Motions of charges between neurons produce some currents. These currents emit some electromagnetic waves which could be taken by electrodes on the scalp and form topographic images. In this research, a model is proposed which formulate EEG topographic parameters in terms of charge and mass of exchanged particles between neurons, number of neurons and length of synapses. In this model, by having densities of frequencies in different regions of brain, one can predict type, charge and velocity of particles which are exchanged between neurons. Testing the model by experimental data gives the good values for parameters which are in agreement with previous predictions.