Is sham cTBS real cTBS? The effect on EEG dynamics

Opitz, Alexander; Legon, Wynn; Mueller, Jenna L.; Barbour, Aaron J.; Paulus, Walter; Tyler, William J.

doi:10.3389/fnhum.2014.01043

Cited by 42 publications

(42 citation statements)

References 44 publications

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“…There was some evidence that shows decreased coherence in beta band coherence after stimulation of the motor cortex with inhibitory protocol (Mima et al, 2003;Tamura et al, 2005), but also after periods of rest (Fuggetta et al, 2007). Recent evidence also showed a decrease in beta wave at 100-200 ms after sham cTBS (Opitz et al, 2015), in congruence with our sham result. Thus, the decrease in high beta coherence we observed in the sham condition could be related either to a placebo effect of the stimulation, or to the fact that the participants were at rest during the stimulation.…”

Section: Discussionsupporting

confidence: 89%

Interhemispheric and Intrahemispheric Connectivity From the Left Pars Opercularis Within the Language Network Is Modulated by Transcranial Stimulation in Healthy Subjects

Yoo

Kim

Brem

et al. 2020

Front. Hum. Neurosci.

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Neural activity related to language can be modulated within widespread networks following learning or in response to disruption-including the experimental application of noninvasive brain stimulation. However, the spatiotemporal characteristics of such modulation remain insufficiently explored. The present study combined transcranial magnetic stimulation (TMS) and electroencephalography (EEG) to explore the modulation of activity across the language network following continuous theta-burst stimulation (cTBS) of the left pars opercularis. In 10 healthy subjects (21 ± 2 years old, four females), neuronavigated cTBS was delivered over the left pars opercularis of the frontal operculum (part of the traditional Broca's area) at 80% of active motor threshold (AMT) stimulation intensity. Real cTBS and sham cTBS were performed in two different visits separated by at least 48 h. Before, immediately, and 10 min after cTBS, 30 single pulses of TMS were delivered to the left pars opercularis at 80% of the resting motor threshold (RMT), whereas EEG was simultaneously recorded. We examined the cTBS-induced modulation of phase locking values (PLVs) between the TMS-evoked potentials (TEPs) recorded over the pars opercularis and those recorded over its right-hemispheric homolog area, the left supramarginal area, and the left superior temporal area in different EEG frequency bands and different time windows following cTBS. cTBS to the left pars opercularis induced within the gamma band: (1) a significant increase in TEP phase synchronization between the left and right pars opercularis at an early time window (250-350 ms) following cTBS; and (2) significantly increased PLV with the left supramarginal area and the left superior temporal area at a later time window (600-700 ms). In the theta and delta band, cTBS to Frontiers in Human Neuroscience | www.frontiersin.org 1 March 2020 | Volume 14 | Article 63 Yoo et al. Language Network Modulation by cTBSthe left pars opercularis induced significantly increased phase synchronization of TEPs between the left pars opercularis and the posterior left hemispheric language areas at a late time window. In sham condition, there was a significant decrease in TEP phase synchronization of the high beta band between left pars opercularis and left superior temporal area at 200-300 ms. These results contribute to characterize the dynamics of the language network and may have implications in the development of noninvasive stimulation protocols to promote the language rehabilitation in aphasia patients.

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Section: Discussionsupporting

confidence: 89%

Interhemispheric and Intrahemispheric Connectivity From the Left Pars Opercularis Within the Language Network Is Modulated by Transcranial Stimulation in Healthy Subjects

Yoo

Kim

Brem

et al. 2020

Front. Hum. Neurosci.

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“…Future studies could possibly address this issue, which is somewhat complicated as there is no clear linear relationship between the absolute electric field strength and outcomes of plasticity inducing protocols e.g. (Doeltgen and Ridding, 2011; Opitz et al, 2015). …”

Section: Discussionmentioning

confidence: 99%

An integrated framework for targeting functional networks via transcranial magnetic stimulation

et al. 2016

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Transcranial magnetic stimulation (TMS) is a powerful investigational tool for in vivo manipulation of regional or network activity, with a growing number of potential clinical applications. Unfortunately, the vast majority of targeting strategies remain limited by their reliance on non-realistic brain models, and assumptions that anatomo-functional relationships are 1:1. Here, we present an integrated framework that combines anatomically realistic finite element models of the human head with resting functional MRI to predict functional networks targeted via TMS at a given coil location and orientation. Using data from the Human Connectome Project, we provide an example implementation focused on dorsolateral prefrontal cortex (DLPFC). Three distinct DLPFC stimulation zones were identified, differing with respect to the network to be affected (default, frontoparietal) and sensitivity to coil orientation. Network profiles generated for DLPFC targets previously published for treating depression revealed substantial variability across studies, highlighting a potentially critical technical issue.

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“…The mere control by median nerve stimulation-evoked somatosensory potentials (Paus et al, 2001; Rosanova et al, 2009) not only lacks auditory stimulation but the evoked potentials may also not resemble those evoked by stimulating the scalp (Hashimoto, 1988). Sham TMS coils, generating only a very small electric field in the cortex, provide simultaneous somatosensory and auditory stimulation (Bonato et al, 2006; Opitz et al, 2014), but the area of stimulation is broader (Opitz et al, 2014) and somatosensory stimulation may be markedly reduced compared to real TMS (Bonato et al, 2006; Opitz et al, 2014). On the other hand, even when the transducing coil is placed on another body part such as the shoulder blade, stimulation still produced late evoked components reminiscent of those commonly seen in TEPs caused by real TMS (Herring et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

The non-transcranial TMS-evoked potential is an inherent source of ambiguity in TMS-EEG studies

Conde

Tomasevic

Akopian

et al. 2018

Preprint

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7Tel: +45 3862 6541; Email: hartwig.siebner@drcmr.dk; http://www.drcmr.dk/siebner 2 8All rights reserved. No reuse allowed without permission.was not peer-reviewed) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity.The copyright holder for this preprint (which . http://dx.doi.org/10.1101/337782 doi: bioRxiv preprint first posted online Jun. 4, 2018; 2 Abstract (246 words) 2 9Transcranial Magnetic Stimulation (TMS) excites populations of neurons in the stimulated cortex, and the 3 0 resulting activation may spread to connected brain regions. The distributed cortical response can be 3 1 recorded with electroencephalography (EEG). Since TMS also stimulates peripheral sensory and motor 3 2 axons and generates a loud "click" sound, the TMS-evoked EEG potential (TEP) not only reflects neural 3 3 activity induced by transcranial neuronal excitation but also neural activity reflecting somatosensory and 3 4 auditory processing. In 17 healthy young individuals, we systematically assessed the contribution of 3 5 multisensory peripheral stimulation to TEPs using a TMS-compatible EEG system. Real TMS was 3 6 delivered with a figure-of-eight coil over the left para-median posterior parietal cortex or superior frontal 3 7 gyrus with the coil being oriented perpendicularly or in parallel to the target gyrus. We also recorded the 3 8 EEG responses evoked by sham stimulation over the posterior parietal and superior frontal cortex, 3 9 mimicking the auditory and somatosensory sensations evoked by real TMS. We applied state-of-the-art 4 0 procedures to attenuate somatosensory and auditory confounds during real TMS, including the placement 4 1 of a foam layer underneath the coil and auditory noise masking. Despite these precautions, the temporal 4 2 and spatial features of the cortical potentials evoked by real TMS at the prefrontal and parietal site closely 4 3 resembled the cortical potentials evoked by realistic sham TMS, both for early and late TEP components. 4Our findings stress the need to include a peripheral multisensory control stimulation in the study design to 4 5 enable a dissociation between truly transcranial and non-transcranial components of TEPs. 4 6 4 7All rights reserved. No reuse allowed without permission.was not peer-reviewed) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity.

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Is sham cTBS real cTBS? The effect on EEG dynamics

Cited by 42 publications

References 44 publications

Interhemispheric and Intrahemispheric Connectivity From the Left Pars Opercularis Within the Language Network Is Modulated by Transcranial Stimulation in Healthy Subjects

Interhemispheric and Intrahemispheric Connectivity From the Left Pars Opercularis Within the Language Network Is Modulated by Transcranial Stimulation in Healthy Subjects

An integrated framework for targeting functional networks via transcranial magnetic stimulation

The non-transcranial TMS-evoked potential is an inherent source of ambiguity in TMS-EEG studies

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