[P4–023]: HIGH‐DEFINITION TRANSCRANIAL DIRECT CURRENT STIMULATION MODULATES BOLD SIGNAL DURING SPATIAL NAVIGATION IN OLDER CONTROLS AND PATIENTS WITH MCI. (1st July 2017) - Hampstead, Benjamin M.; Lesnovskaya, Alina; Garcia, Sarah; Ma, Sean; Bhaumik, Arijit K.; Giordani, Bruno; Peltier, Scott