Propagation and summation of EPSP was studied by means of a numerical model of rat Purkinje neuron. It was shown that the difference between the membrane resistivity of the soma and dendrites can be determined experimentally by the character of EPSP attenuation, while comparing intra- and extracellular recordings. It was also shown that at an increase of synaptic input the nonlinear increase of the potential is more pronounced in the soma that in the synaptic region. The role of this fact for the interpretation of the experimental data is discussed.