The Illusion of Uniformity Does Not Depend on the Primary Visual Cortex: Evidence From Sensory Adaptation.

Marta Suárez-Pinilla,Anil K Seth,Warrick Roseboom

doi:10.1177/2041669518800728

Abstract

Visual experience appears richly detailed despite the poor resolution of the majority of the visual field, thanks to foveal-peripheral integration. The recently described uniformity illusion (UI), wherein peripheral elements of a pattern take on the appearance of foveal elements, may shed light on this integration. We examined the basis of UI by generating adaptation to a pattern of Gabors suitable for producing UI on orientation. After removing the pattern, participants reported the tilt of a single peripheral Gabor. The tilt aftereffect followed the physical adapting orientation rather than the global orientation perceived under UI, even when the illusion had been reported for a long time. Conversely, a control experiment replacing illusory uniformity with a physically uniform Gabor pattern for the same durations did produce an aftereffect to the global orientation. Results indicate that UI is not associated with changes in sensory encoding at V1 but likely depends on higher level processes.

Highlights

Visual experience appears richly detailed despite the poor sensory precision of the majority of the visual field
uniformity illusion (UI) describes a phenomenon wherein apparent perceptual uniformity occurs when variable sensory stimulation is presented in peripheral vision, while the central visual field is presented with uniform stimuli
The UI is a striking phenomenon in which experience across the whole visual field is modified by higher precision foveal information, yet its underlying mechanisms remain unknown

Summary

Introduction

Visual experience appears richly detailed despite the poor sensory precision of the majority (periphery) of the visual field. This topic has received considerable recent attention (Cohen, Dennett, & Kanwisher, 2016; Haun, Tononi, Koch, & Tsuchiya, 2017), with debate about the degree to which visual experience is rich and the potential perceptual processes that may contribute to apparent richness. UI describes a phenomenon wherein apparent perceptual uniformity occurs when variable sensory stimulation is presented in peripheral vision, while the central visual field is presented with uniform stimuli. We utilize the spatial specificity of TAE to examine whether the apparent perceptual uniformity in UI can be attributed to changes in V1based neural coding for visual orientation. Following prolonged exposure to global illusory uniformity (UI), we contrasted whether the resultant TAE was consistent with the local, physical orientation or the illusory global orientation

Methods

Results

Conclusion