Representational similarity precedes category selectivity in the developing ventral visual pathway

Michael A. Cohen, Daniel D. Dilks, Kami Koldewyn, Sarah Weigelt, Jenelle Feather, Alexander J. E. Kell, Boris Keil, Bruce Fischl, Lilla Zöllei, Lawrence L. Wald, Rebecca Saxe, Nancy Kanwisher

Abstract: Highlights • Visual representations are implemented in the ventral visual pathway via category-selective regions and distributed activation patterns. • Which develops first in children: small, selective regions or large-scale activation patterns? • We found that even in children with no category-selective regions whatsoever, they still had mature distributed activation patterns. • We speculate that these distributed representational structures serve as a foundation upon whichcategory-selective regions are later built. Abstract Many studies have investigated the development of face-, scene-, and body-selective regions in the ventral visual pathway. This work has primarily focused on comparing the size and univariate selectivity of these neural regions in children versus adults. In contrast, very few studies have investigated the developmental trajectory of more distributed activation patterns within and across neural regions. Here, we scanned both children (ages 5–7) and adults to test the hypothesis that distributed representational patterns arise before category selectivity (for faces, bodies, or scenes) in the ventral pathway. Consistent with this hypothesis, we found mature representational patterns in several ventral pathway regions (e.g., FFA, PPA, etc.), even in children who showed no hint of univariate selectivity. These results suggest that representational patterns emerge first in each region, perhaps forming a scaffold upon which univariate category selectivity can subsequently develop. More generally, our findings demonstrate an important dissociation between category selectivity and distributed response patterns, and raise questions about the relative roles of each in development and adult cognition.