Easily-implantable electrodes for chronic recording of electromyogram activity in small fetuses

A method is described for the construction of simple, robust electrodes suitable for obtaining long-term chronic recordings of electromyogram activity from delicate muscles of small experimental animals. The electrodes are equipped with small, gold-plated barbed tips which have the form of harpoons that may be pushed directly into a muscle, where they remain without being sutured into place. These features greatly facilitate the instrumentation of muscles which are very thin or of limited accessibility. The electrodes have been used successfully to obtain chronic recordings of respiratory muscle activity from early gestation fetal lambs in utero.