Figure 6.

Control analysis with eye tracking during scanning. (A) Position discrimination data for two additional subjects scanned on the same task as in the main experiment, with eye tracking. Error bars represent ±1 SEM. The data are consistent with the results of the main experiment; the position discrimination estimates from these subjects fell within the range of estimates acquired for subjects in the main experiment in each visual area (most significant differences were MT+: z_physical = 1.81, p = .07 and PPA: Z_percept = 0.87, p = .39, for physical and percept discrimination scores, respectively). Discrimination of physical position hovered near zero for these subjects; this pattern is not atypical compared with the individual subject data from the main experiment, although there were also subjects that showed substantial discrimination of physical position (see Supplementary Figure 3). (B) Sample eye trace for one run from Subject 1a. The x position of gaze (sampled at 60 Hz) is plotted for the duration of the run, and the presentation of the five position conditions is indicated behind the trace in shades of blue. The correlation between eye position and the stimulus conditions for this run was r = .031, p = .86. The largest correlation for any run was r = .048, p = .78. The mean stimulus position, indicated with gray dashed lines, was at ±6.4° from fixation. (C) Mean values for the x position (purple) and y position (green) are shown for each of the five physical positions (left plots) and perceived positions (right plots) for the two control subjects. Eye position was not correlated with the stimulus position or the responses made for either subject (see Results for statistics). There was also no correlation between physical or perceived position and variability of eye position (see Results for statistics). (D) Collections of the recorded gaze positions corresponding to each of the physical and perceived conditions for Subject 1a. The fixation point fell at position (0,0) in the center of each plot; the scatterplots show the collected position measurements sampled during the presentation of each condition (physical plots on the left) as well as the collected eye positions corresponding to each reported condition (percept plots on the right). The adjoining histograms show the x and y distributions of recorded eye positions composing each scatterplot.