Response of the SFA units as a function of orientation of sinusoidal gratings.

A SFA unit response as a function of orientation. Solid red (dashed blue) lines indicate excitatory (inhibitory) response. B Orientation tuning functions of V1 cells of macaque monkey (figure adapted from DeValois et al. (1982) [55]). Note that inhibitory effects were not investigated by DeValois et al. [55], and thus there are no inhibitory responses plotted in B.