Collateral nerve sprouting and twitch forces of single motor units in conditions with partial denervation in man.
Single motor units (MUs) were studied in the first dorsal interosseus muscle of 7 patients with slight partial denervation and in 10 controls. MU action potentials were recorded using the macro-EMG technique and their size was taken to assess collateral nerve sprouting. Simultaneously, the muscle force was monitored to determine the voluntary recruitment thresholds of the MUs and spike-triggered-averaging was applied to measure their twitch forces. At comparable force recruitment thresholds, both macro-EMG potentials and twitch forces were increased in the patients. We conclude, that collateral nerve sprouting increases MU force and can compensate for MU loss.
Dengler
R
R
Department of Neurology, Technical University Munich, F.R.G.
Konstanzer
A
A
Hesse
S
S
Schubert
M
M
Wolf
W
W
D000328:Adult; D000368:Aged; D006801:Humans; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology*; D009119:Muscle Contraction; D009121:Muscle Denervation; D009135:Muscular Diseases / Q000503:physiopathology*; D011999:Recruitment, Neurophysiological