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Birca A, Vakorin VA, Porayette P, Madathil S, Chau V, Seed M, Doesburg SM, Blaser S, Nita DA, Sharma R, Duerden EG, Hickey EJ, Miller SP, Hahn CD. Interplay of brain structure and function in neonatal congenital heart disease. Ann Clin Transl Neurol 2016; 3:708-22. [PMID: 27648460 PMCID: PMC5018583 DOI: 10.1002/acn3.336] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Accepted: 07/05/2016] [Indexed: 12/16/2022] Open
Abstract
Objective To evaluate whether structural and microstructural brain abnormalities in neonates with congenital heart disease (CHD) correlate with neuronal network dysfunction measured by analysis of EEG connectivity. Methods We studied a prospective cohort of 20 neonates with CHD who underwent continuous EEG monitoring before surgery to assess functional brain maturation and network connectivity, structural magnetic resonance imaging (MRI) to determine the presence of brain injury and structural brain development, and diffusion tensor MRI to assess brain microstructural development. Results Neonates with MRI brain injury and delayed structural and microstructural brain development demonstrated significantly stronger high‐frequency (beta and gamma frequency band) connectivity. Furthermore, neonates with delayed microstructural brain development demonstrated significantly weaker low‐frequency (delta, theta, alpha frequency band) connectivity. Neonates with brain injury also displayed delayed functional maturation of EEG background activity, characterized by greater background discontinuity. Interpretation These data provide new evidence that early structural and microstructural developmental brain abnormalities can have immediate functional consequences that manifest as characteristic alterations of neuronal network connectivity. Such early perturbations of developing neuronal networks, if sustained, may be responsible for the persistent neurocognitive impairment prevalent in adolescent survivors of CHD. These foundational insights into the complex interplay between evolving brain structure and function may have relevance for a wide spectrum of neurological disorders manifesting early developmental brain injury.
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Affiliation(s)
- Ala Birca
- Division of Neurology Department of Paediatrics The Hospital for Sick Children and the University of Toronto Toronto Canada; Division of Neurology Department of Neuroscience CHU Sainte-Justine and the University of Montreal Montreal Canada
| | - Vasily A Vakorin
- Department of Biomedical Physiology and Kinesiology Simon Fraser University Burnaby Canada
| | - Prashob Porayette
- Division of Cardiology Department of Paediatrics The Hospital for Sick Children and the University of Toronto Toronto Canada
| | - Sujana Madathil
- Program in Neurosciences and Mental Health SickKids Research Institute Toronto Canada
| | - Vann Chau
- Division of Neurology Department of Paediatrics The Hospital for Sick Children and the University of Toronto Toronto Canada; Program in Neurosciences and Mental Health Sick Kids Research Institute Toronto Canada
| | - Mike Seed
- Division of Cardiology Department of PaediatricsThe Hospital for Sick Children and the University of Toronto Toronto Canada; Program in Neurosciences and Mental Health Sick Kids Research Institute Toronto Canada
| | - Sam M Doesburg
- Department of Biomedical Physiology and Kinesiology Simon Fraser University Burnaby Canada
| | - Susan Blaser
- Program in Neurosciences and Mental Health Sick Kids Research Institute Toronto Canada; Department of Diagnostic Imaging The Hospital for Sick Children Toronto Canada
| | - Dragos A Nita
- Division of Neurology Department of Paediatrics The Hospital for Sick Children and the University of Toronto Toronto Canada; Program in Neurosciences and Mental Health Sick Kids Research Institute Toronto Canada
| | - Rohit Sharma
- Division of Neurology Department of Paediatrics The Hospital for Sick Children and the University of Toronto Toronto Canada
| | - Emma G Duerden
- Program in Neurosciences and Mental Health SickKids Research Institute Toronto Canada
| | - Edward J Hickey
- Program in Neurosciences and Mental Health Sick Kids Research Institute Toronto Canada; Division of Cardiovascular Surgery Department of Surgery The Hospital for Sick Children and the University of Toronto Toronto Canada
| | - Steven P Miller
- Division of Neurology Department of Paediatrics The Hospital for Sick Children and the University of Toronto Toronto Canada; Program in Neurosciences and Mental Health Sick Kids Research Institute Toronto Canada
| | - Cecil D Hahn
- Division of Neurology Department of Paediatrics The Hospital for Sick Children and the University of Toronto Toronto Canada; Program in Neurosciences and Mental Health Sick Kids Research Institute Toronto Canada
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Filley CM, Fields RD. White matter and cognition: making the connection. J Neurophysiol 2016; 116:2093-2104. [PMID: 27512019 DOI: 10.1152/jn.00221.2016] [Citation(s) in RCA: 242] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 08/04/2016] [Indexed: 12/14/2022] Open
Abstract
Whereas the cerebral cortex has long been regarded by neuroscientists as the major locus of cognitive function, the white matter of the brain is increasingly recognized as equally critical for cognition. White matter comprises half of the brain, has expanded more than gray matter in evolution, and forms an indispensable component of distributed neural networks that subserve neurobehavioral operations. White matter tracts mediate the essential connectivity by which human behavior is organized, working in concert with gray matter to enable the extraordinary repertoire of human cognitive capacities. In this review, we present evidence from behavioral neurology that white matter lesions regularly disturb cognition, consider the role of white matter in the physiology of distributed neural networks, develop the hypothesis that white matter dysfunction is relevant to neurodegenerative disorders, including Alzheimer's disease and the newly described entity chronic traumatic encephalopathy, and discuss emerging concepts regarding the prevention and treatment of cognitive dysfunction associated with white matter disorders. Investigation of the role of white matter in cognition has yielded many valuable insights and promises to expand understanding of normal brain structure and function, improve the treatment of many neurobehavioral disorders, and disclose new opportunities for research on many challenging problems facing medicine and society.
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Affiliation(s)
- Christopher M Filley
- Behavioral Neurology Section, Departments of Neurology and Psychiatry, University of Colorado School of Medicine, Aurora, Colorado; .,Denver Department of Veterans Affairs Medical Center, Denver, Colorado; and
| | - R Douglas Fields
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
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Renauld E, Descoteaux M, Bernier M, Garyfallidis E, Whittingstall K. Semi-Automatic Segmentation of Optic Radiations and LGN, and Their Relationship to EEG Alpha Waves. PLoS One 2016; 11:e0156436. [PMID: 27383146 PMCID: PMC4934857 DOI: 10.1371/journal.pone.0156436] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 05/13/2016] [Indexed: 12/13/2022] Open
Abstract
At rest, healthy human brain activity is characterized by large electroencephalography (EEG) fluctuations in the 8-13 Hz range, commonly referred to as the alpha band. Although it is well known that EEG alpha activity varies across individuals, few studies have investigated how this may be related to underlying morphological variations in brain structure. Specifically, it is generally believed that the lateral geniculate nucleus (LGN) and its efferent fibres (optic radiation, OR) play a key role in alpha activity, yet it is unclear whether their shape or size variations contribute to its inter-subject variability. Given the widespread use of EEG alpha in basic and clinical research, addressing this is important, though difficult given the problems associated with reliably segmenting the LGN and OR. For this, we employed a multi-modal approach and combined diffusion magnetic resonance imaging (dMRI), functional magnetic resonance imaging (fMRI) and EEG in 20 healthy subjects to measure structure and function, respectively. For the former, we developed a new, semi-automated approach for segmenting the OR and LGN, from which we extracted several structural metrics such as volume, position and diffusivity. Although these measures corresponded well with known morphology based on previous post-mortem studies, we nonetheless found that their inter-subject variability was not significantly correlated to alpha power or peak frequency (p >0.05). Our results therefore suggest that alpha variability may be mediated by an alternative structural source and our proposed methodology may in general help in better understanding the influence of anatomy on function such as measured by EEG or fMRI.
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Affiliation(s)
- Emmanuelle Renauld
- Department of Nuclear Medecine and Radiobiology, Faculty of Medicine and Health Science, University of Sherbrooke, Sherbrooke, Qc, Canada
| | - Maxime Descoteaux
- Sherbrooke Connectivity Imaging Lab (SCIL), Computer Science Department, Faculty of Science, University of Sherbrooke, Sherbrooke, Qc, Canada
- Centre Hospitalier Universitaire de Sherbrooke (CHUS), Sherbrooke, Qc, Canada
- Centre d’Imagerie Moléculaire de Sherbrooke (CIMS), Centre de Recherche du CHUS, Sherbrooke, Qc, Canada
| | - Michaël Bernier
- Department of Nuclear Medecine and Radiobiology, Faculty of Medicine and Health Science, University of Sherbrooke, Sherbrooke, Qc, Canada
| | - Eleftherios Garyfallidis
- Sherbrooke Connectivity Imaging Lab (SCIL), Computer Science Department, Faculty of Science, University of Sherbrooke, Sherbrooke, Qc, Canada
| | - Kevin Whittingstall
- Department of Nuclear Medecine and Radiobiology, Faculty of Medicine and Health Science, University of Sherbrooke, Sherbrooke, Qc, Canada
- Department of Diagnostic Radiology, Faculty of Medicine and Health Science, University of Sherbrooke, Sherbrooke, Qc, Canada
- Centre Hospitalier Universitaire de Sherbrooke (CHUS), Sherbrooke, Qc, Canada
- Centre d’Imagerie Moléculaire de Sherbrooke (CIMS), Centre de Recherche du CHUS, Sherbrooke, Qc, Canada
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Wang Y, Liu G, Hong D, Chen F, Ji X, Cao G. White matter injury in ischemic stroke. Prog Neurobiol 2016; 141:45-60. [PMID: 27090751 PMCID: PMC5677601 DOI: 10.1016/j.pneurobio.2016.04.005] [Citation(s) in RCA: 183] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 04/01/2016] [Accepted: 04/10/2016] [Indexed: 02/06/2023]
Abstract
Stroke is one of the major causes of disability and mortality worldwide. It is well known that ischemic stroke can cause gray matter injury. However, stroke also elicits profound white matter injury, a risk factor for higher stroke incidence and poor neurological outcomes. The majority of damage caused by stroke is located in subcortical regions and, remarkably, white matter occupies nearly half of the average infarct volume. Indeed, white matter is exquisitely vulnerable to ischemia and is often injured more severely than gray matter. Clinical symptoms related to white matter injury include cognitive dysfunction, emotional disorders, sensorimotor impairments, as well as urinary incontinence and pain, all of which are closely associated with destruction and remodeling of white matter connectivity. White matter injury can be noninvasively detected by MRI, which provides a three-dimensional assessment of its morphology, metabolism, and function. There is an urgent need for novel white matter therapies, as currently available strategies are limited to preclinical animal studies. Optimal protection against ischemic stroke will need to encompass the fortification of both gray and white matter. In this review, we discuss white matter injury after ischemic stroke, focusing on clinical features and tools, such as imaging, manifestation, and potential treatments. We also briefly discuss the pathophysiology of WMI and future research directions.
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Affiliation(s)
- Yuan Wang
- Department of Neurology, Xuanwu Hospital, Capital University of Medicine, Beijing 100053, China
| | - Gang Liu
- Department of Neurology, Xuanwu Hospital, Capital University of Medicine, Beijing 100053, China
| | - Dandan Hong
- Department of Bioengineering, University of Pittsburgh School of Engineering, United States
| | - Fenghua Chen
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, United States
| | - Xunming Ji
- Department of Neurosurgery, Xuanwu Hospital, Capital University of Medicine, Beijing 100053, China.
| | - Guodong Cao
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, United States; Geriatric Research Education and Clinical Centers, VA Pittsburgh Healthcare System, Pittsburgh, PA 15240, United States.
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Alexander DM, Nikolaev AR, Jurica P, Zvyagintsev M, Mathiak K, van Leeuwen C. Global Neuromagnetic Cortical Fields Have Non-Zero Velocity. PLoS One 2016; 11:e0148413. [PMID: 26953886 PMCID: PMC4783027 DOI: 10.1371/journal.pone.0148413] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 01/17/2016] [Indexed: 11/19/2022] Open
Abstract
Globally coherent patterns of phase can be obscured by analysis techniques that aggregate brain activity measures across-trials, whether prior to source localization or for estimating inter-areal coherence. We analyzed, at single-trial level, whole head MEG recorded during an observer-triggered apparent motion task. Episodes of globally coherent activity occurred in the delta, theta, alpha and beta bands of the signal in the form of large-scale waves, which propagated with a variety of velocities. Their mean speed at each frequency band was proportional to temporal frequency, giving a range of 0.06 to 4.0 m/s, from delta to beta. The wave peaks moved over the entire measurement array, during both ongoing activity and task-relevant intervals; direction of motion was more predictable during the latter. A large proportion of the cortical signal, measurable at the scalp, exists as large-scale coherent motion. We argue that the distribution of observable phase velocities in MEG is dominated by spatial filtering considerations in combination with group velocity of cortical activity. Traveling waves may index processes involved in global coordination of cortical activity.
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Affiliation(s)
- David M. Alexander
- Brain and Cognition Research Unit, KU Leuven - University of Leuven, Leuven, Belgium
- * E-mail:
| | - Andrey R. Nikolaev
- Brain and Cognition Research Unit, KU Leuven - University of Leuven, Leuven, Belgium
| | | | - Mikhail Zvyagintsev
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical School, RWTH Aachen University, Aachen, Germany
| | - Klaus Mathiak
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical School, RWTH Aachen University, Aachen, Germany
| | - Cees van Leeuwen
- Brain and Cognition Research Unit, KU Leuven - University of Leuven, Leuven, Belgium
- Kaiserslautern University of Technology, Kaiserslautern, Germany
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Lea-Carnall CA, Montemurro MA, Trujillo-Barreto NJ, Parkes LM, El-Deredy W. Cortical Resonance Frequencies Emerge from Network Size and Connectivity. PLoS Comput Biol 2016; 12:e1004740. [PMID: 26914905 PMCID: PMC4767278 DOI: 10.1371/journal.pcbi.1004740] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 01/06/2016] [Indexed: 11/25/2022] Open
Abstract
Neural oscillations occur within a wide frequency range with different brain regions exhibiting resonance-like characteristics at specific points in the spectrum. At the microscopic scale, single neurons possess intrinsic oscillatory properties, such that is not yet known whether cortical resonance is consequential to neural oscillations or an emergent property of the networks that interconnect them. Using a network model of loosely-coupled Wilson-Cowan oscillators to simulate a patch of cortical sheet, we demonstrate that the size of the activated network is inversely related to its resonance frequency. Further analysis of the parameter space indicated that the number of excitatory and inhibitory connections, as well as the average transmission delay between units, determined the resonance frequency. The model predicted that if an activated network within the visual cortex increased in size, the resonance frequency of the network would decrease. We tested this prediction experimentally using the steady-state visual evoked potential where we stimulated the visual cortex with different size stimuli at a range of driving frequencies. We demonstrate that the frequency corresponding to peak steady-state response inversely correlated with the size of the network. We conclude that although individual neurons possess resonance properties, oscillatory activity at the macroscopic level is strongly influenced by network interactions, and that the steady-state response can be used to investigate functional networks. When entrained using repetitive stimulation, sensory cortices appear to respond maximally, or resonate, at different driving frequencies: 10Hz in visual cortex; 20Hz and 40Hz in somatosensory and auditory cortices, respectively. The resonance frequencies are inversely correlated to the cortical volume of the respective regions, but it is unclear what drives this relationship. Here we used both computational and empirical data to demonstrate that resonance frequencies are emergent properties of the connectivity parameters of the underlying networks. The experimental paradigm stimulated large and small areas of visual cortex with different size objects made of flickering dots, and varied the driving frequency. Larger cortical areas exhibited maximum response at lower frequency than smaller areas, suggesting the inverse relationship between cortical size and resonance frequency holds, even within the same sensory modality. Computationally, we simulated cortical patches of different sizes and varied their connectivity parameters. We demonstrate that the size of the activated network is inversely related to its resonance frequency and that this change is due to the increased transmission delay and greater node degree within the larger network. The results are important for understanding the functional significance of oscillatory processes, and as a tool for probing changes in functional connectivity.
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Affiliation(s)
- Caroline A. Lea-Carnall
- Faculty of Medical and Human Sciences, University of Manchester, Manchester, United Kingdom
- * E-mail:
| | | | | | - Laura M. Parkes
- Faculty of Medical and Human Sciences, University of Manchester, Manchester, United Kingdom
| | - Wael El-Deredy
- Faculty of Medical and Human Sciences, University of Manchester, Manchester, United Kingdom
- School of Biomedical Engineering, University of Valparaiso, Valparaiso, Chile
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57
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A new mechanism of nervous system plasticity: activity-dependent myelination. Nat Rev Neurosci 2016; 16:756-67. [PMID: 26585800 DOI: 10.1038/nrn4023] [Citation(s) in RCA: 441] [Impact Index Per Article: 55.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The synapse is the focus of experimental research and theory on the cellular mechanisms of nervous system plasticity and learning, but recent research is expanding the consideration of plasticity into new mechanisms beyond the synapse, notably including the possibility that conduction velocity could be modifiable through changes in myelin to optimize the timing of information transmission through neural circuits. This concept emerges from a confluence of brain imaging that reveals changes in white matter in the human brain during learning, together with cellular studies showing that the process of myelination can be influenced by action potential firing in axons. This Opinion article summarizes the new research on activity-dependent myelination, explores the possible implications of these studies and outlines the potential for new research.
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Alba G, Pereda E, Mañas S, Méndez LD, González A, González JJ. Electroencephalography signatures of attention-deficit/hyperactivity disorder: clinical utility. Neuropsychiatr Dis Treat 2015; 11:2755-69. [PMID: 26543369 PMCID: PMC4622521 DOI: 10.2147/ndt.s51783] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The techniques and the most important results on the use of electroencephalography (EEG) to extract different measures are reviewed in this work, which can be clinically useful to study subjects with attention-deficit/hyperactivity disorder (ADHD). First, we discuss briefly and in simple terms the EEG analysis and processing techniques most used in the context of ADHD. We review techniques that both analyze individual EEG channels (univariate measures) and study the statistical interdependence between different EEG channels (multivariate measures), the so-called functional brain connectivity. Among the former ones, we review the classical indices of absolute and relative spectral power and estimations of the complexity of the channels, such as the approximate entropy and the Lempel-Ziv complexity. Among the latter ones, we focus on the magnitude square coherence and on different measures based on the concept of generalized synchronization and its estimation in the state space. Second, from a historical point of view, we present the most important results achieved with these techniques and their clinical utility (sensitivity, specificity, and accuracy) to diagnose ADHD. Finally, we propose future research lines based on these results.
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Affiliation(s)
- Guzmán Alba
- Physiology Unit, Health Sciences Faculty (S Medicine), University of La Laguna, Tenerife, Spain
| | - Ernesto Pereda
- Department of Industrial Engineering, School of Engineering and Technology, University of La Laguna, Tenerife, Spain
| | - Soledad Mañas
- Clinical Neurophysiology Unit, University Hospital La Candelaria, Tenerife, Spain
| | - Leopoldo D Méndez
- Clinical Neurophysiology Unit, University Hospital La Candelaria, Tenerife, Spain
| | - Almudena González
- Physiology Unit, Health Sciences Faculty (S Medicine), University of La Laguna, Tenerife, Spain
| | - Julián J González
- Physiology Unit, Health Sciences Faculty (S Medicine), University of La Laguna, Tenerife, Spain
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59
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Tenke CE, Kayser J. Surface Laplacians (SL) and phase properties of EEG rhythms: Simulated generators in a volume-conduction model. Int J Psychophysiol 2015; 97:285-98. [PMID: 26004020 PMCID: PMC4537832 DOI: 10.1016/j.ijpsycho.2015.05.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Revised: 05/04/2015] [Accepted: 05/08/2015] [Indexed: 11/30/2022]
Abstract
Surface Laplacian (SL) methods offer advantages in spectral analysis owing to the well-known implications of volume conduction. Although recognition of the superiority of SL over reference-dependent measures is widespread, well-reasoned cautions have precluded their universal adoption. Notably, the expected selectivity of SL for superficial rather than deep generators has relegated SL to the role of an add-on to conventional analyses, rather than as an independent area of inquiry, despite empirical findings supporting the consistency and replicability of physiological effects of interest. It has also been reasoned that the contrast-enhancing effects of SL necessarily make it insensitive to broadly distributed generators, including those suspected for oscillatory rhythms such as EEG alpha. These concerns are further exacerbated for phase-sensitive measures (e.g., phase-locking, coherence), where key features of physiological generators have yet to be evaluated. While the neuronal generators of empirically-derived EEG measures cannot be precisely known due to the inverse problem, simple dipole generator configurations can be simulated using a 4-sphere head model and linearly combined. We simulated subdural and deep generators and distributed dipole layers using sine and cosine waveforms, quantified at 67-scalp sites corresponding to those used in previous research. Reference-dependent (nose, average, mastoids reference) EEG and corresponding SL topographies were used to probe signal fidelity in the topography of the measured amplitude spectra, phase and coherence of sinusoidal stimuli at and between "active" recording sites. SL consistently outperformed the conventional EEG measures, indicating that continued reluctance by the research community is unfounded.
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Affiliation(s)
- Craig E Tenke
- Division of Cognitive Neuroscience, New York State Psychiatric Institute, New York, NY, USA; Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA.
| | - Jürgen Kayser
- Division of Cognitive Neuroscience, New York State Psychiatric Institute, New York, NY, USA; Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA
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Fields RD, Woo DH, Basser PJ. Glial Regulation of the Neuronal Connectome through Local and Long-Distant Communication. Neuron 2015; 86:374-86. [PMID: 25905811 DOI: 10.1016/j.neuron.2015.01.014] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
If "the connectome" represents a complete map of anatomical and functional connectivity in the brain, it should also include glia. Glia define and regulate both the brain's anatomical and functional connectivity over a broad range of length scales, spanning the whole brain to subcellular domains of synaptic interactions. This Perspective article examines glial interactions with the neuronal connectome (including long-range networks, local circuits, and individual synaptic connections) and highlights opportunities for future research. Our understanding of the structure and function of the neuronal connectome would be incomplete without an understanding of how all types of glia contribute to neuronal connectivity and function, from single synapses to circuits.
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Affiliation(s)
- R Douglas Fields
- Nervous System Development and Plasticity Section, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA.
| | - Dong Ho Woo
- Nervous System Development and Plasticity Section, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
| | - Peter J Basser
- Section on Tissue Biophysics and Biomimetics, Program on Pediatric Imaging and Tissue Sciences, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA
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Ramos RT. The concepts of representation and information in explanatory theories of human behavior. Front Psychol 2014; 5:1034. [PMID: 25278921 PMCID: PMC4165208 DOI: 10.3389/fpsyg.2014.01034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 08/29/2014] [Indexed: 11/17/2022] Open
Abstract
Focusing in experimental study of human behavior, this article discusses the concepts of information and mental representation aiming the integration of their biological, computational, and semantic aspects. Assuming that the objective of any communication process is ultimately to modify the receiver's state, the term correlational information is proposed as a measure of how changes occurring in external world correlate with changes occurring inside an individual. Mental representations are conceptualized as a special case of information processing in which correlational information is received, recorded, but also modified by a complex emergent process of associating new elements. In humans, the acquisition of information and creation of mental representations occurs in a two-step process. First, a sufficiently complex brain structure is necessary to establishing internal states capable to co-vary with external events. Second, the validity or meaning of these representations must be gradually achieved by confronting them with the environment. This contextualization can be considered as part of the process of ascribing meaning to information and representations. The hypothesis introduced here is that the sophisticated psychological constructs classically associated with the concept of mental representation are essentially of the same nature of simple interactive behaviors. The capacity of generating elaborated mental phenomena like beliefs and desires emerges gradually during evolution and, in a given individual, by learning and social interaction.
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Affiliation(s)
- Renato T. Ramos
- Laboratory of Psychophysiology and Neurophysiology (LIM-23), Department of Psychiatry, Institute of Psychiatry, University of São Paulo Medical SchoolSão Paulo, Brazil
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