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Havlík M, Hlinka J, Klírová M, Adámek P, Horáček J. Towards causal mechanisms of consciousness through focused transcranial brain stimulation. Neurosci Conscious 2023; 2023:niad008. [PMID: 37089451 PMCID: PMC10120840 DOI: 10.1093/nc/niad008] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 01/10/2023] [Accepted: 03/30/2023] [Indexed: 04/25/2023] Open
Abstract
Conscious experience represents one of the most elusive problems of empirical science, namely neuroscience. The main objective of empirical studies of consciousness has been to describe the minimal sets of neural events necessary for a specific neuronal state to become consciously experienced. The current state of the art still does not meet this objective but rather consists of highly speculative theories based on correlates of consciousness and an ever-growing list of knowledge gaps. The current state of the art is defined by the limitations of past stimulation techniques and the emphasis on the observational approach. However, looking at the current stimulation technologies that are becoming more accurate, it is time to consider an alternative approach to studying consciousness, which builds on the methodology of causal explanations via causal alterations. The aim of this methodology is to move beyond the correlates of consciousness and focus directly on the mechanisms of consciousness with the help of the currently focused brain stimulation techniques, such as geodesic transcranial electric neuromodulation. This approach not only overcomes the limitations of the correlational methodology but will also become another firm step in the following science of consciousness.
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Affiliation(s)
- Marek Havlík
- Center for Advanced Studies of Brain and Consciousness, National Institute of Mental Health, Topolová 748, Klecany 250 67, Czech Republic
| | - Jaroslav Hlinka
- Center for Advanced Studies of Brain and Consciousness, National Institute of Mental Health, Topolová 748, Klecany 250 67, Czech Republic
- Department of Complex Systems, Institute of Computer Science of the Czech Academy of Sciences, Pod Vodárenskou věží 271/2, Prague 182 07, Czech Republic
| | - Monika Klírová
- Center for Advanced Studies of Brain and Consciousness, National Institute of Mental Health, Topolová 748, Klecany 250 67, Czech Republic
- Third Faculty of Medicine, Charles University, Ruská 87, Prague 10 100 00, Czech Republic
| | - Petr Adámek
- Center for Advanced Studies of Brain and Consciousness, National Institute of Mental Health, Topolová 748, Klecany 250 67, Czech Republic
- Third Faculty of Medicine, Charles University, Ruská 87, Prague 10 100 00, Czech Republic
| | - Jiří Horáček
- Center for Advanced Studies of Brain and Consciousness, National Institute of Mental Health, Topolová 748, Klecany 250 67, Czech Republic
- Third Faculty of Medicine, Charles University, Ruská 87, Prague 10 100 00, Czech Republic
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Bauer PR, Sabourdy C, Chatard B, Rheims S, Lachaux JP, Vidal JR, Lutz A. Neural dynamics of mindfulness meditation and hypnosis explored with intracranial EEG: A feasibility study. Neurosci Lett 2022; 766:136345. [PMID: 34785313 DOI: 10.1016/j.neulet.2021.136345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 10/26/2021] [Accepted: 11/09/2021] [Indexed: 12/17/2022]
Abstract
PURPOSE Intracranial electroencephalography (iEEG) offers a unique window on brain dynamics with excellent temporal and spatial resolution and is less prone to recording artefacts than surface EEG. This study used a within-subject design to explore the feasibility to compare iEEG data during mind wandering, mindfulness meditation and hypnosis. RESULTS Three patients who had iEEG for clinical monitoring and who were new to mindfulness meditation and hypnosis were able to enter these states. We found non-specific and wide-spread amplitude modulations. Data-driven connectivity analysis revealed widespread connectivity patterns that were common across the three conditions. These were predominant in the low frequencies (delta, theta and alpha) and characterised by positively correlated activity. Connectivity patterns that were unique to the three conditions predominated in the gamma band, one third of the correlations in these patterns were negative. CONCLUSIONS This study is the first to support the feasibility of a direct comparison of the neural correlates of mindfulness meditation and hypnosis using iEEG. These modulations may reflect the complex interplay between different known brain networks, and warrant further functional investigations in particular in the gamma band.
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Affiliation(s)
- Prisca R Bauer
- Lyon Neuroscience Research Center, INSERM U1028 - CNRS UMR5292 -Lyon 1 University, Centre Hospitalier Le Vinatier (Bât. 462) - Neurocampus, 95 Bd Pinel, 69675 Bron cédex, France; Department of Psychosomatic Medicine and Psychotherapy University Medical Center Freiburg, Faculty of Medicine, University of Freiburg Freiburg, Germany.
| | - Cécile Sabourdy
- Neurophysiology Unit, Division of Neurology, Grenoble Alpes University, Grenoble, France
| | - Benoît Chatard
- Lyon Neuroscience Research Center, INSERM U1028 - CNRS UMR5292 -Lyon 1 University, Centre Hospitalier Le Vinatier (Bât. 462) - Neurocampus, 95 Bd Pinel, 69675 Bron cédex, France
| | - Sylvain Rheims
- Lyon Neuroscience Research Center, INSERM U1028 - CNRS UMR5292 -Lyon 1 University, Centre Hospitalier Le Vinatier (Bât. 462) - Neurocampus, 95 Bd Pinel, 69675 Bron cédex, France; Department of Functional Neurology and Epileptology, Hospices Civils de Lyon and Lyon 1 University, Lyon, France
| | - Jean-Philippe Lachaux
- Lyon Neuroscience Research Center, INSERM U1028 - CNRS UMR5292 -Lyon 1 University, Centre Hospitalier Le Vinatier (Bât. 462) - Neurocampus, 95 Bd Pinel, 69675 Bron cédex, France
| | - Juan R Vidal
- Catholic University of Lyon, Sciences and Humanities Confluence Research Center, 2 Place des Archives, 69002 Lyon, France
| | - Antoine Lutz
- Lyon Neuroscience Research Center, INSERM U1028 - CNRS UMR5292 -Lyon 1 University, Centre Hospitalier Le Vinatier (Bât. 462) - Neurocampus, 95 Bd Pinel, 69675 Bron cédex, France
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Abstract
The amplitude of prestimulus alpha oscillations over parieto-occipital cortex has been shown to predict visual detection of masked and threshold-level stimuli. Whether alpha activity similarly predicts target visibility in perceptual suppression paradigms, another type of illusion commonly used to investigate visual awareness, is presently unclear. Here, we examined prestimulus alpha activity in the electroencephalogram (EEG) of healthy participants in the context of a generalized flash suppression (GFS) task during which salient target stimuli are rendered subjectively invisible in a subset of trials following the onset of a full-field motion stimulus. Unlike for masking or threshold paradigms, alpha (8-12 Hz) amplitude prior to motion onset was significantly higher when targets remained subjectively visible compared to trials during which the targets became perceptually suppressed. Furthermore, individual prestimulus alpha amplitudes strongly correlated with the individual trial-to-trial variability quenching following motion stimulus onset, indicating that variability quenching in visual cortex is closely linked to prestimulus alpha activity. We conclude that predictive correlates of conscious perception derived from perceptual suppression paradigms differ substantially from those obtained with "near threshold paradigms", possibly reflecting the effectiveness of the suppressor stimulus.
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Intracranial Recordings Reveal Unique Shape and Timing of Responses in Human Visual Cortex during Illusory Visual Events. Curr Biol 2020; 30:3089-3100.e4. [PMID: 32619489 DOI: 10.1016/j.cub.2020.05.082] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 05/01/2020] [Accepted: 05/27/2020] [Indexed: 02/06/2023]
Abstract
During binocular rivalry, perception spontaneously changes without any alteration to the visual stimulus. What neural events bring about this illusion that a constant stimulus is changing? We recorded from intracranial electrodes placed on the occipital and posterior temporal cortex of two patients with epilepsy while they experienced illusory changes of a face-house binocular-rivalry stimulus or observed a control stimulus that physically changed. We performed within-patient comparisons of broadband high-frequency responses, focusing on single epochs recorded along the ventral processing stream. We found transient face- and house-selective responses localized to the same electrodes for illusory and physical changes, but the temporal characteristics of these responses markedly differed. In comparison with physical changes, responses to illusory changes were longer lasting, in particular exhibiting a characteristic slow rise. Furthermore, the temporal order of responses across the visual hierarchy was reversed for illusory as compared to physical changes: for illusory changes, higher order fusiform and parahippocampal regions responded before lower order occipital regions. Our tentative interpretation of these findings is that two stages underlie the initiation of illusory changes: a destabilization stage in which activity associated with the impending change gradually accumulates across the visual hierarchy, ultimately graduating in a top-down cascade of activity that may stabilize the new perceptual interpretation of the stimulus.
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Avramiea AE, Hardstone R, Lueckmann JM, Bím J, Mansvelder HD, Linkenkaer-Hansen K. Pre-stimulus phase and amplitude regulation of phase-locked responses are maximized in the critical state. eLife 2020; 9:e53016. [PMID: 32324137 PMCID: PMC7217696 DOI: 10.7554/elife.53016] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 04/20/2020] [Indexed: 01/23/2023] Open
Abstract
Understanding why identical stimuli give differing neuronal responses and percepts is a central challenge in research on attention and consciousness. Ongoing oscillations reflect functional states that bias processing of incoming signals through amplitude and phase. It is not known, however, whether the effect of phase or amplitude on stimulus processing depends on the long-term global dynamics of the networks generating the oscillations. Here, we show, using a computational model, that the ability of networks to regulate stimulus response based on pre-stimulus activity requires near-critical dynamics-a dynamical state that emerges from networks with balanced excitation and inhibition, and that is characterized by scale-free fluctuations. We also find that networks exhibiting critical oscillations produce differing responses to the largest range of stimulus intensities. Thus, the brain may bring its dynamics close to the critical state whenever such network versatility is required.
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Affiliation(s)
- Arthur-Ervin Avramiea
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research (CNCR), Amsterdam NeuroscienceAmsterdamNetherlands
| | - Richard Hardstone
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research (CNCR), Amsterdam NeuroscienceAmsterdamNetherlands
- Neuroscience Institute, New York University School of MedicineNew YorkUnited States
| | - Jan-Matthis Lueckmann
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research (CNCR), Amsterdam NeuroscienceAmsterdamNetherlands
- Technical University of MunichMunichGermany
| | - Jan Bím
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research (CNCR), Amsterdam NeuroscienceAmsterdamNetherlands
- Czech Technical University in PraguePragueCzech Republic
| | - Huibert D Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research (CNCR), Amsterdam NeuroscienceAmsterdamNetherlands
| | - Klaus Linkenkaer-Hansen
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research (CNCR), Amsterdam NeuroscienceAmsterdamNetherlands
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Neuronal correlates of full and partial visual conscious perception. Conscious Cogn 2019; 78:102863. [PMID: 31887533 DOI: 10.1016/j.concog.2019.102863] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 11/20/2022]
Abstract
Stimuli may induce only partial consciousness-an intermediate between null and full consciousness-where the presence but not identity of an object can be reported. The differences in the neuronal basis of full and partial consciousness are poorly understood. We investigated if evoked and oscillatory activity could dissociate full from partial conscious perception. We recorded human cortical activity with magnetoencephalography (MEG) during a visual perception task in which stimulus could be either partially or fully perceived. Partial consciousness was associated with an early increase in evoked activity and theta/low-alpha-band oscillations while full consciousness was also associated with late evoked activity and beta-band oscillations. Full from partial consciousness was dissociated by stronger evoked activity and late increase in theta oscillations that were localized to higher-order visual regions and posterior parietal and prefrontal cortices. Our results reveal both evoked activity and theta oscillations dissociate partial and full consciousness.
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Chassoux F, Navarro V, Catenoix H, Valton L, Vignal JP. Planning and management of SEEG. Neurophysiol Clin 2018; 48:25-37. [DOI: 10.1016/j.neucli.2017.11.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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Intracranial Recordings of Occipital Cortex Responses to Illusory Visual Events. J Neurosci 2017; 36:6297-311. [PMID: 27277806 DOI: 10.1523/jneurosci.0242-15.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Accepted: 05/05/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Ambiguous visual stimuli elicit different perceptual interpretations over time, creating the illusion that a constant stimulus is changing. We investigate whether such spontaneous changes in visual perception involve occipital brain regions specialized for processing visual information, despite the absence of concomitant changes in stimulation. Spontaneous perceptual changes observed while viewing a binocular rivalry stimulus or an ambiguous structure-from-motion stimulus were compared with stimulus-induced perceptual changes that occurred in response to an actual stimulus change. Intracranial recordings from human occipital cortex revealed that spontaneous and stimulus-induced perceptual changes were both associated with an early transient increase in high-frequency power that was more spatially confined than a later transient decrease in low-frequency power. We suggest that the observed high-frequency and low-frequency modulations relate to initiation and maintenance of a percept, respectively. Our results are compatible with the idea that spontaneous changes in perception originate from competitive interactions within visual neural networks. SIGNIFICANCE STATEMENT Ambiguous visual stimuli elicit different perceptual interpretations over time, creating the illusion that a constant stimulus is changing. The literature on the neural correlates of conscious visual perception remains inconclusive regarding the extent to which such spontaneous changes in perception involve sensory brain regions. In an attempt to bridge the gap between existing animal and human studies, we recorded from intracranial electrodes placed on the human occipital lobe. We compared two different kinds of ambiguous stimuli, binocular rivalry and the phenomenon of ambiguous structure-from-motion, enabling generalization of our findings across different stimuli. Our results indicate that spontaneous and stimulus-induced changes in perception (i.e., "illusory" and "real" changes in the stimulus, respectively) may involve sensory regions to a similar extent.
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Hirvonen J, Palva S. Cortical localization of phase and amplitude dynamics predicting access to somatosensory awareness. Hum Brain Mapp 2015; 37:311-26. [PMID: 26485310 DOI: 10.1002/hbm.23033] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 10/02/2015] [Accepted: 10/06/2015] [Indexed: 11/06/2022] Open
Abstract
Neural dynamics leading to conscious sensory perception have remained enigmatic in despite of large interest. Human functional magnetic resonance imaging (fMRI) studies have revealed that a co-activation of sensory and frontoparietal areas is crucial for conscious sensory perception in the several second time-scale of BOLD signal fluctuations. Electrophysiological recordings with magneto- and electroencephalography (MEG and EEG) and intracranial EEG (iEEG) have shown that event related responses (ERs), phase-locking of neuronal activity, and oscillation amplitude modulations in sub-second timescales are greater for consciously perceived than for unperceived stimuli. The cortical sources of ER and oscillation dynamics predicting the conscious perception have, however, remained unclear because these prior studies have utilized MEG/EEG sensor-level analyses or iEEG with limited neuroanatomical coverage. We used a somatosensory detection task, magnetoencephalography (MEG), and cortically constrained source reconstruction to identify the cortical areas where ERs, local poststimulus amplitudes and phase-locking of neuronal activity are predictive of the conscious access of somatosensory information. We show here that strengthened ERs, phase-locking to stimulus onset (SL), and induced oscillations amplitude modulations all predicted conscious somatosensory perception, but the most robust and widespread of these was SL that was sustained in low-alpha (6-10 Hz) band. The strength of SL and to a lesser extent that of ER predicted conscious perception in the somatosensory, lateral and medial frontal, posterior parietal, and in the cingulate cortex. These data suggest that a rapid phase-reorganization and concurrent oscillation amplitude modulations in these areas play an instrumental role in the emergence of a conscious percept.
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Affiliation(s)
- Jonni Hirvonen
- Neuroscience Center, University of Helsinki, Finland.,BioMag Laboratory, HUS Medical Imaging Center, Finland
| | - Satu Palva
- Neuroscience Center, University of Helsinki, Finland
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Levy J, Vidal JR, Fries P, Démonet JF, Goldstein A. Selective Neural Synchrony Suppression as a Forward Gatekeeper to Piecemeal Conscious Perception. Cereb Cortex 2015; 26:3010-22. [PMID: 26045565 DOI: 10.1093/cercor/bhv114] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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.
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Affiliation(s)
- Jonathan Levy
- 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
| | - Juan R Vidal
- University Grenoble Alpes, LPNC, F-38040 Grenoble, France CNRS, LPNC, UMR 5105, F-38040 Grenoble, France
| | - Pascal Fries
- 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
| | - Jean-François Démonet
- 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
| | - Abraham Goldstein
- The Gonda Multidisciplinary Brain Research Center Department of Psychology, Bar-Ilan University, Ramat Gan 52900, Israel
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Aru J, Bachmann T. Still wanted-the mechanisms of consciousness! Front Psychol 2015; 6:5. [PMID: 25653636 PMCID: PMC4300864 DOI: 10.3389/fpsyg.2015.00005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 01/04/2015] [Indexed: 11/13/2022] Open
Affiliation(s)
- Jaan Aru
- Faculty of Mathematics and Computer Science/Faculty of Law, University of Tartu Tartu, Estonia
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