Chapter 20 Potentiation of the extrageniculo-striate pathway: a possible role in visual pattern discrimination

Abstract

Publisher Summary In young animals, simple receptive fields (RFs) are experience insensitive, while complex RFs possess certain adaptivity. Complex cells are higher order output neurons, which transmit information to other visual cortical areas and properties of their RFs are formed later during the course of development, but these cells have worse detector characteristics than simple cells. The visual responses of pulvinar-lateral posterior (Pulv-LP) can be increased in situations of interest to visual stimuli, and the activity of Pulv-LP neurons depend on visually evoked eye movements. Experiments with lesions of Pulv-LP also show that this structure is involved in processes of visual discrimination and attention. Consequently, it is concluded from these data that potentiation of pulvinar input results in improvement of visual discrimination. The reduction of the orientation selectivity of complex cells after tetanization of the pulvinar input can mean that the selective attention to visual stimuli (our potentiation of pulvinar input is considered as a model of this process) actively depresses (masks) some reactions of sign detectors, and as a result, sub serves the finer discrimination of visual patterns. The involvement of pulvinar input into the process of the formation of complex RFs is important for providing the plasticity of cortical reactions.