Figure 1.

Example GABA spectrum acquisition from the RAC in one typical subject. A, Orthogonal section view (neurological convention; L, left; R, right) of voxel placement. Voxels were placed parallel with and superiorly abutting the Sylvian fissure and were otherwise centered on Heschl's sulcus. This volume encompassed nearly all of Heschl's gyrus, including the primary auditory cortex, the planum temporale, the superior temporal sulcus, planum polare, and also small parts of the insula and middle temporal gyrus adjacent to these auditory regions. B, Edited spectrum, including the GABA peak for quantification at 3 ppm. C, Expanded view of B, showing 3 ppm GABA peak and fitted Gaussian function used for quantification.