Proton magnetic resonance spectroscopy (1H-MRS) is a valuable, non-invasive method to study in-vivo brain biochemistry. Of the novel imaging paradigms, MRS is uniquely positioned to investigate biochemical mechanism of drug action that is objectively measurable and clinically relevant. As there is increasing interest in glutamatergic dysregulation in mood disorders, this project will utilize 1H-MRS to study glutamate and glutamine levels in brain regions implicated in bipolar disorder (anterior cingulate and dorsolateral prefrontal cortex).