Fig. 8.

The size tuning function depends on the spatial frequency of the stimulus grating. A: divisive normalization model (DNM) complex cell with standard parameters. B: a real V1 neuron (replotted from Osaki et al. 2011, Figs. 2A and 4A, anesthetized cat; error bars =  ±SE). C: the stimulus and suppressive drive terms of the DNM equation. The stimulus frequency matched the preference of the respective neuron in the Opt condition, was lower in the Spf_L condition, and was higher in the Spf_H condition. The side frequencies in A were determined by the half-height points of the DNM frequency tuning curve. See text for details. The data in B were collected with Spf_L = 0.10 cpd, Opt = 0.20 cpd, and Spf_H = 0.30 cpd (Osaki et al. 2011). All gratings had maximal contrast (c = 1), and their orientation matched the preference of the respective neuron. (See phenomenon 4 in Table 1.)