Localizing the human primary auditory cortex in vivo using structural MRI

We developed a fully automatic method to identify the PAC in conventional anatomical data using a combination of two complementary MR contrasts, i.e., T1 and T2, at 3 T with 0.7 mm isotropic resolution. Our algorithm maps the anatomical MR data to reconstructed cortical surfaces and uses a classification approach to create an artificial contrast that is highly sensitive to the effects of an increased myelination of the cortex. Consistent with the location of the PAC defined in post-mortem brains, we found a compact region on the medial two thirds of Heschl's gyrus in both hemispheres of all 39 subjects. With further improvements in signal-to-noise ratio of the anatomical data and manual correction of segmentation errors, the results suggest that the primary auditory cortex can be defined in the living brain of single subjects.