Local brain-state dependency of effective connectivity: A pilot TMS-EEG study

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openAccess

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Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2022

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Mcode

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Language

en

Pages

17

Series

Open Research Europe, Volume 2

Abstract

Background: Spontaneous cortical oscillations have been shown to modulate cortical responses to transcranial magnetic stimulation (TMS). However, whether these oscillations influence cortical effective connectivity is largely unknown. We conducted a pilot study to set the basis for addressing how spontaneous oscillations affect cortical effective connectivity measured through TMS-evoked potentials (TEPs). Methods: We applied TMS to the left primary motor cortex and right pre-supplementary motor area of three subjects while recording EEG. We classified trials off-line into positive- and negative-phase classes according to the mu and beta rhythms. We calculated differences in the global mean-field amplitude (GMFA) and compared the cortical spreading of the TMS-evoked activity between the two classes. Results: Phase affected the GMFA in four out of 12 datasets (3 subjects × 2 stimulation sites × 2 frequency bands). Two of the observed significant intervals were before 50 ms, two between 50 and 100 ms, and one after 100 ms post-stimulus. Source estimates showed complex spatial differences between the classes in the cortical spreading of the TMS-evoked activity. Conclusions: TMS-evoked effective connectivity seems to depend on the phase of local cortical oscillations at the stimulated site. This work paves the way to design future closed-loop stimulation paradigms.

Description

| openaire: EC/H2020/810377/EU//ConnectToBrain

Keywords

Transcranial magnetic stimulation; electroencephalography; brain state; effective connectivity

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Citation

Granö, I, Mutanen, T P, Tervo, A, Nieminen, J O, Souza, V H, Fecchio, M, Rosanova, M, Lioumis, P & Ilmoniemi, R J 2022, ' Local brain-state dependency of effective connectivity: A pilot TMS-EEG study ', Open Research Europe, vol. 2, 45 . https://doi.org/10.12688/openreseurope.14634.2