Fig. 6.

Subunit properties do not depend on retinal location. The integrated strength (left) and subunit radii (right) of the mean-increasing (open circles) and mean-decreasing (filled circles) mechanisms are plotted against the eccentricity of recorded Y-cells (n = 25). Trends in the data are weak at best. Linear regression estimated the mean-increasing subunit radius, for example, to grow by ∼25% over 30° of eccentricity, which is not much larger than the variability in subunit radius at a given eccentricity. Disk diameter, 10–15°; grating contrast and temporal frequency, 50% and 1 Hz, respectively. Thelower and upper solid lines plot the regression fits of Linsenmeier et al. (1982) for the X- and Y-cell center radius, respectively, as a function of retinal eccentricity.deg, Degree.