title: Neural Correlates of Subliminal Language Processing.
abstract: Language is a high-level cognitive function, so exploring the neural correlates of unconscious language processing is essential for understanding the limits of unconscious processing in general. The results of several functional magnetic resonance imaging studies have suggested that unconscious lexical and semantic processing is confined to the posterior temporal lobe, without involvement of the frontal lobe-the regions that are indispensable for conscious language processing. However, previous studies employed a similarly designed masked priming paradigm with briefly presented single and contextually unrelated words. It is thus possible, that the stimulation level was insufficiently strong to be detected in the high-level frontal regions. Here, in a high-resolution fMRI and multivariate pattern analysis study we explored the neural correlates of subliminal language processing using a novel paradigm, where written meaningful sentences were suppressed from awareness for extended duration using continuous flash suppression. We found that subjectively and objectively invisible meaningful sentences and unpronounceable nonwords could be discriminated not only in the left posterior superior temporal sulcus (STS), but critically, also in the left middle frontal gyrus. We conclude that frontal lobes play a role in unconscious language processing and that activation of the frontal lobes per se might not be sufficient for achieving conscious awareness.
authors.affiliation: The Gonda Multidisciplinary Brain Research Center, Bar Ilan University, Ramat Gan, Israel UCL Institute of Cognitive Neuroscience.
authors.forename: Vadim
authors.initials: V
authors.lastname: Axelrod
authors.affiliation: The Gonda Multidisciplinary Brain Research Center, Bar Ilan University, Ramat Gan, Israel Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA.
authors.forename: Moshe
authors.initials: M
authors.lastname: Bar
authors.affiliation: UCL Institute of Cognitive Neuroscience Wellcome Trust Centre for Neuroimaging, University College London, London, UK.
authors.forename: Geraint
authors.initials: G
authors.lastname: Rees
authors.affiliation: School of Psychological Sciences Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Galit
authors.initials: G
authors.lastname: Yovel
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D004192:Discrimination, Psychological / Q000502:physiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D015999:Multivariate Analysis; D009483:Neuropsychological Tests; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011932:Reading; D013360:Subliminal Stimulation; D014473:Unconscious, Psychology; D055815:Young Adult
keywords: continuous flash suppression (CFS); decoding subliminal content; fMRI imaging of unconscious processing; multivoxel pattern classification analysis (MVPA); subliminal language processing