Does neural synchrony reflect conscious visual perception?

Abstract

This study investigated the relationship between synchronous neural activity and conscious visual perception by directly measuring neural synchrony in human EEG data collected during a perceptual task that controlled for the influence of attention. Improving a recently developed experimental paradigm and synchrony detection method (Rodriguez et al., 1999), participants viewed upright and scrambled Mooney face stimuli (fragmented black and white shapes that are perceived as faces upon visual closure) over 1000 ms exposures while performing a secondary attention task. During both presentation conditions, gamma-band synchrony increased to a maximum and then decreased to an above-baseline stationary level. Synchrony for the upright condition was significantly greater than synchrony for the scrambled condition during early and late portions of the exposure period. This result supports the hypothesis that neural synchrony mediates conscious visual organization and feature binding, although the possibility for a role in perception-related attention processes cannot be excluded.