Modelling compound action potentials of peripheral nerves in situ. I. Model description: evidence for a non-linear relation between fibre diameter and velocity.

Compound sensory nerve action potentials of sural nerves of healthy volunteers have been measured at 7 different distances between the site of stimulation and the site of recording. The results are used to adjust a model description for the generation of compound nerve action potentials. A fairly good agreement between experiment and model is obtained when a weak non-linear, S-shaped relation between external fibre diameter and propagation velocity of the single fibre action potential is assumed. This result corresponds surprisingly well with findings in "classical' reconstruction attempts reported in the literature.