Comparison of numerical simulations performed by IA, NPA and SA to the data measured in vivo . A. Comparison of U(I) characteristics calculated in nonlinear model and linear to the in vivo data. B. The relationships σL(E) and constant conductivities σL(E) = σ0 = const. in nonlinear and linear models, respectively. The diameter of needle electrodes was 1.1 mm.