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Hu R, Li S, Yuan P, Wang Y, Jiang Y. Temporal integration by multi-level regularities fosters the emergence of dynamic conscious experience. Ann N Y Acad Sci 2024; 1533:156-168. [PMID: 38294967 DOI: 10.1111/nyas.15099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
The relationship between integration and awareness is central to contemporary theories and research on consciousness. Here, we investigated whether and how information integration over time, by incorporating the underlying regularities, contributes to our awareness of the dynamic world. Using binocular rivalry, we demonstrated that structured visual streams, constituted by shape, motion, or idiom sequences containing perceptual- or semantic-level regularities, predominated over their nonstructured but otherwise matched counterparts in the competition for visual awareness. Despite the apparent resemblance, a substantial dissociation of the observed rivalry advantages emerged between perceptual- and semantic-level regularities. These effects stem from nonconscious and conscious temporal integration processes, respectively, with the former but not the latter being vulnerable to perturbations in the spatiotemporal integration window. These findings corroborate the essential role of structure-guided information integration in visual awareness and highlight a multi-level mechanism where temporal integration by perceptually and semantically defined regularities fosters the emergence of continuous conscious experience.
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Affiliation(s)
- Ruichen Hu
- State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Shuo Li
- State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Peijun Yuan
- State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Ying Wang
- State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Yi Jiang
- State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
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2
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Chu KT, Lei WC, Wu MH, Fuh JL, Wang SJ, French IT, Chang WS, Chang CF, Huang NE, Liang WK, Juan CH. A holo-spectral EEG analysis provides an early detection of cognitive decline and predicts the progression to Alzheimer's disease. Front Aging Neurosci 2023; 15:1195424. [PMID: 37674782 PMCID: PMC10477374 DOI: 10.3389/fnagi.2023.1195424] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 07/25/2023] [Indexed: 09/08/2023] Open
Abstract
Aims Our aim was to differentiate patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD) from cognitively normal (CN) individuals and predict the progression from MCI to AD within a 3-year longitudinal follow-up. A newly developed Holo-Hilbert Spectral Analysis (HHSA) was applied to resting state EEG (rsEEG), and features were extracted and subjected to machine learning algorithms. Methods A total of 205 participants were recruited from three hospitals, with CN (n = 51, MMSE > 26), MCI (n = 42, CDR = 0.5, MMSE ≥ 25), AD1 (n = 61, CDR = 1, MMSE < 25), AD2 (n = 35, CDR = 2, MMSE < 16), and AD3 (n = 16, CDR = 3, MMSE < 16). rsEEG was also acquired from all subjects. Seventy-two MCI patients (CDR = 0.5) were longitudinally followed up with two rsEEG recordings within 3 years and further subdivided into an MCI-stable group (MCI-S, n = 36) and an MCI-converted group (MCI-C, n = 36). The HHSA was then applied to the rsEEG data, and features were extracted and subjected to machine-learning algorithms. Results (a) At the group level analysis, the HHSA contrast of MCI and different stages of AD showed augmented amplitude modulation (AM) power of lower-frequency oscillations (LFO; delta and theta bands) with attenuated AM power of higher-frequency oscillations (HFO; beta and gamma bands) compared with cognitively normal elderly controls. The alpha frequency oscillation showed augmented AM power across MCI to AD1 with a reverse trend at AD2. (b) At the individual level of cross-sectional analysis, implementation of machine learning algorithms discriminated between groups with good sensitivity (Sen) and specificity (Spec) as follows: CN elderly vs. MCI: 0.82 (Sen)/0.80 (Spec), CN vs. AD1: 0.94 (Sen)/0.80 (Spec), CN vs. AD2: 0.93 (Sen)/0.90 (Spec), and CN vs. AD3: 0.75 (Sen)/1.00 (Spec). (c) In the longitudinal MCI follow-up, the initial contrasted HHSA between MCI-S and MCI-C groups showed significantly attenuated AM power of alpha and beta band oscillations. (d) At the individual level analysis of longitudinal MCI groups, deploying machine learning algorithms with the best seven features resulted in a sensitivity of 0.9 by the support vector machine (SVM) classifier, with a specificity of 0.8 yielded by the decision tree classifier. Conclusion Integrating HHSA into EEG signals and machine learning algorithms can differentiate between CN and MCI as well as also predict AD progression at the MCI stage.
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Affiliation(s)
- Kwo-Ta Chu
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
- Yang-Ming Hospital, Taoyuan, Taiwan
| | - Weng-Chi Lei
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan, Taiwan
| | - Ming-Hsiu Wu
- Division of Neurology, Department of Internal Medicine, Chi Mei Medical Center, Tainan, Taiwan
- Department of Long-Term Care and Health Promotion, Min-Hwei Junior College of Health Care Management, Tainan, Taiwan
| | - Jong-Ling Fuh
- Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Shuu-Jiun Wang
- Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Isobel T. French
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Central University and Academia Sinica, Taipei, Taiwan
| | - Wen-Sheng Chang
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
| | - Chi-Fu Chang
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
| | - Norden E. Huang
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan, Taiwan
- Key Laboratory of Data Analysis and Applications, First Institute of Oceanography, SOA, Qingdao, China
| | - Wei-Kuang Liang
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan, Taiwan
| | - Chi-Hung Juan
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan, Taiwan
- Department of Psychology, Kaohsiung Medical University, Kaohsiung, Taiwan
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Carlson BM, Mitchell BA, Dougherty K, Westerberg JA, Cox MA, Maier A. Does V1 response suppression initiate binocular rivalry? iScience 2023; 26:107359. [PMID: 37520732 PMCID: PMC10382945 DOI: 10.1016/j.isci.2023.107359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 06/02/2023] [Accepted: 07/07/2023] [Indexed: 08/01/2023] Open
Abstract
During binocular rivalry (BR) only one eye's view is perceived. Neural underpinnings of BR are debated. Recent studies suggest that primary visual cortex (V1) initiates BR. One trigger might be response suppression across most V1 neurons at the onset of BR. Here, we utilize a variant of BR called binocular rivalry flash suppression (BRFS) to test this hypothesis. BRFS is identical to BR, except stimuli are shown with a ∼1s delay. If V1 response suppression was required to initiate BR, it should occur during BRFS as well. To test this, we compared V1 spiking in two macaques observing BRFS. We found that BRFS resulted in response facilitation rather than response suppression across V1 neurons. However, BRFS still reduces responses in a subset of V1 neurons due to the adaptive effects of asynchronous stimulus presentation. We argue that this selective response suppression could serve as an alternate initiator of BR.
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Affiliation(s)
- Brock M. Carlson
- Department of Psychology, College of Arts and Science, Vanderbilt Vision Research Center, Center for Integrative and Cognitive Neuroscience, Vanderbilt University, Nashville, TN 37235, USA
| | - Blake A. Mitchell
- Department of Psychology, College of Arts and Science, Vanderbilt Vision Research Center, Center for Integrative and Cognitive Neuroscience, Vanderbilt University, Nashville, TN 37235, USA
| | - Kacie Dougherty
- Department of Psychology, College of Arts and Science, Vanderbilt Vision Research Center, Center for Integrative and Cognitive Neuroscience, Vanderbilt University, Nashville, TN 37235, USA
- Department of Psychology, Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08540, USA
| | - Jacob A. Westerberg
- Department of Psychology, College of Arts and Science, Vanderbilt Vision Research Center, Center for Integrative and Cognitive Neuroscience, Vanderbilt University, Nashville, TN 37235, USA
- Department of Vision and Cognition, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam 1105 BA, the Netherlands
| | - Michele A. Cox
- Department of Psychology, College of Arts and Science, Vanderbilt Vision Research Center, Center for Integrative and Cognitive Neuroscience, Vanderbilt University, Nashville, TN 37235, USA
- Center for Visual Science, University of Rochester, Rochester, NY 14627, USA
| | - Alexander Maier
- Department of Psychology, College of Arts and Science, Vanderbilt Vision Research Center, Center for Integrative and Cognitive Neuroscience, Vanderbilt University, Nashville, TN 37235, USA
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Tsoneva T, Garcia-Molina G, Desain P. Electrophysiological model of human temporal contrast sensitivity based on SSVEP. Front Neurosci 2023; 17:1180829. [PMID: 37599998 PMCID: PMC10433170 DOI: 10.3389/fnins.2023.1180829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 06/27/2023] [Indexed: 08/22/2023] Open
Abstract
The present study aims to connect the psychophysical research on the human visual perception of flicker with the neurophysiological research on steady-state visual evoked potentials (SSVEPs) in the context of their application needs and current technological developments. In four experiments, we investigated whether a temporal contrast sensitivity model could be established based on the electrophysiological responses to repetitive visual stimulation and, if so, how this model compares to the psychophysical models of flicker visibility. We used data from 62 observers viewing periodic flicker at a range of frequencies and modulation depths sampled around the perceptual visibility thresholds. The resulting temporal contrast sensitivity curve (TCSC) was similar in shape to its psychophysical counterpart, confirming that the human visual system is most sensitive to repetitive visual stimulation at frequencies between 10 and 20 Hz. The electrophysiological TCSC, however, was below the psychophysical TCSC measured in our experiments for lower frequencies (1-50 Hz), crossed it when the frequency was 50 Hz, and stayed above while decreasing at a slower rate for frequencies in the gamma range (40-60 Hz). This finding provides evidence that SSVEPs could be measured even without the conscious perception of flicker, particularly at frequencies above 50 Hz. The cortical and perceptual mechanisms that apply at higher temporal frequencies, however, do not seem to directly translate to lower frequencies. The presence of harmonics, which show better response for many frequencies, suggests non-linear processing in the visual system. These findings are important for the potential applications of SSVEPs in studying, assisting, or augmenting human cognitive and sensorimotor functions.
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Affiliation(s)
- Tsvetomira Tsoneva
- Department of Digital Engagement, Cognition and Behavior, Philips Research, Eindhoven, Netherlands
- Centre for Cognition, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Gary Garcia-Molina
- Sleep Number Labs, San Jose, CA, United States
- Center for Sleep and Consciousness, University of Wisconsin, Madison, WI, United States
| | - Peter Desain
- Centre for Cognition, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
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Ciaunica A, Shmeleva EV, Levin M. The brain is not mental! coupling neuronal and immune cellular processing in human organisms. Front Integr Neurosci 2023; 17:1057622. [PMID: 37265513 PMCID: PMC10230067 DOI: 10.3389/fnint.2023.1057622] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 04/18/2023] [Indexed: 06/03/2023] Open
Abstract
Significant efforts have been made in the past decades to understand how mental and cognitive processes are underpinned by neural mechanisms in the brain. This paper argues that a promising way forward in understanding the nature of human cognition is to zoom out from the prevailing picture focusing on its neural basis. It considers instead how neurons work in tandem with other type of cells (e.g., immune) to subserve biological self-organization and adaptive behavior of the human organism as a whole. We focus specifically on the immune cellular processing as key actor in complementing neuronal processing in achieving successful self-organization and adaptation of the human body in an ever-changing environment. We overview theoretical work and empirical evidence on "basal cognition" challenging the idea that only the neuronal cells in the brain have the exclusive ability to "learn" or "cognize." The focus on cellular rather than neural, brain processing underscores the idea that flexible responses to fluctuations in the environment require a carefully crafted orchestration of multiple cellular and bodily systems at multiple organizational levels of the biological organism. Hence cognition can be seen as a multiscale web of dynamic information processing distributed across a vast array of complex cellular (e.g., neuronal, immune, and others) and network systems, operating across the entire body, and not just in the brain. Ultimately, this paper builds up toward the radical claim that cognition should not be confined to one system alone, namely, the neural system in the brain, no matter how sophisticated the latter notoriously is.
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Affiliation(s)
- Anna Ciaunica
- Centre for Philosophy of Science, Faculty of Science, University of Lisbon, Lisbon, Portugal
- Faculty of Brain Sciences, Institute of Cognitive Neuroscience, University College London, London, United Kingdom
| | - Evgeniya V. Shmeleva
- Department of Biology, Tufts University, Medford, MA, United States
- Allen Discovery Center, Tufts University, Medford, MA, United States
| | - Michael Levin
- Department of Biology, Tufts University, Medford, MA, United States
- Allen Discovery Center, Tufts University, Medford, MA, United States
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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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Safavi S, Panagiotaropoulos TI, Kapoor V, Ramirez-Villegas JF, Logothetis NK, Besserve M. Uncovering the organization of neural circuits with Generalized Phase Locking Analysis. PLoS Comput Biol 2023; 19:e1010983. [PMID: 37011110 PMCID: PMC10109521 DOI: 10.1371/journal.pcbi.1010983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 04/17/2023] [Accepted: 02/27/2023] [Indexed: 04/05/2023] Open
Abstract
Despite the considerable progress of in vivo neural recording techniques, inferring the biophysical mechanisms underlying large scale coordination of brain activity from neural data remains challenging. One obstacle is the difficulty to link high dimensional functional connectivity measures to mechanistic models of network activity. We address this issue by investigating spike-field coupling (SFC) measurements, which quantify the synchronization between, on the one hand, the action potentials produced by neurons, and on the other hand mesoscopic "field" signals, reflecting subthreshold activities at possibly multiple recording sites. As the number of recording sites gets large, the amount of pairwise SFC measurements becomes overwhelmingly challenging to interpret. We develop Generalized Phase Locking Analysis (GPLA) as an interpretable dimensionality reduction of this multivariate SFC. GPLA describes the dominant coupling between field activity and neural ensembles across space and frequencies. We show that GPLA features are biophysically interpretable when used in conjunction with appropriate network models, such that we can identify the influence of underlying circuit properties on these features. We demonstrate the statistical benefits and interpretability of this approach in various computational models and Utah array recordings. The results suggest that GPLA, used jointly with biophysical modeling, can help uncover the contribution of recurrent microcircuits to the spatio-temporal dynamics observed in multi-channel experimental recordings.
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Affiliation(s)
- Shervin Safavi
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- IMPRS for Cognitive and Systems Neuroscience, University of Tübingen, Tübingen, Germany
| | - Theofanis I. Panagiotaropoulos
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Cognitive Neuroimaging Unit, INSERM, CEA, CNRS, Université Paris-Saclay, NeuroSpin center, 91191 Gif/Yvette, France
| | - Vishal Kapoor
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- International Center for Primate Brain Research (ICPBR), Center for Excellence in Brain Science and Intelligence Technology (CEBSIT), Chinese Academy of Sciences (CAS), Shanghai 201602, China
| | - Juan F. Ramirez-Villegas
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Nikos K. Logothetis
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- International Center for Primate Brain Research (ICPBR), Center for Excellence in Brain Science and Intelligence Technology (CEBSIT), Chinese Academy of Sciences (CAS), Shanghai 201602, China
- Centre for Imaging Sciences, Biomedical Imaging Institute, The University of Manchester, Manchester, United Kingdom
| | - Michel Besserve
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Department of Empirical Inference, Max Planck Institute for Intelligent Systems and MPI-ETH Center for Learning Systems, Tübingen, Germany
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Conscious interpretation: A distinct aspect for the neural markers of the contents of consciousness. Conscious Cogn 2023; 108:103471. [PMID: 36736210 DOI: 10.1016/j.concog.2023.103471] [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: 07/29/2022] [Revised: 12/22/2022] [Accepted: 01/11/2023] [Indexed: 02/04/2023]
Abstract
Progress in the science of consciousness depends on the experimental paradigms and varieties of contrastive analysis available to researchers. Here we highlight paradigms where the object is represented in consciousness as a set of its features but the interpretation of this set alternates in consciousness. We group experimental paradigms with this property under the label "conscious interpretation". We compare the paradigms studying conscious interpretation of the already consciously perceived objects with other types of experimental paradigms. We review previous and recent studies investigating this interpretative aspect of consciousness and propose future directions. We put forward the hypothesis that there are types of stimuli with a hierarchy of interpretations for which the rule applies: conscious experience is drawn towards higher-level interpretation and reverting back to the lower level of interpretation is impossible. We discuss how theories of consciousness might incorporate knowledge and constraints arising from the characteristics of conscious interpretation.
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McFadden J. Consciousness: Matter or EMF? Front Hum Neurosci 2023; 16:1024934. [PMID: 36741784 PMCID: PMC9889563 DOI: 10.3389/fnhum.2022.1024934] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 12/28/2022] [Indexed: 01/20/2023] Open
Abstract
Conventional theories of consciousness (ToCs) that assume that the substrate of consciousness is the brain's neuronal matter fail to account for fundamental features of consciousness, such as the binding problem. Field ToC's propose that the substrate of consciousness is the brain's best accounted by some kind of field in the brain. Electromagnetic (EM) ToCs propose that the conscious field is the brain's well-known EM field. EM-ToCs were first proposed only around 20 years ago primarily to account for the experimental discovery that synchronous neuronal firing was the strongest neural correlate of consciousness (NCC). Although EM-ToCs are gaining increasing support, they remain controversial and are often ignored by neurobiologists and philosophers and passed over in most published reviews of consciousness. In this review I examine EM-ToCs against established criteria for distinguishing between ToCs and demonstrate that they outperform all conventional ToCs and provide novel insights into the nature of consciousness as well as a feasible route toward building artificial consciousnesses.
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Xiang L, Harel A, Todorova R, Gao H, Sara SJ, Wiener SI. Locus coeruleus noradrenergic neurons phase-lock to prefrontal and hippocampal infra-slow rhythms that synchronize to behavioral events. Front Cell Neurosci 2023; 17:1131151. [PMID: 37025702 PMCID: PMC10070758 DOI: 10.3389/fncel.2023.1131151] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 02/23/2023] [Indexed: 04/08/2023] Open
Abstract
The locus coeruleus (LC) is the primary source of noradrenergic projections to the forebrain, and, in prefrontal cortex, is implicated in decision-making and executive function. LC neurons phase-lock to cortical infra-slow wave oscillations during sleep. Such infra-slow rhythms are rarely reported in awake states, despite their interest, since they correspond to the time scale of behavior. Thus, we investigated LC neuronal synchrony with infra-slow rhythms in awake rats performing an attentional set-shifting task. Local field potential (LFP) oscillation cycles in prefrontal cortex and hippocampus on the order of 0.4 Hz phase-locked to task events at crucial maze locations. Indeed, successive cycles of the infra-slow rhythms showed different wavelengths, as if they are periodic oscillations that can reset phase relative to salient events. Simultaneously recorded infra-slow rhythms in prefrontal cortex and hippocampus could show different cycle durations as well, suggesting independent control. Most LC neurons (including optogenetically identified noradrenergic neurons) recorded here were phase-locked to these infra-slow rhythms, as were hippocampal and prefrontal units recorded on the LFP probes. The infra-slow oscillations also phase-modulated gamma amplitude, linking these rhythms at the time scale of behavior to those coordinating neuronal synchrony. This would provide a potential mechanism where noradrenaline, released by LC neurons in concert with the infra-slow rhythm, would facilitate synchronization or reset of these brain networks, underlying behavioral adaptation.
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Affiliation(s)
- Liyang Xiang
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
- Zhejiang Key Laboratory of Neuroelectronics and Brain Computer Interface Technology, Hangzhou, China
| | - Antoine Harel
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
| | - Ralitsa Todorova
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
| | - HongYing Gao
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
| | - Susan J. Sara
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
- Department of Child and Adolescent Psychiatry, New York University Medical School, New York, NY, United States
| | - Sidney I. Wiener
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
- *Correspondence: Sidney I. Wiener,
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11
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Perceptual Awareness and Its Relationship with Consciousness: Hints from Perceptual Multistability. NEUROSCI 2022. [DOI: 10.3390/neurosci3040039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Many interesting theories of consciousness have been proposed, but so far, there is no “unified” theory capable of encompassing all aspects of this phenomenon. We are all aware of what it feels like to be conscious and what happens if there is an absence of consciousness. We are becoming more and more skilled in measuring consciousness states; nevertheless, we still “don’t get it” in its deeper essence. How does all the processed information converge from different brain areas and structures to a common unity, giving us this very private “feeling of being conscious”, despite the constantly changing flow of information between internal and external states? “Multistability” refers to a class of perceptual phenomena where subjective awareness spontaneously and continuously alternates between different percepts, although the objective stimuli do not change, supporting the idea that the brain “interprets” sensorial input in a “constructive” way. In this perspective paper, multistability and perceptual awareness are discussed as a methodological window for understanding the “local” states of consciousness, a privileged position from which it is possible to observe the brain dynamics and mechanisms producing the subjective phenomena of perceptual awareness in the very moment they are happening.
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Yu M, Xiao S, Hua M, Wang H, Chen X, Tian F, Li Y. EEG-based emotion recognition in an immersive virtual reality environment: From local activity to brain network features. Biomed Signal Process Control 2022. [DOI: 10.1016/j.bspc.2021.103349] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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13
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Yu M, Li Y, Tian F. Responses of functional brain networks while watching 2D and 3D videos: An EEG study. Biomed Signal Process Control 2021. [DOI: 10.1016/j.bspc.2021.102613] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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14
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Boyadzhieva A, Kayhan E. Keeping the Breath in Mind: Respiration, Neural Oscillations, and the Free Energy Principle. Front Neurosci 2021; 15:647579. [PMID: 34267621 PMCID: PMC8275985 DOI: 10.3389/fnins.2021.647579] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 05/27/2021] [Indexed: 11/22/2022] Open
Abstract
Scientific interest in the brain and body interactions has been surging in recent years. One fundamental yet underexplored aspect of brain and body interactions is the link between the respiratory and the nervous systems. In this article, we give an overview of the emerging literature on how respiration modulates neural, cognitive and emotional processes. Moreover, we present a perspective linking respiration to the free-energy principle. We frame volitional modulation of the breath as an active inference mechanism in which sensory evidence is recontextualized to alter interoceptive models. We further propose that respiration-entrained gamma oscillations may reflect the propagation of prediction errors from the sensory level up to cortical regions in order to alter higher level predictions. Accordingly, controlled breathing emerges as an easily accessible tool for emotional, cognitive, and physiological regulation.
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Affiliation(s)
| | - Ezgi Kayhan
- Department of Developmental Psychology, University of Potsdam, Potsdam, Germany
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
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15
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Bastos AM, Donoghue JA, Brincat SL, Mahnke M, Yanar J, Correa J, Waite AS, Lundqvist M, Roy J, Brown EN, Miller EK. Neural effects of propofol-induced unconsciousness and its reversal using thalamic stimulation. eLife 2021; 10:60824. [PMID: 33904411 PMCID: PMC8079153 DOI: 10.7554/elife.60824] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 03/28/2021] [Indexed: 01/05/2023] Open
Abstract
The specific circuit mechanisms through which anesthetics induce unconsciousness have not been completely characterized. We recorded neural activity from the frontal, parietal, and temporal cortices and thalamus while maintaining unconsciousness in non-human primates (NHPs) with the anesthetic propofol. Unconsciousness was marked by slow frequency (~1 Hz) oscillations in local field potentials, entrainment of local spiking to Up states alternating with Down states of little or no spiking activity, and decreased coherence in frequencies above 4 Hz. Thalamic stimulation ‘awakened’ anesthetized NHPs and reversed the electrophysiologic features of unconsciousness. Unconsciousness is linked to cortical and thalamic slow frequency synchrony coupled with decreased spiking, and loss of higher-frequency dynamics. This may disrupt cortical communication/integration.
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Affiliation(s)
- André M Bastos
- The Picower Institute for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Jacob A Donoghue
- The Picower Institute for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Scott L Brincat
- The Picower Institute for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Meredith Mahnke
- The Picower Institute for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Jorge Yanar
- The Picower Institute for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Josefina Correa
- The Picower Institute for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Ayan S Waite
- The Picower Institute for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Mikael Lundqvist
- The Picower Institute for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Jefferson Roy
- The Picower Institute for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Emery N Brown
- The Picower Institute for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States.,The Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital/Harvard Medical School, Boston, United States.,The Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, United States
| | - Earl K Miller
- The Picower Institute for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
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16
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Katyal S, Goldin P. Neural correlates of nonjudgmental perception induced through meditation. Ann N Y Acad Sci 2021; 1499:70-81. [PMID: 33893655 DOI: 10.1111/nyas.14603] [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: 01/27/2021] [Revised: 03/25/2021] [Accepted: 04/07/2021] [Indexed: 12/26/2022]
Abstract
Ambiguous sensory stimuli provide insight into the dynamics of the human mind. When viewing substantially different images in the two eyes (i.e., binocular rivalry (BR)), perception spontaneously fluctuates between the two images along with patch-like mixtures of the two, with limited ability to control such fluctuations. Previous studies have shown that long-term meditation training can enable a more stable perception by reducing such fluctuations. Using electroencephalography, we investigated the neural bases of perceptual stabilization in long-term meditators (LTMs) and age-matched meditation-naive control participants. We measured BR alternations before and after participants practiced meditation. We expected that perceptual stabilization through meditation could occur via one of two neurocognitive mechanisms: (1) a more engaged/effortful attention reflected by increased long-range phase synchronization between early visual sensory and higher-level brain regions, or (2) a disengaged/nonevaluative form of attention reflected by decreased phase synchronization. We found that compared with control participants, LTMs were in a significantly longer mixed perceptual state following concentrative meditation practice. The increase in mixed percepts across individuals was strongly correlated with reduced parietal-occipital gamma-band (30-50 Hz) phase synchrony. These findings suggest that concentrative meditation enables a nonevaluative perceptual stance supported by reduced communication between hierarchical visual brain regions.
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Affiliation(s)
- Sucharit Katyal
- University of California Davis Medical Center, Sacramento, California
| | - Philippe Goldin
- University of California Davis Medical Center, Sacramento, California
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17
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Pariz A, Fischer I, Valizadeh A, Mirasso C. Transmission delays and frequency detuning can regulate information flow between brain regions. PLoS Comput Biol 2021; 17:e1008129. [PMID: 33857135 PMCID: PMC8049288 DOI: 10.1371/journal.pcbi.1008129] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 02/16/2021] [Indexed: 12/28/2022] Open
Abstract
Brain networks exhibit very variable and dynamical functional connectivity and flexible configurations of information exchange despite their overall fixed structure. Brain oscillations are hypothesized to underlie time-dependent functional connectivity by periodically changing the excitability of neural populations. In this paper, we investigate the role of the connection delay and the detuning between the natural frequencies of neural populations in the transmission of signals. Based on numerical simulations and analytical arguments, we show that the amount of information transfer between two oscillating neural populations could be determined by their connection delay and the mismatch in their oscillation frequencies. Our results highlight the role of the collective phase response curve of the oscillating neural populations for the efficacy of signal transmission and the quality of the information transfer in brain networks.
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Affiliation(s)
- Aref Pariz
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran
- Instituto de Física Interdisciplinar y Sistemas Complejos IFISC (UIB-CSIC), Campus Universitat de les Illes Balears, Palma de Mallorca, Spain
| | - Ingo Fischer
- Instituto de Física Interdisciplinar y Sistemas Complejos IFISC (UIB-CSIC), Campus Universitat de les Illes Balears, Palma de Mallorca, Spain
| | - Alireza Valizadeh
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran
- School of biological sciences, Institute for research in fundamental sciences (IPM), Tehran, Iran
- * E-mail: (AV); (CM)
| | - Claudio Mirasso
- Instituto de Física Interdisciplinar y Sistemas Complejos IFISC (UIB-CSIC), Campus Universitat de les Illes Balears, Palma de Mallorca, Spain
- * E-mail: (AV); (CM)
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18
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Mheich A, Dufor O, Yassine S, Kabbara A, Biraben A, Wendling F, Hassan M. HD-EEG for tracking sub-second brain dynamics during cognitive tasks. Sci Data 2021; 8:32. [PMID: 33504796 PMCID: PMC7840668 DOI: 10.1038/s41597-021-00821-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 12/22/2020] [Indexed: 11/09/2022] Open
Abstract
This work provides the community with high-density Electroencephalography (HD-EEG, 256 channels) datasets collected during task-free and task-related paradigms. It includes forty-three healthy participants performing visual naming and spelling tasks, visual and auditory naming tasks and a visual working memory task in addition to resting state. The HD-EEG data are furnished in the Brain Imaging Data Structure (BIDS) format. These datasets can be used to (i) track brain networks dynamics and their rapid reconfigurations at sub-second time scale in different conditions, (naming/spelling/rest) and modalities, (auditory/visual) and compare them to each other, (ii) validate several parameters involved in the methods used to estimate cortical brain networks through scalp EEG, such as the open question of optimal number of channels and number of regions of interest and (iii) allow the reproducibility of results obtained so far using HD-EEG. We hope that delivering these datasets will lead to the development of new methods that can be used to estimate brain cortical networks and to better understand the general functioning of the brain during rest and task. Data are freely available from https://openneuro.org. Measurement(s) | brain measurement • cognitive behavior trait | Technology Type(s) | electroencephalography (EEG) | Factor Type(s) | task • age • sex | Sample Characteristic - Organism | Homo sapiens |
Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.13560311
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Affiliation(s)
- A Mheich
- Neurokyma, 35700, Rennes, France.
| | - O Dufor
- L@bISEN-Yncréa Ouest, ISEN, Brest, France
| | | | - A Kabbara
- Univ Rennes, LTSI - U1099, F-35000, Rennes, France
| | - A Biraben
- Univ Rennes, LTSI - U1099, F-35000, Rennes, France.,Neurology department, CHU, Rennes, 35000, France
| | - F Wendling
- Univ Rennes, LTSI - U1099, F-35000, Rennes, France
| | - M Hassan
- Neurokyma, 35700, Rennes, France.,Univ Rennes, LTSI - U1099, F-35000, Rennes, France
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19
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Dheer P, Pati S, Chowdhury KK, Majumdar KK. Enhanced gamma band mutual information is associated with impaired consciousness during temporal lobe seizures. Heliyon 2021; 6:e05769. [PMID: 33409386 PMCID: PMC7773881 DOI: 10.1016/j.heliyon.2020.e05769] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 07/24/2020] [Accepted: 12/14/2020] [Indexed: 11/24/2022] Open
Abstract
Background Epileptic seizures are characterized by aberrant synchronization. We hypothesized that higher synchronization across the seizure onset zone (SOZ) channels during a temporal lobe seizure contributes to impaired consciousness. New method All symmetric bivariate synchronization measures were extended to multivariate measure by a principal component analysis (PCA) based technique. A novel nonparametric method has been proposed to test the statistical significance between increased synchronization across the seizure onset zone (SOZ) channels and reduced consciousness. Results Increased synchronization in the gamma band towards seizure termination significantly contributes to impaired consciousness (p < 0.1). Synchronization reaches its peak in the extratemporal region (frontal lobe) ahead of the temporal region (p < 0.05). Synchronization is prominent in beta and gamma bands by most methods and it is more in the second half of seizure duration than in the first (p < 0.05). Conclusions Mutual information is the only synchronization measure out of the six that we studied, whose increase can be associated with the loss of consciousness in a statistically significant way.
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Affiliation(s)
- Puneet Dheer
- Systems Science and Informatics Unit, Indian Statistical Institute, 8th Mile, Mysore Road, Bangalore, India, 560059
| | - Sandipan Pati
- UAB Epilepsy Center, Department of Neurology, University of Alabama at Birmingham, CIRC 312, 1719 6th Avenue South, Birmingham, AL, 35294, USA
| | - Kalyan Kumar Chowdhury
- Statistical Quality Control Unit, Indian Statistical Institute, 8th Mile, Mysore Road, Bangalore, 560059, India
| | - Kaushik Kumar Majumdar
- Systems Science and Informatics Unit, Indian Statistical Institute, 8th Mile, Mysore Road, Bangalore, India, 560059
- Corresponding author.
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20
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Zeki S. "Multiplexing" cells of the visual cortex and the timing enigma of the binding problem. Eur J Neurosci 2020; 52:4684-4694. [PMID: 32722893 DOI: 10.1111/ejn.14921] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 07/11/2020] [Accepted: 07/19/2020] [Indexed: 12/01/2022]
Abstract
In this opinion essay, I address the perennial binding problem, that is to say of how independently processed visual attributes such as form, colour and motion are brought together to give us a unified and holistic picture of the visual world. A solution to this central issue in neurobiology remains as elusive as ever. No one knows today how it is implemented. The issue is not a new one and, though discussed most commonly in the context of the visual brain, it is not unique to it either. Karl Lashley summarized it well years ago when he wrote that a critical problem for brain studies is to understand how "the specialized areas of the cerebral cortex interact to provide the integration evident in thought and behaviour" (Lashley, 1931).
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Affiliation(s)
- Semir Zeki
- Laboratory of Neurobiology, Division of Cell & Developmental Biology, University College London, London, UK
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21
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Valencia AL, Froese T. What binds us? Inter-brain neural synchronization and its implications for theories of human consciousness. Neurosci Conscious 2020; 2020:niaa010. [PMID: 32547787 PMCID: PMC7288734 DOI: 10.1093/nc/niaa010] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/27/2020] [Accepted: 04/04/2020] [Indexed: 12/22/2022] Open
Abstract
The association between neural oscillations and functional integration is widely recognized in the study of human cognition. Large-scale synchronization of neural activity has also been proposed as the neural basis of consciousness. Intriguingly, a growing number of studies in social cognitive neuroscience reveal that phase synchronization similarly appears across brains during meaningful social interaction. Moreover, this inter-brain synchronization has been associated with subjective reports of social connectedness, engagement, and cooperativeness, as well as experiences of social cohesion and ‘self-other merging’. These findings challenge the standard view of human consciousness as essentially first-person singular and private. We therefore revisit the recent controversy over the possibility of extended consciousness and argue that evidence of inter-brain synchronization in the fastest frequency bands overcomes the hitherto most convincing sceptical position. If this proposal is on the right track, our understanding of human consciousness would be profoundly transformed, and we propose a method to test this proposal experimentally.
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Affiliation(s)
- Ana Lucía Valencia
- Psychobiology and Neuroscience Department, Faculty of Psychology, National Autonomous University of Mexico, Mexico City, Mexico.,Embodied Cognitive Science Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Tom Froese
- Embodied Cognitive Science Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
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22
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Adaptation to transients disrupts spatial coherence in binocular rivalry. Sci Rep 2020; 10:8673. [PMID: 32457469 PMCID: PMC7251118 DOI: 10.1038/s41598-020-65678-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 05/07/2020] [Indexed: 11/08/2022] Open
Abstract
When one eye is presented with an image that is distinct from the image presented to the other eye, the eyes start to rival and suppress each other's image. Binocular rivalry leads to perceptual alternations between the images of each eye, during which only one of the images is perceived at a time. However, when the eyes exert weak and shallow suppression, participants tend to perceive both images intermixed more often. A recent study proposed that the precedence of mixed percepts positively correlates with the degree of adaptation to conflict between the eyes. However, this study neglected the role of visual transients, which covaried with the degree of conflict in the stimulus design. Here we report that not the conflict between the eyes but prolonged and repeated observations of strong visual transients cause participants to report more mixed percepts. We conclude that visual transients, such as sudden changes in contrast, draw attention, strengthen both eyes' image representations, and facilitate the adaptation to interocular suppression, which consequentially disrupts the spatial coherence in binocular rivalry. This finding is relevant to virtual- and augmented reality for which it is crucial to design stereoscopic environments in which binocular rivalry is limited.
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23
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Losacco J, Ramirez-Gordillo D, Gilmer J, Restrepo D. Learning improves decoding of odor identity with phase-referenced oscillations in the olfactory bulb. eLife 2020; 9:e52583. [PMID: 31990271 PMCID: PMC6986879 DOI: 10.7554/elife.52583] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 12/30/2019] [Indexed: 01/04/2023] Open
Abstract
Local field potential oscillations reflect temporally coordinated neuronal ensembles-coupling distant brain regions, gating processing windows, and providing a reference for spike timing-based codes. In phase amplitude coupling (PAC), the amplitude of the envelope of a faster oscillation is larger within a phase window of a slower carrier wave. Here, we characterized PAC, and the related theta phase-referenced high gamma and beta power (PRP), in the olfactory bulb of mice learning to discriminate odorants. PAC changes throughout learning, and odorant-elicited changes in PRP increase for rewarded and decrease for unrewarded odorants. Contextual odorant identity (is the odorant rewarded?) can be decoded from peak PRP in animals proficient in odorant discrimination, but not in naïve mice. As the animal learns to discriminate the odorants the dimensionality of PRP decreases. Therefore, modulation of phase-referenced chunking of information in the course of learning plays a role in early sensory processing in olfaction.
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Affiliation(s)
- Justin Losacco
- Neuroscience Graduate ProgramUniversity of Colorado Anschutz Medical CampusAuroraUnited States
- Department of Cell and Developmental BiologyUniversity of Colorado Anschutz Medical CampusAuroraUnited States
| | - Daniel Ramirez-Gordillo
- Department of Cell and Developmental BiologyUniversity of Colorado Anschutz Medical CampusAuroraUnited States
| | - Jesse Gilmer
- Neuroscience Graduate ProgramUniversity of Colorado Anschutz Medical CampusAuroraUnited States
- Department of Physiology and BiophysicsUniversity of Colorado Anschutz Medical CampusAuroraUnited States
| | - Diego Restrepo
- Neuroscience Graduate ProgramUniversity of Colorado Anschutz Medical CampusAuroraUnited States
- Department of Cell and Developmental BiologyUniversity of Colorado Anschutz Medical CampusAuroraUnited States
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24
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Baudot P. Elements of qualitative cognition: An information topology perspective. Phys Life Rev 2019; 31:263-275. [PMID: 31679788 DOI: 10.1016/j.plrev.2019.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 10/16/2019] [Indexed: 11/29/2022]
Abstract
Elementary quantitative and qualitative aspects of consciousness are investigated conjointly from the biology, neuroscience, physic and mathematic point of view, by the mean of a theory written with Bennequin that derives and extends information theory within algebraic topology. Information structures, that accounts for statistical dependencies within n-body interacting systems are interpreted a la Leibniz as a monadic-panpsychic framework where consciousness is information and physical, and arise from collective interactions. The electrodynamic intrinsic nature of consciousness, sustained by an analogical code, is illustrated by standard neuroscience and psychophysic results. It accounts for the diversity of the learning mechanisms, including adaptive and homeostatic processes on multiple scales, and details their expression within information theory. The axiomatization and logic of cognition are rooted in measure theory expressed within a topos intrinsic probabilistic constructive logic. Information topology provides a synthesis of the main models of consciousness (Neural Assemblies, Integrated Information, Global Neuronal Workspace, Free Energy Principle) within a formal Gestalt theory, an expression of information structures and patterns in correspondence with Galois cohomology and discrete symmetries. The methods provide new formalization of deep neural network with homologicaly imposed architecture applied to challenges in AI-machine learning.
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Affiliation(s)
- Pierre Baudot
- Median Technologies, Valbonne, France; Inserm UNIS UMR1072, Université Aix-Marseille AMU, Marseille, France.
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25
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Oprisan SA, Clementsmith X, Tompa T, Lavin A. Dopamine receptor antagonists effects on low-dimensional attractors of local field potentials in optogenetic mice. PLoS One 2019; 14:e0223469. [PMID: 31618234 PMCID: PMC6795423 DOI: 10.1371/journal.pone.0223469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 09/16/2019] [Indexed: 11/18/2022] Open
Abstract
The goal of this study was to investigate the effects of acute cocaine injection or dopamine (DA) receptor antagonists on the medial prefrontal cortex (mPFC) gamma oscillations and their relationship to short term neuroadaptation that may mediate addiction. For this purpose, optogenetically evoked local field potentials (LFPs) in response to a brief 10 ms laser light pulse were recorded from 17 mice. D1-like receptor antagonist SCH 23390 or D2-like receptor antagonist sulpiride, or both, were administered either before or after cocaine. A Euclidian distance-based dendrogram classifier separated the 100 trials for each animal in disjoint clusters. When baseline and DA receptor antagonists trials were combined in a single trial, a minimum of 20% overlap occurred in some dendrogram clusters, which suggests a possible common, invariant, dynamic mechanism shared by both baseline and DA receptor antagonists data. The delay-embedding method of neural activity reconstruction was performed using the correlation time and mutual information to determine the lag/correlation time of LFPs and false nearest neighbors to determine the embedding dimension. We found that DA receptor antagonists applied before cocaine cancels out the effect of cocaine and leaves the lag time distributions at baseline values. On the other hand, cocaine applied after DA receptor antagonists shifts the lag time distributions to longer durations, i.e. increase the correlation time of LFPs. Fourier analysis showed that a reasonable accurate decomposition of the LFP data can be obtained with a relatively small (less than ten) Fourier coefficients.
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Affiliation(s)
- Sorinel A. Oprisan
- Department of Physics and Astronomy, College of Charleston, Charleston, SC, United States of America
- * E-mail:
| | - Xandre Clementsmith
- Department of Computer Science, College of Charleston, Charleston, SC, United States of America
| | - Tamas Tompa
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States of America
- Faculty of Healthcare, Department of Preventive Medicine, University of Miskolc, Miskolc, Hungary
| | - Antonieta Lavin
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States of America
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26
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Kopec J, Russo N, Antshel KM, Fremont W, Kates WR. Specific differences in temporal binding aspects of the attentional blink in Chromosome 22q11.2 Deletion Syndrome. Cortex 2018; 108:67-79. [PMID: 30130634 PMCID: PMC7730721 DOI: 10.1016/j.cortex.2018.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 06/17/2018] [Accepted: 07/20/2018] [Indexed: 11/29/2022]
Abstract
Chromosome 22q11.2 Deletion Syndrome (22q11DS) is a genetic syndrome characterized by a variety of cognitive impairments, including difficulty with attention. 22q11DS is the strongest known genetic risk factor for developing schizophrenia, a disorder characterized by impairments in visual attention and temporal binding processes. Here we examine a specific temporal visual attention phenomenon (the attentional blink; AB) within two rapid serial visual presentation tasks, and compare those with 22q11DS to groups of typically developing individuals matched on chronological (CA) and mental age (MA). Performance of individuals with 22q11DS was sensitive to differing task demands. On a Category Task, individuals with 22q11DS performed similarly to control groups on all measures of the AB, with the exception of lower detection accuracy of the first of two targets. In contrast, on a feature-based Color Task which required temporal binding of stimulus features, individuals with 22q11DS differed from CA and MA matched control groups on all AB performance measures, exhibiting lower target accuracy, more temporal binding errors, and a deeper, more protracted AB. Temporal binding in the visual domain is thought to be dependent on a serial attention mechanism that facilitates simultaneous firing of neurons in multiple areas of the visual cortex, activating short-term working memory for storage of bound features. Given the discrepancy between these two tasks, results suggest that temporal binding processes may be significantly affected in individuals with 22q11DS, a finding that importantly, has been previously demonstrated among individuals with schizophrenia.
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Affiliation(s)
- Justin Kopec
- Department of Psychology, Syracuse University, Syracuse, NY, USA.
| | - Natalie Russo
- Department of Psychology, Syracuse University, Syracuse, NY, USA
| | - Kevin M Antshel
- Department of Psychology, Syracuse University, Syracuse, NY, USA; Department of Psychiatry and Behavioral Sciences, State University of New York at Upstate Medical University, Syracuse, NY, USA
| | - Wanda Fremont
- Department of Psychiatry and Behavioral Sciences, State University of New York at Upstate Medical University, Syracuse, NY, USA
| | - Wendy R Kates
- Department of Psychology, Syracuse University, Syracuse, NY, USA; Department of Psychiatry and Behavioral Sciences, State University of New York at Upstate Medical University, Syracuse, NY, USA
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27
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Heitmann S, Breakspear M. Putting the "dynamic" back into dynamic functional connectivity. Netw Neurosci 2018; 2:150-174. [PMID: 30215031 PMCID: PMC6130444 DOI: 10.1162/netn_a_00041] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Accepted: 12/30/2017] [Indexed: 01/17/2023] Open
Abstract
The study of fluctuations in time-resolved functional connectivity is a topic of substantial current interest. As the term "dynamic functional connectivity" implies, such fluctuations are believed to arise from dynamics in the neuronal systems generating these signals. While considerable activity currently attends to methodological and statistical issues regarding dynamic functional connectivity, less attention has been paid toward its candidate causes. Here, we review candidate scenarios for dynamic (functional) connectivity that arise in dynamical systems with two or more subsystems; generalized synchronization, itinerancy (a form of metastability), and multistability. Each of these scenarios arises under different configurations of local dynamics and intersystem coupling: We show how they generate time series data with nonlinear and/or nonstationary multivariate statistics. The key issue is that time series generated by coupled nonlinear systems contain a richer temporal structure than matched multivariate (linear) stochastic processes. In turn, this temporal structure yields many of the phenomena proposed as important to large-scale communication and computation in the brain, such as phase-amplitude coupling, complexity, and flexibility. The code for simulating these dynamics is available in a freeware software platform, the Brain Dynamics Toolbox.
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28
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Chen J, Chen Y, Liu Y. Color-motion feature binding occurs unconsciously. Neurosci Lett 2018; 675:54-58. [PMID: 29604405 DOI: 10.1016/j.neulet.2018.03.060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 03/23/2018] [Accepted: 03/27/2018] [Indexed: 11/16/2022]
Abstract
The relationship between consciousness and feature binding has long been a topic of debate. Although they may be associated, there is growing evidence supporting the notion that feature binding and visual consciousness can be separated to some degree. In our study, we manipulated the visibility of priming stimuli, which consisted of color-motion features, and then measured the effects of those manipulations on reporting of cued targets' direction of rotation. A priming effect was observed even when the priming stimuli were invisible, implying that the color-motion features of the prime could bind unconsciously. These findings support the notion that, at least under certain conditions, feature binding and visual consciousness are separable psychological processes wherein feature binding is not sufficient to establish visual awareness.
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Affiliation(s)
- Jiacheng Chen
- School of Kinesiology, Shanghai University of Sport, China
| | - Yifan Chen
- School of Kinesiology, Shanghai University of Sport, China
| | - Ying Liu
- School of Kinesiology, Shanghai University of Sport, China; Key Lab of Cognitive Evaluation and Regulation in Sport, General Administration of Sport, China.
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29
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Michel CM, Koenig T. EEG microstates as a tool for studying the temporal dynamics of whole-brain neuronal networks: A review. Neuroimage 2017; 180:577-593. [PMID: 29196270 DOI: 10.1016/j.neuroimage.2017.11.062] [Citation(s) in RCA: 514] [Impact Index Per Article: 73.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 11/07/2017] [Accepted: 11/27/2017] [Indexed: 12/27/2022] Open
Abstract
The present review discusses a well-established method for characterizing resting-state activity of the human brain using multichannel electroencephalography (EEG). This method involves the examination of electrical microstates in the brain, which are defined as successive short time periods during which the configuration of the scalp potential field remains semi-stable, suggesting quasi-simultaneity of activity among the nodes of large-scale networks. A few prototypic microstates, which occur in a repetitive sequence across time, can be reliably identified across participants. Researchers have proposed that these microstates represent the basic building blocks of the chain of spontaneous conscious mental processes, and that their occurrence and temporal dynamics determine the quality of mentation. Several studies have further demonstrated that disturbances of mental processes associated with neurological and psychiatric conditions manifest as changes in the temporal dynamics of specific microstates. Combined EEG-fMRI studies and EEG source imaging studies have indicated that EEG microstates are closely associated with resting-state networks as identified using fMRI. The scale-free properties of the time series of EEG microstates explain why similar networks can be observed at such different time scales. The present review will provide an overview of these EEG microstates, available methods for analysis, the functional interpretations of findings regarding these microstates, and their behavioral and clinical correlates.
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Affiliation(s)
- Christoph M Michel
- Department of Basic Neurosciences, University of Geneva, Campus Biotech, Switzerland; Lemanic Biomedical Imaging Centre (CIBM), Lausanne and Geneva, Switzerland.
| | - Thomas Koenig
- Translational Research Center, University Hospital of Psychiatry, University of Bern, Switzerland
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30
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Havlík M, Kozáková E, Horáček J. Why and How. The Future of the Central Questions of Consciousness. Front Psychol 2017; 8:1797. [PMID: 29075226 PMCID: PMC5641624 DOI: 10.3389/fpsyg.2017.01797] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 09/28/2017] [Indexed: 11/24/2022] Open
Abstract
In this review, we deal with two central questions of consciousness how and why, and we outline their possible future development. The question how refers to the empirical endeavor to reveal the neural correlates and mechanisms that form consciousness. On the other hand, the question why generally refers to the “hard problem” of consciousness, which claims that empirical science will always fail to provide a satisfactory answer to the question why is there conscious experience at all. Unfortunately, the hard problem of consciousness will probably never completely disappear because it will always have its most committed supporters. However, there is a good chance that its weight and importance will be highly reduced by empirically tackling consciousness in the near future. We expect that future empirical endeavor of consciousness will be based on a unifying brain theory and will answer the question as to what is the function of conscious experience, which will in turn replace the implications of the hard problem. The candidate of such a unifying brain theory is predictive coding, which will have to explain both perceptual consciousness and conscious mind-wandering in order to become the truly unifying theory of brain functioning.
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Affiliation(s)
- Marek Havlík
- National Institute of Mental Health, Klecany, Czechia
| | - Eva Kozáková
- National Institute of Mental Health, Klecany, Czechia.,Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Jiří Horáček
- National Institute of Mental Health, Klecany, Czechia.,Third Faculty of Medicine, Charles University, Prague, Czechia
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31
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Baroni F, van Kempen J, Kawasaki H, Kovach CK, Oya H, Howard MA, Adolphs R, Tsuchiya N. Intracranial markers of conscious face perception in humans. Neuroimage 2017; 162:322-343. [PMID: 28882629 DOI: 10.1016/j.neuroimage.2017.08.074] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 08/15/2017] [Accepted: 08/24/2017] [Indexed: 12/29/2022] Open
Abstract
Investigations of the neural basis of consciousness have greatly benefited from protocols that involve the presentation of stimuli at perceptual threshold, enabling the assessment of the patterns of brain activity that correlate with conscious perception, independently of any changes in sensory input. However, the comparison between perceived and unperceived trials would be expected to reveal not only the core neural substrate of a particular conscious perception, but also aspects of brain activity that facilitate, hinder or tend to follow conscious perception. We take a step towards the resolution of these confounds by combining an analysis of neural responses observed during the presentation of faces partially masked by Continuous Flash Suppression, and those responses observed during the unmasked presentation of faces and other images in the same subjects. We employed multidimensional classifiers to decode physical properties of stimuli or perceptual states from spectrotemporal representations of electrocorticographic signals (1071 channels in 5 subjects). Neural activity in certain face responsive areas located in both the fusiform gyrus and in the lateral-temporal/inferior-parietal cortex discriminated seen vs. unseen faces in the masked paradigm and upright faces vs. other categories in the unmasked paradigm. However, only the former discriminated upright vs. inverted faces in the unmasked paradigm. Our results suggest a prominent role for the fusiform gyrus in the configural perception of faces, and possibly other objects that are holistically processed. More generally, we advocate comparative analysis of neural recordings obtained during different, but related, experimental protocols as a promising direction towards elucidating the functional specificities of the patterns of neural activation that accompany our conscious experiences.
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Affiliation(s)
- Fabiano Baroni
- School of Psychological Sciences, Faculty of Biomedical and Psychological Sciences, Monash University, Australia; NeuroEngineering Laboratory, Department of Electrical & Electronic Engineering, The University of Melbourne, Australia.
| | - Jochem van Kempen
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom; School of Psychological Sciences, Faculty of Biomedical and Psychological Sciences, Monash University, Australia
| | - Hiroto Kawasaki
- Department of Neurosurgery, University of Iowa, Iowa City, IA, USA
| | | | - Hiroyuki Oya
- Department of Neurosurgery, University of Iowa, Iowa City, IA, USA
| | - Matthew A Howard
- Department of Neurosurgery, University of Iowa, Iowa City, IA, USA
| | - Ralph Adolphs
- Division of Humanities and Social Sciences, California Institute of Technology, Pasadena, CA, USA
| | - Naotsugu Tsuchiya
- School of Psychological Sciences, Faculty of Biomedical and Psychological Sciences, Monash University, Australia; Monash Institute of Cognitive and Clinical Neuroscience, Monash University, Australia; Decoding and Controlling Brain Information, Japan Science and Technology Agency, Chiyoda-ku, Tokyo, Japan.
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32
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Lowet E, Roberts MJ, Peter A, Gips B, De Weerd P. A quantitative theory of gamma synchronization in macaque V1. eLife 2017; 6:26642. [PMID: 28857743 PMCID: PMC5779232 DOI: 10.7554/elife.26642] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 08/21/2017] [Indexed: 12/13/2022] Open
Abstract
Gamma-band synchronization coordinates brief periods of excitability in oscillating neuronal populations to optimize information transmission during sensation and cognition. Commonly, a stable, shared frequency over time is considered a condition for functional neural synchronization. Here, we demonstrate the opposite: instantaneous frequency modulations are critical to regulate phase relations and synchronization. In monkey visual area V1, nearby local populations driven by different visual stimulation showed different gamma frequencies. When similar enough, these frequencies continually attracted and repulsed each other, which enabled preferred phase relations to be maintained in periods of minimized frequency difference. Crucially, the precise dynamics of frequencies and phases across a wide range of stimulus conditions was predicted from a physics theory that describes how weakly coupled oscillators influence each other's phase relations. Hence, the fundamental mathematical principle of synchronization through instantaneous frequency modulations applies to gamma in V1 and is likely generalizable to other brain regions and rhythms.
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Affiliation(s)
- Eric Lowet
- Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Mark J Roberts
- Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Alina Peter
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Frankfurt, Germany
| | - Bart Gips
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands
| | - Peter De Weerd
- Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands.,Maastricht Centre for Systems Biology, Maastricht University, Maastricht, Netherlands
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33
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Herreros L, Lambert AJ, Chica AB. Orienting of attention with and without cue awareness. Neuropsychologia 2017; 99:165-171. [PMID: 28284987 DOI: 10.1016/j.neuropsychologia.2017.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 03/07/2017] [Accepted: 03/07/2017] [Indexed: 11/15/2022]
Abstract
Many cognitive processes operate without consciousness, and exogenous attentional capture seems to be one of them. While endogenously attending to the opposite location of a cue cannot occur without cue awareness, attending the cued location in an exogenous or stimulus driven form can occur even when participants are not aware of the presence of the cue (McCormick, 1997). Orienting attention to a specific location shortens reaction times to supra-threshold stimuli, and increases the likelihood of consciously perceiving near-threshold stimuli in that location. Effects of unconscious cues have mostly been demonstrated in reaction times to supra-threshold targets. In some studies, unconscious cues were perceptually less salient than conscious cues, which introduced a confound between cue awareness and cue saliency. In the present study, we used near-threshold cues and targets, which were titrated to be consciously perceived in ~50% of the trials, therefore eliminating the cue saliency confound. Moreover, we explored for the first time the effects of cue awareness on the conscious perception of subsequently presented near-threshold targets. Our results demonstrate that when cues and targets did not spatially overlap, conscious cues enhanced target localization when they appeared near the target location. In contrast, non-consciously perceived cues impaired target localization when they appeared near the target location, producing a cost in detecting subsequently presented near-threshold targets. This indicates that attentional orienting by unconscious cues cannot be accounted for by the idea that attention modulates perceptual representations, boosting them nearer to the conscious threshold. Rather, the effect of unconscious cues on target localization is qualitatively different to that elicited by conscious cues.
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Affiliation(s)
- Laura Herreros
- Department of Experimental Psychology, and Brain, Mind, and Behavior Research Center (CIMCYC), University of Granada, Spain.
| | - Anthony J Lambert
- School of Psychology, and Research Centre for Cognitive Neuroscience, University of Auckland, Auckland, New Zealand
| | - Ana B Chica
- Department of Experimental Psychology, and Brain, Mind, and Behavior Research Center (CIMCYC), University of Granada, Spain.
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34
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Numan T, Slooter AJC, van der Kooi AW, Hoekman AML, Suyker WJL, Stam CJ, van Dellen E. Functional connectivity and network analysis during hypoactive delirium and recovery from anesthesia. Clin Neurophysiol 2017; 128:914-924. [PMID: 28402867 DOI: 10.1016/j.clinph.2017.02.022] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 02/08/2017] [Accepted: 02/25/2017] [Indexed: 01/02/2023]
Abstract
OBJECTIVE To gain insight in the underlying mechanism of reduced levels of consciousness due to hypoactive delirium versus recovery from anesthesia, we studied functional connectivity and network topology using electroencephalography (EEG). METHODS EEG recordings were performed in age and sex-matched patients with hypoactive delirium (n=18), patients recovering from anesthesia (n=20), and non-delirious control patients (n=20), all after cardiac surgery. Functional and directed connectivity were studied with phase lag index and directed phase transfer entropy. Network topology was characterized using the minimum spanning tree (MST). A random forest classifier was calculated based on all measures to obtain discriminative ability between the three groups. RESULTS Non-delirious control subjects showed a back-to-front information flow, which was lost during hypoactive delirium (p=0.01) and recovery from anesthesia (p<0.01). The recovery from anesthesia group had more integrated network in the delta band compared to non-delirious controls. In contrast, hypoactive delirium showed a less integrated network in the alpha band. High accuracy for discrimination between hypoactive delirious patients and controls (86%) and recovery from anesthesia and controls (95%) were found. Accuracy for discrimination between hypoactive delirium and recovery from anesthesia was 73%. CONCLUSION Loss of functional and directed connectivity were observed in both hypoactive delirium and recovery from anesthesia, which might be related to the reduced level of consciousness in both states. These states could be distinguished in topology, which was a less integrated network during hypoactive delirium. SIGNIFICANCE Functional and directed connectivity are similarly disturbed during a reduced level of consciousness due to hypoactive delirium and sedatives, however topology was differently affected.
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Affiliation(s)
- Tianne Numan
- Department of Intensive Care Medicine, Brain Center Rudolf Magnus, University Medical Center Utrecht, Heidelberglaan 100, Utrecht, The Netherlands.
| | - Arjen J C Slooter
- Department of Intensive Care Medicine, Brain Center Rudolf Magnus, University Medical Center Utrecht, Heidelberglaan 100, Utrecht, The Netherlands
| | - Arendina W van der Kooi
- Department of Intensive Care Medicine, Brain Center Rudolf Magnus, University Medical Center Utrecht, Heidelberglaan 100, Utrecht, The Netherlands
| | - Annemieke M L Hoekman
- Department of Intensive Care Medicine, Brain Center Rudolf Magnus, University Medical Center Utrecht, Heidelberglaan 100, Utrecht, The Netherlands
| | - Willem J L Suyker
- Department of Cardiothoracic Surgery, University Medical Center Utrecht, Heidelberglaan 100, The Netherlands
| | - Cornelis J Stam
- Department of Clinical Neurophysiology and MEG Center, Neuroscience Campus Amsterdam, VU University Medical Center, De Boelelaan 1085, Amsterdam, The Netherlands
| | - Edwin van Dellen
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Heidelberglaan 100, Utrecht, The Netherlands
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35
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Havlík M. Missing piece of the puzzle in the science of consciousness: Resting state and endogenous correlates of consciousness. Conscious Cogn 2017; 49:70-85. [DOI: 10.1016/j.concog.2017.01.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 12/19/2016] [Accepted: 01/22/2017] [Indexed: 10/20/2022]
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Abstract
AbstractMorsella et al. put forward an interesting theory about the functions of consciousness. However, I argue that this theory is more about showing what is not the function of consciousness, and claiming that it does not integrate, than vice versa – as opposed to its proclaimed goal. In addition, the question of phenomenality and its relations with integration is still left open.
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37
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Babiloni C, Marzano N, Soricelli A, Cordone S, Millán-Calenti JC, Del Percio C, Buján A. Cortical Neural Synchronization Underlies Primary Visual Consciousness of Qualia: Evidence from Event-Related Potentials. Front Hum Neurosci 2016; 10:310. [PMID: 27445750 PMCID: PMC4927634 DOI: 10.3389/fnhum.2016.00310] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 06/08/2016] [Indexed: 11/13/2022] Open
Abstract
This article reviews three experiments on event-related potentials (ERPs) testing the hypothesis that primary visual consciousness (stimulus self-report) is related to enhanced cortical neural synchronization as a function of stimulus features. ERP peak latency and sources were compared between "seen" trials and "not seen" trials, respectively related and unrelated to the primary visual consciousness. Three salient features of visual stimuli were considered (visuospatial, emotional face expression, and written words). Results showed the typical visual ERP components in both "seen" and "not seen" trials. There was no statistical difference in the ERP peak latencies between the "seen" and "not seen" trials, suggesting a similar timing of the cortical neural synchronization regardless the primary visual consciousness. In contrast, ERP sources showed differences between "seen" and "not seen" trials. For the visuospatial stimuli, the primary consciousness was related to higher activity in dorsal occipital and parietal sources at about 400 ms post-stimulus. For the emotional face expressions, there was greater activity in parietal and frontal sources at about 180 ms post-stimulus. For the written letters, there was higher activity in occipital, parietal and temporal sources at about 230 ms post-stimulus. These results hint that primary visual consciousness is associated with an enhanced cortical neural synchronization having entirely different spatiotemporal characteristics as a function of the features of the visual stimuli and possibly, the relative qualia (i.e., visuospatial, face expression, and words). In this framework, the dorsal visual stream may be synchronized in association with the primary consciousness of visuospatial and emotional face contents. Analogously, both dorsal and ventral visual streams may be synchronized in association with the primary consciousness of linguistic contents. In this line of reasoning, the ensemble of the cortical neural networks underpinning the single visual features would constitute a sort of multi-dimensional palette of colors, shapes, regions of the visual field, movements, emotional face expressions, and words. The synchronization of one or more of these cortical neural networks, each with its peculiar timing, would produce the primary consciousness of one or more of the visual features of the scene.
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Affiliation(s)
- Claudio Babiloni
- Department of Physiology and Pharmacology "Vittorio Erspamer", Sapienza University of RomeRome, Italy; Department of Neuroscience, IRCCS San Raffaele PisanaRome, Italy
| | - Nicola Marzano
- Department of Integrated Imaging, IRCCS SDN Naples, Italy
| | - Andrea Soricelli
- Department of Integrated Imaging, IRCCS SDNNaples, Italy; Department of Motor Sciences and Healthiness, University of Naples ParthenopeNaples, Italy
| | - Susanna Cordone
- Department of Physiology and Pharmacology "Vittorio Erspamer", Sapienza University of Rome Rome, Italy
| | - José Carlos Millán-Calenti
- Gerontology Research Group, Department of Medicine, Faculty of Health Sciences, University of A Coruña A Coruña, Spain
| | | | - Ana Buján
- Gerontology Research Group, Department of Medicine, Faculty of Health Sciences, University of A Coruña A Coruña, Spain
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38
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Abstract
Despite decades of research, the mechanism by which general anesthetics produce loss of consciousness remains mysterious. A clue may be provided by the evidence that synchronous firing of cortical neurons underlies higher forms of neural processing. In order for these synchrony codes to be precise, transmission time must be independent of path length over all the connected sites between any two cortical areas. Because path lengths vary, developmental mechanisms must compensate for the resulting delay variations. Delay variations could be detected by spike-timing-dependent cues and compensation implemented by systematic changes in axon diameter, myelin thickness, or internodal distance. Anesthetics have been shown to increase conduction velocity in myelinated fibers and may therefore disrupt path-length compensation by changing velocities by different amounts in different types of axon. This simple and testable theory explains why anesthetics interfere selectively with higher cognitive functions but leave those dominated by rate-based firing relatively intact.
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Affiliation(s)
- Nicholas V Swindale
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, Canada.
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39
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Zeki S. Multiple asynchronous stimulus- and task-dependent hierarchies (STDH) within the visual brain's parallel processing systems. Eur J Neurosci 2016; 44:2515-2527. [DOI: 10.1111/ejn.13270] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 04/25/2016] [Accepted: 05/03/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Semir Zeki
- Wellcome Laboratory of Neurobiology; University College London; London WC1E 6BT UK
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40
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Abstract
When visual information enters the brain, it is relayed to different specialized regions, processing features such as shape, color, or motion. And yet, in our conscious experience of a colored, moving shape, all the different features seem to be integrated into one unified percept. Therefore, it has been hypothesized that consciousness and feature binding share an intimate relationship. To study this relationship, we used a paradigm in which the behavioral effects of feature binding can be measured. Using masks, we investigated whether spontaneous binding between the orientation and location of a Gabor patch takes place when the Gabor patch is processed consciously or unconsciously. The results of our study suggest that orientation and location of a visually presented object are automatically integrated, even when subjects are unaware of that object. We conclude that binding and consciousness share a less intimate relationship than previously hypothesized, since consciousness is not a necessary condition for binding to occur.
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41
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Primary motor and sensory cortical areas communicate via spatiotemporally coordinated networks at multiple frequencies. Proc Natl Acad Sci U S A 2016; 113:5083-8. [PMID: 27091982 DOI: 10.1073/pnas.1600788113] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Skilled movements rely on sensory information to shape optimal motor responses, for which the sensory and motor cortical areas are critical. How these areas interact to mediate sensorimotor integration is largely unknown. Here, we measure intercortical coherence between the orofacial motor (MIo) and somatosensory (SIo) areas of cortex as monkeys learn to generate tongue-protrusive force. We report that coherence between MIo and SIo is reciprocal and that neuroplastic changes in coherence gradually emerge over a few days. These functional networks of coherent spiking and local field potentials exhibit frequency-specific spatiotemporal properties. During force generation, theta coherence (2-6 Hz) is prominent and exhibited by numerous paired signals; before or after force generation, coherence is evident in alpha (6-13 Hz), beta (15-30 Hz), and gamma (30-50 Hz) bands, but the functional networks are smaller and weaker. Unlike coherence in the higher frequency bands, the distribution of the phase at peak theta coherence is bimodal with peaks near 0° and ±180°, suggesting that communication between somatosensory and motor areas is coordinated temporally by the phase of theta coherence. Time-sensitive sensorimotor integration and plasticity may rely on coherence of local and large-scale functional networks for cortical processes to operate at multiple temporal and spatial scales.
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42
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Lu H, Wang L, Rea WW, Brynildsen JK, Jaime S, Zuo Y, Stein EA, Yang Y. Low- but Not High-Frequency LFP Correlates with Spontaneous BOLD Fluctuations in Rat Whisker Barrel Cortex. Cereb Cortex 2016; 26:683-694. [PMID: 25331598 PMCID: PMC4712799 DOI: 10.1093/cercor/bhu248] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Resting-state magnetic resonance imaging (rsMRI) is thought to reflect ongoing spontaneous brain activity. However, the precise neurophysiological basis of rsMRI signal remains elusive. Converging evidence supports the notion that local field potential (LFP) signal in the high-frequency range correlates with fMRI response evoked by a task (e.g., visual stimulation). It remains uncertain whether this relationship extends to rsMRI. In this study, we systematically modulated LFP signal in the whisker barrel cortex (WBC) by unilateral deflection of rat whiskers. Results show that functional connectivity between bilateral WBC was significantly modulated at the 2 Hz, but not at the 4 or 6 Hz, stimulus condition. Electrophysiologically, only in the low-frequency range (<5 Hz) was the LFP power synchrony in bilateral WBC significantly modulated at 2 Hz, but not at 4- or 6-Hz whisker stimulation, thus distinguishing these 2 experimental conditions, and paralleling the findings in rsMRI. LFP power synchrony in other frequency ranges was modulated in a way that was neither unique to the specific stimulus conditions nor parallel to the fMRI results. Our results support the hypothesis that emphasizes the role of low-frequency LFP signal underlying rsMRI.
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Affiliation(s)
| | | | - William W. Rea
- Neuroimaging Research Branch and
- Integrative Neurobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
| | | | - Saul Jaime
- Neuroimaging Research Branch and
- Department of Physiology, School of Medicine, University of Texas Health Science Center in San Antonio, TX 78229, USA
| | - Yantao Zuo
- Neuroimaging Research Branch and
- Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC 27705, USA
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Lowet E, Roberts MJ, Bonizzi P, Karel J, De Weerd P. Quantifying Neural Oscillatory Synchronization: A Comparison between Spectral Coherence and Phase-Locking Value Approaches. PLoS One 2016; 11:e0146443. [PMID: 26745498 PMCID: PMC4706353 DOI: 10.1371/journal.pone.0146443] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 12/17/2015] [Indexed: 11/18/2022] Open
Abstract
Synchronization or phase-locking between oscillating neuronal groups is considered to be important for coordination of information among cortical networks. Spectral coherence is a commonly used approach to quantify phase locking between neural signals. We systematically explored the validity of spectral coherence measures for quantifying synchronization among neural oscillators. To that aim, we simulated coupled oscillatory signals that exhibited synchronization dynamics using an abstract phase-oscillator model as well as interacting gamma-generating spiking neural networks. We found that, within a large parameter range, the spectral coherence measure deviated substantially from the expected phase-locking. Moreover, spectral coherence did not converge to the expected value with increasing signal-to-noise ratio. We found that spectral coherence particularly failed when oscillators were in the partially (intermittent) synchronized state, which we expect to be the most likely state for neural synchronization. The failure was due to the fast frequency and amplitude changes induced by synchronization forces. We then investigated whether spectral coherence reflected the information flow among networks measured by transfer entropy (TE) of spike trains. We found that spectral coherence failed to robustly reflect changes in synchrony-mediated information flow between neural networks in many instances. As an alternative approach we explored a phase-locking value (PLV) method based on the reconstruction of the instantaneous phase. As one approach for reconstructing instantaneous phase, we used the Hilbert Transform (HT) preceded by Singular Spectrum Decomposition (SSD) of the signal. PLV estimates have broad applicability as they do not rely on stationarity, and, unlike spectral coherence, they enable more accurate estimations of oscillatory synchronization across a wide range of different synchronization regimes, and better tracking of synchronization-mediated information flow among networks.
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Affiliation(s)
- Eric Lowet
- Department of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Mark J. Roberts
- Department of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Pietro Bonizzi
- Department of Knowledge Engineering, Maastricht University, Maastricht, The Netherlands
| | - Joël Karel
- Department of Knowledge Engineering, Maastricht University, Maastricht, The Netherlands
| | - Peter De Weerd
- Department of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
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44
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Gamma Oscillations. Netw Neurosci 2016. [DOI: 10.1016/b978-0-12-801560-5.00021-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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45
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Avella Gonzalez OJ, Mansvelder HD, van Pelt J, van Ooyen A. H-Channels Affect Frequency, Power and Amplitude Fluctuations of Neuronal Network Oscillations. Front Comput Neurosci 2015; 9:141. [PMID: 26635594 PMCID: PMC4652018 DOI: 10.3389/fncom.2015.00141] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 10/30/2015] [Indexed: 11/19/2022] Open
Abstract
Oscillations in network activity are ubiquitous in the brain and are involved in diverse cognitive functions. Oscillation characteristics, such as power, frequency, and temporal structure, depend on both network connectivity and intrinsic cellular properties, such as ion channel composition. An important class of channels, with key roles in regulating cell excitability, are h-channels. The h-current (Ih) is a slow, hyperpolarization-activated, depolarizing current that contributes to neuronal resonance and membrane potential. The impact of Ih on network oscillations, however, remains poorly understood. To elucidate the network effects of Ih, we used a computational model of a generic oscillatory neuronal network consisting of inhibitory and excitatory cells that were externally driven by excitatory action potentials and sustained depolarizing currents. We found that Ih increased the oscillation frequency and, in combination with external action potentials, representing input from areas outside the network, strongly decreased the synchrony of firing. As a consequence, the oscillation power and the duration of episodes during which the network exhibited high-amplitude oscillations were greatly reduced in the presence of Ih. Our results suggest that modulation of Ih or impaired expression of h-channels, as observed in epilepsy, could, by affecting oscillation dynamics, markedly alter network-level activity and potentially influence oscillation-dependent cognitive processes such as learning, memory and attention.
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Affiliation(s)
- Oscar J Avella Gonzalez
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam Amsterdam, Netherlands
| | - Huibert D Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam Amsterdam, Netherlands
| | - Jaap van Pelt
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam Amsterdam, Netherlands
| | - Arjen van Ooyen
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam Amsterdam, Netherlands
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A prolonged maturational time course in brain development for cortical processing of temporal modulations. Clin Neurophysiol 2015; 127:994-998. [PMID: 26480832 DOI: 10.1016/j.clinph.2015.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 08/27/2015] [Accepted: 09/01/2015] [Indexed: 11/21/2022]
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47
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Liljeström M, Stevenson C, Kujala J, Salmelin R. Task- and stimulus-related cortical networks in language production: Exploring similarity of MEG- and fMRI-derived functional connectivity. Neuroimage 2015; 120:75-87. [DOI: 10.1016/j.neuroimage.2015.07.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 06/28/2015] [Accepted: 07/07/2015] [Indexed: 11/30/2022] Open
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48
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Besserve M, Lowe SC, Logothetis NK, Schölkopf B, Panzeri S. Shifts of Gamma Phase across Primary Visual Cortical Sites Reflect Dynamic Stimulus-Modulated Information Transfer. PLoS Biol 2015; 13:e1002257. [PMID: 26394205 PMCID: PMC4579086 DOI: 10.1371/journal.pbio.1002257] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Accepted: 08/19/2015] [Indexed: 11/19/2022] Open
Abstract
Distributed neural processing likely entails the capability of networks to reconfigure dynamically the directionality and strength of their functional connections. Yet, the neural mechanisms that may allow such dynamic routing of the information flow are not yet fully understood. We investigated the role of gamma band (50-80 Hz) oscillations in transient modulations of communication among neural populations by using measures of direction-specific causal information transfer. We found that the local phase of gamma-band rhythmic activity exerted a stimulus-modulated and spatially-asymmetric directed effect on the firing rate of spatially separated populations within the primary visual cortex. The relationships between gamma phases at different sites (phase shifts) could be described as a stimulus-modulated gamma-band wave propagating along the spatial directions with the largest information transfer. We observed transient stimulus-related changes in the spatial configuration of phases (compatible with changes in direction of gamma wave propagation) accompanied by a relative increase of the amount of information flowing along the instantaneous direction of the gamma wave. These effects were specific to the gamma-band and suggest that the time-varying relationships between gamma phases at different locations mark, and possibly causally mediate, the dynamic reconfiguration of functional connections.
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Affiliation(s)
- Michel Besserve
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Max Planck Institute for Intelligent Systems, Tübingen, Germany
- * E-mail:
| | - Scott C. Lowe
- Institute for Adaptive and Neural Computation, School of Informatics, University of Edinburgh, Edinburgh, United Kingdom
| | - Nikos K. Logothetis
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Division of Imaging Science and Biomedical Engineering, University of Manchester, Manchester, United Kingdom
| | | | - Stefano Panzeri
- Laboratory of Neural Computation, Center for Neuroscience and Cognitive Systems @UniTn, Istituto Italiano di Tecnologia, Rovereto, Italy
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Chan HL, Chen LF, Chen IT, Chen YS. Beamformer-based spatiotemporal imaging of linearly-related source components using electromagnetic neural signals. Neuroimage 2015; 114:1-17. [DOI: 10.1016/j.neuroimage.2015.03.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Revised: 01/17/2015] [Accepted: 03/14/2015] [Indexed: 11/15/2022] Open
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50
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Hadjipapas A, Lowet E, Roberts MJ, Peter A, De Weerd P. Parametric variation of gamma frequency and power with luminance contrast: A comparative study of human MEG and monkey LFP and spike responses. Neuroimage 2015; 112:327-340. [PMID: 25769280 DOI: 10.1016/j.neuroimage.2015.02.062] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 02/20/2015] [Accepted: 02/27/2015] [Indexed: 10/23/2022] Open
Abstract
Gamma oscillations contribute significantly to the manner in which neural activity is bound into functional assemblies. The mechanisms that underlie the human gamma response, however, are poorly understood. Previous computational models of gamma rely heavily on the results of invasive recordings in animals, and it is difficult to assess whether these models hold in humans. Computational models of gamma predict specific changes in gamma spectral response with increased excitatory drive. Hence, differences and commonalities between spikes, LFPs and MEG in the spectral responses to changes in excitatory drive can lead to a refinement of existing gamma models. We compared gamma spectral responses to varying contrasts in a monkey dataset acquired previously (Roberts et al., 2013) with spectral responses to similar contrast variations in a new human MEG dataset. We found parametric frequency shifts with increasing contrast in human MEG at the single-subject and the single-trial level, analogous to those observed in the monkey. Additionally, we observed parametric modulations of spectral asymmetry, consistent across spikes, LFP and MEG. However, while gamma power scaled linearly with contrast in MEG, it saturated at high contrasts in both the LFP and spiking data. Thus, while gamma frequency changes to varying contrasts were comparable across spikes, LFP and MEG, gamma power changes were not. This indicates that gamma frequency may be a more stable parameter across scales of measurements and species than gamma power. The comparative approach undertaken here represents a fruitful path towards a better understanding of gamma oscillations in the human brain.
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Affiliation(s)
- A Hadjipapas
- University of Nicosia Medical School, Cyprus; St George's University of London, UK.
| | - E Lowet
- Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands; Maastricht University, Maastricht, The Netherlands.
| | - M J Roberts
- Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands; Maastricht University, Maastricht, The Netherlands
| | - A Peter
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Germany; International Max Planck Research School for Neural Circuits, Frankfurt, Germany
| | - P De Weerd
- Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands; Maastricht University, Maastricht, The Netherlands
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