LONG-RANGE INTERACTIONS IN VISUAL-PERCEPTION

Classical receptive-field concepts have been used to explain local per ceptual effects such as border contrast and Mach bands, but are not su fficient to explain global perceptual effects. Examples ave the percep tion of illusory contours, area contrast, color constancy, depth plane s, coherent motion and texture contrast, These diverse effects require neurophysiological mechanisms within the visual pathways with long-ra nge interactions. Candidate mechanisms ave suggested, including conver ging feedforward projection to account for the emergence of new respon se properties at higher levels, recruitment of lateral connections to compensate for loss of afference and explain filling-in, and re-entran t projections from higher levels using synchronization of neuronal res ponses to account for binding.