A Probabilistic Map of Human Visual Cortical Areas from Quantitative Microscopy

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Most of our knowledge on the organization of the human visual cortex derives from neuroimaging studies that have localized numerous areas based on their functional properties.

The relative topography of functional areas is consistent across subjects, but individual anatomical variability obscures their relationship with the macroscopic landmarks that are visible by Magnetic Resonance Imaging (MRI). Similarly, the complex relationship between cortical folding patterns and the underlying microscopic architecture of the cortex has not yet been understood. For these reasons, there to-date there is not a reliable method to report functional activation in terms of cortical areas or to infer with low prediction error the location of cortical areas from the folding pattern of the cortical mantle.

Computational tools are available for 'upholstering' neuroimaging datasets with the most notable classic architectonic parcellation of the cortex, that of Brodmann. However, this forceful registration of a schematic 2-dimensional chart onto individual anatomy is defeated by the range of morphological complexity and individual variability. This is especially true in the case of the visual cortex, where Brodmann's tripartite parcellation is inadequate to account for the number functionally mapped visual fields and for which only very few modern studies provide histological descriptions of the cortical areas beyond area 17.

The goal of our project is to revisit the classical architectonic method using multiple stains and validated quantitative techniques, and to use surface-based intersubject registration methods to create a probabilistic atlas of visual cortical areas. The result of the proposed project is the localization of the primary and higher visual areas in relation to the geometry of the cortex. These maps and corollary histological templates that characterize each area will constitute the long-awaited microscopic common framework for the integration of multiple functional and morphometric studies, as well as for the validation of upcoming microMRI studies of cortical anatomy.

Funded by The National Eye Institute.