RecruitingDevice studyMRS Measurement of Glutamate and GABA Metabolism in BrainThis study will use magnetic resonance spectroscopy (MRS) to measure in the brain the transfer of \[13\]C as it is naturally metabolized from glucose to specific chemical transmitters. From this method, we can measure the rate of production of an important excitatory neurotransmitter (glutamate) as well as an inhibitory neurotransmitter (GABA).