Excitability decreasing central motor plasticity is retained in multiple sclerosis patients

<p>Abstract</p> <p>Background</p> <p>Compensation of brain injury in multiple sclerosis (MS) may in part work through mechanisms involving neuronal plasticity on local and interregional scales. Mechanisms limiting excessive neuronal activity may have special significanc...

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Main Authors: Zeller Daniel, Dang Su-Yin, Weise David, Rieckmann Peter, Toyka Klaus V, Classen Joseph
Format: Article
Language:English
Published: BMC 2012-09-01
Series:BMC Neurology
Subjects:
Online Access:http://www.biomedcentral.com/1471-2377/12/92
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author Zeller Daniel
Dang Su-Yin
Weise David
Rieckmann Peter
Toyka Klaus V
Classen Joseph
author_facet Zeller Daniel
Dang Su-Yin
Weise David
Rieckmann Peter
Toyka Klaus V
Classen Joseph
author_sort Zeller Daniel
collection DOAJ
description <p>Abstract</p> <p>Background</p> <p>Compensation of brain injury in multiple sclerosis (MS) may in part work through mechanisms involving neuronal plasticity on local and interregional scales. Mechanisms limiting excessive neuronal activity may have special significance for retention and (re-)acquisition of lost motor skills in brain injury. However, previous neurophysiological studies of plasticity in MS have investigated only excitability enhancing plasticity and results from neuroimaging are ambiguous. Thus, the aim of this study was to probe long-term depression-like central motor plasticity utilizing continuous theta-burst stimulation (cTBS), a non-invasive brain stimulation protocol. Because cTBS also may trigger behavioral effects through local interference with neuronal circuits, this approach also permitted investigating the functional role of the primary motor cortex (M1) in force control in patients with MS.</p> <p>Methods</p> <p>We used cTBS and force recordings to examine long-term depression-like central motor plasticity and behavioral consequences of a M1 lesion in 14 patients with stable mild-to-moderate MS (median EDSS 1.5, range 0 to 3.5) and 14 age-matched healthy controls. cTBS consisted of bursts (50 Hz) of three subthreshold biphasic magnetic stimuli repeated at 5 Hz for 40 s over the hand area of the left M1. Corticospinal excitability was probed via motor-evoked potentials (MEP) in the abductor pollicis brevis muscle over M1 before and after cTBS. Force production performance was assessed in an isometric right thumb abduction task by recording the number of hits into a predefined force window.</p> <p>Results</p> <p>cTBS reduced MEP amplitudes in the contralateral abductor pollicis brevis muscle to a comparable extent in control subjects (69 ± 22% of baseline amplitude, p < 0.001) and in MS patients (69 ± 18%, p < 0.001). In contrast, post-cTBS force production performance was only impaired in controls (2.2 ± 2.8, p = 0.011), but not in MS patients (2.0 ± 4.4, p = 0.108). The decline in force production performance following cTBS correlated with corticomuscular latencies (CML) in MS patients, but did not correlate with MEP amplitude reduction in patients or controls.</p> <p>Conclusions</p> <p>Long-term depression-like plasticity remains largely intact in mild-to-moderate MS. Increasing brain injury may render the neuronal networks less responsive toward lesion-induction by cTBS.</p>
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spelling doaj.art-6e241f02d20e42dcaca9d5030ff1b4562022-12-22T00:24:19ZengBMCBMC Neurology1471-23772012-09-011219210.1186/1471-2377-12-92Excitability decreasing central motor plasticity is retained in multiple sclerosis patientsZeller DanielDang Su-YinWeise DavidRieckmann PeterToyka Klaus VClassen Joseph<p>Abstract</p> <p>Background</p> <p>Compensation of brain injury in multiple sclerosis (MS) may in part work through mechanisms involving neuronal plasticity on local and interregional scales. Mechanisms limiting excessive neuronal activity may have special significance for retention and (re-)acquisition of lost motor skills in brain injury. However, previous neurophysiological studies of plasticity in MS have investigated only excitability enhancing plasticity and results from neuroimaging are ambiguous. Thus, the aim of this study was to probe long-term depression-like central motor plasticity utilizing continuous theta-burst stimulation (cTBS), a non-invasive brain stimulation protocol. Because cTBS also may trigger behavioral effects through local interference with neuronal circuits, this approach also permitted investigating the functional role of the primary motor cortex (M1) in force control in patients with MS.</p> <p>Methods</p> <p>We used cTBS and force recordings to examine long-term depression-like central motor plasticity and behavioral consequences of a M1 lesion in 14 patients with stable mild-to-moderate MS (median EDSS 1.5, range 0 to 3.5) and 14 age-matched healthy controls. cTBS consisted of bursts (50 Hz) of three subthreshold biphasic magnetic stimuli repeated at 5 Hz for 40 s over the hand area of the left M1. Corticospinal excitability was probed via motor-evoked potentials (MEP) in the abductor pollicis brevis muscle over M1 before and after cTBS. Force production performance was assessed in an isometric right thumb abduction task by recording the number of hits into a predefined force window.</p> <p>Results</p> <p>cTBS reduced MEP amplitudes in the contralateral abductor pollicis brevis muscle to a comparable extent in control subjects (69 ± 22% of baseline amplitude, p < 0.001) and in MS patients (69 ± 18%, p < 0.001). In contrast, post-cTBS force production performance was only impaired in controls (2.2 ± 2.8, p = 0.011), but not in MS patients (2.0 ± 4.4, p = 0.108). The decline in force production performance following cTBS correlated with corticomuscular latencies (CML) in MS patients, but did not correlate with MEP amplitude reduction in patients or controls.</p> <p>Conclusions</p> <p>Long-term depression-like plasticity remains largely intact in mild-to-moderate MS. Increasing brain injury may render the neuronal networks less responsive toward lesion-induction by cTBS.</p>http://www.biomedcentral.com/1471-2377/12/92Multiple sclerosisLTDMotor plasticityTMSMotor cortex
spellingShingle Zeller Daniel
Dang Su-Yin
Weise David
Rieckmann Peter
Toyka Klaus V
Classen Joseph
Excitability decreasing central motor plasticity is retained in multiple sclerosis patients
BMC Neurology
Multiple sclerosis
LTD
Motor plasticity
TMS
Motor cortex
title Excitability decreasing central motor plasticity is retained in multiple sclerosis patients
title_full Excitability decreasing central motor plasticity is retained in multiple sclerosis patients
title_fullStr Excitability decreasing central motor plasticity is retained in multiple sclerosis patients
title_full_unstemmed Excitability decreasing central motor plasticity is retained in multiple sclerosis patients
title_short Excitability decreasing central motor plasticity is retained in multiple sclerosis patients
title_sort excitability decreasing central motor plasticity is retained in multiple sclerosis patients
topic Multiple sclerosis
LTD
Motor plasticity
TMS
Motor cortex
url http://www.biomedcentral.com/1471-2377/12/92
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