Abstract
The visual system continues beyond the well-documented retinotopic early visual areas, V1 to V4, through to category-selective high-level visual areas within visual cortex. Previous work on retinotopic organization has shown that early visual areas are retinotopic, but the organization of higher-level visual regions is not as well documented. The relationship between receptive field size and eccentricity plays a role in how information is pooled and transmitted from early-level visual areas to high-level visual cortex. Therefore, the anatomical organization of receptive field properties provides insights into the visual processing pipeline. In our study, we mapped the relationships between function and organization of population receptive fields (pRFs) within visual cortex by way of their anatomical organization within four functionally localized visual processing regions: FFA, OPA, PPA and LOC. The pRF parameters were algorithmically fit using code from Kay (2013) to voxels in the Human Connectome Project (HCP) dataset, made publicly accessible by Benson and Winawer (2018), and mapped onto their respective anatomical locations of the four functionally defined high-level visual areas. The high degree of power available in the data from 181 subjects was collected using functional MRI at 7 Tesla makes the comparison of form and function especially informative of the processing capacity and specialization of each of the high-level visual areas. The resulting anatomical maps of the retinal field size and eccentricity along the three cardinal neuroanatomical axes show that the organization of the receptive fields generally follows a pattern of small retinal field size in the posterior areas and larger retinal field size in the anterior areas, which indicates that in addition to retinotopic mapping in these areas, a gradient of retinal field sizes exists along the posterior to anterior axis.