MODELING SELECTIVE ACTIVATION OF SMALL MYELINATED NERVE-FIBERS USING A MONOPOLAR POINT ELECTRODE

The aim of this study is to investigate theoretically the possibility for activation of small myelinated nerve fibres without activating lar ger ones when stimulating a nerve fibre bundle using a monopolar point electrode. Therefore, the Sensitivity of excitation and blocking thre shold currents of nerve fibres to fibre diameter, electrode-fibre dist ance and pulse duration has been simulated by a computer model. A simp le infinite, homogeneous volume conductor and a cathodal point source were used in combination with a model representing the electrical prop erties of a myelinated nerve fibre. The results show that selective ac tivation of small myelinated fibres may be possible in a region at som e distance from the electrode.