BRAIN EVOKED-POTENTIAL TOPOGRAPHIC MAPPING BASED ON THE DIFFUSE APPROXIMATION

Evoked potential mapping is a convenient technique to describe brain e lectrical activity using pictorial representation. A new interpolation method based on the diffuse approximation is applied to represent evo ked potential distribution over the skull. The method retains most of the attractive features of the finite-element method but does not requ ire explicit elements. In the simulation examples, the human head is a ssumed to be a single-layer sphere with homogeneous conductivity, and Ary eccentricity transformation is considered to approximate the more realistic three-shell model. The patterns shown in the computed maps s uggest the ability of the proposed method to extract coherent informat ion from the data from different electrodes. In the application protoc ol, visual evoked potentials are used to test the method with a realis tic head shape.