title: Selective Neural Synchrony Suppression as a Forward Gatekeeper to Piecemeal Conscious Perception.
abstract: The emergence of conscious visual perception is assumed to ignite late (∼250 ms) gamma-band oscillations shortly after an initial (∼100 ms) forward sweep of neural sensory (nonconscious) information. However, this neural evidence is not utterly congruent with rich behavioral data which rather point to piecemeal (i.e., graded) perceptual processing. To address the unexplored neural mechanisms of piecemeal ignition of conscious perception, hierarchical script sensitivity of the putative visual word form area (VWFA) was exploited to signal null (i.e., sensory), partial (i.e., letter-level), and full (i.e., word-level) conscious perception. Two magnetoencephalography experiments were conducted in which healthy human participants viewed masked words (Experiment I: active task, Dutch words; Experiment II: passive task, Hebrew words) while high-frequency (broadband gamma) brain activity was measured. Findings revealed that piecemeal conscious perception did not ignite a linear piecemeal increase in oscillations. Instead, whereas late (∼250 ms) gamma-band oscillations signaled full conscious perception (i.e., word-level), partial conscious perception (i.e., letter-level) was signaled via the inhibition of the early (∼100 ms) forward sweep. This inhibition regulates the downstream broadcast to filter out irrelevant (i.e., masks) information. The findings thus highlight a local (VWFA) gatekeeping mechanism for conscious perception, operating by filtering out and in selective percepts.
authors.affiliation: The Gonda Multidisciplinary Brain Research Center Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen 6500 GL, The Netherlands Inserm UMR825, Imagerie Cerebrale et Handicaps Neurologiques, Toulouse 31024, France Université de Toulouse, UPS, Toulouse 31062, France Centre Hospitalier Universitaire de Toulouse, Pôle Neurosciences, CHU Purpan, Toulouse 31024, France.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Levy
authors.affiliation: University Grenoble Alpes, LPNC, F-38040 Grenoble, France CNRS, LPNC, UMR 5105, F-38040 Grenoble, France.
authors.forename: Juan R
authors.initials: JR
authors.lastname: Vidal
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen 6500 GL, The Netherlands Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max-Planck-Society, Frankfurt 60528, Germany.
authors.forename: Pascal
authors.initials: P
authors.lastname: Fries
authors.affiliation: Inserm UMR825, Imagerie Cerebrale et Handicaps Neurologiques, Toulouse 31024, France Université de Toulouse, UPS, Toulouse 31062, France Leenaards Memory Center, Department of Clinical Neurosciences, CHUV and University of Lausanne, Lausanne 1011, Switzerland.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Démonet
authors.affiliation: The Gonda Multidisciplinary Brain Research Center Department of Psychology, Bar-Ilan University, Ramat Gan 52900, Israel.
authors.forename: Abraham
authors.initials: A
authors.lastname: Goldstein
mesh_terms: D001921:Brain / Q000502:physiology*; D003243:Consciousness / Q000502:physiology*; D005260:Female; D065818:Gamma Rhythm / Q000502:physiology*; D006801:Humans; D016014:Linear Models; D015225:Magnetoencephalography; D008297:Male; D009483:Neuropsychological Tests; D011932:Reading; D012815:Signal Processing, Computer-Assisted; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: MEG; VWFA; conscious perception; gamma-band oscillations; partial conscious perception; synchrony