Early Cortical Influences in Object Segregation and the Perception of Surface Lightness

Abstract

The apparent brightness of a surface is profoundly influenced by the brightness of an adjacent surface, but these contrast effects are reduced when the surfaces are perceived as separate three-dimensional entities Previous work has suggested that high-level perceptual and cognitive processes involved in scene segmentation may be responsible for modifying a surface s appearance We demonstrate large reductions in contrast effects when the cues available for segmentation are restricted to those that isolate separate groups of early cortical neurons in the visual system Our data contradict standard contrast-signaling models of brightness perception and imply that mechanisms of figure-ground segmentation are already available at low levels of visual processing