title: Distinct MEG correlates of conscious experience, perceptual reversals and stabilization during binocular rivalry.
abstract: During binocular rivalry, visual perception alternates spontaneously between two different monocular images. Such perceptual reversals are slowed or halted if stimuli are presented intermittently with inter-stimulus intervals larger than ~400 ms--a phenomenon called stabilization. Often, the neural correlates of reversal and stabilization are studied separately, and both phenomena in turn are studied separately from the neural correlates of conscious perception. To distinguish the neural correlates of perceptual content, stabilization and reversal, we recorded MEG signals associated with each in the same group of healthy humans observing repeated trials of intermittent presentation of a dichoptic stimulus. Perceptual content correlated mainly with modulation of stimulus-specific activity in occipital/temporal areas 150-270 ms after stimulus onset, possibly reflecting inhibition of the neural populations representing the suppressed image. Stability of perception reflected a gradual build-up of this modulation across at least 10 trials and was also, to some extent, associated with parietal activity 40-90 ms and 220-270 ms after stimulus onset. Perceptual reversals, in contrast, were associated with parietal (150-270 ms) and temporal (150-210 ms) activity on the trial before the reversal and a gradual change in perception-specific activity in occipital (150-270 ms) and temporal (220-420 ms) areas across at least 10 trials leading up to a reversal. Mechanistically, these findings suggest that stability of perception during rivalry is maintained by modulation of activity related to the two monocular images, and gradual adaptation of neuronal populations leads to instability that is eventually resolved by signals from parietal and late sensory cortices.
authors.affiliation: Cognitive Neuroscience Research Unit, Hammel Rehabilitation and Research Center, Voldbyvej 15, 8450 Hammel, Denmark; Cognitive Neuroscience Research Unit, Aarhus University Hospital, Noerrebrogade 44, Building 10G, 8000 Aarhus C, Denmark; Institute of Cognitive Neuroscience, University College London, 17 Queen Square, WC1N 3AR London, United Kingdom. Electronic address: krissand@rm.dk.
authors.forename: Kristian
authors.initials: K
authors.lastname: Sandberg
authors.affiliation: Wellcome Trust Centre for Neuroimaging, Institute of Neurology, 12 Queen Square, WC1N 3AR London, United Kingdom.
authors.forename: Gareth Robert
authors.initials: GR
authors.lastname: Barnes
authors.affiliation: Institute of Cognitive Neuroscience, University College London, 17 Queen Square, WC1N 3AR London, United Kingdom; Interacting Minds Centre, Aarhus University, Jens Chr. Skous Vej 4, Building 1483, 3rd floor 8000 Aarhus C, Denmark.
authors.forename: Bahador
authors.initials: B
authors.lastname: Bahrami
authors.affiliation: Institute of Cognitive Neuroscience, University College London, 17 Queen Square, WC1N 3AR London, United Kingdom; Sackler Centre for Consciousness Science, School of Psychology, Pevensey 1, BN1 9QH Falmer, United Kingdom.
authors.forename: Ryota
authors.initials: R
authors.lastname: Kanai
authors.affiliation: Cognitive Neuroscience Research Unit, Hammel Rehabilitation and Research Center, Voldbyvej 15, 8450 Hammel, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Overgaard
authors.affiliation: Institute of Cognitive Neuroscience, University College London, 17 Queen Square, WC1N 3AR London, United Kingdom; Wellcome Trust Centre for Neuroimaging, Institute of Neurology, 12 Queen Square, WC1N 3AR London, United Kingdom.
authors.forename: Geraint
authors.initials: G
authors.lastname: Rees
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology*; D005260:Female; D059907:Functional Neuroimaging / Q000379:methods*; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D015348:Vision, Binocular / Q000502:physiology; D015349:Vision, Monocular / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: Binocular rivalry; Consciousness; MEG; Magnetoencephalography; Perceptual reversals; Stabilization