Cortical thickness systematically varies with curvature and depth in healthy human brains

Abstract

Cortical thickness varies throughout the cortex in a systematic way. However, it is challenging to investigate the patterns of cortical thickness due to the intricate geometry of the cortex. The cortex has a folded nature both in radial and tangential directions which forms not only gyri and sulci but also tangential folds and intersections.In this article, cortical curvature and depth are used to characterize the spatial distribution of the cortical thickness with much higher resolution than conventional regional atlases. To do this, a computational pipeline was developed that is capable of calculating a variety of quantitative measures such as surface area, cortical thickness, curvature (mean curvature, Gaussian curvature, shape index, intrinsic curvature index, and folding index), and sulcal depth. By analyzing 501 neurotypical adult human subjects from the ABIDE-I dataset, we show that cortex has a very organized structure and cortical thickness is strongly correlated with local shape. Our results indicate that cortical thickness consistently increases along the gyral-sulcal spectrum from concave to convex shape, encompassing the saddle shape along the way. Additionally, tangential folds influence cortical thickness in a similar way as gyral and sulcal folds; outer folds are consistently thicker than inner.

Motor symptoms in Parkinson’s disease are related to the interplay between cortical curvature and thickness

“…The association between cortical curvature and thickness likely reflects a systematically and spatially varying pattern of thickness and curvature, which both show subtle local variations when considered independently ( Demirci & Holland, 2022 ). However, the exact neurobiological basis of the cortical curvature-thickness interplay in neurodegeneration is currently unknown.…”

“…The morphology of the cortex is determined by a complex interplay between genetic, biochemical, and physical factors ( Ronan & Fletcher, 2015 ), with cortical morphological characteristics such as thickness and curvature showing local variations ( Demirci & Holland, 2022 ). Individual brain morphological measures such as cortical thickness or brain volumes are likely not able to efficiently capture these systematically varying properties.…”

“…Individual brain morphological measures such as cortical thickness or brain volumes are likely not able to efficiently capture these systematically varying properties. The interplay between different morphological measures across the cortex, however, could reflect aspects of these systematically varying morphological patterns ( Demirci & Holland, 2022 ). Therefore, associations between cortical morphological characteristics could provide a unique perspective on neurodegeneration in PD that would not be apparent if morphological features are considered independently.…”

NBS-SNI, an extension of the Network-based statistic: Abnormal functional connections between important structural actors

“…In the second real dataset that we investigated (see section 4), the anatomical measure of intrinsic curvature index (ICI) was employed as a node property. Its calculation was introduced by D. Van Essen and Drury 1997, and is defined as follows (Demirci & Holland, 2022): where K is the Gaussian curvature, defined as where N is the number of triangles connected to the vertex p (see Fig. 1).…”

Altered Cerebral Curvature in Preterm Infants Is Associated with the Common Genetic Variation Related to Autism Spectrum Disorder and Lipid Metabolism

“…Preterm birth disrupts cortical maturation during the critical period of fetal brain growth [ 4 ]. In normal development, the interaction between the faster tangential growth of the cortex and the underlying white-matter core contributes to local changes in the gyrification and sulcation patterns of the cerebral cortex [ 5 ]. The prenatal and postnatal periods of brain development, with an extensive period of synaptic modulation and pruning, are observed throughout the first year of life [ 6 ].…”