Spatiotemporal isosensitivity fields in the human visual system.

The human visual system is capable of detecting correlations, manifested perceptually as global pattern, in mathematically constrained dynamic textures. This ability has given rise to speculation that correlative mechanisms in the human visual system exist and that they have a neural basis similar to the orientationally selective structures discovered in area 17 of the mammalian visual cortex. The limits to the detection of correlation were mapped, spatially and temporally, by means of a psychophysical technique. Evidence is presented that, at least in the spatial domain, the correlation mechanism may be served by a population of such neural units.