Crossed facilitation and post-contraction depression of abductor pollicis brevis motor neurons.
Crossed facilitation of abductor pollicis brevis (APB) motor neurons by voluntary contraction of the contralateral APB was investigated using F response analysis. The integrated F response EMG showed a mean 4-fold increase during contraction. This enhancement was maintained until the onset of subjective fatigue and then declined. After isometric or isotonic contraction of the ipsilateral APB there was a significant depression of F responses with a progressive return to baseline values over a 6 minute period. The significance of the findings is discussed.
Knezevic
W
W
Department of Neurology, Queen Elizabeth II Medical Centre, Perth, Western Australia.
Mastaglia
F L
FL
Thickbroom
G W
GW
Carroll
W M
WM
D000328:Adult; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D008475:Median Nerve / Q000502:physiology; D009046:Motor Neurons / Q000502:physiology*; D009119:Muscle Contraction; D009132:Muscles / Q000294:innervation*; D013933:Thumb / Q000294:innervation*