Cortical mapping by magnetic resonance imaging (MRI) and quantitative cytological analysis in the human brain: A feasibility study in the fusiform gyrus

We have designed a multi-modal neuroimaging protocol that combines MRI and quantitative microscopic analysis in the same individual to clarify the topography of cytoarchitecture underlying gross anatomical landmarks in the cerebral cortex. We tested our approach in the region of the fusiform gyrus (FG) because, in spite of its seemingly smooth appearance on the ventral aspect of both hemispheres, this structure houses many functionally defined areas whose histological borders remain unclear. In practice, we used MRI-based automated segmentation to define the region of interest from which we could then collect quantitative histological data (specifically, neuronal size and density). A modified stereological approach was used to sample the cortex within the FG without a priori assumptions on the location of architectonic boundaries. The results of these analyses illustrate architectonic variations along the FG and demonstrate that it is possible to correlate quantitative histological data to measures that are obtained in the context of large-scale, non-invasive MRI-based population studies.