Instrumentation for TMS-EEG Experiment: ArTGen and a Custom EEG Interface

Abstract

In transcranial magnetic stimulation (TMS) and electroencephalography (EEG) experiments, two researchers typically collaborate in the lab. This study addresses the challenge a single researcher faces in managing the TMS experiment's timing while operating the TMS coil. It introduces the Arduino Trigger Generator (ArTGen) to remotely control the timing of TMS experiments using a footswitch pedal. Moreover, a bespoke printed circuit board (PCB) is designed to interface the eegoMylab amplifier with off-the-shelf EEG caps. The ArTGen facilitates accurate timing of the TMS stimulator's inter-pulse intervals (IPIs) through a footswitch pedal, enhancing researchers' control over TMS-EEG experiments. The PCB interface provides a cost-effective tool to extend the functionality of the eegoMylab amplifier. The integration of our PCB interface has been validated in a custom TMS-EEG setup by analyzing TMS-evoked potentials (TEPs), global mean field power (GMFP), butterfly plots, and event-related spectral potentials (ERSPs). The PCB reliably preserved EEG signal integrity, ensuring accurate data acquisition. Thorough channel-wise consistency checks across components confirmed data accuracy. ArTGen's portability and footswitch feature streamline experimental control, aiding TMS-EEG research and clinical applications. Moreover, our PCB resolves compatibility between the eegoMylab amplifier and the Waveguard EEG cap by extending the amplifier to connect to off-the-shelf EEG caps. The ArTGen serves as a robust remote control tool for TMS stimulators, while our PCB interface presents a solution for integrating a customized TMS-EEG setup. This study addresses the gap in existing TMS-EEG research by introducing innovative technological enhancements that not only augment experimental flexibility but also streamline procedural workflows.