T4TE: A collaborative effort to improve reproducibility in TMS-EEG studies

Transcranial Magnetic Stimulation coupled with Electroencephalography (TMS-EEG) is a powerful technique to probe cortical excitability and connectivity. While widely applied in clinical and basic research to investigate neurophysiological processes and cognitive states, methodological variability in both data acquisition and data processing remains a major challenge, hindering reproducibility and interpretability of outcome measures, e.g., TMS-evoked potentials (TEPs). To address these issues, the Team for TMS-EEG (T4TE) initiative proposes a large-scale, international collaborative approach aimed at improving methodological rigor, reproducibility, and standardization of TMS-EEG measures. Specifically, this talk will focus on the first study launched by T4TE, investigating how methodological variability impacts TEPs following stimulation of the primary motor cortex (M1), a widely studied cortical area. This study has gathered the contribution of more than 30 labs that will work together to reach three aims: 1) Impact of methodological variability on spatio-temporal features of M1-TEPs: By documenting lab-specific acquisition and analysis pipelines, we will assess variability in M1-TEP components across labs and disentangle the contributions to such variability of data acquisition versus data processing; 2) Modulation of M1-TEPs and Cortico-spinal Excitability: We will evaluate how methodological differences influence findings on the relationship between TEP amplitude and motor-evoked potentials (MEPs); 3) Influence of Prestimulus Oscillations: We will investigate how methodological differences influence findings on the association between TEP amplitude and prestimulus oscillatory power, focusing on alpha-band (mu-rhythm) activity in motor areas. By overcoming statistical power limitations and standardizing methodologies, this initiative aims to accelerate advancements in TMS-EEG research, facilitating its clinical and basic science applications.