A polyimide pressure-contact multielectrode array for implantation along a submillimeter neural process in small animals

We describe a microelectrode system for recordings from nerve bundles with diameters ranging from 20-200 microm. A novel polyimide structure allows for a planar microfabricated device to constrain a free neural process against several recording sites. This polyimide array contains multiple zigzag vias through which a small nerve process may be woven while remaining functionally intact in a live preparation. Our electrode construct features the benefits of nerve cuffs (evenly spaced electrodes in a polymer) and the functionality of a nerve hook (ability to connect to submillimeter processes). The device records extracellular action potentials in the red-swamp crayfish, Procambarus clarkii. Action potential propagation is monitored at several sites along a constrained nerve in this model organism's peripheral nervous system. Details of temporal accuracy and error sources in absolute conduction velocity measurements from microelectrode arrays are discussed.