Transcranial direct current stimulation (tDCS) of the prefrontal cortex (PFC) is currently investigated as therapeutic non-invasive brain stimulation (NIBS) approach in major depressive (MDD) and other neuropsychiatric disorders. In both conditions, different sub regions of the PFC (e.g. the dorsolateral prefrontal cortex, the dorsomedial prefrontal cortex and others) are critically involved in their respective pathophysiology. Although the neurophysiological properties of tDCS have been extensively investigated at the motor cortex level, the action of PFC tDCS on resting state and functional MRI connectivity of neural networks is largely unexplored. Beyond motor cortex paradigms, we aim to establish a model for PFC tDCS modulating functional connectivity in different conditions to provide tailored tDCS protocols for clinical efficacy studies in major psychiatric disorders such as MDD and schizophrenia. One major obstacle in brain research is that patients represent themselves as individuals not as groups. Recent research has shown that the individual human brain functional MRI connectivity shows different within-variability than the variability found between subjects. Several neuroimaging methods may be useful to find a classifier that can be reliable used to predict NIBS effects. These neuroimaging methods include individual brain properties as well as the evaluation of state-dependency. Anatomical targeted analyses of rTMS and tDCS in neuropsychiatric patients and healthy subjects have found promising results.

By combining neuroimaging and NIBS new functional models can be developed and compared in different health and pathology states, e.g. in the development of any given psychiatric disorder.