Anchoring Functional Connectivity to Individual Sulcal Morphology Yields Insights in a Pediatric Study of Reasoning

A salient neuroanatomical feature of the human brain is its pronounced cortical folding, and there is mounting evidence that sulcal morphology is relevant to functional brain architecture and cognition. However, the relationships between sulcal anatomy, brain activity, and behavior are still poorly understood. We previously found that the depth of three small, shallow sulci in the lateral prefrontal cortex (LPFC) was linked to reasoning performance during development (Voorhies et al., 2021). These findings beg the question: What is the linking mechanism between sulcal morphology and cognition? Here, we investigated functional connectivity among sulci in LPFC and the lateral parietal cortex in participants drawn from the same sample as our previous study. We leveraged manual parcellations (21 sulci/hemisphere, 1,806 total) and functional magnetic resonance imaging data from a reasoning task from 43 participants aged 7-18 years (20 females). We conducted clustering and classification analyses of individual-level functional connectivity among sulci. Broadly, we found that (1) connectivity patterns of individual sulci could be differentiated and more accurately than cortical patches equated for size and shape; (2) sulcal connectivity did not consistently correspond with that of probabilistic labels or large-scale networks; (3) sulci clustered based on connectivity patterns, not dictated by spatial proximity; and (4) across individuals, greater depth was associated with higher network centrality for several sulci under investigation. These results illustrate how sulcal morphology can be functionally relevant and provide proof of concept that using sulci to define an individual coordinate space for functional connectomes is a promising future direction.