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Proceedings Paper

Determination of sources using brain-evoked potential maps
Author(s): Avner Amir; Don L. Jewett
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Paper Abstract

Methods to localize the sources of Brain Evoked Potential Maps based on modeling of the sources as point dipoles have been widely used for more than twenty years. Such methods still lack a basic theory which can answer questions regarding the resolution and uniqueness of the results in the context of a realistic head model, with no a prior restrictions on the sources. In the first part of the paper we present simple physical models for the origin of far-field potentials associated with the auditory and somatosensory systems. An action potential travels along a straight axon can only produce a quadrupole field at far distances. We show that the far field potentials must originate when the action potential passes through a bent axon or through changes in the conductivities or in the external boundaries of the volume conductor surrounding the axon. We discuss the question of uniqueness of the solution for the 'inverse problem' of evoked potentials. This problem involved the reconstruction of the location and pattern of activity of the neuronal generators in the brain, given the map of the scalp electric potentials. We show that in a head shape with a realistic geometry spatially distinct points, line or open surface generators cannot create the same scalp potential map. The same applies to two non-overlapping generators occupying finite volumes.

Paper Details

Date Published: 27 August 1993
PDF: 8 pages
Proc. SPIE 1887, Physiological Imaging, Spectroscopy, and Early-Detection Diagnostic Methods, (27 August 1993); doi: 10.1117/12.151196
Show Author Affiliations
Avner Amir, Abratech Corp. and Univ. of California/San Francisco (United States)
Don L. Jewett, Abratech Corp. and Univ. of California/San Francisco (United States)

Published in SPIE Proceedings Vol. 1887:
Physiological Imaging, Spectroscopy, and Early-Detection Diagnostic Methods
Randall Locke Barbour; Mark J. Carvlin, Editor(s)

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