Abstract
Transcranial magnetic stimulation (TMS) is a noninvasive neuromodulation method that enables in vivo perturbation of neural activity in humans through the application of electromagnetic fields. Significant variability in brain response to TMS makes it necessary to improve current stimulation protocols. Many research efforts have focused on the spatial aspect of stimulation (Where); however, only limited focus has been given to the timing (When) of stimulation. Previous studies have shown that the phase of Electroencephalogram (EEG) oscillations is related to local brain excitability. Therefore, an EEG phase-aligned application of TMS can lead to more consistent stimulation effects. To this end, the necessary biomarkers from ongoing EEG data need to be extracted in real-time to use them to trigger TMS at the desired brain state. While the hardware for the development of such a closed-loop TMS-EEG system is now available, developing software solutions to perform such experiments is challenging. We introduce some of these challenges and discuss the methodology to address them in this talk. Furthermore, we examine our experimental results on the relationship of brain excitability with different phases of mu and beta oscillations at the primary motor cortex. These results show the importance of EEG-triggered brain stimulation and provide insight into complex brain dynamics. Recent advances in this field can make this methodology accessible to researchers and has the potential to improve clinical performance for mental and psychiatric disorders.