The 7th International Congress of the International Society for Brain Electromagnetic Topography (ISBET), Rio de Janeiro, Brazil

Autor: M.J. Peters, S.P. van den Broek, M. Donderwinkel
Rok vydání: 1997
Předmět:
Zdroj: Brain Topography. 9:229-242
ISSN: 1573-6792
0896-0267
Popis: A realistically shaped model of the head, consisting of tetrahedral elements, is used to investigate the influence of inhomogeneities in the volume conductor (e.g., ventricles and holes) on EEG and MEG. The potential is computed using the finite-element method. The magnetic field is calculated from this potential distribution, applying the law of Biot-Savart. In order to study the influence of the ventricles, computations are carried out using two models: one in which the elements within the ventricles are given the same conductivity as the brain and one in which these elements have a higher conductivity. The influence of holes in the skull layer is examined by giving some elements in the skull layer the same conductivity as that of the brain. The geometry of compartments is obtained semiautomatically from Magnetic Resonance Imaging (MRI) scans. The surface of the ventricles is obtained by manually selecting points on the interface between ventricle and brain. The computation time depends on the total number of tetrahedrons. Therefore, the vertices are distributed in, such a way that a sufficiently high accuracy is obtained with as few tetrahedrons as possible.
Databáze: OpenAIRE
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