Mapping the Human Cortical Surface by Combining Quantitative T1 with Retinotopy

We combined quantitative relaxation rate (R-1 1/T-1) mappinguto measure local myelinationuwith fMRI-based retinotopy. Graywhite and pial surfaces were reconstructed and used to sample R-1 at different cortical depths. Like myelination, R-1 decreased from deeper to superficial layers. R-1 decreased passing from V1 and MT, to immediately surrounding areas, then to the angular gyrus. High R-1 was correlated across the cortex with convex local curvature so the data was first de-curved. By overlaying R-1 and retinotopic maps, we found that many visual area borders were associated with significant R-1 increases including V1, V3A, MT, V6, V6A, V8/VO1, FST, and VIP. Surprisingly, retinotopic MT occupied only the posterior portion of an oval-shaped lateral occipital R-1 maximum. R-1 maps were reproducible within individuals and comparable between subjects without intensity normalization, enabling multi-center studies of development, aging, and disease progression, and structure/function mapping in other modalities.