An efficient algorithm for computing multishell spherical volume conductor models in EEG dipole source localization.
Computationally localizing electrical current sources of the electroencephalographic signal requires a volume conductor model which relates theoretical scalp potentials to the dipolar source located within the modeled brain. The commonly used multishell spherical model provides this source-potential relationship using a sum of infinite series whose computation is difficult. This paper provides a closed-form approximation to this sum based on an optimal fitting to the weights of the Legendre polynomials. The second-order (third-order) approximation algorithm, implemented by a provided C-routine, requires only 100 (140) floating point operations to compute a single scalp potential in response to an arbitrary current dipole located within a four-shell spherical volume conductor model. This cost of computation represents only 6.3% (8.9%) of that required by the direct method. The relative mean square error, measured by using 20,000 random dipoles distributed within the modeled brain, in only 0.29% (0.066%).
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Department of Neurosurgery, University of Pittsburgh, PA 15213, USA. mrsun@neuronet.pitt.edu
D000465:Algorithms; D001921:Brain / Q000502:physiology; D003198:Computer Simulation / Q000191:economics; D003365:Costs and Cost Analysis; D004569:Electroencephalography / Q000191:economics / Q000706:statistics & numerical data; D004594:Electrophysiology; D006257:Head; D006801:Humans; D008959:Models, Neurological; D012535:Scalp / Q000502:physiology