Impaired regulation of the firing pattern of single motor units.
The firing pattern of single motor units from the anterior tibial muscle was studied during constant isometric contraction. Recordings were made with bipolar, fine-wire electrodes from 4 normal subjects and from 10 patients with spasticity. A microcomputer was used to classify the motor unit potentials automatically and to measure the interspike intervals. The patients had reduced firing frequencies and reduced variability between neighbor intervals. Seven patients with spasticity due to supraspinal lesions had positive correlation between neighbor intervals.
D000200:Action Potentials; D001927:Brain Diseases / Q000175:diagnosis / Q000503:physiopathology*; D004576:Electromyography; D006801:Humans; D007537:Isometric Contraction; D008838:Microcomputers; D009046:Motor Neurons / Q000502:physiology*; D009128:Muscle Spasticity / Q000503:physiopathology*; D009132:Muscles / Q000503:physiopathology*