The influence of biophysical parameters in a biomechanical model of cortical folding patterns

AbstractAbnormal cortical folding patterns, such as lissencephaly, pachygyria and polymicrogyria malformations, may be related to neurodevelopmental disorders. In this context, computational modeling is a powerful tool to provide a better understanding of the early brain folding process. Recent studies based on biomechanical modeling have shown that mechanical forces play a crucial role in the formation of cortical convolutions. However, the effect of biophysical parameters in these models remain unclear. In this paper, we investigate the effect of the cortical growth, the initial geometry and the initial cortical thickness on folding patterns. In addition, we not only use several descriptors of the folds such as the dimensionless mean curvature, the surface-based three-dimensional gyrification index and the sulcal depth, but also propose a new metric to quantify the folds orientation. The results demonstrate that the cortical growth mode does almost not affect the complexity degree of surface morphology; the variation in the initial geometry changes the folds orientation and depth, and in particular, the slenderer the shape is, the more folds along its longest axis could be seen and the deeper the sulci become. Moreover, the thinner the initial cortical thickness is, the higher the spatial frequency of the folds is, but the shallower the sulci become, which is in agreement with the previously reported effects of cortical thickness.

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The Heritability of Cortical Folding: Evidence from the Human Connectome Project

Cerebral Cortex ◽

10.1093/cercor/bhaa254 ◽

2020 ◽

Vol 31 (1) ◽

pp. 702-715

Author(s):

J Eric Schmitt ◽

Armin Raznahan ◽

Siyuan Liu ◽

Michael C Neale

Keyword(s):

Individual Differences ◽

Mean Curvature ◽

Genetic Factors ◽

Cortical Folding ◽

Quantitative Genetic ◽

Large N ◽

Human Connectome Project ◽

Surface Metrics ◽

Permutation Analysis ◽

Sulcal Depth

Abstract The mechanisms underlying cortical folding are incompletely understood. Prior studies have suggested that individual differences in sulcal depth are genetically mediated, with deeper and ontologically older sulci more heritable than others. In this study, we examine FreeSurfer-derived estimates of average convexity and mean curvature as proxy measures of cortical folding patterns using a large (N = 1096) genetically informative young adult subsample of the Human Connectome Project. Both measures were significantly heritable near major sulci and primary fissures, where approximately half of individual differences could be attributed to genetic factors. Genetic influences near higher order gyri and sulci were substantially lower and largely nonsignificant. Spatial permutation analysis found that heritability patterns were significantly anticorrelated to maps of evolutionary and neurodevelopmental expansion. We also found strong phenotypic correlations between average convexity, curvature, and several common surface metrics (cortical thickness, surface area, and cortical myelination). However, quantitative genetic models suggest that correlations between these metrics are largely driven by nongenetic factors. These findings not only further our understanding of the neurobiology of gyrification, but have pragmatic implications for the interpretation of heritability maps based on automated surface-based measurements.

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Regional Alterations in Cortical Sulcal Depth in Living Fetuses with Down Syndrome

Cerebral Cortex ◽

10.1093/cercor/bhaa255 ◽

2020 ◽

Author(s):

Hyuk Jin Yun ◽

Juan David Ruiz Perez ◽

Patricia Sosa ◽

J Alejandro Valdés ◽

Neel Madan ◽

...

Keyword(s):

Down Syndrome ◽

Fetal Brain ◽

Brain Magnetic Resonance Imaging ◽

Fetal Life ◽

Cortical Folding ◽

Neurocognitive Impairments ◽

Gyrification Index ◽

Advanced Analysis ◽

Magnetic Resonance Imaging Mri ◽

Sulcal Depth

Abstract Down syndrome (DS) is the most common genetic cause of developmental disabilities. Advanced analysis of brain magnetic resonance imaging (MRI) has been used to find brain abnormalities and their relationship to neurocognitive impairments in children and adolescents with DS. Because genetic factors affect brain development in early fetal life, there is a growing interest in analyzing brains from living fetuses with DS. In this study, we investigated regional sulcal folding depth as well as global cortical gyrification from fetal brain MRIs. Nine fetuses with DS (29.1 ± 4.24 gestational weeks [mean ± standard deviation]) were compared with 17 typically developing [TD] fetuses (28.4 ± 3.44). Fetuses with DS showed lower whole-brain average sulcal depths and gyrification index than TD fetuses. Significant decreases in sulcal depth were found in bilateral Sylvian fissures and right central and parieto-occipital sulci. On the other hand, significantly increased sulcal depth was shown in the left superior temporal sulcus, which is related to atypical hemispheric asymmetry of cortical folding. Moreover, these group differences increased as gestation progressed. This study demonstrates that regional sulcal depth is a sensitive marker for detecting alterations of cortical development in DS during fetal life, which may be associated with later neurocognitive impairment.

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Novel Volumetric and Surface-Based Magnetic Resonance Indices of the Aging Brain – Does Male and Female Brain Age in the Same Way?

Frontiers in Neurology ◽

10.3389/fneur.2021.645729 ◽

2021 ◽

Vol 12 ◽

Author(s):

Przemysław Podgórski ◽

Joanna Bladowska ◽

Marek Sasiadek ◽

Anna Zimny

Keyword(s):

Fractal Dimension ◽

Magnetic Resonance ◽

Cortical Thickness ◽

Brain Mri ◽

Aging Brain ◽

Men And Women ◽

Male And Female ◽

Brain Volumetry ◽

Gyrification Index ◽

Sulcal Depth

Introduction: Novel post-processing methods allow not only for assessment of brain volumetry or cortical thickness based on magnetic resonance imaging (MRI) but also for more detailed analysis of cortical shape and complexity using parameters such as sulcal depth, gyrification index, or fractal dimension. The aim of this study was to analyze changes in brain volumetry and other cortical indices during aging in men and women.Material and Methods: Material consisted of 697 healthy volunteers (aged 38–80 years; M/F, 264/443) who underwent brain MRI using a 1.5-T scanner. Voxel-based volumetry of total gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) was performed followed by assessment of cortical parameters [cortical thickness (CT), sulcal depth (SD), gyrification index (GI), and fractal dimension (FD)] in 150 atlas locations using surface-based morphometry with a region-based approach. All parameters were compared among seven age groups (grouped every 5 years) separately for men and women. Additionally, percentile curves for men and women were provided for total volumes of GM, WM, and CSF.Results: In men and women, a decrease in GM and WM volumes and an increase in CSF volume seem to progress slowly since the age of 45. In men, significant GM and WM loss as well as CSF increase start above 55 years of age, while in women, significant GM loss starts above 50 and significant WM loss as well as CSF increase above 60. CT was found to significantly decrease with aging in 39% of locations in women and in 36% of locations in men, SD was found to increase in 13.5% of locations in women and in 1.3% of locations in men, GI was decreased in 3.4% of locations in women and in 2.0% of locations in men, and FD was changed in 2.7% of locations in women compared to 2.0% in men.Conclusions: Male and female brains start aging at the similar age of 45. Compared to men, in women, the cortex is affected earlier and in the more complex pattern regarding not only cortical loss but also other alterations within the cortical shape, with relatively longer sparing of WM volume.

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Mechanical Evaluation of the Pronator Teres Rerouting Tendon Transfer

Journal of Hand Surgery (European Volume) ◽

10.1016/j.jhsb.2004.01.004 ◽

2004 ◽

Vol 29 (3) ◽

pp. 257-262 ◽

Cited By ~ 18

Author(s):

H. E. J. VEEGER ◽

M. KREULEN ◽

M. J. C. SMEULDERS

Keyword(s):

Biceps Brachii ◽

External Rotation ◽

Three Dimensional ◽

Muscle Length ◽

Biomechanical Model ◽

Elbow Flexion ◽

Axial Rotation ◽

Original Position ◽

Pronator Quadratus ◽

Pronator Teres

We simulated pronator teres rerouting using a three-dimensional biomechanical model of the arm. Simulations comprised the evaluation of changes in muscle length and the moment arm of pronator teres with changes in forearm axial rotation and elbow flexion. The rerouting of Pronator Teres was simulated by defining a path for it through the interosseous membrane with re-attachment to its original insertion. However the effect of moving the insertion to new positions, 2 cm below and above, the original position was also assessed. The effect on total internal rotation and external rotation capacity was determined by calculating the potential moments for pronator teres, supinator, pronator quadratus, biceps brachii and brachioradialis. Pronator teres was found to be a weak internal rotator in extreme pronation, but a strong internal rotator in neutral rotation and in supination. After rerouting pronator teres was only a strong external rotator in full pronation and not at other forearm positions, where the effect of rerouting was comparable to a release procedure.

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Variability of the paracingulate sulcus and morphometry of the medial frontal cortex: Associations with cortical thickness, surface area, volume, and sulcal depth

Human Brain Mapping ◽

10.1002/hbm.20381 ◽

2008 ◽

Vol 29 (2) ◽

pp. 222-236 ◽

Cited By ~ 71

Author(s):

Alex Fornito ◽

Stephen J. Wood ◽

Sarah Whittle ◽

Jack Fuller ◽

Chris Adamson ◽

...

Keyword(s):

Frontal Cortex ◽

Surface Area ◽

Cortical Thickness ◽

Medial Frontal Cortex ◽

Sulcal Depth

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Stereological estimation of gyrification index and related measures of cortical folding from MR data in schizophrenia

Schizophrenia Research ◽

10.1016/s0920-9964(97)82452-8 ◽

1997 ◽

Vol 24 (1-2) ◽

pp. 157 ◽

Cited By ~ 1

Author(s):

Martin D. Stefan ◽

Tonmoy Sharma ◽

Zoe Ellison ◽

Robin Murray ◽

Ian Everall

Keyword(s):

Cortical Folding ◽

Gyrification Index

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Integral criteria for closed surfaces with constant mean curvature

Proceedings of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rspa.2007.1818 ◽

2007 ◽

Vol 463 (2081) ◽

pp. 1199-1210

Author(s):

Luca Guzzardi ◽

Epifanio G Virga

Keyword(s):

Mean Curvature ◽

Constant Mean Curvature ◽

Three Dimensional ◽

Dimensional Euclidean Space ◽

Second Variation ◽

Closed Surfaces ◽

Area Functional ◽

Symmetric Surface ◽

The Second Variation ◽

Integral Identities

We propose three integral criteria that must be satisfied by all closed surfaces with constant mean curvature immersed in the three-dimensional Euclidean space. These criteria are integral identities that follow from requiring the second variation of the area functional to be invariant under rigid displacements. We obtain from them a new proof of the old result by Delaunay, to the effect that the sphere is the only closed axis-symmetric surface.

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