Journal ArticleDOI
High-resolution EEG using spline generated surface Laplacians on spherical and ellipsoidal surfaces
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TLDR
The spline-Laplacian accurately estimates isolated dipoles or distributed sources, is insensitive to subcortical sources and to sources which originate outside the boundaries of the electrode array, and acts as a bandpass spatial filter whose characteristics appear to provide a good match to the volume conduction of intracranial sources through human heads.Abstract:
Spline generated surface Laplacians are introduced as an effective method for estimating neocortical source activity at moderate scales. The method appears to be robust to the unavoidable perturbations of measured potentials and errors of head geometry and resistivity that are certain to occur in clinical or research settings. In particular, the surface Laplacian is derived for general ellipsoidal surfaces in terms of the spline function. The spline-Laplacian accurately estimates isolated dipoles or distributed sources, is insensitive to subcortical sources and to sources which originate outside the boundaries of the electrode array, and acts as a bandpass spatial filter whose characteristics appear to provide a good match to the volume conduction of intracranial sources through human heads. As a result, spatial resolution is improved over that obtained with conventional EEG by at least a factor of three. This improvement is likely to have a significant impact on both medical and cognitive studies involving EEG. >read more
Citations
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Journal ArticleDOI
Event-related EEG/MEG synchronization and desynchronization: basic principles.
TL;DR: Quantification of ERD/ERS in time and space is demonstrated on data from a number of movement experiments, whereby either the same or different locations on the scalp can display ERD and ERS simultaneously.
Journal ArticleDOI
EEG coherency: I: statistics, reference electrode, volume conduction, Laplacians, cortical imaging, and interpretation at multiple scales
Paul L. Nunez,Ramesh Srinivasan,Andrew F. Westdorp,Andrew F. Westdorp,Ranjith S. Wijesinghe,Ranjith S. Wijesinghe,Don M. Tucker,Richard B. Silberstein,Peter J. Cadusch +8 more
TL;DR: Conventional reference, average reference, bipolar, Laplacian, and cortical image coherencies are shown to be partly independent measures of neocortical dynamic function at different spatial scales, due to each method's unique spatial filtering of intracranial source activity.
Journal ArticleDOI
Flow of activation from V1 to frontal cortex in humans. A framework for defining "early" visual processing.
John J. Foxe,Gregory V. Simpson +1 more
TL;DR: Data suggest that activity represented in the "early" ERP components such as P1 and N1 (and possibly even C1) is likely to reflect relatively late processing, after the initial volley of sensory afference through the visual system and involving top-down influences from parietal and frontal regions.
Journal Article
Event-related EEG/MEG synchronization and desynchronization: Basic principles
TL;DR: In this article, an internally or externally paced event results not only in the generation of an ERP but also in a change in the ongoing EEG/MEG in form of an event-related desynchronization (ERD) or eventrelated synchronization (ERS).
Journal ArticleDOI
Spatial-temporal structures of human alpha rhythms: theory, microcurrent sources, multiscale measurements, and global binding of local networks
TL;DR: A theoretical framework supporting experimental measures of dynamic properties of human EEG is proposed with emphasis on distinct alpha rhythms, and new EEG data demonstrate that both globally coherent and locally dominated behavior can occur within the alpha band, depending on narrow band frequency, spatial measurement scale, and brain state.
References
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Journal ArticleDOI
Methods of Theoretical Physics. By P.M. Morse and H. Feschbach. 2vols., Pp.xxii, 1978. 120s. each vol. 1953.(McGraw-Hill)
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Multiquadric equations of topography and other irregular surfaces
TL;DR: In this paper, a method of representing irregular surfaces that involves the summation of equations of quadric surfaces having unknown coefficients is described, and procedures are given for solving multiquadric equations of topography that are based on coordinate data.
Book
Electric Fields of the Brain: The Neurophysics of Eeg
Paul L. Nunez,Erich Harth +1 more
TL;DR: In this article, the authors present an overview of the physics-EEG interface, including the physics of electromagnetic fields and EEG, as well as EEG-based recording strategies, reference issues, and dipole localization.
Journal ArticleDOI
Spherical splines for scalp potential and current density mapping
TL;DR: Description of mapping methods using spherical splines, both to interpolate scalp potentials (SPs) and to approximate scalp current densities (SCDs) with greater accuracy in areas with few electrodes.