Motor cortex changes in spinal cord injury: a TMS study

Saturno, E.; Bonato, Claudio; Miniussi, Carlo; Lazzaro, V. Di; Callea, L.

doi:10.1179/174313208x332968

Cited by 43 publications

(25 citation statements)

References 10 publications

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“…These data support previous findings reporting increased excitability after complete SCI in spared neural pathways (Topka et al, 1991). Reduced intracortical inhibition after SCI is thought to enable unmasking of latent synaptic connections at the cortical level, providing a possible causal mechanism for cerebral plasticity after SCI (Saturno et al, 2008). As MI and PP are assumed to be functionally equivalent, it is plausible that changes in intracortical inhibition of the sensorimotor cortex (allowing the reshaping of actual motor performance) may be reflected during MI, hence confirming some shared neural substrates between these two processes.…”

Section: Clinical Experimentsmentioning

confidence: 99%

Imagining is Not Doing but Involves Specific Motor Commands: A Review of Experimental Data Related to Motor Inhibition

Guillot¹,

Rienzo²,

MacIntyre³

et al. 2012

Front. Hum. Neurosci.

217

178

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There is now compelling evidence that motor imagery (MI) and actual movement share common neural substrate. However, the question of how MI inhibits the transmission of motor commands into the efferent pathways in order to prevent any movement is largely unresolved. Similarly, little is known about the nature of the electromyographic activity that is apparent during MI. In addressing these gaps in the literature, the present paper argues that MI includes motor execution commands for muscle contractions which are blocked at some level of the motor system by inhibitory mechanisms. We first assemble data from neuroimaging studies that demonstrate that the neural networks mediating MI and motor performance are not totally overlapping, thereby highlighting potential differences between MI and actual motor execution. We then review MI data indicating the presence of subliminal muscular activity reflecting the intrinsic characteristics of the motor command as well as increased corticomotor excitability. The third section not only considers the inhibitory mechanisms involved during MI but also examines how the brain resolves the problem of issuing the motor command for action while supervising motor inhibition when people engage in voluntary movement during MI. The last part of the paper draws on imagery research in clinical contexts to suggest that some patients move while imagining an action, although they are not aware of such movements. In particular, experimental data from amputees as well as from patients with Parkinson’s disease are discussed. We also review recent studies based on comparing brain activity in tetraplegic patients with that from healthy matched controls that provide insights into inhibitory processes during MI. We conclude by arguing that based on available evidence, a multifactorial explanation of motor inhibition during MI is warranted.

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Section: Clinical Experimentsmentioning

confidence: 99%

Imagining is Not Doing but Involves Specific Motor Commands: A Review of Experimental Data Related to Motor Inhibition

Guillot¹,

Rienzo²,

MacIntyre³

et al. 2012

Front. Hum. Neurosci.

217

178

View full text Add to dashboard Cite

show abstract

“…Although both groups did not have significant differences in exercise intensity and WP speed, there were different PAF reactions following WP exercise for both groups. A prior study showed that brain activity in SCI individuals was different from healthy controls because of deafferentation (16,17), resulting in the imbalance of excitation and inhibition (36). Consequently, brain wave activity and functional changes in the motor cortex after SCI resulted in a different PAF reaction to WP exercise compared with the HC group.…”

Section: The Authors Declare No Conflicts Of Interestmentioning

confidence: 99%

Effects of wheelchair propulsion on neuropathic pain and resting electroencephalography after spinal cord injury

Sato¹,

Osumi²,

Morioka³

2017

J Rehabil Med

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Objectives: To investigate the effects of wheelchair propulsion on neuropathic pain and to examine resting electroencephalography pre-and post-wheelchair propulsion after spinal cord injury. Design: Cross-sectional study. Participants: Eleven individuals with spinal cord injury and pain and 10 healthy controls. Methods: Single-session 15-min wheelchair propulsion and measurement of resting electroencephalography. Effects of wheelchair propulsion were investigated using numerical rating scale (NRS) for neuropathic pain and short-form Profile of Mood States-Brief for mood. Peak alpha frequency on electroencephalography was calculated in 4 regions of interest; frontal, central, parietal and occipital areas. These outcomes were compared between pre-and post-wheelchair propulsion. Results: Ten participants with spinal cord injury and all healthy controls completed the wheelchair propulsion exercise. NRS scores and negative mood were significantly improved following the wheelchair propulsion exercise. Pre-wheelchair propulsion, parietal and occipital peak alpha frequencies were significantly lower in the spinal cord injury group compared with the healthy controls group. Post-wheelchair propulsion, central peak alpha frequency increased in the spinal cord injury group. Conclusion: Wheelchair propulsion exercise temporarily decreased neuropathic pain intensity, improved negative mood, and modified alpha activity in spinal cord injury.

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“…4,10 Two single-subject reports have shown that the short-interval intracortical inhibition (SICI) 11 is reduced after incomplete SCI. 5,8 However, SICI was examined only with one single conditioning and test stimulus intensity. Studying SICI over a range of intensities has become increasingly important for the recruitment of neurons by the test stimulus pulse that are differentially susceptible to SICI modulation, [12][13][14] and the contribution from short-interval intracortical facilitation activated by the conditioning stimulus cannot be ruled out.…”

Section: Introductionmentioning

confidence: 99%

“…3 Previous studies evaluating motor cortex excitability after SCI showed that the activity of intracortical inhibitory circuits may be reduced after incomplete SCI. [4][5][6][7][8] Cortical inhibition has been studied using the application of sub-threshold TMS, 4,6,7 a technique that temporarily inhibits the ongoing electromyogram (EMG), likely through the activation of intracortical inhibitory neurons with connections onto fast-conducing corticospinal axons that drive the motoneurones during voluntary contractions. 9 Within several weeks of SCI, the onset of EMG suppression is~25 ms longer than the latency of the motor evoked potential (MEP), whereas the latency difference is only~13 ms in healthy controls.…”

Section: Introductionmentioning

confidence: 99%

Assessment of corticospinal excitability after traumatic spinal cord injury using MEP recruitment curves: a preliminary TMS study

et al. 2015

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Study design: Transcranial magnetic stimulation study. Objectives: To further investigate the corticospinal excitability changes after spinal cord injury (SCI), as assessed by means of transcranial magnetic stimulation (TMS). Setting: Merano (Italy) and Salzburg (Austria). Methods: We studied resting motor threshold (RMT), motor evoked potential (MEP) amplitude and recruitment curve in five subjects with good recovery after traumatic incomplete cervical SCI. Results: RMT did not differ significantly between patients and controls, whereas the slope of MEP recruitment curve was significantly increased in the patients. Conclusion: This abnormal finding may represent an adaptive response after SCI. The impaired ability of the motor cortex to generate proper voluntary movement may be compensated by increasing spinal excitability. The easily performed measurement of MEP recruitment curve may provide a useful additional tool to improve the assessment and monitoring of motor cortical function in subjects with SCI. Increasing our knowledge of the corticospinal excitability changes in the functional recovery after SCI may also support the development of effective therapeutic strategies.

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Motor cortex changes in spinal cord injury: a TMS study

Cited by 43 publications

References 10 publications

Imagining is Not Doing but Involves Specific Motor Commands: A Review of Experimental Data Related to Motor Inhibition

Imagining is Not Doing but Involves Specific Motor Commands: A Review of Experimental Data Related to Motor Inhibition

Effects of wheelchair propulsion on neuropathic pain and resting electroencephalography after spinal cord injury

Assessment of corticospinal excitability after traumatic spinal cord injury using MEP recruitment curves: a preliminary TMS study

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