Aim 1: To test the behavioral effects of tDCS during social rejection. The first step will be to obtain behavioral effects of transcranial direct current stimulation (tDCS) during social rejection without functional magnetic resonance imaging (fMRI). Whereas previous studies used Cyberball (a computerized ball-tossing game that simulates social exclusion), we will use the Social Feedback Task. This task was created by Dr. Hsu to be more ethologically-relevant, has been shown to sustain negative moods during rejection and activates the right ventral lateral prefrontal cortex (rVLPFC) (preliminary fMRI data from 50 healthy controls in Dr. Hsu's previous study). Anodal tDCS will be applied over the right or left VLPFC to measure changes in mood during rejection and neutral conditions. Depending on results, alternate regions in separate subjects may also be stimulated: dorsolateral prefrontal cortex, insula, anterior cingulate cortex, pre-supplementary, and supplementary motor area [all regions may be right or left hemisphere]. All of these regions have been shown to be involved in emotion regulation. Questionnaires will be given before, during, and after the task to assess cognitive and emotional states.~Aim 2: To identify neural pathways regulating negative moods during social rejection, using tDCS for activation and fMRI for assessment. Using a cross-over, sham-controlled design similar to previous tDCS+fMRI studies, we will measure the effects of anodal tDCS over the right or left VLPFC on neural activity and negative mood during rejection and neutral conditions. Alternate regions in separate subjects may also be stimulated including the dorsolateral prefrontal cortex, insula, anterior cingulate cortex, pre-supplementary, and supplementary motor area [all regions may be right or left hemisphere]. All of these regions have been shown to be involved in emotion regulation.
This research study identifies neural pathways regulating negative moods during rejection by combining transcranial direct current stimulation (tDCS) and fMRI in a sample of healthy controls.