ABSTRACT
Electromyography provides the most sensitive measure of muscle activity now available, and since covert muscle responses are the most indicative of cognitive functioning, this response category requires most of our attention. The recording of muscle action potentials through electromyography provides the electromyogram, which is a record of the electrical properties of muscular activity. The muscle fiber is the structural unit of striate muscle; in appearance it looks like a fine piece of thread. In size, muscle fibers generally vary in length of 1 mm-10 cm, and in width from 10-100 microns, although they may exceed 34 cm in length. Muscle fiber components of a muscle are aligned in parallel and probably stretch from the origin as a single entity. Inserted electrodes have an advantage over surface electrodes when the researcher seeks to study localized, subcutaneous events. The surface electrode potential is a summation over both space and time.
