Abstract:
Neuronal activity in the brain cortex is replaced by a small current dipole, and hence
the localized electric activities of the cortex are well approximated by equivalent
current dipoles. Position and moments of these equivalent dipoles are estimated from
the scalp potentials. In this analysis, the head as a conductor is divided into three
volumes with uniform electric conductivity: Scalp, Skull and Brain tissue; we call
this head model the SSB Head Model. The boundary element method is used in solving this problem and reliability of the
final result mainly depends on the arrangement of nodal points on the surfaces of
these three regions for numerical calculation, the electric conductivity ratios of
the three regions in the model, and the number of electrodes. By means of computer
simulation we investigated dependence of errors in the estimated dipole position on
these factors. It is found that arrangement of nodal points must be decided adaptively
depending on the source position.
Keywords
Dipole Tracing - Head Model - Nodal Points - Conductivity Ratios - Equivalent Dipole
