Neuronal synchrony does not represent texture segregation.

Abstract

The visual environment is perceived as an organized whole of objects and their surroundings. In many visual cortical areas, however, neurons are typically activated when a stimulus is presented over a very limited portion of the visual field, the receptive field of that neuron. To bridge the gap between this piecewise neuronal analysis and our global visual percepts, it has been postulated that neurons representing elements of the same object fire in synchrony to represent the perceptual organization of a scene. Experiments with stimuli such as moving bars or gratings have provided evidence for this hypothesis. We have further tested this by presenting monkeys with various textured scenes consisting of a figure on a background, and recorded neuronal activity in the primary visual cortex (area V1). Our results show no systematic relationship between the synchrony of firing of pairs of neurons and the perceptual organization of the scene. Instead, pairs of recording sites representing elements of the same figure most commonly showed equal amounts of synchrony between them as did pairs of which one site represented the figure and the other the background. We conclude that synchrony in V1 does not reflect the binding of features that leads to texture segregation.