Photoneural systems are a class of hybrid, optoelectronic processors designed to mimic rather closely the neural mechanisms and architectures involved in visual perception and other cognitive processes. In these systems optical linkages provide complex and adaptable neural-like interconnections between different synaptic centers which may be realized as autonomous elements of monolithically integrated optoelectronic arrays. The perception of sensory stimuli is mediated by a vastly complex hierarchy of "permeatively" linked processes. However, each step in perception seems to involve relatively simple "antagonistic" responses and the structure of perceptual responses remain topographic coherent when "mapped" to various subsystems of the brain. The topographic invariance of cognitive data transmission is suggestive of optical imaging operations and is the essential rationale for photoneural design. The basic synaptic elements are autonomous, optoelectronic processors which are, essentially, optical transceivers activated by con-trasting input stimuli. Recent developments in technology make feasible a class of promising photoneural devices which are simple integrated configurations of light emitting diodes, heterojunction phototransistors and liquid crystal light switches.