Two different MRS sequences were used to measure the brain chemicals in a single 2 x 2 x 2 cm cube located in the center of anterior cingulate cortex: an intermediate echo-time PRESS sequence and a 2D J-resolved averaged PRESS sequence. Spectroscopic data were inspected for quality; subjects whose data were contaminated by artifact were excluded from the study. Spectra were then processed using LCModel to quantify brain chemical levels. Regular brain MRI images were segmented, yielding a map of the amount of CSF in the head. The MRS cube was overlaid onto the CSF map and the fraction of CSF within the cube measured. This measurement was used to "remove" the CSF from the MRS cube giving brain chemical concentrations. The concentrations were then used for statistical analysis.