Transcranial magnetic stimulation of the brain: What is stimulated? – A consensus and critical position paper

Siebner, Hartwig R.; Funke, Klaus; Aberra, Aman S.; Antal, Andrea; Bestmann, Sven; Chen, Robert; Claßen, Joseph; Davare, Marco; Lazzaro, Vincenzo Di; Fox, Peter T.; Hallett, Mark; Karabanov, Anke Ninija; Kesselheim, Janine; Beck, Mikkel Malling; Koch, Giacomo; Liebetanz, David; Meunier, Sabine; Miniussi, Carlo; Paulus, Walter; Peterchev, Angel V.; Popa, Traian; Ridding, Michael C.; Thielscher, Axel; Ziemann, Ulf; Rothwell, John C.; Ugawa, Yoshikazu

doi:10.1016/j.clinph.2022.04.022

Cited by 237 publications

(172 citation statements)

References 435 publications

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“…The first step is to find the largest piece of the target functional network that is located on a gyral crown. Attempting to stimulate pieces of the target network in a sulcus would inevitably result in greater stimulation of whichever functional networks are represented on the nearest gyrus because the E-field is strongest on the gyral crown (Bungert et al, 2017;Siebner et al, 2022;Thielscher et al, 2011) (this effect is demonstrated in Figures S2A and S2B).…”

Section: Neuroresourcementioning

confidence: 99%

Automated optimization of TMS coil placement for personalized functional network engagement

Lynch

Elbau

et al. 2022

Neuron

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Section: Neuroresourcementioning

confidence: 99%

Automated optimization of TMS coil placement for personalized functional network engagement

Lynch

Elbau

et al. 2022

Neuron

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“…In such epistemic circumstances, application of systematic perturbations, and measurement of their effects, is a central tool in the scientific armoury 2;3 . For human brains, the technological combination that best supports this non-invasive perturbation-based modus operandi is concurrent transcranial magnetic stimulation (TMS) and electroencephalography (EEG) 4;5 . TMS-EEG allows millisecond-level tracking of stimulation-evoked activity propagation throughout the brain 6;7 , originating from a target region that is perturbed by the secondary electrical currents of a focal (2-2.5cm diameter), brief (∼1ms), and powerful (1.5-2T) magnetic field 8 .…”

Section: Introductionmentioning

confidence: 99%

TMS-Evoked Responses Are Driven by Recurrent Large-Scale Network Dynamics

Griffiths

Momi

Wang

2022

Preprint

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A major question in systems and cognitive neuroscience is to what extent neurostimulation responses are driven by recurrent activity. This question finds sharp relief in the case of TMS-EEG evoked potentials (TEPs). TEPs are spatiotemporal waveform patterns with characteristic inflections at ∼50ms, ∼100ms, and ∼150-200ms following a single TMS pulse that disperse from, and later reconverge to, the primary stimulated regions. What parts of the TEP are due to recurrent activity? And what light might this shed on more general principles of brain organization? We studied this using source-localized TMS-EEG analyses and whole-brain connectome-based computational modelling. Results indicated that recurrent network feedback begins to drive TEP responses from ∼100ms post-stimulation, with earlier TEP components being attributable to local reverberatory activity within the stimulated region. Subject-specific estimation of neurophysiological parameters additionally indicated an important role for inhibitory GABAergic neural populations in scaling cortical excitability levels, as reflected in TEP waveform characteristics.

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“…On the other hand, TMS is known to simultaneously activate different neural populations (pyramidal cells and interneurons) within the stimulated area, with pyramidal V neurons being more prone to be activated. First, their specific shape and spatial orientation within the gyrus makes them more sensitive to the electrical field induced by TMS 18,72 . Second, a recent study by Chameh et al 74 using in vitro whole-cell recordings from cortical layer 2 to 5 of the human cortex showed that L5 pyramidal cells were the most excitable neurons.…”

Section: Unmasking Complementary Intracortical Inhibition Mechanisms ...mentioning

confidence: 99%

“…Gathering information on the time course of the excitatory/inhibitory systems in vivo in humans after a stroke is challenging as only few non-invasive methods are currently available to determine these transmitter systems. By using Transcranial Magnetic Stimulation (TMS), one can assess the status of the cortico-spinal and intracortical excitability, and cortico-spinal tract (CST) integrity with the measure of Motor-Evoked Potentials (MEP) generated by stimulation of the primary motor cortex 18 . While the use of TMS have helped to investigate crucial mechanisms occurring after a stroke [19][20][21][22] , a non-negligible subset of stroke patients presents a damaged CST that prevents the formation of MEP 23 and thus the use of TMS to extract information on their central and peripheral reactivity.…”

Section: Introductionmentioning

confidence: 99%

Stroke recovery-related changes in cortical reactivity based on modulation of intracortical inhibition

Cadic‐Melchior

Harquel

Morishita

et al. 2022

Preprint

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The neuronal processes sustaining motor recovery after stroke are still largely unknown. Cortical excitation/inhibition dynamics have been previously suggested as a key mechanism occurring after a stroke. Their supportive or maladaptive role after a stroke and during the process of recovery are still not completely understood; it is hypothesized that similar mechanisms (e.g., disinhibition) might yield differential functional roles depending on the stage after the stroke (e.g., acute vs. subacute vs. chronic) and the degree of deficit. Here, we used TMS-EEG to study brain reactivity, motor cortical excitability as well as intracortical inhibition and their impact on residual motor function and recovery longitudinally in a large cohort of stroke patients. EEG responses evoked by TMS applied to the ipsilesional motor cortex (iMC) were acquired in 66 stroke patients in the acute (1-week), sub-acute (3-weeks) and chronic stage (3-months). Readouts of ipsilesional cortical reactivity, excitability and intracortical inhibition were drawn from TMS-evoked potentials and derived metrics. Residual function of the upper limb was quantified through a detailed motor evaluation. A large proportion of patients, especially the most affected ones, exhibited large, simple TMS-evoked neuronal responses. Bayesian correlations revealed a link between higher excitability in iMC in the acute and stronger reduction of impairment determined by the upper extremity Fugl-Meyer (FM-UE) score in the early chronic stage. Furthermore, a decrease of this abnormally large response in the following months was related to better motor recovery. When investigating the underlying mechanisms with a focus on the intracortical GABAergic system, the present results revealed changes in intracortical inhibition in the first week after stroke that were associated with better recovery. Restoration of intracortical inhibition was present in patients who recovered the most. Furthermore, the large component observed in a relevant part of the patients masks underlying mechanisms reflecting the importance of changes in intracortical inhibition for successful recovery. The present results strongly support the view of a beneficial role of cortical disinhibition in the first week after a stroke that promotes neuronal plasticity and recovery. However, to sustain long-term motor recovery, cortical disinhibition needs to be transient with crucial restoration of normal levels of intracortical inhibition. TMS-EEG has the exciting potential to provide proxies to better understand underlying mechanisms, to determine outcome and to help to tailor interventional treatment strategies to each patient based on the brain reactivity status.

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Transcranial magnetic stimulation of the brain: What is stimulated? – A consensus and critical position paper

Cited by 237 publications

References 435 publications

Automated optimization of TMS coil placement for personalized functional network engagement

Automated optimization of TMS coil placement for personalized functional network engagement

TMS-Evoked Responses Are Driven by Recurrent Large-Scale Network Dynamics

Stroke recovery-related changes in cortical reactivity based on modulation of intracortical inhibition

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