Different anisotropies for texture and grating stimuli in the visual map of cat striate cortex.

A comparison was made of the directional preferences of cat area 17 cells tested with two different stimuli, gratings and random-dot patterns. Depending on the stimulus, different distributions of direction preferences (anisotropies) were found in the same cells of the central representation of upper layers. With gratings most common preferred directions were vertical and horizontal. With textures, however, horizontal preferred directions were most common. In contrast, lower layer neurons had a bias for vertical preferred directions regardless of the type of stimulus used.