A Neurodynamical Model of Brightness Induction in V1

Olivier Penacchio,Xavier Otazu,Laura Dempere-Marco,Maurice Ptito

doi:10.1371/journal.pone.0064086

Olivier Penacchio, Xavier Otazu + Show 2 more

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https://doi.org/10.1371/journal.pone.0064086

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Abstract

Brightness induction is the modulation of the perceived intensity of an area by the luminance of surrounding areas. Recent neurophysiological evidence suggests that brightness information might be explicitly represented in V1, in contrast to the more common assumption that the striate cortex is an area mostly responsive to sensory information. Here we investigate possible neural mechanisms that offer a plausible explanation for such phenomenon. To this end, a neurodynamical model which is based on neurophysiological evidence and focuses on the part of V1 responsible for contextual influences is presented. The proposed computational model successfully accounts for well known psychophysical effects for static contexts and also for brightness induction in dynamic contexts defined by modulating the luminance of surrounding areas. This work suggests that intra-cortical interactions in V1 could, at least partially, explain brightness induction effects and reveals how a common general architecture may account for several different fundamental processes, such as visual saliency and brightness induction, which emerge early in the visual processing pathway.

Highlights

Brightness induction (BI) is the modulation of the perceived intensity of an area by the luminance of surrounding areas
A recent study presented by Coen-Cagli et al [23] relates the computational and ecological principles underlying contextual effects and suggests that the influence of the context on a target stimulus is determined by their degree of statistical dependence. This provides a link between the two approaches and, as will be stressed later, lends statistical support to the theory that V1 computes visual saliency, a notion that is closely related to principles of the model that we propose for explaining BI effects
The proposed model is based on that introduced by Li [31,35], which was originally developed to investigate the neurodynamical basis of contour integration and pre-attentive visual segmentation in V1

Summary

Introduction

Brightness induction (BI) is the modulation of the perceived intensity of an area by the luminance of surrounding areas. The study of BI, which has been thoroughly investigated from a psychophysical perspective, offers an excellent opportunity to investigate the neural mechanisms that underlie brightness perception and the role of early visual cortical areas in such processing. To this end, computational neuroscience may prove an invaluable asset in bringing together psychophysical and neurophysiological experimental evidence with theoretical models that help establish links between them. The high-level approach finds a clear association with Hermann von Helmholtz’s view He considered visual perception as a product of unconscious inference that occurs when our visual system performs its best guess as to what is in the visual scene. Both the sensory information and prior experiences constitute the basis of the perceptual process, and BI would merely be a byproduct of the inferential process

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