NEURONAL SYNCHRONY DOES NOT REPRESENT TEXTURE SEGREGATION

The visual environment is perceived as an organized whole of objects a nd their surroundings. In many visual cortical areas, however, neurons are typically activated when a stimulus is presented over a very limi ted portion of the visual field, the receptive field of that neuron(1- 4). To bridge the gap between this piecewise neuronal analysis and our global visual percepts, it has been postulated that neurons represent ing elements of the same object fire in synchrony to represent the per ceptual organization of a scene(5-10). Experiments with stimuli such a s moving bars or gratings have provided evidence for this hypothesis(1 1-16). We have further tested this by presenting monkeys with various textured scenes consisting of a figure on a background, and recorded n euronal activity in the primary visual cortex (area V1). Our results s how no systematic relationship between the synchrony of firing of pair s of neurons and the perceptual organization of the scene. Instead, pa irs of recording sites representing elements of the same figure most c ommonly showed equal amounts of synchrony between them as did pairs of which one site represented the figure and the other the background. W e conclude that synchrony in V1 does not reflect the binding of featur es that leads to texture segregation.