Observed elevated Cr in amygdala-hippocampus in ASD, and Levitt et 
al. observed effects of ASD diagnosis on Cr in occipital cortex and caudate, so there is precedence for abnormal Cr in ASD, albeit in other brain regions. Elevated tNAA was found in pACC in ASD in Experiment 2 only. Again, abnormal tNAA in ASD may be harder to reproduce than elevated Glx. In prior work, Oner et al. registered higher tNAA/Cr and tNAA/Cho in right anterior cingulate cortex in subjects with Asperger’s syndrome than in controls and Fujii et al. found lower tNAA/Cr in anterior cingulate in subjects with autism than in controls. Interpretation of these results is partially obscured by normalization to Cr, which itself may vary, but they do suggest heterogeneous effects of ASD on tNAA. In other brain regions, investigators have often found below-normal tNAA or its ratios in ASD, although findings of above-normal and no difference also exist. How plausible is a local elevation of tNAA in the pACC? In addition to the above-cited MRS results, data from recent fMRI and hybrid fMRI-MRS experiments do, in fact, strongly suggest a special role for the pACC in ASD and autistic symptomatology. The pACC, for example, was one of the few brain Chloroquine Phosphate regions demonstrating significant effects of ASD diagnosis in a recent metaanalysis of fMRI studies. Working in healthy subjects, the same researchers related fMRI functional connectivity with the pACC with elevated levels of autistic traits. Also in healthy controls, Duncan et al. found correlations localized to pACC between MRS Glx and an fMRI effect related to subject empathy, low empathy being a common symptom of ASD. Finally, elevated intensity was observed in at-risk carriers of an autism-associated CNTNAP2 allele in pACC. These and other neuroimaging results give ample evidence for focal effects of ASD diagnosis and autistic traits and autistic symptoms in the pACC. It is therefore not surprising to find MRS metabolic effects particular to that brain region. Experiment 2 alleviated several but not all limitations of Experiment 1. Both studies were still conducted at low-field and expressed their results as Glx rather than as Glu and Gln separately. Based on low field strength and, in the case of MRSI, small voxel size, our quality control procedures used the standard 20% SD criterion of the LCModel fitting package and a SNR cutoff of 3 for MRSI and 5 for single-voxel MRS. Although some spectroscopists might prefer stricter cut-offs, working with these values we found that individual metabolite peaks were typically readily identified by eye and easily fit by automated routines. Also single-subject data quality was frequently higher than the cut-off values. In neither study was it possible to match between-group voxel tissue-composition thoroughly. Efforts to match tissue composition may have been aggravated by putative effects of ASD on anterior cingulate cortical volume or thickness. Future MRS and MRSI studies at 3 T will allow smaller, hopefully more tissue-pure voxels and also better spectral segregation of Glu and Gln. Regarding the latter, better segregation might also be achieved by acquiring spectra, thought to be optimal for quantifying Glu. Future investigations should also include MR relaxation studies, as autism may affect metabolite and water relaxation times. Finally, in both Experiments, several subjects with ASD were undergoing treatment with psychotropic medication at time of scan. Ideally, one would test only drug-naive subjects, although, given LOUREIRIN-B clinical realities, this can be difficult to achieve on a practical time scale.