TMS-EEG Integration: Synchronizing Brain Products and MagVenture for closed-loop brain-state dependent stimulation

Simulating and recording brain activity simultaneously requires a seamless integration of high-energy magnetic stimulation and sensitive electrical recording. The combination of Brain Products EEG and MagVenture TMS systems provides a robust platform for investigating network-specific activations, such as the Default Mode Network (DMN) and Dorsal Attention Network (DAN). Hardware Synergy and Specifications:. Stimulation (MagVenture): The integration utilizes the MagPro X100 stimulator paired with a Cool B-65 liquid-cooled figure-of-eight coil. The cooling system is essential for high-intensity, long-duration research protocols (e.g., 120% RMT)., Recording (Brain Products): Data is captured using the actiCHamp amplifier system and actiCAP slim active electrodes. These electrodes are specifically designed with a low profile to allow the TMS coil to be placed as close to the scalp as possible, minimizing the distance between the magnetic field and the cortex. Achieving High-Quality TMS-EEG Data:. To minimize the inevitable TMS-induced pulse artifacts and peripheral-evoked potentials, the integration follows a strict methodological protocol:. Low Impedance: Goal impedances are set below 5 kOhm using actiCAP slim’s integrated LED feedback., Artifact Masking: Continuous auditory masking and thin foam layers under the coil are used to mitigate auditory and somatosensory-evoked potentials., Trigger Synchronization: Precise millisecond-level timing between the MagVenture pulse and the actiCHamp recording ensures that the early TMS artifact (typically -2 to 14 ms) can be accurately segmented and removed during post-processing. Network-Specific Insights:. By combining these technologies with Brainsight TMS Neuronavigation , researchers can target individualized cortical nodes defined by fMRI. This methodology allows for the characterization of cognitively relevant network-level dynamics, providing a high-temporal-resolution alternative to traditional resting-state fMRI. Data Processing Workflow: Analysis is typically conducted using EEGLAB with the TMS-EEG Signal Analyzer (TESA) extension. The workflow involves two rounds of Independent Component Analysis (ICA) to remove residual TMS artifacts, eye blinks, and auditory-evoked potentials, resulting in clean TMS-evoked EEG potentials (TEPs).