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Coldea A, Veniero D, Morand S, Trajkovic J, Romei V, Harvey M, Thut G. Effects of Rhythmic Transcranial Magnetic Stimulation in the Alpha-Band on Visual Perception Depend on Deviation From Alpha-Peak Frequency: Faster Relative Transcranial Magnetic Stimulation Alpha-Pace Improves Performance. Front Neurosci 2022; 16:886342. [PMID: 35784849 PMCID: PMC9247279 DOI: 10.3389/fnins.2022.886342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 06/01/2022] [Indexed: 12/02/2022] Open
Abstract
Alpha-band oscillatory activity over occipito-parietal areas is involved in shaping perceptual and cognitive processes, with a growing body of electroencephalographic (EEG) evidence indicating that pre-stimulus alpha-band amplitude relates to the subjective perceptual experience, but not to objective measures of visual task performance (discrimination accuracy). The primary aim of the present transcranial magnetic stimulation (TMS) study was to investigate whether causality can be established for this relationship, using rhythmic (alpha-band) TMS entrainment protocols. It was anticipated that pre-stimulus 10 Hz-TMS would induce changes in subjective awareness ratings but not accuracy, in the visual hemifield contralateral to TMS. To test this, we administered 10 Hz-TMS over the right intraparietal sulcus prior to visual stimulus presentation in 17 participants, while measuring their objective performance and subjective awareness in a visual discrimination task. Arrhythmic and 10 Hz sham-TMS served as control conditions (within-participant design). Resting EEG was used to record individual alpha frequency (IAF). A study conducted in parallel to ours with a similar design but reported after we completed data collection informed further, secondary analyses for a causal relationship between pre-stimulus alpha-frequency and discrimination accuracy. This was explored through a regression analysis between rhythmic-TMS alpha-pace relative to IAF and performance measures. Our results revealed that contrary to our primary expectation, pre-stimulus 10 Hz-TMS did not affect subjective measures of performance, nor accuracy, relative to control-TMS. This null result is in accord with a recent finding showing that for influencing subjective measures of performance, alpha-TMS needs to be applied post-stimulus. In addition, our secondary analysis showed that IAF was positively correlated with task accuracy across participants, and that 10 Hz-TMS effects on accuracy—but not awareness ratings—depended on IAF: The slower (or faster) the IAF, relative to the fixed 10 Hz TMS frequency, the stronger the TMS-induced performance improvement (or worsening), indicating that 10 Hz-TMS produced a gain (or a loss) in individual performance, directly depending on TMS-pace relative to IAF. In support of recent reports, this is evidence for alpha-frequency playing a causal role in perceptual sensitivity likely through regulating the speed of sensory sampling.
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Affiliation(s)
- Andra Coldea
- Centre for Cognitive Neuroimaging, School of Psychology and Neuroscience, University of Glasgow, Glasgow, United Kingdom
| | - Domenica Veniero
- School of Psychology, University of Nottingham, Nottingham, United Kingdom
| | - Stephanie Morand
- Centre for Cognitive Neuroimaging, School of Psychology and Neuroscience, University of Glasgow, Glasgow, United Kingdom
| | - Jelena Trajkovic
- Centre for Cognitive Neuroimaging, School of Psychology and Neuroscience, University of Glasgow, Glasgow, United Kingdom
- Dipartimento di Psicologia, Centro Studi e Ricerche in Neuroscienze Cognitive, Alma Mater Studiorum – Università di Bologna, Bologna, Italy
| | - Vincenzo Romei
- Dipartimento di Psicologia, Centro Studi e Ricerche in Neuroscienze Cognitive, Alma Mater Studiorum – Università di Bologna, Bologna, Italy
| | - Monika Harvey
- Centre for Cognitive Neuroimaging, School of Psychology and Neuroscience, University of Glasgow, Glasgow, United Kingdom
| | - Gregor Thut
- Centre for Cognitive Neuroimaging, School of Psychology and Neuroscience, University of Glasgow, Glasgow, United Kingdom
- *Correspondence: Gregor Thut,
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Overgaard M, Sandberg K. The Perceptual Awareness Scale-recent controversies and debates. Neurosci Conscious 2021; 2021:niab044. [PMID: 34925909 PMCID: PMC8672240 DOI: 10.1093/nc/niab044] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 11/10/2021] [Accepted: 11/25/2021] [Indexed: 12/30/2022] Open
Abstract
Accurate insight into subjective experience is crucial for the science of consciousness. The Perceptual Awareness Scale (PAS) was created in 2004 as a method for obtaining precise introspective reports for participants in research projects, and since then, the scale has become increasingly popular. This does not mean, of course, that no critiques have been voiced. Here, we briefly recapitulate our main thoughts on the intended PAS usage and the findings of the first decade, and we update this with the latest empirical and theoretical developments. We focus specifically on findings with relevance to whether consciousness is gradual or all-or-none phenomenon, to what should be considered conscious/unconscious, and to whether PAS is preferable to alternative measures of awareness. We respond in detail to some recent, selected articles.
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Affiliation(s)
- Morten Overgaard
- Aarhus Institute of Advanced Studies, Aarhus University, Nørrebrogade 1A, Aarhus 8000, Denmark
- Department of Clinical Medicine, Center for Functionally Integrative Neuroscience, Aarhus University, Universitetsbyen 3, Building 1710, Aarhus 8000, Denmark
| | - Kristian Sandberg
- Department of Clinical Medicine, Center for Functionally Integrative Neuroscience, Aarhus University, Universitetsbyen 3, Building 1710, Aarhus 8000, Denmark
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