scholarly journals A Short Bout of High-intensity Exercise Alters Ipsilesional Motor Cortical Excitability Post-stroke

2019 ◽  
Author(s):  
Xin Li ◽  
Charalambos C. Charalambous ◽  
Darcy S. Reisman ◽  
Susanne M. Morton

AbstractBackgroundAcute exercise can increase motor cortical excitability and enhance motor learning in healthy individuals, an effect known as exercise priming. Whether it has the same effects in people with stroke is unclear.ObjectivesThe objective of this study was to investigate whether a short, clinically-feasible high-intensity exercise protocol can increase motor cortical excitability in non-exercised muscles of chronic stroke survivors.MethodsThirteen participants with chronic, unilateral stroke participated in two sessions, at least one week apart, in a crossover design. In each session, they underwent either high-intensity lower extremity exercise or quiet rest. Motor cortical excitability of the extensor carpi radialis muscles was measured bilaterally with transcranial magnetic stimulation before and immediately after either exercise or rest. Motor cortical excitability changes (post-exercise or rest measures normalized to pre-test measures) were compared between exercise vs. rest conditions.ResultsAll participants were able to reach the target high-intensity exercise level. Blood lactate levels increased significantly after exercise (p < 0.001, d = 2.85). Resting motor evoked potentials from the lesioned hemisphere increased after exercise compared to the rest condition (p = 0.046, d = 2.76), but this was not the case for the non-lesioned hemisphere (p = 0.406, d = 0.25).ConclusionsHigh-intensity exercise can increase lesioned hemisphere motor cortical excitability in a non-exercised muscle post-stroke. Our short and clinically-feasible exercise protocol shows promise as a potential priming method in stroke rehabilitation.

2021 ◽  
Author(s):  
Asher Reuben Geffen ◽  
Nicholas Bland ◽  
Martin V Sale

Converging evidence suggests that transcranial alternating current stimulation (tACS) may entrain endogenous neural oscillations to match the frequency and phase of the exogenously applied current and this entrainment may outlast the stimulation (although only for a few oscillatory cycles following the cessation of stimulation). However, observing entrainment in the electroencephalograph (EEG) during stimulation is extremely difficult due to the presence of complex tACS artefacts. The present study assessed entrainment to slow oscillatory (SO) tACS by measuring motor cortical excitability across different oscillatory phases during (i.e., online) and outlasting (i.e., offline) stimulation. 30 healthy participants received 60 trials of intermittent SO tACS (0.75 Hz; 16s on / off interleaved) at an intensity of 2mA peak-to-peak. Motor cortical excitability was assessed using transcranial magnetic stimulation (TMS) of the hand region of the primary motor cortex (M1HAND) to induce motor evoked potentials (MEPs) in the contralateral thumb. MEPs were acquired at four time-points within each trial - early online, late online, early offline, and late offline - as well as at the start and end of the overall stimulation period (to probe longer-lasting aftereffects of tACS). A significant increase in MEP amplitude was observed from pre- to post-tACS (P = 0.013) and from the first to the last tACS block (P = 0.008). However, no phase-dependent modulation of excitability was observed. Therefore, although SO tACS had a facilitatory effect on motor cortical excitability that outlasted stimulation, there was no evidence supporting entrainment of endogenous oscillations as the underlying mechanism.


1999 ◽  
Vol 4 (1) ◽  
pp. 44-48 ◽  
Author(s):  
Raimondo Traversa ◽  
Paola Cicinelli ◽  
Maria Filippi ◽  
Massimiliano Oliveri ◽  
Maria Giuseppina Palmieri ◽  
...  

Brain ◽  
1999 ◽  
Vol 122 (12) ◽  
pp. 2259-2277 ◽  
Author(s):  
Yasuo Terao ◽  
Yoshikazu Ugawa ◽  
Ritsuko Hanajima ◽  
Toshiaki Furubayashi ◽  
Katsuyuki Machii ◽  
...  

2019 ◽  
Vol 122 (4) ◽  
pp. 1397-1405 ◽  
Author(s):  
Hiroki Ohashi ◽  
Paul L. Gribble ◽  
David J. Ostry

Motor learning is associated with plasticity in both motor and somatosensory cortex. It is known from animal studies that tetanic stimulation to each of these areas individually induces long-term potentiation in its counterpart. In this context it is possible that changes in motor cortex contribute to somatosensory change and that changes in somatosensory cortex are involved in changes in motor areas of the brain. It is also possible that learning-related plasticity occurs in these areas independently. To better understand the relative contribution to human motor learning of motor cortical and somatosensory plasticity, we assessed the time course of changes in primary somatosensory and motor cortex excitability during motor skill learning. Learning was assessed using a force production task in which a target force profile varied from one trial to the next. The excitability of primary somatosensory cortex was measured using somatosensory evoked potentials in response to median nerve stimulation. The excitability of primary motor cortex was measured using motor evoked potentials elicited by single-pulse transcranial magnetic stimulation. These two measures were interleaved with blocks of motor learning trials. We found that the earliest changes in cortical excitability during learning occurred in somatosensory cortical responses, and these changes preceded changes in motor cortical excitability. Changes in somatosensory evoked potentials were correlated with behavioral measures of learning. Changes in motor evoked potentials were not. These findings indicate that plasticity in somatosensory cortex occurs as a part of the earliest stages of motor learning, before changes in motor cortex are observed. NEW & NOTEWORTHY We tracked somatosensory and motor cortical excitability during motor skill acquisition. Changes in both motor cortical and somatosensory excitability were observed during learning; however, the earliest changes were in somatosensory cortex, not motor cortex. Moreover, the earliest changes in somatosensory cortical excitability predict the extent of subsequent learning; those in motor cortex do not. This is consistent with the idea that plasticity in somatosensory cortex coincides with the earliest stages of human motor learning.


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