title: Equivalent representation of real and illusory contours in macaque V4.
abstract: The cortical processing of illusory contours provides a unique window for exploring the brain mechanisms underlying visual perception. Previous electrophysiological single-cell recordings demonstrate that a subgroup of cells in macaque V1 and V2 signal the presence of illusory contours, whereas recent human brain imaging studies reveal higher-order visual cortices playing a central role in illusory figure processing. It seems that the processing of illusory contours/figures may engage multiple cortical interactions between hierarchically organized processing stages in the ventral visual pathway of primates. However, it is not yet known in which brain areas illusory contours are represented in the same manner as real contours at both the population and single-cell levels. Here, by combining intrinsic optical imaging in anesthetized rhesus macaques with single-cell recordings in awake ones, we found a complete overlap of orientation domains in visual cortical area V4 for processing real and illusory contours. In contrast, the orientation domains mapped in early visual areas V1 and V2 mainly encoded the local physical stimulus features inducing the subjective perception of global illusory contours. Our results indicate that real and illusory contours are encoded equivalently by the same functional domains in V4, suggesting that V4 is a key cortical locus for integration of local features into global contours.
authors.affiliation: Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, People's Republic of China.
authors.forename: Yanxia
authors.initials: Y
authors.lastname: Pan
authors.forename: Minggui
authors.initials: M
authors.lastname: Chen
authors.forename: Jiapeng
authors.initials: J
authors.lastname: Yin
authors.forename: Xu
authors.initials: X
authors.lastname: An
authors.forename: Xian
authors.initials: X
authors.lastname: Zhang
authors.forename: Yiliang
authors.initials: Y
authors.lastname: Lu
authors.forename: Hongliang
authors.initials: H
authors.lastname: Gong
authors.forename: Wu
authors.initials: W
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001931:Brain Mapping / Q000379:methods / Q000523:psychology*; D008253:Macaca mulatta; D008297:Male; D009474:Neurons / Q000502:physiology; D009903:Optical Illusions / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D014793:Visual Cortex / Q000502:physiology*