-state gain fields (Figure 4C, two-saccade cells). The remainder of the cells (n = 7, 15%) did so by 350 ms (Figure 4D,

two-saccade cells). The median values of the gain field indices had a similar time course (Figure 4E). We also calculated the time point of transition from nonveridical to veridical eye position information (see Experimental find more Procedures; Figure 4F). 43 of the 47 cells (91%) reported the steady-state values in the same stimulus interval for saccades in both directions. We recorded 13 cells that had no eye-position modulation of visual responses to test if the spatial inaccuracy BAY 73-4506 of immediate postsaccadic visual responses were simply the result of flashing stimuli around the time of a saccade. For these cells, responses to visual probes were not statistically different (p > 0.05 by KS test) regardless of the probe delay and the direction of the first saccade (Figure S2). Although the gain fields among the population of neurons reflect eye position inaccurately immediately after the first saccade in the two-saccade task, there is a potential shortcoming to using

this task to assess the monkey’s behavioral performance during this period. In the two-saccade task, the retinal location of the second target and the vector of the saccade necessary to acquire it are coincident. Therefore, it could be argued that the task does not depend on the accuracy

of the gain fields since it can be solved without employing a supraretinal many mechanism. The double-step task has been used to show that the oculomotor system can compensate for an intervening saccade and accurately acquire a target even when there is a dissonance between the retinal location of a target and the vector of the saccade necessary to acquire it (Hallett and Lightstone, 1976). If the brain used a gain-field mechanism to solve the double-step task, the position of targets flashed immediately after a saccade would be calculated as if the eyes had not moved. We used the three-saccade task (Figure 5A), which cannot be solved without employing a supraretinal mechanism, to test if the inaccuracy of the gain fields immediately after a conditioning saccade was reflected in the monkeys’ behavior. In this task, the monkey performed a traditional double-step task following a conditioning saccade in the high-to-low or low-to-high gain field direction. Two targets, one blue and one red (the probe), appeared simultaneously 50, 550, or 1,050 ms after the end of the first saccade. The red probe flashed in the cell’s receptive field for 75 ms and disappeared.