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Fulltext Theta-burst Transcranial Magnetic Stimulation Alters the Functional Topography of the Cortical Motor Network

Noh NA, Fuggetta G, Manganotti P

Malays J Med Sci, 2015 Dec;22(Spec Issue):36-44.
PMID: 27006636 MyJurnal

Transcranial magnetic stimulation (TMS) is a non-invasive tool that is able to modulate the electrical activity of the brain depending upon its protocol of stimulation. Theta burst stimulation (TBS) is a high-frequency TMS protocol that is able to induce prolonged plasticity changes in the brain. The induction of plasticity-like effects by TBS is useful in both experimental and therapeutic settings; however, the underlying neural mechanisms of this modulation remain unclear. The aim of this study was to investigate the effects of continuous TBS (cTBS) on the intrahemispheric and interhemispheric functional connectivity of the resting and active brain.

Matched MeSH terms: Transcranial Magnetic Stimulation
Fulltext Second Courses of Transcranial Magnetic Stimulation (TMS) in Major Depressive Episodes for Initial Responders and Non-Responders

Pridmore S, Erger S, May T

Malays J Med Sci, 2019 May;26(3):102-109.
PMID: 31303854 DOI: 10.21315/mjms2019.26.3.8

Background: Transcranial Magnetic Stimulation (TMS) is effective in major depressive episodes (MDE). However, MDE may follow a chronic, relapsing course, and some individuals may not satisfactorily respond to a first course of TMS.
Objective: To investigate the outcome of second courses of TMS.
Method: A naturalistic investigation-we prospectively studied 30 MDE in-patients and routinely collected information, including pre- and post-treatment with Six-item Hamilton Depression Rating Scale (HAMD6), a six-item Visual Analogue Scale (VAS6) and the Clinical Global Impression-Severity (CGI-S). Two categories of patients were considered: i) those who had remitted with a first course, but relapsed, and ii) those who had not remitted with the first course.
Results: Thirty individuals received a second TMS course. The mean time to the second course was 27.5 weeks. Based on the HAMD6, 26 (87%) achieved remission after the first course, and 22 (73%) achieved remission after the second course. Furthermore, based on the HAMD6 results, of the four patients who did not achieve remission with a first course, three (75%) did so with a second course.
Conclusion: In MDE, a second course of TMS is likely to help those who remitted to a first course and then relapsed, as well as those who did not achieve remission with a first course.

Matched MeSH terms: Transcranial Magnetic Stimulation
Fulltext Exploring Cortical Plasticity and Oscillatory Brain Dynamics via Transcranial Magnetic Stimulation and Resting-State Electroencephalogram

Noh NA

Malays J Med Sci, 2016 Jul;23(4):5-16.
PMID: 27660540 MyJurnal DOI: 10.21315/mjms2016.23.4.2

Transcranial magnetic stimulation (TMS) is a non-invasive, non-pharmacological technique that is able to modulate cortical activity beyond the stimulation period. The residual aftereffects are akin to the plasticity mechanism of the brain and suggest the potential use of TMS for therapy. For years, TMS has been shown to transiently improve symptoms of neuropsychiatric disorders, but the underlying neural correlates remain elusive. Recently, there is evidence that altered connectivity of brain network dynamics is the mechanism underlying symptoms of various neuropsychiatric illnesses. By combining TMS and electroencephalography (EEG), the functional connectivity patterns among brain regions, and the causal link between function or behaviour and a specific brain region can be determined. Nonetheless, the brain network connectivity are highly complex and involve the dynamics interplay among multitude of brain regions. In this review article, we present previous TMS-EEG co-registration studies, which explore the functional connectivity patterns of human cerebral cortex. We argue the possibilities of neural correlates of long-term potentiation/depression (LTP-/LTD)-like mechanisms of synaptic plasticity that drive the TMS aftereffects as shown by the dissociation between EEG and motor evoked potentials (MEP) cortical output. Here, we also explore alternative explanations that drive the EEG oscillatory modulations post TMS. The precise knowledge of the neurophysiological mechanisms underlying TMS will help characterise disturbances in oscillatory patterns, and the altered functional connectivity in neuropsychiatric illnesses.

Matched MeSH terms: Transcranial Magnetic Stimulation
Fulltext The Effect of Repetitive Transcranial Magnetic Stimulation on Postural Stability After Acute Stroke: A Clinical Trial

Forogh B, Ahadi T, Nazari M, Sajadi S, Abdul Latif L, Akhavan Hejazi SM, et al.

Basic Clin Neurosci, 2017 Sep-Oct;8(5):405-411.
PMID: 29167727 DOI: 10.18869/nirp.bcn.8.5.405

Introduction: Balance impairment is a common problem and a major cause of motor disability after stroke. Therefore, this study aimed to investigate whether low-frequency repetitive Transcranial Magnetic Stimulation (rTMS) improves the postural balance problems in stroke patients.

Methods: This randomized double blind clinical trial with 12 weeks follow-up was conducted on stroke patients. Treatment was carried with 1 Hz rTMS in contralateral brain hemisphere over the primary motor area for 20 minutes (1200 pulses) for 5 consecutive days. Static postural stability, Medical Research Council (MRC), Berg Balance Scale (BBS), and Fugl-Meyer assessments were evaluated immediately, 3 weeks and 12 weeks after intervention.

Results: A total of 26 patients were enrolled (age range=53 to 79 years; 61.5% were male) in this study. Administering rTMS produced a significant recovery based on BBS (df=86, 7; F=7.4; P=0.01), Fugl-Meyer Scale (df=86, 7; F=8.7; P<0.001), MRC score (df=87, 7; F=2.9; P=0.01), and static postural stability (df=87, 7; F=9.8; P<0.001) during the 12 weeks follow-up.

Conclusion: According to the findings, rTMS as an adjuvant therapy may improve the static postural stability, falling risk, coordination, motor recovery, and muscle strength in patients with stroke.

Matched MeSH terms: Transcranial Magnetic Stimulation
Aftereffects of 2 noninvasive brain stimulation techniques on corticospinal excitability in persons with chronic stroke: a pilot study

Goh HT, Chan HY, Abdul-Latif L

J Neurol Phys Ther, 2015 Jan;39(1):15-22.
PMID: 25427033 DOI: 10.1097/NPT.0000000000000064

Noninvasive brain stimulation, including repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), have gained popularity in the stroke rehabilitation literature. Little is known about the time course and duration of effects of noninvasive brain stimulation on corticospinal excitability in individuals with stroke. We examined the aftereffects of a single session of high-frequency rTMS (5 Hz) and anodal tDCS on corticospinal excitability in the same sample of participants with chronic stroke.

Matched MeSH terms: Transcranial Magnetic Stimulation*
Effects of action observation on corticospinal excitability: Muscle specificity, direction, and timing of the mirror response

Naish KR, Houston-Price C, Bremner AJ, Holmes NP

Neuropsychologia, 2014 11;64:331-48.
PMID: 25281883 DOI: 10.1016/j.neuropsychologia.2014.09.034

Many human behaviours and pathologies have been attributed to the putative mirror neuron system, a neural system that is active during both the observation and execution of actions. While there are now a very large number of papers on the mirror neuron system, variations in the methods and analyses employed by researchers mean that the basic characteristics of the mirror response are not clear. This review focuses on three important aspects of the mirror response, as measured by modulations in corticospinal excitability: (1) muscle specificity; (2) direction; and (3) timing of modulation. We focus mainly on electromyographic (EMG) data gathered following single-pulse transcranial magnetic stimulation (TMS), because this method provides precise information regarding these three aspects of the response. Data from paired-pulse TMS paradigms and peripheral nerve stimulation (PNS) are also considered when we discuss the possible mechanisms underlying the mirror response. In this systematic review of the literature, we examine the findings of 85 TMS and PNS studies of the human mirror response, and consider the limitations and advantages of the different methodological approaches these have adopted in relation to discrepancies between their findings. We conclude by proposing a testable model of how action observation modulates corticospinal excitability in humans. Specifically, we propose that action observation elicits an early, non-specific facilitation of corticospinal excitability (at around 90ms from action onset), followed by a later modulation of activity specific to the muscles involved in the observed action (from around 200ms). Testing this model will greatly advance our understanding of the mirror mechanism and provide a more stable grounding on which to base inferences about its role in human behaviour.

Matched MeSH terms: Transcranial Magnetic Stimulation
The Two-Brains Hypothesis: Towards a guide for brain-brain and brain-machine interfaces

Goodman G, Poznanski RR, Cacha L, Bercovich D

J Integr Neurosci, 2015 Sep;14(3):281-93.
PMID: 26477360 DOI: 10.1142/S0219635215500235

Great advances have been made in signaling information on brain activity in individuals, or passing between an individual and a computer or robot. These include recording of natural activity using implants under the scalp or by external means or the reverse feeding of such data into the brain. In one recent example, noninvasive transcranial magnetic stimulation (TMS) allowed feeding of digitalized information into the central nervous system (CNS). Thus, noninvasive electroencephalography (EEG) recordings of motor signals at the scalp, representing specific motor intention of hand moving in individual humans, were fed as repetitive transcranial magnetic stimulation (rTMS) at a maximum intensity of 2.0[Formula: see text]T through a circular magnetic coil placed flush on each of the heads of subjects present at a different location. The TMS was said to induce an electric current influencing axons of the motor cortex causing the intended hand movement: the first example of the transfer of motor intention and its expression, between the brains of two remote humans. However, to date the mechanisms involved, not least that relating to the participation of magnetic induction, remain unclear. In general, in animal biology, magnetic fields are usually the poor relation of neuronal current: generally "unseen" and if apparent, disregarded or just given a nod. Niels Bohr searched for a biological parallel to complementary phenomena of physics. Pertinently, the two-brains hypothesis (TBH) proposed recently that advanced animals, especially man, have two brains i.e., the animal CNS evolved as two fundamentally different though interdependent, complementary organs: one electro-ionic (tangible, known and accessible), and the other, electromagnetic (intangible and difficult to access) - a stable, structured and functional 3D compendium of variously induced interacting electro-magnetic (EM) fields. Research on the CNS in health and disease progresses including that on brain-brain, brain-computer and brain-robot engineering. As they grow even closer, these disciplines involve their own unique complexities, including direction by the laws of inductive physics. So the novel TBH hypothesis has wide fundamental implications, including those related to TMS. These require rethinking and renewed research engaging the fully complementary equivalence of mutual magnetic and electric field induction in the CNS and, within this context, a new mathematics of the brain to decipher higher cognitive operations not possible with current brain-brain and brain-machine interfaces. Bohr may now rest.

Matched MeSH terms: Transcranial Magnetic Stimulation