Receptive-field symmetry probed using converging gratings

Contrast-sensitivity functions (CSF's) for converging and diverging gratings were obtained under voluntary fixation at several field widths and under retinal stabilization at one field width. In general, these types of gratings had similar CSF's at all temporal frequencies tested, a result that can be explained by plausible spatiotemporal receptive-field models possessing spatial antisymmetry but not by models possessing pure (even) spatial symmetry. Phase condition at the central line in converging and diverging gratings affected grating detectability at high spatial frequencies, as expected.