Realistic modeling of VEP topography.
A finite element model of the human head was constructed from digitized contours of a cadaver head cut at 1 cm intervals parallel to the cantho-meatal plane. The boundary element method was used to calculate the potential fields produced by dipoles in the cortex at various locations and orientations. Field profiles and their Fourier transforms established the Nyquist Sampling interval necessary to faithfully reconstruct scalp fields from discrete measurements. The interval varies from approx. 1 cm for sources near the occipital pole to 2 cm for sources near the Rolandic fissure. The resolution of the VEP was also estimated. For signal-to-noise ratios ranging from 4 to 10, source displacements ranging from approx. 1.4 to 0.4 cm in the cortex can be resolved.
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Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas 75235-9057.
D001921:Brain / Q000033:anatomy & histology; D003198:Computer Simulation; D005074:Evoked Potentials, Visual / Q000502:physiology*; D006801:Humans; D008722:Methods; D008953:Models, Anatomic; D012535:Scalp / Q000502:physiology; D014793:Visual Cortex / Q000502:physiology