Abstract
It is well documented that the adult brain contains a mosaic of domain-specific networks (or sets of cortical regions). But how do these domain-specific networks emerge? One hypothesis is that the brain comes prewired with connections that ensure the development of particular domain-specific networks. Here we addressed this hypothesis by considering the test case of the cortical face processing network, a network of face-selective regions in ventral visual cortex that is perhaps the most extensively studied domain-specific network in adults. Using resting-state fMRI in the youngest human sample tested to date, we found that two cortical regions that will later develop face selectivity similar to adults – the “proto” occipital face area (OFA) and fusiform face area (FFA) – already show adult-like functional connectivity in as little as 24 days after birth. Importantly, while this connection may serve to ensure that these regions go on to develop similar functions later in life, it cannot explain why this network always develops selectivity for faces in particular, and not other domains (e.g., scenes). Addressing this question, one proposal is that the ultimate function of the network depends on inputs from regions earlier in the visual hierarchy. For example, given that neonates receive extensive experience with faces at the fovea, face selectivity may develop in regions that receive biased foveal input. Consistent with this proposal, we found that the proto cortical face network shows stronger connectivity with foveal than peripheral V1. Taken together, these results suggest that connectivity of regions that will later develop strong face selectivity in adulthood is strikingly early developing, if not innate, and likely scaffolds subsequent functional development of these regions, providing novel evidence for what may be a general mechanism of the origins of domain-specific networks.
Acknowledgement: The work was supported by Emory College, Emory University (DDD), National Eye Institute grant T32EY7092 (FSK), the National Science Foundation Graduate Research Fellowship Program grant DGE-1444932 (CLH), a NARSAD Young Investigator Award (CLH), and an Emory University HERCULES Center grant NIEHS P30 ES019776 (DDD).