The role of vision in the neural representation of unique entities

Famous places and famous people are different from their common counterparts in that we have unique knowledge about individual items, including specific knowledge about their visual appearance and other sensory properties. Previous studies have shown that the processing of unique entities selectively activates a network of brain regions that includes the bilateral anterior temporal lobes (ATL), posterior cingulate cortex and adjacent medial precuneus (PCC/medPrec), medial prefrontal cortex (medPFC), and temporal-parietal junction (TPJ). The degree to which these regions represent visual properties associated with famous people/places is unknown. Here we compared fMRI responses in congenitally and sighted individuals to test whether visual experience contributes to the development of unique-entity responses in these regions. Names of unique entities (famous places, famous people) and generic items (daily scenes such as "bridge", face parts) were presented aurally to 13 congenitally blind and 16 sighted participants. Sighted participants additionally viewed corresponding photographs. We found that bilateral PCC/medPrec, medPFC, left TPJ, left ATL and right superior frontal gyrus were more strongly activated by pictures of unique entities compared to generic items. Importantly, all regions showed similar selectivity for unique entities in both groups when only names were presented. Furthermore, resting-state functional connectivity analysis revealed that these regions were tightly interconnected in both groups. Together, these results provide evidence for a visually-independent brain network underlying unique entity processing.