• Article

• Open access

• Published: 30 January 2026

• Pedro C. Gordon1,2,

• Johanna Metsomaa3,4,

• Paolo Belardinelli1,2,5 &

• …

• Ulf Ziemann1,2

Scientific Reports , Article number: (2026) Cite this article

We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.

Abstract

The combination of transcranial magnetic stimulation (TMS) and electroencephalography (EEG) has emerged as a non-invasive technique to probe cortical responsivity. However, interpreting TMS–EEG data is challenging due to sensory inputs generated by TMS, which cause peripherally evoked potentials (PEPs) that overlap with TMS-evoked potentials (TEPs). These sensory inputs may also modulate the cortical response, potentially distorting TEPs. To address this and evaluate methods for reducing PEP contamination, we compared two sham designs: a “PEP saturation” method, which delivers high-intensity somatosensory stimuli in both sham and real TMS to saturate PEPs in both conditions, and a “PEP individualized matching stimulus intensity calibration” method, which individually adjusts stimulus intensity to match the PEP amplitude of real TMS. In both conditions, the PEPs from sham and real TMS conditions should match, enabling the subtraction of this confounder. If the TEPs after this subtraction were not different between the two conditions this would indicate the absence of a relevant interaction between PEPs and TEPs, justifying the removal of PEPs from TEPs by subtraction. Our results showed no significant difference in TEPs within 110 ms post-stimulation after sham subtraction regardless of the sham protocol, and whether stimulating the primary motor cortex or the supplementary motor area. These findings provide evidence for the absence of a relevant interaction between TMS-related somatosensory input and TEPs, and indicate the appropriateness of the two sham protocols in removing PEPs from the TMS-EEG response.

Data availability

The datasets generated and analyzed during the current study are available from the corresponding author upon reasonable request. The analysis code is publicly available on GitHub: [https://github.com/pcgordon/optimized_supraliminal_sham](https:/github.com/pcgordon/optimized_supraliminal_sham) . The codes were designed for MATLAB version 2021b and using the open-source toolbox Fieldtrip, version 20210212.

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Funding

Open Access funding enabled and organized by Projekt DEAL. PCG reports receiving funding from the German Research Foundation (Deutsche Forschungsgemeinschaft - DFG - project number 466 458 984). UZ was supported by funding from the European Research Council (ERC Synergy) under the European Union’s Horizon 2020 research and innovation programme (ConnectToBrain; grant agreement No. 810377).

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Authors and Affiliations

Department of Neurology & Stroke, University of Tübingen, Tübingen, Germany

Pedro C. Gordon, Paolo Belardinelli & Ulf Ziemann 1.

Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany

Pedro C. Gordon, Paolo Belardinelli & Ulf Ziemann 1.

Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland

Johanna Metsomaa 1.

BioMag Laboratory, HUS Medical Imaging Center, Helsinki University Hospital, Helsinki University and Aalto University School of Science, Helsinki, Finland

Johanna Metsomaa 1.

Center for Mind/Brain Sciences—CIMeC, University of Trento, Trento, I-38123, Italy

Paolo Belardinelli

Authors

1. Pedro C. Gordon
2. Johanna Metsomaa
3. Paolo Belardinelli
4. Ulf Ziemann

Contributions

PCG, and UZ designed the study. PCG carried out the data acquisition. JM contributed to the TMS–EEG data processing pipeline. PB created the MRI based head models. PCG analyzed the experimental data and drafted the manuscript. All authors contributed to the writing of the manuscript and approved its final version. All persons designated as authors qualify for authorship, and all those who qualify for authorship are listed.

Corresponding author

Correspondence to Ulf Ziemann.

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Gordon, P.C., Metsomaa, J., Belardinelli, P. et al. Investigating the effects of TMS-related somatosensory inputs on TMS-evoked potentials provides evidence against significant interaction. Sci Rep (2026). https://doi.org/10.1038/s41598-026-37418-w

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Received: 12 October 2025

Accepted: 21 January 2026

Published: 30 January 2026

DOI: https://doi.org/10.1038/s41598-026-37418-w

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