Year: 2023
Type: article
Abstract: BACKGROUND: Intermittent theta-burst stimulation (i) (TBS) is a transcranial magnetic stimulation (TMS) plasticity protocol. Conventionally, TBS is applied using biphasic pulses due to hardware limitations. However, monophasic pulses are hypothesised to recruit cortical neurons more selectively than biphasic pulses, predicting stronger plasticity effects. Monophasic and biphasic TBS can be generated using a custom-made pulse-width modulation-based TMS device (pTMS). OBJECTIVE: Using pTMS, we tested the hypothesis that monophasic iTBS would induce a stronger plasticity effect than biphasic, measured as induced increases in motor corticospinal excitability. METHODS: In a repeated-measures design, thirty healthy volunteers participated in three separate sessions, where monophasic and biphasic iTBS was applied to the primary motor cortex (M1 condition) or the vertex (control condition). Plasticity was quantified as increases in motor corticospinal excitability after versus before iTBS, by comparing peak-to-peak amplitudes of motor evoked potentials (MEP) measured at baseline and over 60 min after iTBS. RESULTS: (1) = 27.615, p < 0.001) with monophasic iTBS leading to significantly stronger plasticity than biphasic iTBS (t (693) = 2.311, p = 0.021). Control vertex iTBS had no effect. CONCLUSIONS: In this study, monophasic iTBS induced a stronger motor corticospinal excitability increase than biphasic within participants. This greater physiological effect suggests that monophasic iTBS may also have potential for greater functional impact, of interest for future fundamental and clinical applications of TBS.
Source: Brain stimulation
Language: English
Subfield: Neurology
Field: Neuroscience
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $3,830
Funders: Wellcome Trust, National Institute for Health and Care Research, Department of Health and Social Care, Royal Academy of Engineering, Royal Society, Guarantors of Brain, University of Oxford, Medical Research Council, John Fell Fund, University of Oxford, NIHR Oxford Biomedical Research Centre
Awards: G1126217917, G1546619145, Wellcome Centre for Integrative Neuroimaging, G2097733102, Towards physiologically-informed rehabilitation therapies, G2792775314, Towards personalized cognitive brain stimulation for depression, G5219700674, University of Oxford – Confidence in Concept 2019, G6248927271, G6986121384, Wellcome Centre for Integrative Neuroimaging, Wellcome Centre for Integrative Neuroimaging - extension, Towards personalized cognitive brain stimulation for depression, G8601578174
OpenAlex ID: W4385565024