Global Corticospinal Excitability as Assessed in A Non-Exercised Upper Limb Muscle Compared Between Concentric and Eccentric Modes of Leg Cycling

AbstractThis study investigated the effects of eccentric (ECC) and concentric (CON) semi-recumbent leg cycling on global corticospinal excitability (CSE), assessed through the activity of a non-exercised hand muscle. Thirteen healthy male adults completed two 30-min bouts of moderate intensity ECC and CON recumbent cycling on separate days. Power output (POutput), heart rate (HR) and cadence were monitored during cycling. Global CSE was assessed using transcranial magnetic stimulation to elicit motor-evoked potentials (MEP) in the right first dorsal interosseous muscle before (‘Pre’), interleaved (at 10 and 20 mins, t10 and t20, respectively), immediately after (post, P0), and 30-min post exercise (P30). Participants briefly stopped pedalling (no more than 60 s) while stimulation was applied at the t10 and t20 time-points of cycling. Mean POutput, and rate of perceived exertion (RPE) did not differ between ECC and CON cycling and HR was significantly lower during ECC cycling (P = 0.01). Group mean MEP amplitudes were not significantly different between ECC and CON cycling at P0, t10, t20, and P30 and CON (at P > 0.05). Individual participant ratios of POutput and MEP amplitude showed large variability across the two modes of cycling, as did changes in slope of stimulus-response curves. These results suggest that compared to ‘Pre’ values, group mean CSE is not significantly affected by low-moderate intensity leg cycling in both modes. However, POutput and CSE show wide inter-participant variability which has implications for individual neural responses to CON and ECC cycling and rates of adaptation to a novel (ECC) mode. The study of CSE should therefore be analysed for each participant individually in relation to relevant physiological variables and account for familiarisation to semi-recumbent ECC leg cycling.

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Decreased corticospinal excitability after subthreshold 1 Hz rTMS over lateral premotor cortex

Neurology ◽

10.1212/wnl.57.3.449 ◽

2001 ◽

Vol 57 (3) ◽

pp. 449-455 ◽

Cited By ~ 238

Author(s):

Willibald Gerschlager ◽

Hartwig R. Siebner ◽

John C. Rothwell

Keyword(s):

Motor Cortex ◽

Parietal Cortex ◽

Motor Evoked Potentials ◽

Premotor Cortex ◽

Corticospinal Excitability ◽

First Dorsal Interosseous ◽

First Dorsal Interosseous Muscle ◽

The Right ◽

Hand Area ◽

Dorsal Interosseous Muscle

Objective: To study whether trains of subthreshold 1 Hz repetitive transcranial magnetic stimulation (rTMS) over premotor, prefrontal, or parietal cortex can produce changes in excitability of motor cortex that outlast the application of the train.Background: Prolonged 1 Hz rTMS over the motor cortex can suppress the amplitude of motor-evoked potentials (MEP) for several minutes after the end of the train. Because TMS can produce effects not only at the site of stimulation but also at distant sites to which it projects, the authors asked whether prolonged stimulation of sites distant but connected to motor cortex can also lead to lasting changes in MEP.Methods: Eight subjects received 1500 magnetic stimuli given at 1 Hz over the left lateral frontal cortex, the left lateral premotor cortex, the hand area of the left motor cortex, and the left anterior parietal cortex on four separate days. Stimulus intensity was set at 90% active motor threshold. Corticospinal excitability was probed by measuring the amplitude of MEP evoked in the right first dorsal interosseous muscle by single suprathreshold stimuli over the left motor hand area before, during, and after the conditioning trains.Results: rTMS over the left premotor cortex suppressed the amplitude of MEP in the right first dorsal interosseous muscle. The effect was maximized (approximately 50% suppression) after 900 pulses and outlasted the full train of 1500 stimuli for at least 15 minutes. Conditioning rTMS over the other sites did not modify the size of MEP. A control experiment showed that left premotor cortex conditioning had no effect on MEP evoked in the left first dorsal interosseous muscle.Conclusions: Subthreshold 1 Hz rTMS of the left premotor cortex induces a short-lasting inhibition of corticospinal excitability in the hand area of the ipsilateral motor cortex. This may provide a model for studying the functional interaction between premotor and motor cortex in healthy subjects and patients with movement disorders.

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Abstract 15566: Autonomic Modulation by Cardiopulmonary Rehabilitation in Heart Failure With Reduced Ejection Fraction: Who Benefits?

Circulation ◽

10.1161/circ.142.suppl_3.15566 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

Catherine F Notarius ◽

Daniel A Keir ◽

Mark B Badrov ◽

Philip J Millar ◽

Paul Oh ◽

...

Keyword(s):

Heart Failure ◽

Heart Rate ◽

Ejection Fraction ◽

Cardiac Rehabilitation ◽

Perceived Exertion ◽

Group Interaction ◽

Moderate Intensity ◽

Autonomic Modulation ◽

Reduced Ejection Fraction ◽

Leg Cycling

Introduction: Elevated muscle sympathetic nerve activity (MSNA) both at rest and during dynamic cycling relates inversely to peak oxygen uptake (VO 2peak ) in patients with heart failure due to a reduced ejection fraction (HFrEF). We observed a drop in MSNA both rest (-6±2 bursts/min) and mild exercise (-4±2) in HFrEF patients after 6 months of cardiac rehabilitation. Hypothesis: We hypothesized that after training those HFrEF patients with LOW VO2peak (less than median 74% of age predicted) would have a larger decrease in MSNA during dynamic exercise than those with HIGH VO2peak (over 74%). Methods: In 21 optimally treated HFrEF patients (5 Female) (13 HIGH: mean VO 2peak =26 ml·kg/min; 98% of predicted; 8 LOW VO 2peak =12; 50%) we assessed VO 2peak (open-circuit spirometry), heart rate variability (HRV) and fibular MSNA (microneurography) at rest, during 1-leg cycling (2 min each of mild and moderate intensity upright 1-leg cycling, n=19) and recovery before and after 6 months of exercise training (45 min aerobic exercise, 5 days/ wk at 60-70 % of VO 2peak; and resistance training 2 days/wk). Results: HIGH and LOW groups had similar age (63±3 vs 63±4 years) , LVEF (30±2 vs 28±3%), BMI, resting heart rate (HR), blood pressure and MSNA (52±3 vs 50±3 bursts/min). Training increased VO 2peak in both groups (main effect P=0.009), with no group difference in HR response or ratings of perceived exertion. MSNA at rest tended to decrease after training in the HIGH but not LOW group (interaction P=0.08). MSNA during cycling increased in both HIGH (P=0.04) and LOW (P<0.001) groups but was blunted post-training in the HIGH group only (P=0.04 vs. 0.90 in LOW). Training-induced sympatho-inhibition during exercise recovery occurred in the HIGH but not LOW group (interaction P=0.01). In contrast, HRV was not improved by training in either group. Conclusions: Contrary to our hypothesis, the sympatho-inhibitory effect of 6 months of exercise-based cardiac rehabilitation favours HFrEF patients with an already normal VO 2peak . This suggests that increasing initially low VO 2peak may be insufficient to trigger beneficial exercise and recovery autonomic modulation and altered training paradigms may be required in such patients. Funded by Canadian Institutes for Health Research (CIHR)

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Intensity dependency of peripheral nerve stimulation in spinal LTP induced by paired associative corticospinal-motoneuronal stimulation (PCMS)

PLoS ONE ◽

10.1371/journal.pone.0259931 ◽

2021 ◽

Vol 16 (11) ◽

pp. e0259931

Author(s):

Akira Yamashita ◽

Takenobu Murakami ◽

Noriaki Hattori ◽

Ichiro Miyai ◽

Yoshikazu Ugawa

Keyword(s):

Peripheral Nerve ◽

Primary Motor Cortex ◽

Motor Evoked Potentials ◽

Single Pulse ◽

Long Term Potentiation ◽

Facilitatory Effect ◽

Sensory Threshold ◽

Descending Volleys ◽

First Dorsal Interosseous Muscle ◽

The Right

Paired associative corticospinal-motoneuronal stimulation (PCMS) induces plasticity at synapses between corticospinal tracts (CSTs) and spinal motoneurons (SMs). We investigated the effects of peripheral nerve electrical stimulation (PNS) intensity on PCMS-induced plasticity. PCMS consisted of 180 paired stimuli of transcranial magnetic stimulation (TMS) over the left primary motor cortex with PNS on the right ulnar nerve at the wrist. We compared effects induced by different PNS intensities: supramaximal, twice and three times sensory threshold intensities. For evaluating efficacy of the synapse between CSTs and SMs, single-pulse TMS was delivered at cervicomedullary junction level, and cervicomedullary motor-evoked potentials (CMEPs) were recorded from the right first-dorsal interosseous muscle before and after PCMS. PCMS with the supramaximal PNS intensity increased CMEP amplitude. The facilitatory effect of PCMS with the supramaximal PNS was larger than those of PCMS with weaker PNS intensities. Sham TMS with the supramaximal PNS showed no CMEP changes after the intervention. PNS intensity of PCMS influences the magnitude of synaptic plasticity induction between the CSTs and SMs at the spinal level, and the supramaximal intensity is the best for induction of long-term potentiation-like effects. The PNS intensity may influence the number of activated SMs by axonal backpropagating pulses with PNS which must overlap with descending volleys induced by TMS.

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Transcranial static magnetic stimulation over the motor cortex can facilitate the contralateral cortical excitability in human

Scientific Reports ◽

10.1038/s41598-021-84823-4 ◽

2021 ◽

Vol 11 (1) ◽

Cited By ~ 2

Author(s):

Yasuyuki Takamatsu ◽

Satoko Koganemaru ◽

Tatsunori Watanabe ◽

Sumiya Shibata ◽

Yoshihiro Yukawa ◽

...

Keyword(s):

Motor Cortex ◽

Magnetic Stimulation ◽

Primary Motor Cortex ◽

Cortical Excitability ◽

Motor Evoked Potentials ◽

Single Pulse ◽

Brain Network ◽

Corticospinal Excitability ◽

Double Blind ◽

The Right

AbstractTranscranial static magnetic stimulation (tSMS) has been focused as a new non-invasive brain stimulation, which can suppress the human cortical excitability just below the magnet. However, the non-regional effects of tSMS via brain network have been rarely studied so far. We investigated whether tSMS over the left primary motor cortex (M1) can facilitate the right M1 in healthy subjects, based on the hypothesis that the functional suppression of M1 can cause the paradoxical functional facilitation of the contralateral M1 via the reduction of interhemispheric inhibition (IHI) between the bilateral M1. This study was double-blind crossover trial. We measured the corticospinal excitability in both M1 and IHI from the left to right M1 by recording motor evoked potentials from first dorsal interosseous muscles using single-pulse and paired-pulse transcranial magnetic stimulation before and after the tSMS intervention for 30 min. We found that the corticospinal excitability of the left M1 decreased, while that of the right M1 increased after tSMS. Moreover, the evaluation of IHI revealed the reduced inhibition from the left to the right M1. Our findings provide new insights on the mechanistic understanding of neuromodulatory effects of tSMS in human.

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Writing's Shadow: Corticospinal Activation during Letter Observation

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_00205 ◽

2012 ◽

Vol 24 (5) ◽

pp. 1138-1148 ◽

Cited By ~ 6

Author(s):

Masahiro Nakatsuka ◽

Mohamed Nasreldin Thabit ◽

Satoko Koganemaru ◽

Ippei Nojima ◽

Hidenao Fukuyama ◽

...

Keyword(s):

Primary Motor Cortex ◽

Motor Evoked Potentials ◽

Short Interval ◽

Single Pulse ◽

Random Order ◽

Intracortical Inhibition ◽

Corticospinal Excitability ◽

Motor Memory ◽

F Wave ◽

The Right

We can recognize handwritten letters despite the variability among writers. One possible strategy is exploiting the motor memory of orthography. By using TMS, we clarified the excitatory and inhibitory neural circuits of the motor corticospinal pathway that might be activated during the observation of handwritten letters. During experiments, participants looked at the handwritten or printed single letter that appeared in a random order. The excitability of the left and right primary motor cortex (M1) was evaluated by motor-evoked potentials elicited by single-pulse TMS. Short interval intracortical inhibition (SICI) of the left M1 was evaluated using paired-pulse TMS. F waves were measured for the right ulnar nerve. We found significant reduction of corticospinal excitability only for the right hand at 300–400 msec after each letter presentation without significant changes in SICI. This suppression is likely to be of supraspinal origin, because of no significant alteration in F-wave amplitudes. These findings suggest that the recognition of handwritten letters may include the implicit knowledge of “writing” in M1. The M1 activation associated with that process, which has been shown in previous neuroimaging studies, is likely to reflect the active suppression of the corticospinal excitability.

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Visual Attention and Motion Visibility Modulate Motor Resonance during Observation of Human Walking in Different Manners

Brain Sciences ◽

10.3390/brainsci11060679 ◽

2021 ◽

Vol 11 (6) ◽

pp. 679

Author(s):

Tomotaka Ito ◽

Masanori Kamiue ◽

Tomonori Kihara ◽

Yuta Ishimaru ◽

Daisuke Kimura ◽

...

Keyword(s):

Visual Attention ◽

Ankle Joint ◽

Lower Limb ◽

Motor Evoked Potentials ◽

Single Pulse ◽

Corticospinal Excitability ◽

Initial Contact ◽

Motor Resonance ◽

Below The Knee ◽

The Right

To advance our knowledge on the motor system during cyclic gait observation, we aimed to explore the effects of gaze fixation on corticospinal excitability evaluated by single-pulse transcranial magnetic stimulation (TMS). Fourteen healthy adult volunteers watched a video of a demonstrator walking on a treadmill under three different conditions: (1) observing the right lower limb, (2) observing the right ankle joint, and (3) observing the right lower limb on a video focused on the area below the knee. In each condition, motor-evoked potentials elicited by TMS in the tibialis anterior (TA) muscle were measured synchronously with the demonstrator’s initial contact and toe-off points. Directing visual attention to the ankle joint and focusing on its movements caused corticospinal facilitation in the TA muscle compared with watching the video without any visual fixation. In addition, phase-dependent differences in corticospinal excitability between the initial contact and toe-off points were only detected when the visibility range was restricted to below the knee. Our findings indicated that motor resonance during cyclic gait observation is modulated by visual attention and motion visibility in different activation manners.

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Human corticospinal-motoneuronal output is reduced with 5-HT2 receptor antagonism

Journal of Neurophysiology ◽

10.1152/jn.00698.2020 ◽

2021 ◽

Author(s):

Jacob R Thorstensen ◽

Janet Louise Taylor ◽

Justin J Kavanagh

Keyword(s):

Repeated Measures ◽

Biceps Brachii ◽

Motor Evoked Potentials ◽

Silent Period ◽

Human Movement ◽

Moderate Intensity ◽

Response Curves ◽

Stimulus Response ◽

Repeated Measures Design ◽

Double Blinded

Animal models indicate that serotonin (5-HT) release onto motoneurons facilitates motor output, particularly during strong motor activities. However, evidence for 5-HT effects during human movement are limited. This study examined how antagonism of the 5-HT2 receptor, which is a 5-HT receptor that promotes motoneuron excitability, affects human movement. Ten healthy participants (24.2 ± 1.9 yr) ingested 8 mg of cyproheptadine (competitive 5-HT2 antagonist) in a double-blinded, placebo-controlled, repeated-measures design. Transcranial magnetic stimulation (TMS) of the motor cortex was used to elicit motor evoked potentials (MEPs) from biceps brachii. First, stimulus-response curves (90-160% active motor threshold) were obtained during very weak elbow flexions (10% of maximal). Second, to determine if 5-HT effects are scaled to the intensity of muscle contraction, TMS at a fixed intensity was applied during elbow flexions of 20, 40, 60, 80 and 100% of maximal. Cyproheptadine reduced the size of MEPs across the stimulus-response curves (P = 0.045). Notably, MEP amplitude was 22.3% smaller for the cyproheptadine condition for the strongest TMS intensity. In addition, cyproheptadine reduced maximal torque (P = 0.045), lengthened the biceps silent period during maximal elbow flexions (P = 0.037), and reduced superimposed twitch amplitude during moderate-intensity elbow flexions (P = 0.035). This study presents novel evidence that 5-HT2 receptors influence corticospinal-motoneuronal output, which was particularly evident when a large number of descending inputs to motoneurons were active. While it is likely that antagonism of 5-HT2 receptors reduces motoneuron gain to ionotropic inputs, supraspinal mechanisms may have also contributed to the study findings.

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Modulation of Corticospinal Excitability Depends on the Pattern of Mechanical Tactile Stimulation

Neural Plasticity ◽

10.1155/2018/5383514 ◽

2018 ◽

Vol 2018 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Sho Kojima ◽

Hideaki Onishi ◽

Shota Miyaguchi ◽

Shinichi Kotan ◽

Ryoki Sasaki ◽

...

Keyword(s):

Tactile Stimulation ◽

Motor Evoked Potential ◽

Corticospinal Excitability ◽

First Dorsal Interosseous Muscle ◽

Stimulus Probe ◽

Left And Right ◽

The Right ◽

Single Blind ◽

Finger Pad ◽

Dorsal Interosseous Muscle

We investigated the effects of different patterns of mechanical tactile stimulation (MS) on corticospinal excitability by measuring the motor-evoked potential (MEP). This was a single-blind study that included nineteen healthy subjects. MS was applied for 20 min to the right index finger. MS intervention was defined as simple, lateral, rubbing, vertical, or random. Simple intervention stimulated the entire finger pad at the same time. Lateral intervention stimulated with moving between left and right on the finger pad. Rubbing intervention stimulated with moving the stimulus probe, fixed by protrusion pins. Vertical intervention stimulated with moving in the forward and backward directions on the finger pad. Random intervention stimulated to finger pad with either row protrudes. MEPs were measured in the first dorsal interosseous muscle to transcranial magnetic stimulation of the left motor cortex before, immediately after, and 5–20 min after intervention. Following simple intervention, MEP amplitudes were significantly smaller than preintervention, indicating depression of corticospinal excitability. Following lateral, rubbing, and vertical intervention, MEP amplitudes were significantly larger than preintervention, indicating facilitation of corticospinal excitability. The modulation of corticospinal excitability depends on MS patterns. These results contribute to knowledge regarding the use of MS as a neurorehabilitation tool to neurological disorder.

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Anodal transcranial direct current stimulation increases corticospinal excitability, while performance is unchanged

PLoS ONE ◽

10.1371/journal.pone.0254888 ◽

2021 ◽

Vol 16 (7) ◽

pp. e0254888

Author(s):

Mathias Kristiansen ◽

Mikkel Jacobi Thomsen ◽

Jens Nørgaard ◽

Jon Aaes ◽

Dennis Knudsen ◽

...

Keyword(s):

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Perceived Exertion ◽

Motor Evoked Potentials ◽

Time Trial ◽

Corticospinal Excitability ◽

Afferent Feedback ◽

Sham Stimulation ◽

Direct Current Stimulation ◽

Rpe Clamp

Anodal transcranial direct current stimulation (a-tDCS) has been shown to improve bicycle time to fatigue (TTF) tasks at 70–80% of VO2max and downregulate rate of perceived exertion (RPE). This study aimed to investigate the effect of a-tDCS on a RPE-clamp test, a 250-kJ time trial (TT) and motor evoked potentials (MEP). Twenty participants volunteered for three trials; control, sham stimulation and a-tDCS. Transcranial magnetic stimulation was used to determine the corticospinal excitability for 12 participants pre and post sham stimulation and a-tDCS. The a-tDCS protocol consisted of 13 minutes of stimulation (2 mA) with the anode placed above the Cz. The RPE-clamp test consisted of 5 minutes ergometer bicycling at an RPE of 13 on the Borg scale, and the TT consisted of a 250 kJ (∼10 km) long bicycle ergometer test. During each test, power output, heart rate and oxygen consumption was measured, while RPE was evaluated. MEPs increased significantly by 36% (±36%) post a-tDCS, with 8.8% (±31%) post sham stimulation (p = 0.037). No significant changes were found for any parameter at the RPE-clamp or TT. The lack of improvement may be due to RPE being more controlled by afferent feedback during TT tests than during TTF tests. Based on the results of the present study, it is concluded that a-tDCS applied over Cz, does not enhance self-paced cycling performance.

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Evaluation of the Effectiveness of Outdoor Fitness Equipment Intervention in Achieving Fitness Goals for Seniors

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph182312508 ◽

2021 ◽

Vol 18 (23) ◽

pp. 12508

Author(s):

Hsueh-Wen Chow ◽

Kun-Tang Chang ◽

I-Yao Fang

Keyword(s):

Perceived Exertion ◽

Handgrip Strength ◽

Step Test ◽

Repeated Measure ◽

Moderate Intensity ◽

Clinical Test ◽

Right Hand ◽

Eyes Open ◽

Measure Analysis ◽

The Right

Despite the popularity of outdoor fitness equipment (OFE) in public spaces with the aim of increasing physical activity (PA), very little research has been conducted to investigate the effectiveness of the equipment’s use, especially for achieving the target fitness goal. This study designed an OFE training protocol incorporating four modalities of PA: endurance (air walker and ski machine), resistance (rowing machine and bonny rider), flexibility (arm stretch and shoulder wheel), and balance exercise (waist twister). Seniors who completed the protocol demonstrated that for endurance training, participants were at moderate intensity from heart rate and perceived exertion, while significantly improving cardiac endurance in the two min step test. For resistance/flexibility/balance interventions, only the handgrip strength test, the 30 s chair stand test, the right-hand shoulder flexion test, the right-hand shoulder horizontal abduction test, the single-leg stance test, and the eyes open foam surface clinical test for sensory balance were significant, using a repeated measure analysis of variance. The results demonstrated that older adults aim for the OFE target for specific fitness goals can reach moderate intensity and improve their cardiorespiratory endurance. Yet, results for resistance/flexibility/balance are inconclusive. More studies are needed to carefully assess the effectiveness of using OFE.

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