Biology subjects

Leprince, Y.

Publications and source records attributed to Leprince, Y..

7 recordsLinked to original sources

bioRxiv2025

Characterization of aperiodic and theta activity in preterm infants using EEG: Insights into cerebral maturation and inter-individual variability

Disrupting critical processes of brain development, preterm birth interferes with the maturation of brain networks and functional activity, including theta oscillations that are thought to play a key role in early network formation. Traditional EEG spectral analyses have indicated marked development of theta power in early infancy, but these approaches mix oscillatory and non-oscillatory activity, limiting insights into the mechanisms underlying the neural changes. Using spectral parameterization, we aimed to evaluate developmental changes in aperiodic activity and periodic theta power in infants born very preterm compared to full-terms, and to further explore whether clinical factors and brain microstructure could explain the inter-individual variability within preterms. High-density EEG was acquired during active/REM sleep at term-equivalent age (TEA) and 2 months corrected age (2mCA) in 41 very preterm infants (born <32 weeks gestational age [GA]; mean {+/-} standard deviation: 26.9{+/-}1.7 weeks) and 13 full-term controls (born [≥]37 weeks GA; 40.1{+/-}1 weeks). Spectral parameterization was used to extract aperiodic components (offset, exponent) and periodic theta power globally and across spatial clusters of electrodes (anterior, central, posterior). From TEA to 2mCA, offset, exponent, and theta power increased with no differences between preterm and full-term infants. At TEA, metrics of aperiodic activity were stronger in anterior compared with posterior areas, but this regional landscape shifted by 2mCA with pronounced increases in aperiodic offset and exponent in posterior areas from TEA to 2mCA. Within preterms, inter-individual variability in aperiodic and periodic activity at TEA was partly explained by clinical risk factors: male sex, lower gestational-age at birth, small weight at birth, and invasive ventilation were linked to alterations of aperiodic offset, exponent and theta power. Additionally, higher theta power at TEA correlated with lower cortical fractional anisotropy assessed with diffusion MRI at the same age, consistently with more advanced maturation of the brain. Collectively, these findings indicate that EEG spectral parameterization combined with spatial analysis provides a sensitive framework for characterizing the postnatal maturation of brain activity in infants, as well as early vulnerabilities associated with prematurity and perinatal adversity.

neuroscience↗

bioRxiv2025

Multimodal imaging of human fetal brain development at the mesoscopic scale using 11.7 T ex vivo MRI

We present the first release of p-HCP (Prenatal Human Connectome Patterns), an imaging dataset of human fetal brain development covering the second half of gestation. This dataset was acquired ex vivo using magnetic resonance imaging (MRI) at ultra high field (11.7 teslas), and includes whole-hemisphere T2-weighted images at 100 {micro}m isotropic resolution, quantitative relaxometry (T1, T2, and [Formula]), and high angular resolution diffusion-weighted images for multiple b-values at 200 {micro}m. Brains larger than the workspace of the small-bore scanner were sectioned into blocks, acquired blockwise, and digitally reconstructed using a dedicated semi-automatic method. This initial data release includes three gestational ages (18, 27, and 31 post-conceptional weeks) with a complete set of anatomical images, relaxometry maps, and diffusion-based microstructure measurements. This dataset offers new opportunities to investigate neurodevelopmental processes that have not yet been explored with full three-dimensional coverage at this resolution by MRI, and may serve as a multimodal mesoscopic reference template for the fetal brain.

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↗

bioRxiv2025

Siibra: A software tool suite for realizing a Multilevel Human Brain Atlas from complex data resources

Computational technology opens new possibilities towards understanding the complexity of the human brain, but it requires integrating measurements from different modalities and scales in anatomical context and exposing them in interoperable, actionable form. Especially with growing big data resources, accessing information from different scales and modalities coherently for visual exploration, reproducible analysis and application development remains challenging. We present siibra, a tool suite that connects diverse data from cloud resources to reference atlases and coordinate spaces. It supports different use cases by making contents accessible through a web viewer, Python library and HTTP API. Using siibra we implemented a Multilevel Human Brain Atlas linking macro-anatomical concepts and their inter-subject variability with measurements of the microstructural composition and intrinsic variance of brain regions, building on cytoarchitecture as a reference and supporting MRI-based and microscopic templates. The atlas is integrated with the EBRAINS research infrastructure. All software and content are openly accessible.

bioinformatics↗

bioRxiv2025

On the typical development of the central sulcus in infancy: a longitudinal evaluation of its morphology and link to behaviour

IntroductionThe progressive folding of the cortex is an important feature of neurodevelopment starting early during gestation. The central sulcus (CS) is one of the first to fold. Since it represents the anatomical boundary between primary somatosensory and motor functional regions, its developing morphology may inform on the acquisition of sensorimotor skills. We aimed to identify potential asynchronous morphological changes along the CS during infancy, with the hypothesis that this may reflect the gradual emergence of body usage. MethodBased on 3T anatomical magnetic resonance imaging (MRI) and dedicated post-processing, we characterized the evolution in CS depth and curvature in 33 typical infants (aged 1 and 3 months, 22 with longitudinal data) in relation to 23 young adults as a reference. Four regions of interest (ROIs) along the CS, supposed to correspond to different parts of the body and one centred on the hand knob (HK), were reproducibly examined and compared across groups. We also explored the relationship between the age-related changes in morphological features and the global motor scaled scores evaluated at 3 months of age with the Bayley Scales of Infant and Toddler Development. ResultsWhile all ROIs showed significant increases in CS depth and curvature between 3-month-olds and adults, the results were more variable between 1 and 3 months of age depending on cross-sectional and longitudinal analyses. The central-medial and central-lateral regions showed the most consistent increase in depth. Besides, motor development at 3 months of age was not significantly related to CS morphological changes, but a positive trend was observed for depth changes in the (HK-related) central-medial ROI. ConclusionThe rapid evolution of CS folding during infancy may reflect the intense but asynchronous maturation of the brain sensorimotor system, with the differential growth of cortical areas related to body parts and underlying white matter connections. Although it will have to be replicated on larger groups and at other ages, this longitudinal and multimodal study highlights the potential of characterizing CS features as key markers of early sensorimotor development, both at the cerebral and behavioural levels. Combining anatomical and functional neuroimaging could provide deeper insights into the relationship between CS morphology and somatotopic organization in typical infants, but also in infants at risk of developing motor disorders.

neuroscience↗

bioRxiv2023

In vivo mapping of the deep and superficial whitematter connectivity in the chimpanzee brain

Mapping the chimpanzee brain connectome, and comparing it to humans, is key to our understanding of similarities and differences in primate evolution that occurred after the split from their common ancestor around 6 million years ago. In contrast with macaque species brain studies, less studies have specifically addressed the structural connectivity of the chim-panzee brain and its comparison with the human brain. Most comparative studies in the liter-ature focus on the anatomy of the cortex and deep nuclei to evaluate how their morphometry and asymmetry differs from that of the human brain, and some studies have emerged concern-ing the study of brain connectivity between primates. In this work, we established a new white matter atlas of the deep and superficial white matter structural connectivity in chimpanzees. In vivo anatomical and diffusion weighted magnetic resonance imaging (MRI) data were collected on a 3 Tesla magnetic resonance imaging (MRI) system in 39 chimpanzees. These datasets were subsequently processed using a dedicated fiber clustering pipeline adapted to the chimpanzee brain enabling us to create two novel deep and superficial white matter connectivity atlases representative of the chimpanzee brain. These atlases provide the scientific community with an important and novel set of reference data for understanding the commonalities and differ-ences of the structural connectivity between the human and chimpanzee brains, which will contribute to a better understanding of the hominin brain evolution.

neuroscience↗

bioRxiv2022

Early structural connectivity within the sensorimotor network: deviations related to prematurity and association to neurodevelopmental outcome

The sensorimotor (SM) network is crucial for optimal neurodevelopment. However, undergoing rapid maturation during the perinatal period, it is particularly vulnerable to preterm birth. Our work explores the prematurity impact on the microstructure and maturation of primary SM white matter (WM) tracts at term-equivalent age (TEA) and evaluates the relationships between these alterations and neurodevelopmental outcome. We analyzed diffusion MRI data from the developing Human Connectome Project (dHCP) database: 59 preterm (PT) low-risk infants scanned near TEA, compared to a control group of full-term (FT) neonates paired for age at MRI and sex. We dissected pairwise connections between primary SM cortices and subcortical structures using probabilistic tractography and evaluated their microstructure with diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) models. In addition to tract- specific univariate analyses of diffusion metrics, we computed a maturational distance related to prematurity based on a multi-parametric Mahalanobis distance of each PT infant relative to the FT group. Finally, we evaluated the relationships between this distance and Bayley Scales of Infant and Toddler Development (BSID-III) scaled scores at 18 months corrected age. Our results confirm important microstructural differences in SM tracts between PT and FT infants, with effects increasing with lower gestational age at birth. Additionally, comparisons of maturational distances highlight that prematurity has a differential effect on SM tracts which follows the established WM caudo-rostral developmental pattern. Our results suggest a particular vulnerability of projections involving the primary sensorimotor cortices (S1) and of the most rostral tracts, with cortico-cortical and S1-Lenticular tracts presenting the highest alterations at TEA. Finally, NODDI-derived maturational distances of specific tracts seem related to fine motor and cognitive scores. This study expands the understanding of the impact of early WM alterations in the emerging SM network on long-term neurodevelopment. In the future, related approaches have potential to lead to the development of neuroimaging markers for neurodevelopmental disorders, with special interest for subtle neuromotor impairments frequently observed in preterm-born children.

neuroscience↗