scholarly journals A new protocol for multiple muscle mapping using nTMS

2021 ◽  
Author(s):  
Fang Jin ◽  
Sjoerd M Bruijn ◽  
Andreas Daffertshofer
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Single Pulse ◽  
Cortical Representation ◽  
Precentral Gyrus ◽  
Validity And Reliability ◽  
Non Invasive ◽  
Centre Of Gravity

Background: Single-pulse transcranial magnetic stimulation is a safe and non-invasive tool for investigating cortical representation of muscles in the primary motor cortex. While non-navigated TMS has been successfully applied to simultaneously induce motor-evoked potentials (MEPs) in multiple muscles, a more rigorous assessment of the corresponding cortical representation can greatly benefit from navigated transcranial magnetic stimulation (nTMS). Objective: We designed a protocol to map the entire precentral gyrus using neural navigation while recording responses of eight muscles simultaneously. Here, we evaluated the feasibility, validity, and reliability of this protocol. Method: Twenty participants underwent conventional (i.e., muscle-based, grid-constrained) and gyrus-based nTMS mapping. For both protocols, we investigated three different stimulation intensities during two consecutive sessions. Results: The gyrus-based nTMS mapping was received well by all participants and was less time consuming than the grid-constrained standard. On average, MEP amplitudes, latencies, and centre-of-gravity and size of the active areas largely agreed across protocols supporting validity. Intraclass coefficients between sessions unscored the reliability of our protocol. Conclusion: We designed an nTMS protocol for the simultaneous mapping multiple muscles on the cortex. The protocol takes only about ten minutes per participant when including as many as eight muscles. Our assessments revealed that the cortical representation of multiple muscles can be determined with high validity and reliability.

scholarly journals Surround inhibition depends on the force exerted and is abnormal in focal hand dystonia

2009 ◽  
Vol 107 (5) ◽  
pp. 1513-1518 ◽  
Author(s):  
S. Beck ◽  
M. Schubert ◽  
S. Pirio Richardson ◽  
M. Hallett
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Neural Mechanism ◽  
Single Pulse ◽  
Movement Initiation ◽  
Focal Hand Dystonia ◽  
Surround Inhibition ◽  
Hand Dystonia

There is evidence that surround inhibition (SI), a neural mechanism to enhance contrast between signals, may play a role in primary motor cortex during movement initiation, while it is deficient in patients with focal hand dystonia (FHD). To further characterize SI with respect to different force levels, single- and paired-pulse transcranial magnetic stimulation was applied at rest and during index finger movement to evoke potentials in the nonsynergistic, abductor policis muscle. In Experiment 1, in 19 healthy volunteers, SI was tested using single-pulse transcranial magnetic stimulation. Motor-evoked potentials at rest were compared with those during contraction using four different force levels [5, 10, 20, and 40% of maximum force (Fmax)]. In Experiments 2 and 3, SI and short intracortical inhibition (SICI) were tested, respectively, in 16 patients with FHD and 20 age-matched controls for the 10% and 20% Fmax levels. SI was most pronounced for 10% Fmax and abolished for the 40% Fmax level in controls, whereas FHD patients had no SI at all. In contrast, a loss of SICI was observed in FHD patients, which was more pronounced for 10% Fmax than for 20% Fmax. Our results suggest that SI is involved in the generation of fine finger movements with low-force levels. The greater loss of SICI for the 10% Fmax level in patients with FHD than for the 20% Fmax level indicates that this inhibitory mechanism is more abnormal at lower levels of force.

Influence of different transcranial magnetic stimulation current directions on the corticomotor control of lumbar erector spinae muscles during a static task

2021 ◽  
Author(s):  
Mikaël Desmons ◽  
Antoine Rohel ◽  
Amélie Desgagnés ◽  
Catherine Mercier ◽  
Hugo Massé-Alarie
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Erector Spinae ◽  
Recruitment Curve ◽  
Axial Muscles ◽  
Active Motor ◽  
Stimulation Current ◽  
Cortical Representations

Different directions of transcranial magnetic stimulation (TMS) can activate different neuronal circuits. While posteroanterior current (PA-TMS) depolarizes mainly interneurons in primary motor cortex (M1), an anteroposterior current (AP-TMS) has been suggested to activate different M1 circuits and perhaps axons from the premotor regions. Although M1 is also involved in the control of axial muscles, no study has explored if different current directions activate different M1 circuits that may have distinct functional role. The aim of the study was to compare the effect of different current directions (PA- and AP-TMS) on the corticomotor control and spatial cortical organisation of the lumbar erector spinae muscle (LES). Thirthy-four healthy participants were recruited for two independent experiments and LES motor-evoked potentials (MEP) were recorded. In experiment 1 (n=17), active motor threshold (AMT), MEP latencies, recruitment curve (90 to 160% AMT), excitatory and inhibitory intracortical mechanisms using paired-pulse TMS (80% followed by 120% AMT stimuli at 2-3-10 and 15ms inter-stimulus intervals) were tested using a double cone (n=12) and a figure-of-eight (n=5) coils. In experiment 2 (n=17), LES cortical representations were tested using PA- and AP-TMS. AMT was higher for AP- compared to PA-TMS (p=0.002). Longer latencies with AP-TMS were compared to PA-TMS (p=0.017). AP-TMS produced more inhibition compared to PA-TMS at 2ms and 3ms (p=0.010), but no difference was observed for longer intervals. No difference was found for recruitment curve and mapping. Those findings suggest that each PA- and AP-TMS may activate different cortical circuits controlling low back muscles as proposed for hand muscles.

Cerebral Blood-Flow Changes Induced by Paired-Pulse Transcranial Magnetic Stimulation of the Primary Motor Cortex

2001 ◽  
Vol 85 (6) ◽  
pp. 2624-2629 ◽  
Author(s):  
A. P. Strafella ◽  
T. Paus
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Premotor Cortex ◽  
Single Pulse ◽  
Paired Pulse ◽  
Positive Correlation

Positron emission tomography (PET) was used to assess changes in regional cerebral blood flow (CBF) induced by paired-pulse transcranial magnetic stimulation (TMS) of primary motor cortex (M1). The study was performed in eight normal volunteers using two Magstim-200 stimulators linked with a Bistim module. A circular TMS coil was held in the scanner by a mechanical arm and located over the left M1. Surface electrodes were used to record motor evoked potentials (MEPs) from the contralateral first dorsal interosseous muscle (FDI). Cortical excitability was evaluated in the relaxed FDI using a paired conditioning-test stimulus paradigm with two interstimulus intervals (ISIs): 3 and 12 ms. The subjects were scanned three times during each of the following four conditions: 1) baseline with no TMS (BASE); 2) single-pulse TMS (TMSsing); 3) 3-ms paired-pulse TMS (TMS3); and 4) 12-ms paired-pulse TMS (TMS12). CBF and peak-to-peak MEP amplitudes were measured over each 60-s scanning period. To assess TMS-induced changes in CBF, a t-statistic map was generated by first subtracting the single-pulse TMS condition from the 3- and 12-ms paired-pulse TMS conditions and then correlating the CBF differences, respectively, with the amount of suppression and facilitation of the EMG responses. A significant positive correlation was observed between the CBF difference (TMS3-TMSsing) and the amount of suppression of EMG response, as well as between the CBF difference (TMS12-TMSsing) and the amount of facilitation of EMG response. This positive correlation was observed in the left M1, left lateral premotor cortex, and right M1 in the case of 3-ms paired-pulse TMS, but only in the left M1 in the case of 12-ms paired-pulse TMS. The above pattern of CBF response to paired-pulse TMS supports the possibility that suppression and facilitation of the EMG response are mediated by different populations of cortical interneurons.

Hand perceptions induced by single pulse transcranial magnetic stimulation over the primary motor cortex

2019 ◽  
Vol 12 (3) ◽  
pp. 693-701 ◽  
Author(s):  
Matteo Franza ◽  
Giuliana Sorrentino ◽  
Matteo Vissani ◽  
Andrea Serino ◽  
Olaf Blanke ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Single Pulse

scholarly journals Changes in corticospinal excitability during reach adaptation in force fields

2013 ◽  
Vol 109 (1) ◽  
pp. 124-136 ◽  
Author(s):  
Jean-Jacques Orban de Xivry ◽  
Mohammad Ali Ahmadi-Pajouh ◽  
Michelle D. Harran ◽  
Yousef Salimpour ◽  
Reza Shadmehr
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Corticospinal Excitability ◽  
Neural Basis ◽  
Key Factor ◽  
Gradual Group ◽  
Specific Increase ◽  
Stimulation Of

Both abrupt and gradually imposed perturbations produce adaptive changes in motor output, but the neural basis of adaptation may be distinct. Here, we measured the state of the primary motor cortex (M1) and the corticospinal network during adaptation by measuring motor-evoked potentials (MEPs) before reach onset using transcranial magnetic stimulation of M1. Subjects reached in a force field in a schedule in which the field was introduced either abruptly or gradually over many trials. In both groups, by end of the training, muscles that countered the perturbation in a given direction increased their activity during the reach (labeled as the on direction for each muscle). In the abrupt group, in the period before the reach toward the on direction, MEPs in these muscles also increased, suggesting a direction-specific increase in the excitability of the corticospinal network. However, in the gradual group, these MEP changes were missing. After training, there was a period of washout. The MEPs did not return to baseline. Rather, in the abrupt group, off direction MEPs increased to match on direction MEPs. Therefore, we observed changes in corticospinal excitability in the abrupt but not gradual condition. Abrupt training includes the repetition of motor commands, and repetition may be the key factor that produces this plasticity. Furthermore, washout did not return MEPs to baseline, suggesting that washout engaged a new network that masked but did not erase the effects of previous adaptation. Abrupt but not gradual training appears to induce changes in M1 and/or corticospinal networks.

scholarly journals Disrupted Central Inhibition after Transcranial Magnetic Stimulation of Motor Cortex in Schizophrenia with Long-Term Antipsychotic Treatment

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Aulikki Ahlgrén-Rimpiläinen ◽  
Hannu Lauerma ◽  
Seppo Kähkönen ◽  
Ilpo Rimpiläinen
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Silent Period ◽  
Single Pulse ◽  
Contralateral Side ◽  
Antipsychotic Treatment ◽  
Stimulation Of

Aims. Schizophrenia is a neuropsychiatric disorder associated with mental and motor disturbances. We aimed to investigate motor control, especially central silent period (CSP) in subjects with schizophrenia (n=11) on long-term antipsychotic treatment compared to healthy controls (n=9). Methods. Latency and duration of motor evoked potentials (MEPs) and CSPs were measured with the help of single pulse transcranial magnetic stimulation (TMS) and intramuscular electrodes. After stimulation of the dominant and nondominant motor cortex of abductor digiti minimi (ADM) and tibialis anterior (TA) muscle areas, respective responses were measured on the contralateral side. Results. MEPs did not differ significantly between the groups. Multiple CSPs were found predominantly in subjects with schizophrenia, which showed a higher number of CSPs in the dominant ADM and the longest summarized duration of CSPs in the nondominant ADM (P<0.05) compared to controls. Conclusions. There were multiple CSPs predominantly in the upper extremities and in the dominant body side in subjects with schizophrenia. Behind multiple CSPs may lie an impaired regulation of excitatory or inhibitory neurotransmitter systems in central motor pathways. Further research is needed to clarify the role of the intramuscular recording methods and the effect of antipsychotics on the results.

scholarly journals Alertness fluctuations during task performance modulate cortical evoked responses to transcranial magnetic stimulation

2017 ◽  
Author(s):  
Valdas Noreika ◽  
Marc R. Kamke ◽  
Andrés Canales-Johnson ◽  
Srivas Chennu ◽  
Tristan A. Bekinschtein ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Cognitive Neuroscience ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Brain Activity ◽  
Single Pulse ◽  
Neural Recording ◽  
Neural Responses ◽  
Spontaneous Fluctuations

ABSTRACTTranscranial magnetic stimulation (TMS) has been widely used in human cognitive neuroscience to examine the causal role of distinct cortical areas in perceptual, cognitive and motor functions. However, it is widely acknowledged that the effects of focal cortical stimulation on behaviour can vary substantially between participants and even from trial to trial within individuals. Here we asked whether spontaneous fluctuations in alertness can account for the variability in behavioural and neurophysiological responses to TMS. We combined single-pulse TMS with neural recording via electroencephalography (EEG) to quantify changes in motor and cortical reactivity with fluctuating levels of alertness defined objectively on the basis of ongoing brain activity. We observed rapid, non-linear changes in TMS-evoked neural responses – specifically, motor evoked potentials and TMS-evoked cortical potentials – as EEG activity indicated decreasing levels of alertness, even while participants remained awake and responsive in the behavioural task.IMPACT STATEMENTA substantial proportion of inter-trial variability in neurophysiological responses to TMS is due to spontaneous fluctuations in alertness, which should be controlled for during experimental and clinical applications of TMS.

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

2021 ◽  
Vol 11 (1) ◽  
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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