Spatial and temporal frequency tuning and contrast sensitivity of single neurons in area 21a of the cat.

The spatial and temporal selectivities of single neurons in area 21a of the adult cat were investigated using sinusoidal gratings. Optimal spatial frequencies and visual acuity (high cut-off frequency) were fairly low and spatial bandwidth was mainly narrow. Contrast threshold was generally low but a substantial number of cells were only excited by high contrast stimuli. The temporal selectivity suggests that cells responded to a wide range of temporal frequencies.