SINGLE FIBER, SCANNING, AND MACRO EMG: NEW WAYS OF LOOKING AT THE MOTOR UNIT.
The physiologic motor unit (MU) consists of an anterior horn cell, its axon and nerve branches and all the muscle fibers it enervates. The muscle fibers of a single MU are distributed randomly within a certain portion of the muscle (the MU territory), interspersed with muscle fibers from other MUs. Electromyography (EMG) is performed to gather information about the MU and the muscle fibers it comprises. EMG electrodes of different types have been developed to record the electrical activity generated by the muscle fibers of the MU. The main findings of studies using these techniques for the investigation of neuromuscular disease are summarized.