title: Generators of the early and late median thenar premotor potentials.
abstract: The generator sources of the median thenar premotor potentials (PMPs) have remained elusive despite debate in the literature. By studying the median nerve in the hand with a variety of bipolar and referential recording montages, we systematically examined the possible near-field and far-field sources that may determine these potentials. The results suggest that the early PMP is a near-field potential recorded by G1 and generated by the median nerve traversing the distal carpal tunnel. The late PMP represents a far-field potential generated by the median digital nerve fibers as they pass from the palm volume into the thumb volume. Characteristics of the late PMP are explained using the leading/trailing dipole (L/TD) model of far-field potential generation. The diagnostic utility of these PMPs is questionable, since they are recorded from "regions" along the nerve rather than from more clearly defined sites.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Medical College of Wisconsin, Milwaukee, USA.
authors.forename: T A
authors.initials: TA
authors.lastname: Park
authors.forename: D R
authors.initials: DR
authors.lastname: Del Toro
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D004558:Electric Stimulation; D006225:Hand / Q000294:innervation* / Q000502:physiology; D006801:Humans; D008475:Median Nerve / Q000502:physiology*; D009046:Motor Neurons / Q000502:physiology; D009132:Muscles / Q000294:innervation* / Q000502:physiology; D009431:Neural Conduction / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology; D013997:Time Factors