Kelly J. Hiersche¹ (), Zeynep M. Saygin¹; ¹Department of Psychology, The Ohio State University

The ventral temporal cortex contains regions of the brain specialized for recognizing high-level visual categories; the visual word form area (VWFA), the fusiform face area (FFA), and the object-selective posterior fusiform sulcus (PFS). While each region falls in the same general location across individuals, there is substantial individual variability in the exact location of the selective cortex, and we know little about the differences in variability across these regions or the development of variability. Here, we scan over 50 adults and over 100 children (ages 3-12) on a visual localizer to characterize individual variability in word, face, and object fROIs in the mature brain, and examine the development of this variability in children. Variability was measured as the squared distance from the adult group mean (of either location or selectivity of the fROIs) for both children and adults. In adults, variability in selectivity is similar for faces, objects, and words. Children show higher variability in selectivity for words than faces and objects, and higher variability than adults for word- and object-selectivity. Children converge towards adult-like levels of variability in word-selectivity (i.e., variability decreases with age), but we do not observe age-related changes in variability of object selectivity. Interestingly, children and adults show similar variability in fROI location, including for the VWFA, which is highly experience-driven. These results suggest that despite ongoing functional tuning of e.g. VWFA, the location of category-selective visual cortex is pre-constrained, perhaps by innately determined mechanisms (as suggested by the connectivity hypothesis). Ongoing work compares these visual regions to other cortices including higher-order language and social cognition. Understanding the developmental trajectory of individual variability can help us better understand the emergence of knowledge domains in the brain.

Acknowledgements: NIH R01 HD110401-01 and Alfred P Sloan: FG-2018-10994 (to Z.M.S.); NSF GRFP: DGE-1343012 (to K.J.H.)