Sulcal depth in prefrontal cortex: a novel predictor of working memory performance

Abstract

The neuroanatomical changes that underpin cognitive development are of major interest in neuroscience. Of the many aspects of neuroanatomy to consider, tertiary sulci are particularly attractive as they emerge last in gestation, show a protracted development after birth, and are either human- or hominoid-specific. Thus, they are ideal targets for exploring morphological-cognitive relationships with cognitive skills that also show protracted development such as working memory (WM). Yet, the relationship between sulcal morphology and WM is unknown—either in development or more generally. To fill this gap, we adopted a data-driven approach with cross-validation to examine the relationship between sulcal depth in lateral prefrontal cortex (LPFC) and verbal WM in 60 children and adolescents between ages 6 and 18. These analyses identified 9 left, and no right, LPFC sulci (of which 7 were tertiary) whose depth predicted verbal WM performance above and beyond the effect of age. Most of these sulci are located within and around contours of previously proposed functional parcellations of LPFC. This sulcal depth model outperformed models with age or cortical thickness. Together, these findings build empirical support for a classic theory that tertiary sulci serve as landmarks in association cortices that contribute to late-maturing human cognitive abilities.

Ventral temporal and posteromedial sulcal morphology in autism spectrum disorder

“…Specifically, we show that individual differences in IFRMS depth predict individual differences in ADOS score in which the deeper the sulcus, the lower the ADOS score. The fact that only sulcal depth, but not other morphological features, were correlated with ADOS score is consistent with recent results showing a relationship between sulcal depth in lateral prefrontal cortex and higher-level aspects of cognition such as relational reasoning (Voorhies et al, 2021) and working memory (Yao, Voorhies, Miller, Bunge, & Weiner, 2022) in a developmental cohort, as well as inferior frontal cortex in ASD individuals. In terms of the latter, Brun et al (2016) found that sulcal pit depth in the left hemisphere of the ascending ramus of the lateral fissure was correlated with social communication behavior in ASD individuals.…”

“…Thus, generally, gyri have negative values, while sulci have positive values. Given the shallowness and variability in the depth of tertiary sulci (Voorhies et al, 2021; Yao, Voorhies, Miller, Bunge, & Weiner, 2022), some mean depth values extend below zero. We emphasize that this just reflects the metric implemented in FreeSurfer.…”

Sulcal variability in anterior lateral prefrontal cortex contributes to variability in reasoning performance among young adults

“…To date, the patterning and cognitive relevance of the pimfs has only been examined in neurotypical populations [23,24,56]. Numerous studies of disorders such as schizophrenia, autism spectrum disorder, obsessive-compulsive disorder, and fronto-temporal dementia have found that variations in sulcal incidence are clinically relevant -although most of this work has focused on the ACC (e.g., [95][96][97][98][99][100][101][102][103]) and orbitofrontal cortex (for review see [104]).…”

“…Although this project focused on a single sulcus, the manual identification of all LPFC sulci (2,877 sulcal definitions across all 72 participants) was required to ensure the most accurate definitions of the pimfs components. For in-depth descriptions of all LPFC sulci, see [23,30,[55][56][57]60]. The incidence rates of the two pimfs components (i.e., sulcal patterning) were compared within and between hemispheres with Chi-squared and Fischer exact tests, respectively.…”

Sulcal morphology of posteromedial cortex substantially differs between humans and chimpanzees

“…For the present study, we re-assessed the 144 human hemispheres analyzed in our prior work 20 . Manual lines were drawn on the FreeSurfer inflated cortical surface to define sulci with tools in tksurfer based on the most recent schematics of sulcal patterning in PMC by Petrides 60 , as well as by the pial and smoothwm surfaces of each individual as in our prior work 20,27,28,36 . In some cases, the precise start or end point of a sulcus can be difficult to determine on a surface 82 .…”