Local or Global?

Transcranial direct current stimulation (tDCS) has a widespread use in basic and clinical research. Recently, the efficacy of tDCS was challenged, due to a lack of understanding how the tDCS works at the systems level. In this project, I will address this issue and propose to use functional magnetic resonance imaging (fMRI) to study three properties of the tDCS effects: that tDCS effects are distal, flexible and additive. Specifically: 1) Are there distal effects of tDCS that influence the flow and configuration of networks? (Experiment 1); 2) Can we apply tDCS to a node that is shared between two networks and affect a particular network leaving other(s) unaffected? (Experiment 2); 3) Can we apply tDCS to two nodes and have the effects converge additively in a distal but connected node? (Experiment 3). This project will have a great impact on the use of tDCS in clinical and basic research.