The effect of afferent stimuli on the firing pattern of single motor units has been studied in the human first dorsal interosseous muscle of the hand. A reproducible series of changes in the probability of motor unit firing was seen. There was evidence for an excitatory spinal reflex involving median nerve muscle afferent fibres and ulnar nerve motor fibres. Cutaneous and muscle afferent pathwa...

The aim of this study was to examine the mechanomyogram (MMG) and force relationship of the first dorsal interosseous (FDI) muscle as well as the biceps brachii (BB) muscle during voluntary isometric ramp contractions, and to elucidate the MMG responses resulting from the intrinsic motor unit (MU) activation strategy of FDI muscle with reference to the MMG of BB muscle. The subjects were asked ...

Changes in motor unit behavior following isometric fatigue of the first dorsal interosseous 1 muscle 2 by 3 Lara McManus , Xiaogang Hu , William Z. Rymer 2, , Madeleine M. Lowery , Nina L. Suresh 2 4 1) University College Dublin, Belfield, Dublin 4, Ireland 5 2) Rehabilitation Institute of Chicago, Chicago, IL 60611, USA 6 3) Northwestern University, Evanston, IL 60208, USA 7 Abbreviated Title:...

Surface e lec t romyogram (EMG) f rom musc les undergoing sus ta ined i somet r ic voluntary contractions has been well studied. Power spect ra l analys is of the myoelect r ic signals so obtained, characteristically shows a t ime dependant sh i f t of the mean power f requency to lower f requenc ies , as the contraction proceeds (1). Such a compression of the EMG power spec t rum to lower freq...

OBJECTIVE To derive normative values for ulnar nerve conduction study of the active recording electrode on the first dorsal interosseous muscle (FDI) and the reference electrode on the proximal phalanx of the thumb. METHOD Ulnar nerve motor conduction study with FDI and abductor digiti minimi muscle (ADM) recording was performed in 214 hands of 107 healthy subjects. Ulnar NCS was performed wi...

Isolated lesions of the posterior interosseous nerve of the forearm are uncommon. Most follow injury to the elbow region The clinical features of a long-standing lesion of the nerve are wasting of the posterior forearm muscles (excepting brachio-radialis and extensor carpi radialis longus), diminution or loss of active extension of the fingers at the metacarpo-phalangeal joints, and weakness or...

Seeing others performing an action induces the observers' motor cortex to "resonate" with the observed action. Transcranial magnetic stimulation (TMS) studies suggest that such motor resonance reflects the encoding of various motor features of the observed action, including the apparent motor effort. However, it is unclear whether such encoding requires direct observation or whether force requi...

Magnetic stimulation with a double-cone-coil over the back of the head activates the motor tracts at the level of pyramidal decussation (brain stem stimulation [BST]). However, single-pulse BST (single BST) sometimes cannot elicit motor-evoked potentials (MEPs) in patients with corticospinal tract involvement. We developed a technique using double-pulse BST (double BST) to elicit MEPs even in p...

The purpose of this study was to investigate corticospinal modulation of bimanual (BM) movement with different relative phases (RPs). The participants rhythmically abducted and adducted the right index finger (unimanual (UM) movement) or both index fingers (BM movement) with a cyclic duration of 1 s. The RP of BM movement, defined as the time difference between one hand movement and the other h...