Changes of forearm EMG and cerebral evoked potentials following sudden muscle stretch in patients with Huntington's disease

Siedenberg, Ralf; Goodin, Douglas S.; Aminoff, Michael J.

doi:10.1002/(sici)1097-4598(199911)22:11<1557::aid-mus11>3.0.co;2-6

Cited by 6 publications

(1 citation statement)

References 14 publications

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“…While some studies on human skeletal muscle function have been done, most of those have focused on descending control of motor function. Interestingly, EMG studies in HD patients have reported abnormalities in motor unit activity (Harper et al ., 1991) and long latency responses (Noth et al ., 1985; Leblhuber et al ., 1991; Berardelli et al ., 1999; Siedenberg et al ., 1999). Although these deficits have usually been attributed to defects in cortical processing (Noth et al ., 1985; Abbruzzese & Berardelli, 2003), not all of them can be explained by alterations in the primary sensory pathways (Siedenberg et al ., 1999).…”

Section: Morphological Abnormalities In Neuromuscular Junctionsmentioning

confidence: 99%

Progressive abnormalities in skeletal muscle and neuromuscular junctions of transgenic mice expressing the Huntington's disease mutation

Ribchester

Thomson

Wood

et al. 2004

Eur J of Neuroscience

156

151

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Huntington's disease (HD) is a neurodegenerative disorder with complex symptoms dominated by progressive motor dysfunction. Skeletal muscle atrophy is common in HD patients. Because the HD mutation is expressed in skeletal muscle as well as brain, we wondered whether the muscle changes arise from primary pathology. We used R6/2 transgenic mice for our studies. Unlike denervation atrophy, skeletal muscle atrophy in R6/2 mice occurs uniformly. Paradoxically however, skeletal muscles show age-dependent denervation-like abnormalities, including supersensitivity to acetylcholine, decreased sensitivity to mu-conotoxin, and anode-break action potentials. Morphological abnormalities of neuromuscular junctions are also present, particularly in older R6/2 mice. Severely affected R6/2 mice show a progressive increase in the number of motor endplates that fail to respond to nerve stimulation. Surprisingly, there was no constitutive sprouting of motor neurons in R6/2 muscles, even in severely atrophic muscles that showed other denervation-like characteristics. In fact, there was an age-dependent loss of regenerative capacity of motor neurons in R6/2 mice. Because muscle fibers appear to be released from the activity-dependent cues that regulate membrane properties and muscle size, and motor axons and nerve terminals become impaired in their capacity to release neurotransmitter and to respond to stimuli that normally evoke sprouting and adaptive reinnervation, we speculate that in these mice there is a progressive dissociation of trophic signalling between motor neurons and skeletal muscle. However, irrespective of the cause, the abnormalities at neuromuscular junctions we report here are likely to contribute to the pathological phenotype in R6/2 mice, particularly in late stages of the disease.

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Section: Morphological Abnormalities In Neuromuscular Junctionsmentioning

confidence: 99%

Progressive abnormalities in skeletal muscle and neuromuscular junctions of transgenic mice expressing the Huntington's disease mutation

Ribchester

Thomson

Wood

et al. 2004

Eur J of Neuroscience

156

151

View full text Add to dashboard Cite

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Proposed cortical and sub-cortical contributions to the long-latency stretch reflex in the forearm

Lewis

Polych

Byblow

2004

Experimental Brain Research

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The short- and long-latency (SLSR, LLSR) components of the stretch reflex response were investigated in the forearm using a paired transcranial magnetic stimulation (TMS)-stretch reflex protocol. Responses to TMS were recorded in the flexor and extensor carpi radialis muscles (FCR, ECR) after conditioning with a rapid wrist extension movement. The cortical stimuli were timed to elicit a motor-evoked potential (MEP) at either the SLSR or LLSR onset in the FCR muscle. Responses were also collected in TMS-alone and stretch reflex-alone conditions. Six intensities of magnetic stimulation were applied in all conditions. In the FCR muscle, MEP amplitude when timed to arrive at the LLSR onset was significantly greater than the sum of the MEP and stretch reflex responses when given separately. MEP amplitudes at the SLSR onset in the FCR muscle and in the ECR muscle at both SLSR and LLSR onset were not significantly different from that expected from the sum of the two stimuli given separately. This indicates heightened corticospinal excitability at a time corresponding to the passage of an afferent volley induced by the stretch, and raises the possibility of a transcortical loop of the LLSR in the forearm. The extent of MEP facilitation was generally consistent across all stimulus intensities tested. A reduced component of the LLSR was evident when the stretch response was timed to arrive during the silent period following the cortical stimulus, suggesting both cortical and sub-cortical components to the reflex response.

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Neurophysiological study of facial chorea in patients with Huntington's disease

Muñoz

Cervera

Valls‐Solé

2003

Clinical Neurophysiology

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Changes of forearm EMG and cerebral evoked potentials following sudden muscle stretch in patients with Huntington's disease

Cited by 6 publications

References 14 publications

Progressive abnormalities in skeletal muscle and neuromuscular junctions of transgenic mice expressing the Huntington's disease mutation

Progressive abnormalities in skeletal muscle and neuromuscular junctions of transgenic mice expressing the Huntington's disease mutation

Proposed cortical and sub-cortical contributions to the long-latency stretch reflex in the forearm

Neurophysiological study of facial chorea in patients with Huntington's disease

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