Biology subjects

Riviere, D.

Publications and source records attributed to Riviere, D..

9 recordsLinked to original sources

bioRxiv2026

Self-supervised representations reveal the genetic architecture of human cortical folding

Cortical folding emerges during fetal development, is under genetic control, and remains stable throughout life, offering a lasting window into early neurodevelopment. Conventional morphometric descriptors, however, only partially capture the shape variability of cortical folds. Here, we compare 56 regional self-supervised deep learning representations of cortical folds with classical sulcal morphometry via multivariate genome-wide association studies (GWAS) in 35,940 UK Biobank participants. The learned representations identified 567 independent genome-wide significant loci, versus 162 for classical morphometry, 87% of which were also detected by our approach. More than half of these associations replicated in the independent Adolescent Brain Cognitive Development (ABCD) cohort. Gene, gene-set, BrainSpan and single-cell expression enrichment converge on a shared prenatal window of neurogenesis and morphogenesis; spatial gene-association maps recapitulate known regional expression gradients, including for NR2F1. Together, these results establish self-supervised representations of cortical folding as a powerful phenotypic framework for the genetic study of neurodevelopment.

genomics↗

bioRxiv2026

FAST BOLD FMRI REVEALS THE SPATIOTEMPORAL COMPLEXITY OF NEUROVASCULAR COUPLING ALTERATIONS IN CEREBRAL SMALL VESSEL DISEASE

Recent advances in neurophysiology highlighted the potential of high temporal resolution in Blood-Oxygen Level Dependent (BOLD) functional MRI (fMRI), although it is not yet standard practice. We demonstrated that fast BOLD fMRI can detect single-subject, single-stimulus visually evoked responses to brief stimuli at 3T. We used fast fMRI in patients with Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL), a genetic form of cerebral small vessel disease (cSVD). Using 2- and 10-second visual stimuli, we probed different neurovascular coupling regimes and showed that different regions of interest detect different facets of vascular dynamics. CADASIL patients showed significant changes in the amplitude and timing of the BOLD response, indicating early-age neurovascular impairment unrelated to anatomical lesions, and providing strong discriminative and generalization performance. These findings resolve prior inconsistencies in fMRI studies of CADASIL, supporting the use of fast fMRI to develop non-invasive biomarkers for cSVD and other neurodegenerative disorders.

neuroscience↗

bioRxiv2025

Differential microstructural development within sensorimotor cortical regions: A diffusion MRI study in preterm and full-term infants

The sensorimotor system develops early in utero and supports the emergence of body representations critical for perception, action, and interaction with environment. While somatotopic protomaps are already developed in the primary somatosensory and motor cortices in late pregnancy, little is known about the anatomical substrates of this functional specialization. In this study, we aimed to decipher the microstructural properties of these regions in the developing brain. Using advanced diffusion MRI and post-processing tools, we parcellated the pre- and post-central gyri into microstructurally distinct clusters along the lateral-to-medial axis in full-term neonates, confirming the early differentiation within sensorimotor regions. These clusters were further analyzed in preterm infants scanned near birth and at term-equivalent age (TEA), compared with another group of full-term neonates. Applying a multivariate Mahalanobis distance approach, we quantified deviations in preterm cortical microstructure relative to the full-term reference. Preterm infants showed significant region- and position-specific deviations at both ages, though these were smaller at TEA, consistently with ongoing maturation during the pre-term period. Differences between the pre- and post-central gyri, and along the somatotopic axis, suggested differential vulnerability to prematurity. In particular, the motor regions appeared to be at a more advanced stage of maturation close to birth and less vulnerable at TEA than somatosensory regions. An opposite trend was observed for lateral positions related to mouth representation compared with intermediary and medial positions. These findings support the notion that early sensorimotor cortical specialization is microstructurally emergent during gestation and sensitive to atypical developmental context of preterm birth.

neuroscience↗

bioRxiv2023

A bipolar taxonomy of adult human brain sulcal morphology related to timing of fetalsulcation and trans-sulcal gene expression gradients

We developed a computational pipeline (now provided as a resource) for measuring morphological similarity between cortical surface sulci to construct a sulcal phenotype network (SPN) from each magnetic resonance imaging (MRI) scan in an adult cohort (N=34,725; 45-82 years). Networks estimated from pairwise similarities of 40 sulci on 5 morphological metrics comprised two clusters of sulci, represented also by the bipolar distribution of sulci on a linear-to-complex dimension. Linear sulci were more heritable and typically located in unimodal cortex; complex sulci were less heritable and typically located in heteromodal cortex. Aligning these results with an independent fetal brain MRI cohort (N=228; 21-36 gestational weeks), we found that linear sulci formed earlier, and the earliest and latest-forming sulci had the least between-adult variation. Using high-resolution maps of cortical gene expression, we found that linear sulcation is mechanistically underpinned by trans-sulcal gene expression gradients enriched for developmental processes.

neuroscience↗

bioRxiv2022

Exploring the emergence of morphological asymmetries around the brain's Sylvian fissure: a longitudinal study of shape variability in preterm infants.

Brain folding patterns vary within the human species, but some folding properties are common across individuals, including the Sylvian fissures inter-hemispheric asymmetry. Contrarily to the other brain folds (sulci), the Sylvian fissure develops through the process of opercularization, with the frontal, parietal and temporal lobes growing over the insular lobe. Its asymmetry may be related to the leftward functional lateralization for language processing, but the time-course of these asymmetries development is still poorly understood. In this study, we investigated refined shape features of the Sylvian fissure and their longitudinal development in 71 infants born extremely preterm (mean gestational age at birth: 26.5 weeks) and imaged once before and once at term-equivalent age (TEA). We additionally assessed asymmetrical sulcal patterns at TEA in the perisylvian and inferior frontal regions, neighbor to the Sylvian fissure. While reproducing renown strong asymmetries in the Sylvian fissure, we captured an early encoding of its main asymmetrical shape features, and we observed global asymmetrical shape features representative of a more pronounced opercularization in the left-hemisphere, contrasting with the previously reported right-hemisphere advance in sulcation around birth. This added novel insights about the processes governing early-life brain folding mechanisms, potentially linked to the development of language-related capacities. Highlights- Shape features can be isolated to describe quantitatively the development of the Sylvian fissure - Strong asymmetries are encoded as soon as 30 weeks of post-menstrual age - The process of opercularization is more pronounced in the left hemisphere

neuroscience↗

bioRxiv2021

Shape variability of the central sulcus in the developing brain: a longitudinal descriptive and predictive study in preterm infants.

Despite growing evidence of links between sulcation and function in the adult brain, the folding dynamics, occurring mostly before normal-term-birth, is vastly unknown. Looking into the development of cortical sulci in babies can give us keys to address fundamental questions: what is the sulcal shape variability in the developing brain? When are the shape features encoded? How are these morphological parameters related to further functional development? In this study, we aimed to investigate the shape variability of the developing central sulcus, which is the frontier between the primary somatosensory and motor cortices. We studied a cohort of 71 extremely preterm infants scanned twice using MRI - once around 30 weeks post-menstrual age (w PMA) and once at term-equivalent age, around 40w PMA -, in order to quantify the sulcuss shape variability using manifold learning, regardless of age-group or hemisphere. We then used these shape descriptors to evaluate the sulcuss variability at both ages and to assess hemispheric and age- group specificities. This led us to propose a description of ten shape features capturing the variability in the central sulcus of preterm infants. Our results suggested that most of these features (8/10) are encoded as early as 30w PMA. We unprecedentedly observed hemispheric asymmetries at both ages, and the one captured at term-equivalent age seems to correspond with the asymmetry pattern previously reported in adults. We further trained classifiers in order to explore the predictive value of these shape features on manual performance at 5 years of age (handedness and fine motor outcome). The central sulcuss shape alone showed a limited but relevant predictive capacity in both cases. The study of sulcal shape features during early neurodevelopment may participate to a better comprehension of the complex links between morphological and functional organization of the developing brain. Highlights- Shape features can be isolated to describe quantitatively the development of the central sulcus. - Most shape characteristics of the central sulcus are already encoded at 30 weeks of post-menstrual age (w PMA) in preterm newborns. - The central sulcus shows subtle hemispheric asymmetries as soon as 30w PMA. - The early shape of the central sulcus can help predicting handedness and fine motor outcome at 5 years of age.

neuroscience↗

bioRxiv2019

The reliability and heritability of cortical folds and their genetic correlations across hemispheres.

The structure of the brains cortical folds varies considerably in human populations. Specific patterns of cortical variation arise with development and aging, and cortical traits are partially influenced by genetic factors. The degree to which genetic factors affect cortical folding patterning remains unknown, yet may be estimated with large-scale in-vivo brain MRI. Using multiple MRI datasets from around the world, we estimated the reliability and heritability of sulcal morphometric characteristics including length, depth, width, and surface area, for 61 sulci per hemisphere of the human brain. Reliability was assessed across four distinct test-retest datasets. We meta-analyzed the heritability across three independent family-based cohorts (N > 3,000), and one cohort of largely unrelated individuals (N~9,000) to examine the robustness of our findings. Reliability was high (interquartile range for ICC: 0.65-0.85) for sulcal metrics. Most sulcal measures were moderately to highly heritable (heritability estimates = 0.3-0.7). These genetic influences vary regionally, with the earlier forming sulci having higher heritability estimates. The central sulcus, the subcallosal and the collateral fissure were the most highly heritable regions. For some frontal and temporal sulci, left and right genetic influences did not completely overlap, suggesting some lateralization of genetic effects on the cortex.

genetics↗

bioRxiv2018

Analysis of brain network dynamics estimated from fMRI data: A new framework based on communicability and flow

Neuroimaging techniques such as MRI have been widely used to explore the associations between brain areas. Structural connectivity (SC) captures the anatomical pathways across the brain and functional connectivity (FC) measures the correlation between the activity of brain regions. These connectivity measures have been much studied using network theory in order to uncover the distributed organization of brain structures, in particular FC for task-specific brain communication. However, the application of network theory to study FC matrices is often "static" despite the dynamic nature of time series obtained from fMRI. The present study aims to overcome this limitation by introducing a network-oriented analysis applied to whole-brain effective connectivity (EC) useful to interpret the brain dynamics. Technically, we tune a multivariate Ornstein-Uhlenbeck (MOU) process to reproduce the statistics of the whole-brain resting-state fMRI signals, which provides estimates for MOU-EC as well as input properties (similar to local excitabilities). The network analysis is then based on the Green function (or network impulse response) that describes the interactions between nodes across time for the estimated dynamics. This model-based approach provides time-dependent graph-like descriptor, named communicability, that characterize the roles that either nodes or connections play in the propagation of activity within the network. They can be used at both global and local levels, and also enables the comparison of estimates from real data with surrogates (e.g. random network or ring lattice). In contrast to classical graph approaches to study SC or FC, our framework stresses the importance of taking the temporal aspect of fMRI signals into account. Our results show a merging of functional communities over time (in which input properties play a role), moving from segregated to global integration of the network activity. Our formalism sets a solid ground for the analysis and interpretation of fMRI data, including task-evoked activity.

neuroscience↗

bioRxiv2018

eQTL of KCNK2 regionally influences the brain sulcal widening: evidence from 15,597 UK Biobank participants with neuroimaging data

The grey and white matter volumes are known to reduce with age. This cortical shrinkage is visible on magnetic resonance images and is conveniently identified by the increased volume of cerebrospinal fluid in the sulci between two gyri. Here, we replicated this finding using the UK Biobank dataset and studied the genetic influence on these cortical features of aging. We divided all individuals genetically confirmed of British ancestry into two sub-cohorts (12,162 and 3,435 subjects for discovery and replication samples, respectively). We found that the heritability of the sulcal opening ranges from 15 to 45% (s.e.= 4.8%). We identified 4 new loci that contribute to this opening, including one that also affects the sulci grey matter thickness. We identified the most significant variant (rs864736) on this locus as being an expression quantitative trait locus (eQTL) for the KCNK2 gene. This gene regulates the immune-cell into the central nervous system (CNS) and controls the CNS inflammation, which is implicated in cortical atrophy and cognitive decline. These results expand our knowledge of the genetic contribution to cortical shrinking and promote further investigation into these variants and genes in pathological context such as Alzheimers disease in which brain shrinkage is a key biomarker.

genetics↗