Finite element modelling of extracellular potentials around thin-film microelectrode probes in invertebrate peripheral nerve

Thin-film microelectrode probes (microprobes) are being investigated as peripheral nerve neural signal transducers for use in functional electrical stimulation orthoses. Finite element modelling techniques have been used to determine the effects of microprobe substrates on extracellular signals recorded intraneurally from locust peripheral nerve. The models show that probes with widths of the order of one-tenth the longitudinal extent of the action potential can have effects of amplifying signals from nerve fibres in front of the probe, and attenuating signals from fibres behind. The nerve sheath can also contribute to, and modulate, these effects