title: Rivalry-Like Neural Activity in Primary Visual Cortex in Anesthetized Monkeys.
abstract: Two incongruent images viewed by the two eyes cause binocular rivalry, during which observers perceive continuous alternations between these two visual images. Previous studies in both humans and monkeys have shown that the primary visual cortex (V1) plays a critical role in the rivalry perception. However, it is unclear whether the rivalry activity observed in V1 relies on conscious influences. Here, we examine the responses of V1 in monkeys under general anesthesia. With intrinsic signal optical imaging and single-trial analysis, alternating activation of ocular dominance columns in V1 was observed during binocularly incongruent stimulation. Left- and right-eye columns exhibited counterphase activation, which were modulated by stimulus features in ways similar to those found in conscious human observers. These observations indicated that binocular rivalry occurs in V1 without consciousness, suggesting that the low-level automatic mechanisms play a more important role than previously believed in handling visual ambiguities.
  
  
  CONCLUSIONS
  When visual input is ambiguous, for example, in viewing bistable images, human subjects normally perceive one of the interpretations at a particular moment. Previous studies have shown that both low-level visual processing and high-level attention contribute to the establishment of the final visual perception. However, it is not clear whether attention is indispensable in such a process. Here we show that rivalry-like neural activity persisted in monkey V1 when the monkeys were anesthetized and viewed binocularly incongruent stimuli. Such activity has many key features similar to those observed in conscious human subjects. These findings indicate that low-level visual processes play a critical role in solving visual ambiguity such as binocular rivalry.
authors.affiliation: Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, and University of Chinese Academy of Sciences, Shanghai 200031, China and State Key Laboratory of Cognitive Neuroscience and Learning, IDG/McGovern Institute for Brain Research, Collaborative Innovation Center for Brain Science, Beijing Normal University, Beijing 100875, China.
authors.forename: Haoran
authors.identifier: http://orcid.org/0000-0001-5753-8264
authors.initials: H
authors.lastname: Xu
authors.affiliation: Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, and University of Chinese Academy of Sciences, Shanghai 200031, China and State Key Laboratory of Cognitive Neuroscience and Learning, IDG/McGovern Institute for Brain Research, Collaborative Innovation Center for Brain Science, Beijing Normal University, Beijing 100875, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Han
authors.affiliation: Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, and University of Chinese Academy of Sciences, Shanghai 200031, China and State Key Laboratory of Cognitive Neuroscience and Learning, IDG/McGovern Institute for Brain Research, Collaborative Innovation Center for Brain Science, Beijing Normal University, Beijing 100875, China.
authors.forename: Ming
authors.identifier: http://orcid.org/0000-0002-7389-3060
authors.initials: M
authors.lastname: Chen
authors.affiliation: Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, and University of Chinese Academy of Sciences, Shanghai 200031, China and State Key Laboratory of Cognitive Neuroscience and Learning, IDG/McGovern Institute for Brain Research, Collaborative Innovation Center for Brain Science, Beijing Normal University, Beijing 100875, China.
authors.forename: Peichao
authors.identifier: http://orcid.org/0000-0001-5761-9435
authors.initials: P
authors.lastname: Li
authors.affiliation: Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, and University of Chinese Academy of Sciences, Shanghai 200031, China and State Key Laboratory of Cognitive Neuroscience and Learning, IDG/McGovern Institute for Brain Research, Collaborative Innovation Center for Brain Science, Beijing Normal University, Beijing 100875, China.
authors.forename: Shude
authors.initials: S
authors.lastname: Zhu
authors.affiliation: Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, and University of Chinese Academy of Sciences, Shanghai 200031, China and State Key Laboratory of Cognitive Neuroscience and Learning, IDG/McGovern Institute for Brain Research, Collaborative Innovation Center for Brain Science, Beijing Normal University, Beijing 100875, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Fang
authors.affiliation: Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, and University of Chinese Academy of Sciences, Shanghai 200031, China and State Key Laboratory of Cognitive Neuroscience and Learning, IDG/McGovern Institute for Brain Research, Collaborative Innovation Center for Brain Science, Beijing Normal University, Beijing 100875, China.
authors.forename: Jiaming
authors.identifier: http://orcid.org/0000-0002-5306-445X
authors.initials: J
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Cognitive Neuroscience and Learning, IDG/McGovern Institute for Brain Research, Collaborative Innovation Center for Brain Science, Beijing Normal University, Beijing 100875, China.
authors.forename: Heng
authors.identifier: http://orcid.org/0000-0002-0322-278X
authors.initials: H
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Cognitive Neuroscience and Learning, IDG/McGovern Institute for Brain Research, Collaborative Innovation Center for Brain Science, Beijing Normal University, Beijing 100875, China haidong@bnu.edu.cn.
authors.forename: Haidong D
authors.identifier: http://orcid.org/0000-0003-1739-9508
authors.initials: HD
authors.lastname: Lu
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000768:Anesthesia, General; D000818:Animals; D001931:Brain Mapping; D023882:Dominance, Ocular; D008252:Macaca fascicularis; D008253:Macaca mulatta; D008297:Male; D061848:Optical Imaging; D010775:Photic Stimulation; D013057:Spectrum Analysis; D013997:Time Factors; D015348:Vision, Binocular / Q000502:physiology*; D014793:Visual Cortex / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*
keywords: anesthetized; attention; binocular rivalry; ocular dominance; optical imaging; striate cortex