Let’s take a look at the effect of how snug, the electrode cuff, fits the fascicle. In this example I’m thinking of an acute experiment where an electrode has been placed on a target fascicle and connective tissues have not had time to encapsulate the electrode. The figure on the right is shown as a reference for a snug fitting cuff, explored previously. We have a fascicle with a lose fitting cuff with the extra space filled with saline. A stimulus of -1.086 V applied to the electrode results in the activation of 10 µm axons in this region. The same stimulation activates all 20 mm axons in the fascial and doubling the stimulus results in activation of all 10 µm axons in the fascicle. Constraining the stimulus current to flow in the cuff provides a better opportunity to modulate the activated population, slight changes in the magnitude results in a less steep recruitment characteristic.
RR Chintalacharuvu, DA Ksienski, JT Mortimer, Annual Int Conf of the IEEE Engr in Med and Biol Vol 13, No 2 1991, pp 0912-13
Rekha R. Chintalacharuvu, A Numerical Analysis of the Electric Field Generated by the Nerve Cuff Electrode, MS thesis, 1991 Case Western Reserve University