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Assessing neuromodulation effects of theta burst stimulation to the prefrontal cortex using TMS-EEG
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  • Stevan Nikolin,
  • Adriano Moffa,
  • Donel Martin,
  • Colleen Loo,
  • Tjeerd Boonstra
Stevan Nikolin
University of New South Wales

Corresponding Author:[email protected]

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Adriano Moffa
University of New South Wales
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Donel Martin
University of New South Wales
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Colleen Loo
University of New South Wales
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Tjeerd Boonstra
Maastricht University
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Abstract

Theta burst stimulation (TBS), a form of repetitive transcranial magnetic stimulation (TMS), is capable of non-invasively modulating cortical excitability. TBS is gaining popularity as a therapeutic tool for psychiatric disorders such as depression, in which the dorsolateral prefrontal cortex (DLPFC) is the main therapeutic target. However, the neuromodulatory effects of TBS on prefrontal regions remain unclear. Concurrent transcranial magnetic stimulation and electroencephalography (TMS-EEG) can assess neuromodulation in non-motor regions using TMS-evoked potentials (TEPs) and event-related synchronisation/desynchronisation (ERS/D). We assessed twenty-four healthy participants (13 males, mean age 25.2±9.9 years) in a single-blinded crossover study design, following intermittent TBS, continuous TBS, and sham applied to the left DLPFC. TEPs and ERS/ERD were obtained at baseline and 2-, 15-, and 30-min post-stimulation. Four TEP components (N40, P60, N100 and P200) and two frequency bands (theta and gamma) were analysed using mixed effects repeated measures models (MRMM). Results indicated no significant effects for any assessed components or frequency bands. Relative to sham, the largest TEP effect size was obtained for the N100 component at 15 minutes post-iTBS (d = -0.50), and the largest frequency effect was obtained for gamma ERS at 15 minutes post-cTBS (d = 0.53). These results were in the same direction but smaller than found in previous studies, suggesting that effect sizes of the neuromodulatory effects of TBS may be lower than previously reported.
03 Aug 2024Submitted to European Journal of Neuroscience
23 Aug 2024Submission Checks Completed
23 Aug 2024Assigned to Editor
25 Aug 2024Review(s) Completed, Editorial Evaluation Pending
28 Aug 2024Reviewer(s) Assigned