Sulcal morphology of posteromedial cortex substantially differs between humans and chimpanzees

Abstract

Recent studies identify a surprising coupling between evolutionarily new sulci and the functional organization of human posteromedial cortex (PMC). Yet, no study has compared this modern PMC sulcal patterning between humans and non-human hominoids. To fill this gap in knowledge, we first manually defined over 2500 PMC sulci in 120 chimpanzee (Pan Troglodytes) hemispheres and 144 human hemispheres. We uncovered four new sulci, and quantitatively identified species differences in sulcal incidence, depth, and surface area. Interestingly, some sulci are more common in humans and others, in chimpanzees. Further, we found that the prominent marginal ramus of the cingulate sulcus differs significantly between species. Contrary to classic observations, the present results reveal that the surface anatomy of PMC substantially differs between humans and chimpanzees—findings which lay a foundation for better understanding the evolution of neuroanatomical-functional and neuroanatomical-behavioral relationships in this highly expanded region of the human cerebral cortex.

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

“…As in previous work (Clark et al 2010;Rollins et al 2020), the surface area was set to zero for participants with no pimfs component. To control for individual differences in brain size, as in prior work (Willbrand et al 2022c(Willbrand et al , 2023cHathaway et al 2023), we normalized the surface area as a percent of the hemispheric surface area.…”

Dissociable contributions of the medial parietal cortex to recognition memory

“…As can been seen in Figure 2a, whether this dorsal recognition cluster was primarily located in the dPCC or dRSC varied from subject to subject, highlighting these subtle, but important, individual-differences in activation patterns. Additionally, in all but two of the subjects, a reliable recognition cluster was found in the middle of the PCC, around the splenial sulcus 39,40 . However, the exact location of this middle PCC recognition cluster was highly variable across individuals.…”

Updating the sulcal landscape of the human lateral parieto-occipital junction provides anatomical, functional, and cognitive insights

“…A fundamental goal in neuroscience is to understand the complex relationship between brain structure and brain function, as well as how that relationship provides a scaffold for efficient cognition and behavior. Of all the neuroanatomical features to target, recent work shows that morphological features of hominoid-specific, shallow indentations, or sulci, of the cerebral cortex are not only functionally and cognitively meaningful, but also are particularly impacted by multiple brain-related disorders and aging [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. The combination of these findings provides growing support for a classic theory proposing that the late emergence of these structures in gestation within association cortices, as well as their prolonged development, may co-occur with specific functional and microstructural features that could support specific cognitive abilities that also have a protracted development [21].…”

“…The combination of these findings provides growing support for a classic theory proposing that the late emergence of these structures in gestation within association cortices, as well as their prolonged development, may co-occur with specific functional and microstructural features that could support specific cognitive abilities that also have a protracted development [21]. Nevertheless, despite the developmental, evolutionary, functional, cognitive, and theoretical relevance of these findings, they have mainly been restricted to only a subset of association cortices such as the prefrontal, cingulate, and ventral occipitotemporal cortices [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Thus, examining the relationship among these structures (also known as tertiary sulci) relative to architectonic and functional features of the cerebral cortex, as well as relative to cognition, remains uncharted in other association cortices such as the lateral parietal cortex (LPC).…”

“…Second, a majority of the time, the two lines of work are conducted independently from one another and the majority of human neuroimaging studies of LPC implement group analyses on average brain templates-which causes LPC sulci to disappear (figure 1). Third, despite the recently identified complexity of LPC sulcal patterning, recent studies have also uncovered previously overlooked tertiary sulci in association cortices (for example, in the posterior cingulate cortex [13,15]). Thus, fourth, it is unknown if additional LPC tertiary sulci are waiting to be discovered and if so, could improve our understanding of the structural-functional organization of LPC with potential cognitive insights as in other association cortices.…”