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Review
. 2023 Aug 14:17:1247104.
doi: 10.3389/fnhum.2023.1247104. eCollection 2023.

Using TMS-EEG to assess the effects of neuromodulation techniques: a narrative review

Alessandro Cruciani  1   2 , Marco Mancuso  3 , Valerio Sveva  4 , Davide Maccarrone  3 , Antonio Todisco  1   2 , Francesco Motolese  1   2 , Francesca Santoro  1   2 , Fabio Pilato  1   2 , Danny Adrian Spampinato  3 , Lorenzo Rocchi  5 , Vincenzo Di Lazzaro  1   2 , Fioravante Capone  1   2
Affiliations
Review

Using TMS-EEG to assess the effects of neuromodulation techniques: a narrative review

Alessandro Cruciani et al. Front Hum Neurosci. .

Abstract

Over the past decades, among all the non-invasive brain stimulation (NIBS) techniques, those aiming for neuromodulatory protocols have gained special attention. The traditional neurophysiological outcome to estimate the neuromodulatory effect is the motor evoked potential (MEP), the impact of NIBS techniques is commonly estimated as the change in MEP amplitude. This approach has several limitations: first, the use of MEP limits the evaluation of stimulation to the motor cortex excluding all the other brain areas. Second, MEP is an indirect measure of brain activity and is influenced by several factors. To overcome these limitations several studies have used new outcomes to measure brain changes after neuromodulation techniques with the concurrent use of transcranial magnetic stimulation (TMS) and electroencephalogram (EEG). In the present review, we examine studies that use TMS-EEG before and after a single session of neuromodulatory TMS. Then, we focused our literature research on the description of the different metrics derived from TMS-EEG to measure the effect of neuromodulation.

Keywords: TMS-EEG; electroencephalography analysis; motor evoked potentials; neuromodulation; transcranial evoked potentials.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

FIGURE 1
FIGURE 1
Schematic representation of the effect on MEP of different neuromodulatory techniques. The left panel depicts baseline MEPs, which are either increased (upper right panel) or decreased (lower right panel) in amplitude by the NIBS protocols indicated. tDCS, transcranial direct current stimulation; cTBS, continuous theta-burst stimulation; iTBS, intermittent theta-burst stimulation; HF-rTMS, high-frequency repetitive transcranial magnetic stimulation; LF-rTMS, low-frequency repetitive transcranial magnetic stimulation.
FIGURE 2
FIGURE 2
Different techniques of cortical non-invasive neuromodulation and relative protocols using electrical or magnetic stimulation. tACS, transcranial alternating current stimulation; tDCS, transcranial direct current stimulation; rTMS, repetitive transcranial magnetic stimulation; LF, low frequency; HF, high frequency; TBS, theta burst stimulation; cTBS, continuous theta burst stimulation; iTBS, intermittent theta burst stimulation.
FIGURE 3
FIGURE 3
TMS-EEG metrics measuring the effect of neuromodulation after NIBS protocols. (A) TEP; (B) butterfly plot; (C) LMFP; (D) GMFP; (E) TRSP; (F) ITPC. Signals in panels (A,E,F) are derived from C3 electrode. The LMFP in panel (C) is calculated from C3, C1, CP3, and CP1 electrodes. Spectrograms in panels (E,F) are obtained by convolution via Morlet Wavelets, with 1 ms temporal resolution and 1 Hz frequency resolution. Data are taken from a previously published paper (Mancuso et al., 2021). TEP, TMS-evoked potential; LMFP, local mean field potential; GMFP, global mean field potential; TRSP, TMS-related spectral perturbation; ITPC, inter-trial phase clustering.
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References

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