(a) Rate drift in separate oculomotor-range halves during control and caudal right inactivation for individual experiments. (b,c) Rate drift at different positions during the control (b) and inactivation (c) conditions for the population. Gray points correspond to samples over 0.3 s during a fixation; black points, dashes and vertical bars correspond to means, modes and twice the s.d., respectively, of the gray data points in bins of 5 deg. Data on perimeter as in Figure 2d,e. (d) Difference of the average inactivation from average control data. Vertical black segments are 95% confidence intervals, some of which fell within the diameter of point.