2020 Volume 31 Issue 3 Pages 117-122
In 2017, the therapeutic rTMS device for major depression has been finally approved in Japan. However, its efficacy varies among patients and also the optimized stimulation protocol has not been established yet. Brain biomarkers related to rTMS have been a recent focus of psychiatric research, including predictive markers, navigational markers, and monitoring makers. Resting‐state functional MRI (rs‐fMRI) and EEG rhythms are useful to estimate the neuronal circuitry dynamics. Thus, functional connectivity and biotype classification based on rs‐fMRI data and EEG power spectrum and theta‐gamma coupling (TGC) are good candidates for such rTMS biomarkers. Especially, neuronal circuitry associated with subgenual anterior cingulate cortex (sgACC) is so crucial and its associations with dorsolateral prefrontal cortex (DLPFC) and default mode network have been repeatedly reported to be important for rTMS biomarkers of major depression. It has also been reported that gamma power and TGC at awake EEG and delta power during slow wave sleep were locally enhanced around the stimulation site. It should be noted that the focus of rTMS is not limited to the stimulation cortical site of DLPFC but also its associated neuronal circuitries. Furthermore, such circuitry‐related brain biomarkers could optimize and personalize rTMS intervention. No potential conflicts of interest were disclosed.
