Pharmacology of TMS measures

2021 ◽  
Author(s):  
Ulf Ziemann
Keyword(s):  
Mode Of Action ◽  
Healthy Subjects ◽  
Magnetic Stimulation ◽  
Active Drug ◽  
Cortical Excitability ◽  
Drug Effects ◽  
Main Mode ◽  
Physiological Properties ◽  
P Application ◽  
Chronic Drug Effects

Application of a single dose of a central nervous system (CNS) active drug with a defined mode of action has been proven useful to explore pharmaco-physiological properties of transcranial magnetic stimulation (TMS)-evoked electromyographic (EMG) measures of motor cortical excitability. With this approach, it is possible to demonstrate that TMS-EMG measures reflect axonal, or excitatory or inhibitory synaptic excitability in distinct interneuron circuits. On the other hand, the array of pharmaco-physiologically well-characterized TMS-EMG measures can be employed to study the effects of a drug with unknown or multiple modes of action, and hence to determine its main mode of action at the systems level of the motor cortex. Acute drug effects may be rather different from chronic drug effects, and these differences can also be studied in TMS experiments. Moreover, TMS or repetitive TMS (rTMS) may induce changes in endogenous neurotransmitter or neuromodulator systems. This offers the opportunity to study neurotransmission along defined neuronal projections. Finally, more recently, TMS-evoked electroencephalographic (EEG) responses have been developed to study cortical excitability and connectivity. Pharmaco-physiological testing can be employed to also characterize these TMS-EEG measures. All these aspects of the pharmacology of TMS measures in healthy subjects will be reviewed in this chapter.

Pharmacology of TMS measures

2012 ◽  
Author(s):  
Ulf Ziemann
Keyword(s):  
Motor Cortex ◽  
Mode Of Action ◽  
Cortical Excitability ◽  
Drug Effects ◽  
Main Mode ◽  
Multiple Modes ◽  
Modes Of Action ◽  
Health And Disease ◽  
Cortical Physiology ◽  
Chronic Drug Effects

This article discusses various aspects of the pharmacology of transcranial magnetic stimulator (TMS) measures. TMS measures reflect axonal, or excitatory or inhibitory synaptic excitability in distinct interneuron circuits. TMS measures can be employed to study the effects of a drug with unknown or multiple modes of action, and hence to determine its main mode of action at the systems level of the motor cortex. TMS experiments can also study acute drug effects that may be different from chronic drug effects. TMS or repetitive TMS may induce changes in endogenous neurotransmitter or neuromodulator systems. This allows for the study of neurotransmission along defined neuronal projections in health and disease. This article describes pharmacological experiments that have characterized the physiology of TMS measures of motor cortical excitability. Pharmacological challenging of TMS measures has opened a broad window into human cortical physiology.

Normative data of cortical excitability measurements obtained by transcranial magnetic stimulation in healthy subjects

2016 ◽  
Vol 46 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Ana Sofia Cueva ◽  
Ricardo Galhardoni ◽  
Rubens Gisbert Cury ◽  
Daniella Cardoso Parravano ◽  
Guilherme Correa ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Healthy Subjects ◽  
Magnetic Stimulation ◽  
Normative Data ◽  
Cortical Excitability

Abstract #80: Assessment of cortical excitability with Transcranial Magnetic Stimulation in patients with brain tumor

2019 ◽  
Vol 12 (2) ◽  
pp. e28
Author(s):  
Cintya Hayashi ◽  
Iuri S. Nevile ◽  
Cesar C. Almeida ◽  
Priscila Rodrigues ◽  
Ricardo RG. Galhardoni ◽  
...  
Keyword(s):  
Brain Tumor ◽  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Cortical Excitability

scholarly journals Effects of transcranial static magnetic stimulation over the primary motor cortex on local and network spontaneous electroencephalogram oscillations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sumiya Shibata ◽  
Tatsunori Watanabe ◽  
Yoshihiro Yukawa ◽  
Masatoshi Minakuchi ◽  
Ryota Shimomura ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Power Spectrum ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Controlled Study ◽  
Functional Coupling ◽  
Phase Lag ◽  
Theta Band ◽  
Double Blind

AbstractTranscranial static magnetic stimulation (tSMS) is a novel non-invasive brain stimulation technique that reduces cortical excitability at the stimulation site. We investigated the effects of tSMS over the left primary motor cortex (M1) for 20 min on the local electroencephalogram (EEG) power spectrum and interregional EEG coupling. Twelve right-handed healthy subjects participated in this crossover, double-blind, sham-controlled study. Resting-state EEG data were recorded for 3 min before the intervention and 17 min after the beginning of the intervention. The power spectrum at the left central electrode (C3) and the weighted phase lag index (wPLI) between C3 and the other electrodes was calculated for theta (4–8 Hz), alpha (8–12 Hz), and beta (12–30 Hz) frequencies. The tSMS significantly increased theta power at C3 and the functional coupling in the theta band between C3 and the parietal midline electrodes. The tSMS over the left M1 for 20 min exhibited modulatory effects on local cortical activity and interregional functional coupling in the theta band. The neural oscillations in the theta band may have an important role in the neurophysiological effects induced by tSMS over the frontal cortex.

scholarly journals Cerebellar rTMS and PAS effectively induce cerebellar plasticity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Martje G. Pauly ◽  
Annika Steinmeier ◽  
Christina Bolte ◽  
Feline Hamami ◽  
Elinor Tzvi ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Healthy Subjects ◽  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Premotor Cortex ◽  
Motor Pathways ◽  
Non Invasive ◽  
Cerebellar Plasticity

AbstractNon-invasive brain stimulation techniques including repetitive transcranial magnetic stimulation (rTMS), continuous theta-burst stimulation (cTBS), paired associative stimulation (PAS), and transcranial direct current stimulation (tDCS) have been applied over the cerebellum to induce plasticity and gain insights into the interaction of the cerebellum with neo-cortical structures including the motor cortex. We compared the effects of 1 Hz rTMS, cTBS, PAS and tDCS given over the cerebellum on motor cortical excitability and interactions between the cerebellum and dorsal premotor cortex / primary motor cortex in two within subject designs in healthy controls. In experiment 1, rTMS, cTBS, PAS, and tDCS were applied over the cerebellum in 20 healthy subjects. In experiment 2, rTMS and PAS were compared to sham conditions in another group of 20 healthy subjects. In experiment 1, PAS reduced cortical excitability determined by motor evoked potentials (MEP) amplitudes, whereas rTMS increased motor thresholds and facilitated dorsal premotor-motor and cerebellum-motor cortex interactions. TDCS and cTBS had no significant effects. In experiment 2, MEP amplitudes increased after rTMS and motor thresholds following PAS. Analysis of all participants who received rTMS and PAS showed that MEP amplitudes were reduced after PAS and increased following rTMS. rTMS also caused facilitation of dorsal premotor-motor cortex and cerebellum-motor cortex interactions. In summary, cerebellar 1 Hz rTMS and PAS can effectively induce plasticity in cerebello-(premotor)-motor pathways provided larger samples are studied.

scholarly journals Transcranial Magnetic Stimulation as a Tool to Investigate Motor Cortex Excitability in Sport

2021 ◽  
Vol 11 (4) ◽  
pp. 432
Author(s):  
Fiorenzo Moscatelli ◽  
Antonietta Messina ◽  
Anna Valenzano ◽  
Vincenzo Monda ◽  
Monica Salerno ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Motor Coordination ◽  
Cortical Excitability ◽  
Non Invasive ◽  
Motor Cortex Excitability ◽  
Invasive Method ◽  
And Control ◽  
The Impact

Transcranial magnetic stimulation, since its introduction in 1985, has brought important innovations to the study of cortical excitability as it is a non-invasive method and, therefore, can be used both in healthy and sick subjects. Since the introduction of this cortical stimulation technique, it has been possible to deepen the neurophysiological aspects of motor activation and control. In this narrative review, we want to provide a brief overview regarding TMS as a tool to investigate changes in cortex excitability in athletes and highlight how this tool can be used to investigate the acute and chronic responses of the motor cortex in sport science. The parameters that could be used for the evaluation of cortical excitability and the relative relationship with motor coordination and muscle fatigue, will be also analyzed. Repetitive physical training is generally considered as a principal strategy for acquiring a motor skill, and this process can elicit cortical motor representational changes referred to as use-dependent plasticity. In training settings, physical practice combined with the observation of target movements can enhance cortical excitability and facilitate the process of learning. The data to date suggest that TMS is a valid technique to investigate the changes in motor cortex excitability in trained and untrained subjects. Recently, interest in the possible ergogenic effect of non-invasive brain stimulation in sport is growing and therefore in the future it could be useful to conduct new experiments to evaluate the impact on learning and motor performance of these techniques.

scholarly journals Transcranial Evoked Potentials Can Be Reliably Recorded with Active Electrodes

2021 ◽  
Vol 11 (2) ◽  
pp. 145
Author(s):  
Marco Mancuso ◽  
Valerio Sveva ◽  
Alessandro Cruciani ◽  
Katlyn Brown ◽  
Jaime Ibáñez ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
The Other ◽  
Concordance Correlation Coefficient ◽  
Concordance Correlation ◽  
Eeg Signals ◽  
Active Electrode ◽  
Viable Solution ◽  
Space Projection

Electroencephalographic (EEG) signals evoked by transcranial magnetic stimulation (TMS) are usually recorded with passive electrodes (PE). Active electrode (AE) systems have recently become widely available; compared to PE, they allow for easier electrode preparation and a higher-quality signal, due to the preamplification at the electrode stage, which reduces electrical line noise. The performance between the AE and PE can differ, especially with fast EEG voltage changes, which can easily occur with TMS-EEG; however, a systematic comparison in the TMS-EEG setting has not been made. Therefore, we recorded TMS-evoked EEG potentials (TEPs) in a group of healthy subjects in two sessions, one using PE and the other using AE. We stimulated the left primary motor cortex and right medial prefrontal cortex and used two different approaches to remove early TMS artefacts, Independent Component Analysis and Signal Space Projection—Source Informed Recovery. We assessed statistical differences in amplitude and topography of TEPs, and their similarity, by means of the concordance correlation coefficient (CCC). We also tested the capability of each system to approximate the final TEP waveform with a reduced number of trials. The results showed that TEPs recorded with AE and PE do not differ in amplitude and topography, and only few electrodes showed a lower-than-expected CCC between the two methods of amplification. We conclude that AE are a viable solution for TMS-EEG recording.

Low frequency transcranial magnetic stimulation in subacute ischemic stroke: Number of sessions that altered cortical excitability

2020 ◽  
Vol 47 (4) ◽  
pp. 427-434
Author(s):  
Mohammed S. El-Tamawy ◽  
Moshera H. Darwish ◽  
Saly H. Elkholy ◽  
Engy BadrEldin S. Moustafa ◽  
Shimaa T. Abulkassem ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Transcranial Magnetic Stimulation ◽  
Physical Therapy ◽  
Upper Limb ◽  
Magnetic Stimulation ◽  
Cortical Excitability ◽  
Low Frequency ◽  
Cortical Reorganization ◽  
Therapy Program ◽  
Physical Therapy Program

BACKGROUND: Cortical reorganization between both cerebral hemispheres plays an important role in regaining the affected upper extremity motor function post-stroke. OBJECTIVES: The purpose of the current study was to investigate the recommended number of contra-lesion low frequency repetitive transcranial magnetic stimulation (LF-rTMS) sessions that could enhance cortical reorganization post-stroke. METHODS: Forty patients with right hemiparetic subacute ischemic stroke with an age range between 50–65 yrs were randomly assigned into two equal groups: control (GA) and study (GB) groups. Both groups were treated with a selected physical therapy program for the upper limb. Sham and real contra-lesion LF-rTMS was conducted for both groups daily for two consecutive weeks. Sequential changes of cortical excitability were calculated by the end of each session. RESULTS: The significant enhancement in the cortical excitability was observed at the fourth session in favor of the study group (GB). Sequential rate of change in cortical excitability was significant for the first eight sessions. From the ninth session onwards, no difference could be detected between groups. CONCLUSION: The pattern of recovery after stroke is extensive and not all factors could be controlled. Application of LF-rTMS in conjugation with a selected physical therapy program for the upper limb from four to eight sessions seems to be efficient.

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