Schedule of Events | Symposia

Developmental differences in the neural organization of knowledge

Poster Session B - Sunday, March 30, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Alexander W. D. McArthur¹ (alex.mcarthur@mail.utoronto.ca), Sagana Vijayarajah¹, Margaret L. Schlichting¹; ¹University of Toronto

Prior work mapping the neural organization of knowledge in adults has demonstrated that semantic (i.e., meaning-based) and perceptual similarity are coded in overlapping regions of temporal and occipital cortices, with additional distinct contributions from prefrontal regions and parietal regions. However, little is known about how this organization emerges over childhood, and the relatively earlier development of regions involved in perceptual processing suggests that developmental differences in the neural coding of semantic similarity may be particularly pronounced. Here, we had children (N=51; 6-7 years) and adults (N=36) passively view a sequence of items during fMRI scanning. Items were semantically or perceptually related to others in the set. Using pattern similarity searchlights, we identified brain regions in each age group that showed stronger coding for semantically or perceptually related items relative to unrelated items. Both age groups coded perceptual similarity in occipital cortex, such that perceptually related items were more similar than unrelated and semantically related items. Children also showed perceptual coding in posterior hippocampus, and adults in lateral prefrontal, parietal, and temporal regions. Semantic coding was relatively weak across age groups, with no clusters in children or adults showing stronger coding of semantic similarity than unrelated and perceptual similarity. Interestingly, both children and adults de-emphasized semantic similarity in medial prefrontal regions, such that semantically related items were less similar than unrelated items. Thus, contrary to expectations, the findings suggest that despite the relatively early development of perceptual systems, there are substantial shifts in the coding of perceptual similarity across development.

Topic Area: THINKING: Development & aging