Fig. 9.

Responses to annular stimuli containing a circular gray “hole” inside a large circular grating. x-Axis specifies the diameter of the hole for annular stimuli and the outside diameter for disk stimuli (cf. Fig. 5). A: DNM complex cell with standard parameters. Key indicates the contrast of the annular stimuli; the disk had 100% contrast. The measured RF diameter (0.81°) is indicated by arrowhead. B: V1 neuron for which the 2 operational procedures yield comparable diameters (replotted from Jones et al. 2001, Fig. 1, anesthetized macaque; error bars =  ±SE). C: DNM complex cell with a modified parameter set (M = 25, n_d = 2.5, β = 0.005, α = 0.04). Both disk and annulus had 100% contrast. The measured RF diameter (0.36°) is indicated by vertical dashed line. D: V1 neuron for which the annulus-measured diameter is larger than the disk-measured diameter (replotted from Cavanaugh et al. 2002a, Fig. 4, anesthetized macaque). All stimuli are based on gratings whose frequency and orientation matched the preference of the respective neuron. (See phenomena 5 and 6 in Table 1.)