The psychological construct of flow describes an experience that develops when humans engage in a demanding task while those demands are balanced with the level of skill. Therefore, this dissertation reports about experimental tests to define the role of the medial prefrontal cortex (MPFC) in mediating flow experience using transcranial direct current stimulation (tDCS) to interfere with the typical deactivation of the MPFC evoked by a flow paradigm. We used magnetic resonance-based perfusion imaging in a balanced, within-subjects repeated measure design (22 male healthy subjects), in which three different tDCS treatments (sham, anodal, cathodal) were applied. TDCS-modulatory effects on cerebral blood flow (rCBF) in regions - previously described as flow-specific - and the flow-index measuring subjective flow-experience significantly depended on participants’ baseline level of flow experience during sham tDCS, which led us to a post-hoc classification using a median-split. Participants with lower-flow experience during sham tDCS (LF) benefitted from tDCS, particularly from the anodal polarity. The group with relatively higher baseline flow experience (HF) showed significant effects for the interaction of group and treatments. Functionally, in LF subjects, relative deactivation of the right amygdala got more pronounced under both treatments and decreased in different quantity in HF subjects. Finally we discuss the probable reasons for those findings (metaplasticity, inconsistency of polarity driven tDCS effects etc.) and further fields of application in clinic or everyday life
