Cortical mechanisms underlying variability in intermittent theta-burst stimulation-induced plasticity: A TMS-EEG study. Issue 10 (October 2021)

• Record Type: Journal Article
• Authors: Leodori, Giorgio; Fabbrini, Andrea; De Bartolo, Maria Ilenia; Costanzo, Matteo; Asci, Francesco; Palma, Veronica; Belvisi, Daniele; Conte, Antonella; Berardelli, Alfredo
• Is Part Of: Clinical neurophysiology. Volume 132:Issue 10(2021)
• Page Start: 2519
• Page End: 2531
• Publication Date: 2021-10
• Subjects: Beta oscillations -- iTBS -- Motor cortex -- Plasticity -- TMS-EEG -- Variability; TBS Theta burst stimulation -- TMS transcranial magnetic stimulation -- iTBS intermittent theta burst stimulation -- LTP long-term potentiation -- GABA gamma-aminobutyric acid -- M1 primary motor cortex -- MEP motor evoked potential -- EEG electroencephalography -- rsEEG resting-state electroencephalography -- FDI first dorsal interosseous muscle -- RMT resting motor threshold -- AMT active motor threshold -- EMG Electromyography -- CSD current source density -- FFT fast Fourier transform -- iFFT inverse fast Fourier transform -- ANOVA analysis of variance -- MSO maximal stimulator output; Neurophysiology -- Periodicals; Electroencephalography -- Periodicals; Electromyography -- Periodicals; Neurology -- Periodicals; 612.8
• DOI: 10.1016/j.clinph.2021.06.021
• Languages: English
• ISSNs: 1388-2457

Abstract

Highlights: MEP facilitation following intermittent theta-burst stimulation (iTBS) is associated with specific iTBS-evoked EEG oscillations. Baseline MEP amplitude and iTBS-evoked beta oscillations predict iTBS aftereffects. Our TMS-EEG study identified cortical mechanisms underlying iTBS variability that are potentially clinically relevant. Abstract: Objective: To test the hypothesis that intermittent theta burst stimulation (iTBS) variability depends on the ability to engage specific neurons in the primary motor cortex (M1). Methods: In a sham-controlled interventional study on 31 healthy volunteers, we used concomitant transcranial magnetic stimulation (TMS) and electroencephalography (EEG). We compared baseline motor evoked potentials (MEPs), M1 iTBS-evoked EEG oscillations, and resting-state EEG (rsEEG) between subjects who did and did not show MEP facilitation following iTBS. We also investigated whether baseline MEP and iTBS-evoked EEG oscillations could explain inter and intraindividual variability in iTBS aftereffects. Results: The facilitation group had smaller baseline MEPs than the no-facilitation group and showed more iTBS-evoked EEG oscillation synchronization in the alpha and beta frequency bands. Resting-state EEG power was similar between groups and iTBS had a similar non-significant effect on rsEEG in both groups. Baseline MEP amplitude and beta iTBS-evoked EEG oscillation power explained both inter and intraindividual variability in MEP modulation following iTBS. Conclusions: The results show that variability in iTBS-associated plasticity depends on baseline corticospinal excitability and on the ability of iTBS to engage M1 beta oscillations. Significance: These observations can be used to optimize iTBS investigational and therapeutic applications.