Exploring Motor Network Connectivity in State-Dependent Transcranial Magnetic Stimulation : A Proof-of-Concept Study

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2024-05
Major/Subject
Mcode
Degree programme
Language
en
Pages
15
Series
Biomedicines, Volume 12, issue 5, pp. 1-15
Abstract
State-dependent non-invasive brain stimulation (NIBS) informed by electroencephalography (EEG) has contributed to the understanding of NIBS inter-subject and inter-session variability. While these approaches focus on local EEG characteristics, it is acknowledged that the brain exhibits an intrinsic long-range dynamic organization in networks. This proof-of-concept study explores whether EEG connectivity of the primary motor cortex (M1) in the pre-stimulation period aligns with the Motor Network (MN) and how the MN state affects responses to the transcranial magnetic stimulation (TMS) of M1. One thousand suprathreshold TMS pulses were delivered to the left M1 in eight subjects at rest, with simultaneous EEG. Motor-evoked potentials (MEPs) were measured from the right hand. The source space functional connectivity of the left M1 to the whole brain was assessed using the imaginary part of the phase locking value at the frequency of the sensorimotor μ-rhythm in a 1 s window before the pulse. Group-level connectivity revealed functional links between the left M1, left supplementary motor area, and right M1. Also, pulses delivered at high MN connectivity states result in a greater MEP amplitude compared to low connectivity states. At the single-subject level, this relation is more highly expressed in subjects that feature an overall high cortico-spinal excitability. In conclusion, this study paves the way for MN connectivity-based NIBS.
Description
Publisher Copyright: © 2024 by the authors.
Keywords
brain state, corticospinal excitability, electroencephalography (EEG), functional connectivity, motor evoked potential (MEP), Motor Network, transcranial magnetic stimulation (TMS)
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Citation
Marzetti, L, Basti, A, Guidotti, R, Baldassarre, A, Metsomaa, J, Zrenner, C, D’Andrea, A, Makkinayeri, S, Pieramico, G, Ilmoniemi, R J, Ziemann, U, Romani, G L & Pizzella, V 2024, ' Exploring Motor Network Connectivity in State-Dependent Transcranial Magnetic Stimulation : A Proof-of-Concept Study ', Biomedicines, vol. 12, no. 5, 955, pp. 1-15 . https://doi.org/10.3390/biomedicines12050955