Possible model for generation of P9 far-field potentials

The distribution of P9 far-field somatosensory evoked potentials, after ulation of the median nerve with a knee reference, was examined to mine the mechanism of the generation of P9 potentials. In addition to tive potentials (P9s), we found a negative potential (N9) recorded from the chest ipsilateral to the stimulation. The simulation of the distribution of these P9/N9 potentials by an electrical circuit diagram suggested the validity of this model for generation of the P9s.