Schizophrenia patients (SZ) show profound and persistent cognitive deficits in attention, executive processing, and verbal and visuospatial memory, which persist even after psychotic symptoms are ameliorated. Cognitive deficits may be more important in preventing functional, occupational, and social recovery in SZ than other symptom domains and are not effectively treated by current pharmacological approaches. Transcranial direct-current stimulation (tDCS) is less expensive than other modalities (e.g. repetitive transcranial magnetic stimulation; rTMS), easily available, and has a good safety profile in healthy controls (HC) and SZ. However, these prior studies did not make use of a validated measure such as the MATRICS consensus battery (MCCB), which is now established as the standard for assessing cognitive improvement in SZ. Despite these promising preliminary results, this effect of tDCS in SZ needs to be confirmed and the underlying biological mechanism elucidated. Therefore, the investigators employed MCCB to evaluate the effects on improving cognition and functional MRI to explore the underlying mechanism.