scholarly journals Plasticity-Inducing TMS Protocols to Investigate Somatosensory Control of Hand Function

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
M. Jacobs ◽  
A. Premji ◽  
A. J. Nelson
Keyword(s):  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Hand Function ◽  
Hand Movement ◽  
Careful Consideration ◽  
Human Hand ◽  
Motor Behaviour ◽  
Somatosensory Cortices ◽  
Hand Control ◽  
Theta Burst

Hand function depends on sensory feedback to direct an appropriate motor response. There is clear evidence that somatosensory cortices modulate motor behaviour and physiology within primary motor cortex. However, this information is mainly from research in animals and the bridge to human hand control is needed. Emerging evidence in humans supports the notion that somatosensory cortices modulate motor behaviour, physiology and sensory perception. Transcranial magnetic stimulation (TMS) allows for the investigation of primary and higher-order somatosensory cortices and their role in control of hand movement in humans. This review provides a summary of several TMS protocols in the investigation of hand control via the somatosensory cortices. TMS plasticity inducing protocols reviewed include paired associative stimulation, repetitive TMS, theta-burst stimulation as well as other techniques that aim to modulate cortical excitability in sensorimotor cortices. Although the discussed techniques may modulate cortical excitability, careful consideration of experimental design is needed to isolate factors that may interfere with desired results of the plasticity-inducing protocol, specifically events that may lead to metaplasticity within the targeted cortex.

scholarly journals Training Effects Outweigh Effects of Single-Session Conventional rTMS and Theta Burst Stimulation in PD Patients

2008 ◽  
Vol 23 (4) ◽  
pp. 373-381 ◽  
Author(s):  
Holger Rothkegel ◽  
Martin Sommer ◽  
Thomas Rammsayer ◽  
Claudia Trenkwalder ◽  
Walter Paulus
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Single Session ◽  
Theta Burst Stimulation ◽  
Burst Stimulation ◽  
Training Effects ◽  
Pointing Movement ◽  
Theta Burst

Background. Focal single-session repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex has been claimed to be capable of improving motor function in Parkinson's disease. Objective. The authors sought to determine which type of rTMS protocol holds the highest potential for future therapeutic application. Methods. Twenty-two patients with Parkinson's disease received 5 different rTMS protocols on 5 consecutive days in a pseudorandomized and counterbalanced order either in the defined OFF condition or with their usual medication. The protocols tested in the present study included 2 conventional rTMS protocols (0.5 and 10 Hz) as well as the recently introduced theta burst stimulation (cTBS, iTBS) and a sham condition. Cortical excitability, motor performance (pointing movement, pronation-supination, Purdue Pegboard Test, walking), and mood were assessed before and after each session. Results . The authors observed motor training from days 1 to 4, particularly in the group on dopaminergic medication. None of the rTMS paradigms excelled placebo stimulation. The only exception was the Purdue Pegboard Test, in which all active stimulation paradigms yielded slightly stronger effects than sham stimulation. Conclusions. Within a single session, no clinically relevant difference in the rTMS protocols could be detected. Training effects outweigh and may have masked rTMS effects, particularly in the group on dopaminergic mediation.

P 82. Dose-dependent effects of theta-burst rTMS on the cortical excitability and fMRI-connectivity of the primary motor cortex

2013 ◽  
Vol 124 (10) ◽  
pp. e104-e105 ◽  
Author(s):  
C. Nettekoven ◽  
L. Volz ◽  
M. Kutscha ◽  
E.-M. Pool ◽  
A.K. Rehme ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Dose Dependent ◽  
Theta Burst

scholarly journals Variability in cTBS Aftereffects Attributed to the Interaction of Stimulus Intensity With BDNF Val66Met Polymorphism

2021 ◽  
Vol 15 ◽  
Author(s):  
Denise Y. Harvey ◽  
Laura DeLoretta ◽  
Priyanka P. Shah-Basak ◽  
Rachel Wurzman ◽  
Daniela Sacchetti ◽  
...  
Keyword(s):  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Individual Variability ◽  
Theta Burst Stimulation ◽  
Burst Stimulation ◽  
Bdnf Val66met Polymorphism ◽  
Theta Burst ◽  
Continuous Theta Burst Stimulation ◽  
Insight Into

Objective: To evaluate whether a common polymorphism (Val66Met) in the gene for brain-derived neurotrophic factor (BDNF)—a gene thought to influence plasticity—contributes to inter-individual variability in responses to continuous theta-burst stimulation (cTBS), and explore whether variability in stimulation-induced plasticity among Val66Met carriers relates to differences in stimulation intensity (SI) used to probe plasticity.Methods: Motor evoked potentials (MEPs) were collected from 33 healthy individuals (11 Val66Met) prior to cTBS (baseline) and in 10 min intervals immediately following cTBS for a total of 30 min post-cTBS (0 min post-cTBS, 10 min post-cTBS, 20 min post cTBS, and 30 min post-cTBS) of the left primary motor cortex. Analyses assessed changes in cortical excitability as a function of BDNF (Val66Val vs. Val66Met) and SI.Results: For both BDNF groups, MEP-suppression from baseline to post-cTBS time points decreased as a function of increasing SI. However, the effect of SI on MEPs was more pronounced for Val66Met vs. Val66Val carriers, whereby individuals probed with higher vs. lower SIs resulted in paradoxical cTBS aftereffects (MEP-facilitation), which persisted at least 30 min post-cTBS administration.Conclusions: cTBS aftereffects among BDNF Met allele carriers are more variable depending on the SI used to probe cortical excitability when compared to homozygous Val allele carriers, which could, to some extent, account for the inconsistency of previously reported cTBS effects.Significance: These data provide insight into the sources of cTBS response variability, which can inform how best to stratify and optimize its use in investigational and clinical contexts.

scholarly journals Genetic and neurophysiological biomarkers of neuroplasticity inform post-stroke language recovery

2021 ◽  
Author(s):  
Haley C Dresang ◽  
Denise Y Harvey ◽  
Priyanka P Shah-Basak ◽  
Laura DeLoretta ◽  
Rachel Wurzman ◽  
...  
Keyword(s):  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Stroke Recovery ◽  
Lesion Volume ◽  
Theta Burst Stimulation ◽  
Genetic Biomarkers ◽  
Language Recovery ◽  
Theta Burst ◽  
Continuous Theta Burst Stimulation

Background: There is high variability in poststroke aphasia severity, and predicting language recovery remains imprecise. Standard prognostic measures do not include neurophysiological indicators or genetic biomarkers of neuroplasticity, which may be critical sources of variability. Objective: To evaluate whether a common polymorphism (Val66Met) in the gene for brain derived neurotrophic factor (BDNF; a gene related to neuroplasticity) contributes to variability in poststroke language recovery, and to assess whether BDNF polymorphism interacts with neurophysiological indicators of neuroplasticity (cortical excitability and stimulation induced plasticity in response to continuous theta burst stimulation [cTBS]) to improve estimates of aphasia severity. Methods: Saliva samples and motor evoked potentials (MEPs) were collected from participants with chronic aphasia subsequent to a left hemisphere ischemic stroke. MEPs were collected prior to cTBS (index for cortical excitability) and 10 minutes following cTBS (index for stimulation induced neuroplasticity) to the left primary motor cortex. Analyses assessed the extent to which BDNF polymorphism interacted with cortical excitability and stimulation induced neuroplasticity to predict aphasia severity beyond established predictors. Results: Val66Val carriers showed less aphasia severity than Met allele carriers, after controlling for lesion volume and time poststroke. Furthermore, Val66Val carriers showed expected responses of strong effects of age on aphasia severity, and positive associations between both cortical excitability and stimulation induced neuroplasticity and severity. In contrast, Met allele carriers showed weaker effects of age and unexpected negative associations between cortical excitability, stimulation induced neuroplasticity and aphasia severity. Conclusions: Neurophysiological indicators and genetic biomarkers of neuroplasticity improved ability to predict poststroke aphasia severity. Furthermore, BDNF polymorphism interacted with cortical excitability and stimulation-induced neuroplasticity to predict aphasia recovery. These findings provide novel insights into mechanisms of variability in stroke recovery and may improve aphasia prognostics.

scholarly journals Evaluation of Optical and Radar Based Motion Capturing Technologies for Characterizing Hand Movement in Rheumatoid Arthritis—A Pilot Study

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1208
Author(s):  
Uday Phutane ◽  
Anna-Maria Liphardt ◽  
Johanna Bräunig ◽  
Johann Penner ◽  
Michael Klebl ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Continuous Wave ◽  
Hand Function ◽  
Objective Assessment ◽  
Hand Movement ◽  
Human Motion ◽  
Limiting Factors ◽  
Human Hand ◽  
Wave Radar ◽  
Patient Reported

In light of the state-of-the-art treatment options for patients with rheumatoid arthritis (RA), a detailed and early quantification and detection of impaired hand function is desirable to allow personalized treatment regiments and amend currently used subjective patient reported outcome measures. This is the motivation to apply and adapt modern measurement technologies to quantify, assess and analyze human hand movement using a marker-based optoelectronic measurement system (OMS), which has been widely used to measure human motion. We complement these recordings with data from markerless (Doppler radar) sensors and data from both sensor technologies are integrated with clinical outcomes of hand function. The technologies are leveraged to identify hand movement characteristics in RA affected patients in comparison to healthy control subjects, while performing functional tests, such as the Moberg-Picking-Up Test. The results presented discuss the experimental framework and present the limiting factors imposed by the use of marker-based measurements on hand function. The comparison of simple finger motion data, collected by the OMS, to data recorded by a simple continuous wave radar suggests that radar is a promising option for the objective assessment of hand function. Overall, the broad scope of integrating two measurement technologies with traditional clinical tests shows promising potential for developing new pathways in understanding of the role of functional outcomes for the RA pathology.

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 Determining the optimal pulse number for theta burst induced change in cortical excitability

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniel M. McCalley ◽  
Daniel H. Lench ◽  
Jade D. Doolittle ◽  
Julia P. Imperatore ◽  
Michaela Hoffman ◽  
...  
Keyword(s):  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Pulse Number ◽  
Theta Burst Stimulation ◽  
Burst Stimulation ◽  
Non Invasive ◽  
Subject Variability ◽  
Secondary Analyses ◽  
Effective Doses ◽  
Theta Burst

AbstractTheta-burst stimulation (TBS) is a form of non-invasive neuromodulation which is delivered in an intermittent (iTBS) or continuous (cTBS) manner. Although 600 pulses is the most common dose, the goal of these experiments was to evaluate the effect of higher per-dose pulse numbers on cortical excitability. Sixty individuals were recruited for 2 experiments. In Experiment 1, participants received 600, 1200, 1800, or sham (600) iTBS (4 visits, counterbalanced, left motor cortex, 80% active threshold). In Experiment 2, participants received 600, 1200, 1800, 3600, or sham (600) cTBS (5 visits, counterbalanced). Motor evoked potentials (MEP) were measured in 10-min increments for 60 min. For iTBS, there was a significant interaction between dose and time (F = 3.8296, p = 0.01), driven by iTBS (1200) which decreased excitability for up to 50 min (t = 3.1267, p = 0.001). For cTBS, there was no overall interaction between dose and time (F = 1.1513, p = 0.33). Relative to sham, cTBS (3600) increased excitability for up to 60 min (t = 2.0880, p = 0.04). There were no other significant effects of dose relative to sham in either experiment. Secondary analyses revealed high within and between subject variability. These results suggest that iTBS (1200) and cTBS (3600) are, respectively, the most effective doses for decreasing and increasing cortical excitability.

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 Online and offline effects of transcranial alternating current stimulation of the primary motor cortex

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ivan Pozdniakov ◽  
Alicia Nunez Vorobiova ◽  
Giulia Galli ◽  
Simone Rossi ◽  
Matteo Feurra
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Random Noise ◽  
Single Pulse ◽  
Alternating Current ◽  
Online Application ◽  
Transcranial Random Noise Stimulation ◽  
Transcranial Alternating Current Stimulation

AbstractTranscranial alternating current stimulation (tACS) is a non-invasive brain stimulation technique that allows interaction with endogenous cortical oscillatory rhythms by means of external sinusoidal potentials. The physiological mechanisms underlying tACS effects are still under debate. Whereas online (e.g., ongoing) tACS over the motor cortex induces robust state-, phase- and frequency-dependent effects on cortical excitability, the offline effects (i.e. after-effects) of tACS are less clear. Here, we explored online and offline effects of tACS in two single-blind, sham-controlled experiments. In both experiments we used neuronavigated transcranial magnetic stimulation (TMS) of the primary motor cortex (M1) as a probe to index changes of cortical excitability and delivered M1 tACS at 10 Hz (alpha), 20 Hz (beta) and sham (30 s of low-frequency transcranial random noise stimulation; tRNS). Corticospinal excitability was measured by single pulse TMS-induced motor evoked potentials (MEPs). tACS was delivered online in Experiment 1 and offline in Experiment 2. In Experiment 1, the increase of MEPs size was maximal with the 20 Hz stimulation, however in Experiment 2 neither the 10 Hz nor the 20 Hz stimulation induced tACS offline effects. These findings support the idea that tACS affects cortical excitability only during online application, at least when delivered on the scalp overlying M1, thereby contributing to the development of effective protocols that can be applied to clinical populations.

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