Effective Intracerebral Connectivity in Acute Stroke: A TMS–EEG Study

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2023-02
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Mcode
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Language
en
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BRAIN SCIENCES, Volume 13, issue 2
Abstract
Stroke is a major cause of disability because of its motor and cognitive sequelae even when the acute phase of stabilization of vital parameters is overcome. The most important improvements occur in the first 8–12 weeks after stroke, indicating that it is crucial to improve our understanding of the dynamics of phenomena occurring in this time window to prospectively target rehabilitation procedures from the earliest stages after the event. Here, we studied the intracortical excitability properties of delivering transcranial magnetic stimulation (TMS) to the primary motor cortex (M1) of left and right hemispheres in 17 stroke patients who suffered a mono-lateral left hemispheric stroke, excluding pure cortical damage. All patients were studied within 10 days of symptom onset. TMS-evoked potentials (TEPs) were collected via a TMS-compatible electroencephalogram system (TMS–EEG) concurrently with motor-evoked responses (MEPs) induced in the contralateral first dorsal interosseous muscle. Comparison with age-matched healthy volunteers was made by collecting the same bilateral-stimulation data in nine healthy volunteers as controls. Excitability in the acute phase revealed relevant changes in the relationship between left lesioned and contralesionally right hemispheric homologous areas both for TEPs and MEPs. While the paretic hand displayed reduced MEPs compared to the non-paretic hand and to healthy volunteers, TEPs revealed an overexcitable lesioned hemisphere with respect to both healthy volunteers and the contra-lesion side. Our quantitative results advance the understanding of the impairment of intracortical inhibitory networks. The neuronal dysfunction most probably changes the excitatory/inhibitory on-center off-surround organization that supports already acquired learning and reorganization phenomena that support recovery from stroke sequelae.
Description
Funding Information: The work by TP Mutanen was supported by the Finnish Cultural Foundation (Grant No. 00161149) and the Academy of Finland (Grant No. 321631). The work by RJ Ilmoniemi was supported by funding from the Academy of Finland (Grant No. 307963) and from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 810377). | openaire: EC/H2020/810377/EU//ConnectToBrain
Keywords
acute phase, center-on surround-off, central peripheral excitability, electromyography EMG, stroke, TMS–EEG
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Citation
Tecchio , F , Giambattistelli , F , Porcaro , C , Cottone , C , Mutanen , T P , Pizzella , V , Marzetti , L , Ilmoniemi , R J , Vernieri , F & Rossini , P M 2023 , ' Effective Intracerebral Connectivity in Acute Stroke: A TMS–EEG Study ' , Brain Sciences , vol. 13 , no. 2 , 233 . https://doi.org/10.3390/brainsci13020233