Targeting the biased brain: non-invasive brain stimulation to ameliorate cognitive control.

Non-invasive brain stimulation has become important for the investigation of healthy and impaired neuronal functioning. Moreover, non-invasive brain stimulation has emerged as a new means of psychiatric treatment, although the mechanisms of action are still not understood and the optimal mode of application is still under development. Dysfunctional cognitive control is a central characteristic of various psychiatric disorders and is associated with dysregulations of prefrontal cortex activity and biased information processing. With non-invasive brain stimulation, enhancement and reduction of prefrontal cortex activity were shown to ameliorate and impair cognitive control, respectively. These findings suggest a neurocognitive mechanism of therapeutic effects and that non-invasive brain stimulation can be combined with training to target dysfunctional cognitive control and related clinical symptomatology. Nevertheless, the intra-individual and inter-individual diversity of neurocognitive processes, the multiplicity of possible stimulation parameters, and the complexity of interactions between those factors pose considerable challenges for interpretation of these findings and their clinical application.