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MacLean MW, Hadid V, Spreng RN, Lepore F. Revealing robust neural correlates of conscious and unconscious visual processing: activation likelihood estimation meta-analyses. Neuroimage 2023; 273:120088. [PMID: 37030413 DOI: 10.1016/j.neuroimage.2023.120088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 03/30/2023] [Accepted: 04/03/2023] [Indexed: 04/09/2023] Open
Abstract
Our ability to consciously perceive information from the visual scene relies on a myriad of intrinsic neural mechanisms. Functional neuroimaging studies have sought to identify the neural correlates of conscious visual processing and to further dissociate from those pertaining to preconscious and unconscious visual processing. However, delineating what core brain regions are involved in eliciting a conscious percept remains a challenge, particularly regarding the role of prefrontal-parietal regions. We performed a systematic search of the literature that yielded a total of 54 functional neuroimaging studies. We conducted two quantitative meta-analyses using activation likelihood estimation to identify reliable patterns of activation engaged by i. conscious (n = 45 studies, comprising 704 participants) and ii. unconscious (n = 16 studies, comprising 262 participants) visual processing during various task performances. Results of the meta-analysis specific to conscious percepts quantitatively revealed reliable activations across a constellation of regions comprising the bilateral inferior frontal junction, intraparietal sulcus, dorsal anterior cingulate, angular gyrus, temporo-occipital cortex and anterior insula. Neurosynth reverse inference revealed conscious visual processing to be intertwined with cognitive terms related to attention, cognitive control and working memory. Results of the meta-analysis on unconscious percepts revealed consistent activations in the lateral occipital complex, intraparietal sulcus and precuneus. These findings highlight the notion that conscious visual processing readily engages higher-level regions including the inferior frontal junction and unconscious processing reliably recruits posterior regions, mainly the lateral occipital complex.
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Hobot J, Skóra Z, Wierzchoń M, Sandberg K. Continuous Theta Burst Stimulation to the left anterior medial prefrontal cortex influences metacognitive efficiency. Neuroimage 2023; 272:119991. [PMID: 36858333 DOI: 10.1016/j.neuroimage.2023.119991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/04/2023] [Accepted: 02/25/2023] [Indexed: 03/03/2023] Open
Abstract
The contribution of the prefrontal areas to visual awareness is critical for the Global Neuronal Workspace Theory and higher-order theories of consciousness. The goal of the present study was to test the potential engagement of the anterior medial prefrontal cortex (aMPFC) in visual awareness judgements. We aimed to temporarily influence the neuronal dynamics of the left aMPFC via neuroplasticity-like mechanisms. We used different Theta Burst Stimulation (TBS) protocols in combination with a visual identification task and visual awareness ratings. Either continuous TBS (cTBS), intermittent TBS (iTBS), or sham TBS was applied prior to the experimental paradigm in a within-participant design. Compared with sham TBS, we observed an increase in participants' ability to judge their perception adequately (metacognitive efficiency) following cTBS but not iTBS. The effect was accompanied by lower visual awareness ratings in incorrect responses. No significant differences in the identification task performance were observed. We interpret these results as evidence of the involvement of PFC in the brain network that underlies metacognition. Further, we discuss whether the results of TMS studies on perceptual metacognition can be taken as evidence for PFC involvement in awareness itself.
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Affiliation(s)
- Justyna Hobot
- Consciousness Lab, Psychology Institute, Jagiellonian University, Krakow, Poland; Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark.
| | - Zuzanna Skóra
- Colourlab, Department of Computer Science, Norwegian University of Science and Technology, Gjøvik, Norway
| | - Michał Wierzchoń
- Consciousness Lab, Psychology Institute, Jagiellonian University, Krakow, Poland
| | - Kristian Sandberg
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark; Center of Functionally Integrative Neuroscience, Aarhus University Hospital, Aarhus, Denmark
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Gradedness of visual awareness depends on attentional scope: Global perception is more graded than local perception. Conscious Cogn 2021; 94:103174. [PMID: 34399139 DOI: 10.1016/j.concog.2021.103174] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 07/19/2021] [Accepted: 07/19/2021] [Indexed: 11/20/2022]
Abstract
The gradedness or discreteness of our visual awareness has been debated. Here, we investigate the influence of spatial scope of attention on the gradedness of visual awareness. We manipulated scope of attention using hierarchical letter-based tasks (global: broad scope; local: narrow scope). Participants reported the identity of a masked hierarchical letter either at the global level or at the local level. We measured subjective awareness using the perceptual awareness scale ratings and objective performance. The results indicate more graded visual awareness (lesser slope for the awareness rating curve) at the global level compared to the local level. Graded perception was also observed in visibility ratings usage with global level task showing higher usage of the middle PAS ratings. Our results are in line with the prediction of level of processing hypothesis and show that global/local attentional scope and contextual endogenous factors influence the graded nature of our visual awareness.
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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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Bressler DW, Rokem A, Silver MA. Slow Endogenous Fluctuations in Cortical fMRI Signals Correlate with Reduced Performance in a Visual Detection Task and Are Suppressed by Spatial Attention. J Cogn Neurosci 2019; 32:85-99. [PMID: 31560268 DOI: 10.1162/jocn_a_01470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Spatial attention improves performance on visual tasks, increases neural responses to attended stimuli, and reduces correlated noise in visual cortical neurons. In addition to being visually responsive, many retinotopic visual cortical areas exhibit very slow (<0.1 Hz) endogenous fluctuations in functional magnetic resonance imaging signals. To test whether these fluctuations degrade stimulus representations, thereby impairing visual detection, we recorded functional magnetic resonance imaging responses while human participants performed a target detection task that required them to allocate spatial attention to either a rotating wedge stimulus or a central fixation point. We then measured the effects of spatial attention on response amplitude at the frequency of wedge rotation and on the amplitude of endogenous fluctuations at nonstimulus frequencies. We found that, in addition to enhancing stimulus-evoked responses, attending to the wedge also suppressed slow endogenous fluctuations that were unrelated to the visual stimulus in topographically defined areas in early visual cortex, posterior parietal cortex, and lateral occipital cortex, but not in a nonvisual cortical control region. Moreover, attentional enhancement of response amplitude and suppression of endogenous fluctuations were dissociable across cortical areas and across time. Finally, we found that the amplitude of the stimulus-evoked response was not correlated with a perceptual measure of visual target detection. Instead, perceptual performance was accounted for by the amount of suppression of slow endogenous fluctuations. Our results indicate that the amplitude of slow fluctuations of cortical activity is influenced by spatial attention and suggest that these endogenous fluctuations may impair perceptual processing in topographically organized visual cortical areas.
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Lowe MX, Rajsic J, Ferber S, Walther DB. Discriminating scene categories from brain activity within 100 milliseconds. Cortex 2018; 106:275-287. [PMID: 30037637 DOI: 10.1016/j.cortex.2018.06.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 02/26/2018] [Accepted: 06/01/2018] [Indexed: 10/28/2022]
Abstract
Humans have the ability to make sense of the world around them in only a single glance. This astonishing feat requires the visual system to extract information from our environment with remarkable speed. How quickly does this process unfold across time, and what visual information contributes to our understanding of the visual world? We address these questions by directly measuring the temporal dynamics of the perception of colour photographs and line drawings of scenes with electroencephalography (EEG) during a scene-memorization task. Within a fraction of a second, event-related potentials (ERPs) show dissociable response patterns for global scene properties of content (natural versus manmade) and layout (open versus closed). Subsequent detailed analyses of within-category versus between-category discriminations found significant dissociations of basic-level scene categories (e.g., forest; city) within the first 100 msec of perception. The similarity of this neural activity with feature-based discriminations suggests low-level image statistics may be foundational for this rapid categorization. Interestingly, our results also suggest that the structure preserved in line drawings may form a primary and necessary basis for visual processing, whereas surface information may further enhance category selectivity in later-stage processing. Critically, these findings provide evidence that the distinction of both basic-level categories and global properties of scenes from neural signals occurs within 100 msec.
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Affiliation(s)
| | - Jason Rajsic
- Psychology Department, University of Toronto, Canada
| | - Susanne Ferber
- Psychology Department, University of Toronto, Canada; Rotman Research Institute, Baycrest, Toronto, Canada
| | - Dirk B Walther
- Psychology Department, University of Toronto, Canada; Rotman Research Institute, Baycrest, Toronto, Canada
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The levels of perceptual processing and the neural correlates of increasing subjective visibility. Conscious Cogn 2017; 55:106-125. [DOI: 10.1016/j.concog.2017.07.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 07/25/2017] [Accepted: 07/31/2017] [Indexed: 11/19/2022]
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Rosa AM, Miranda ÂC, Patrício M, McAlinden C, Silva FL, Murta JN, Castelo-Branco M. Functional Magnetic Resonance Imaging to Assess the Neurobehavioral Impact of Dysphotopsia with Multifocal Intraocular Lenses. Ophthalmology 2017; 124:1280-1289. [PMID: 28433446 DOI: 10.1016/j.ophtha.2017.03.033] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 03/05/2017] [Accepted: 03/13/2017] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To investigate the association between dysphotopsia and neural responses in visual and higher-level cortical regions in patients who recently received multifocal intraocular lens (IOL) implants. DESIGN Cross-sectional study. PARTICIPANTS Thirty patients 3 to 4 weeks after bilateral cataract surgery with diffractive IOL implantation and 15 age- and gender-matched control subjects. METHODS Functional magnetic resonance imaging (fMRI) was performed when participants viewed low-contrast grating stimuli. A light source surrounded the stimuli in half of the runs to induce disability glare. Visual acuity, wavefront analysis, Quality of Vision (QoV) questionnaire, and psychophysical assessment were performed. MAIN OUTCOME MEASURES Cortical activity (blood oxygen level dependent [BOLD] signal) in the primary visual cortex and in higher-level brain areas, including the attention network. RESULTS When viewing low-contrast stimuli under glare, patients showed significant activation of the effort-related attention network in the early postoperative period, involving the frontal, middle frontal, parietal frontal, and postcentral gyrus (multisubject random-effects general linear model (GLM), P < 0.03). In contrast, controls showed only relative deactivation (due to lower visibility) of visual areas (occipital lobe and middle occipital gyrus, P < 0.03). Patients also had relatively stronger recruitment of cortical areas involved in learning (anterior cingulate gyrus), task planning, and solving (caudate body). Patients reporting greater symptoms induced by dysphotic symptoms showed significantly increased activity in several regions in frontoparietal circuits, as well as cingulate gyrus and caudate nucleus (q < 0.05). We found no correlation between QoV questionnaire scores and optical properties (total and higher order aberration, modulation transfer function, and Strehl ratio). CONCLUSIONS This study shows the association between patient-reported subjective difficulties and fMRI outcomes, independent of optical parameters and psychophysical performance. The increased activity of cortical areas dedicated to attention (frontoparietal circuits), to learning and cognitive control (cingulate), and to task goals (caudate) likely represents the beginning of the neuroadaptation process to multifocal IOLs.
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Affiliation(s)
- Andreia M Rosa
- Faculty of Medicine of the University of Coimbra, Coimbra, Portugal; Ophthalmology Department, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Ângela C Miranda
- Institute for Biomedical Imaging in Life Sciences, Faculty of Medicine of the University of Coimbra, Coimbra, Portugal
| | - Miguel Patrício
- Laboratory of Biostatistics and Medical Informatics, Institute for Biomedical Imaging in Life Sciences, Faculty of Medicine of the University of Coimbra, Coimbra, Portugal
| | - Colm McAlinden
- University Hospitals Bristol, NHS Foundation Trust, Bristol, United Kingdom; ABM University Health Board, Swansea, United Kingdom; Wenzhou Medical University, Wenzhou, Zhejiang, China; Flinders University, Adelaide, South Australia, Australia
| | - Fátima L Silva
- Institute for Biomedical Imaging in Life Sciences, Faculty of Medicine of the University of Coimbra, Coimbra, Portugal
| | - Joaquim N Murta
- Faculty of Medicine of the University of Coimbra, Coimbra, Portugal; Ophthalmology Department, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal.
| | - Miguel Castelo-Branco
- Institute for Biomedical Imaging in Life Sciences, Faculty of Medicine of the University of Coimbra, Coimbra, Portugal; Brain Imaging Network, Coimbra, Portugal
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Alavash M, Hilgetag CC, Thiel CM, Gießing C. Persistency and flexibility of complex brain networks underlie dual-task interference. Hum Brain Mapp 2015; 36:3542-62. [PMID: 26095953 PMCID: PMC6869626 DOI: 10.1002/hbm.22861] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 04/27/2015] [Accepted: 05/19/2015] [Indexed: 12/29/2022] Open
Abstract
Previous studies on multitasking suggest that performance decline during concurrent task processing arises from interfering brain modules. Here, we used graph-theoretical network analysis to define functional brain modules and relate the modular organization of complex brain networks to behavioral dual-task costs. Based on resting-state and task fMRI we explored two organizational aspects potentially associated with behavioral interference when human subjects performed a visuospatial and speech task simultaneously: the topological overlap between persistent single-task modules, and the flexibility of single-task modules in adaptation to the dual-task condition. Participants showed a significant decline in visuospatial accuracy in the dual-task compared with single visuospatial task. Global analysis of topological similarity between modules revealed that the overlap between single-task modules significantly correlated with the decline in visuospatial accuracy. Subjects with larger overlap between single-task modules showed higher behavioral interference. Furthermore, lower flexible reconfiguration of single-task modules in adaptation to the dual-task condition significantly correlated with larger decline in visuospatial accuracy. Subjects with lower modular flexibility showed higher behavioral interference. At the regional level, higher overlap between single-task modules and less modular flexibility in the somatomotor cortex positively correlated with the decline in visuospatial accuracy. Additionally, higher modular flexibility in cingulate and frontal control areas and lower flexibility in right-lateralized nodes comprising the middle occipital and superior temporal gyri supported dual-tasking. Our results suggest that persistency and flexibility of brain modules are important determinants of dual-task costs. We conclude that efficient dual-tasking benefits from a specific balance between flexibility and rigidity of functional brain modules.
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Affiliation(s)
- Mohsen Alavash
- Department of Psychology, Biological Psychology LabEuropean Medical School, Carl von Ossietzky Universität Oldenburg26111OldenburgGermany
| | - Claus C. Hilgetag
- Department of Computational NeuroscienceUniversity Medical Center Hamburg‐Eppendorf20246HamburgGermany
- Department of Health SciencesBoston UniversityBostonMassachusetts02215
| | - Christiane M. Thiel
- Department of Psychology, Biological Psychology LabEuropean Medical School, Carl von Ossietzky Universität Oldenburg26111OldenburgGermany
- Research Center Neurosensory ScienceCarl von Ossietzky Universität Oldenburg26111OldenburgGermany
| | - Carsten Gießing
- Department of Psychology, Biological Psychology LabEuropean Medical School, Carl von Ossietzky Universität Oldenburg26111OldenburgGermany
- Research Center Neurosensory ScienceCarl von Ossietzky Universität Oldenburg26111OldenburgGermany
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Bisenius S, Trapp S, Neumann J, Schroeter ML. Identifying neural correlates of visual consciousness with ALE meta-analyses. Neuroimage 2015; 122:177-87. [PMID: 26241685 DOI: 10.1016/j.neuroimage.2015.07.070] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Revised: 06/18/2015] [Accepted: 07/27/2015] [Indexed: 10/23/2022] Open
Abstract
Neural correlates of consciousness (NCC) have been a topic of study for nearly two decades. In functional imaging studies, several regions have been proposed to constitute possible candidates for NCC, but as of yet, no quantitative summary of the literature on NCC has been done. The question whether single (striate or extrastriate) regions or a network consisting of extrastriate areas that project directly to fronto-parietal regions are necessary and sufficient neural correlates for visual consciousness is still highly debated [e.g., Rees et al., 2002, Nat Rev. Neurosci 3, 261-270; Tong, 2003, Nat Rev. Neurosci 4, 219-229]. The aim of this work was to elucidate this issue and give a synopsis of the present state of the art by conducting systematic and quantitative meta-analyses across functional magnetic resonance imaging (fMRI) studies using several standard paradigms for conscious visual perception. In these paradigms, consciousness is operationalized via perceptual changes, while the visual stimulus remains invariant. An activation likelihood estimation (ALE) meta-analysis was performed, representing the best approach for voxel-wise meta-analyses to date. In addition to computing a meta-analysis across all paradigms, separate meta-analyses on bistable perception and masking paradigms were conducted to assess whether these paradigms show common or different NCC. For the overall meta-analysis, we found significant clusters of activation in inferior and middle occipital gyrus; fusiform gyrus; inferior temporal gyrus; caudate nucleus; insula; inferior, middle, and superior frontal gyri; precuneus; as well as in inferior and superior parietal lobules. These results suggest a subcortical-extrastriate-fronto-parietal network rather than a single region that constitutes the necessary NCC. The results of our exploratory paradigm-specific meta-analyses suggest that this subcortical-extrastriate-fronto-parietal network might be differentially activated as a function of the paradigms used to probe for NCC.
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Affiliation(s)
- Sandrine Bisenius
- Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Leipzig, Germany.
| | - Sabrina Trapp
- Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Leipzig, Germany
| | - Jane Neumann
- Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Leipzig, Germany; Leipzig University Medical Center, IFB Adiposity Diseases, Leipzig, Germany
| | - Matthias L Schroeter
- Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Leipzig, Germany; Clinic of Cognitive Neurology, University of Leipzig, Leipzig Research Center for Civilization Diseases, University of Leipzig & FTLD Consortium Germany, Leipzig, Germany
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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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Al-Subari K, Al-Baddai S, Tomé AM, Volberg G, Hammwöhner R, Lang EW. Ensemble Empirical Mode Decomposition Analysis of EEG Data Collected during a Contour Integration Task. PLoS One 2015; 10:e0119489. [PMID: 25910061 PMCID: PMC4409116 DOI: 10.1371/journal.pone.0119489] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 01/14/2015] [Indexed: 11/18/2022] Open
Abstract
We discuss a data-driven analysis of EEG data recorded during a combined EEG/fMRI study of visual processing during a contour integration task. The analysis is based on an ensemble empirical mode decomposition (EEMD) and discusses characteristic features of event related modes (ERMs) resulting from the decomposition. We identify clear differences in certain ERMs in response to contour vs noncontour Gabor stimuli mainly for response amplitudes peaking around 100 [ms] (called P100) and 200 [ms] (called N200) after stimulus onset, respectively. We observe early P100 and N200 responses at electrodes located in the occipital area of the brain, while late P100 and N200 responses appear at electrodes located in frontal brain areas. Signals at electrodes in central brain areas show bimodal early/late response signatures in certain ERMs. Head topographies clearly localize statistically significant response differences to both stimulus conditions. Our findings provide an independent proof of recent models which suggest that contour integration depends on distributed network activity within the brain.
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Affiliation(s)
- Karema Al-Subari
- Department of Biology, Institute of Biophysics, University of Regensburg, Regensburg, Germany
- Department of Linguistics, Literature and Culture, Institute of Information Science, University of Regensburg, Regensburg, Germany
| | - Saad Al-Baddai
- Department of Biology, Institute of Biophysics, University of Regensburg, Regensburg, Germany
- Department of Linguistics, Literature and Culture, Institute of Information Science, University of Regensburg, Regensburg, Germany
| | - Ana Maria Tomé
- Department of Electrical Engineering, Telecommunication and Informatics, Institut of Electrical Engineering and Electronics, Universidade de Aveiro, Aveiro, Portugal
| | - Gregor Volberg
- Department of Psychology, Pedagogics and Sport, Institute of Experimental Psychology, University of Regensburg, Regensburg, Germany
| | - Rainer Hammwöhner
- Department of Linguistics, Literature and Culture, Institute of Information Science, University of Regensburg, Regensburg, Germany
| | - Elmar W. Lang
- Department of Biology, Institute of Biophysics, University of Regensburg, Regensburg, Germany
- * E-mail:
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