RESUMEN
Differences in brain size between the sexes are consistently reported. However, the consequences of this anatomical difference on sex differences in intrinsic brain function remain unclear. In the current study, we investigate whether sex differences in intrinsic cortical functional organization may be associated with differences in cortical morphometry, namely different measures of brain size, microstructure, and the geodesic distance of connectivity profiles. For this, we compute a low dimensional representation of functional cortical organization, the sensory-association axis, and identify widespread sex differences. Contrary to our expectations, sex differences in functional organization do not appear to be systematically associated with differences in total surface area, microstructural organization, or geodesic distance, despite these morphometric properties being per se associated with functional organization and differing between sexes. Instead, functional sex differences in the sensory-association axis are associated with differences in functional connectivity profiles and network topology. Collectively, our findings suggest that sex differences in functional cortical organization extend beyond sex differences in cortical morphometry.
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Corteza Cerebral , Imagen por Resonancia Magnética , Red Nerviosa , Caracteres Sexuales , Femenino , Masculino , Humanos , Corteza Cerebral/anatomía & histología , Corteza Cerebral/diagnóstico por imagen , Corteza Cerebral/fisiología , Red Nerviosa/anatomía & histología , Red Nerviosa/fisiología , Red Nerviosa/diagnóstico por imagen , Adulto , Mapeo Encefálico/métodos , Adulto Joven , Encéfalo/anatomía & histología , Encéfalo/fisiología , Encéfalo/diagnóstico por imagen , Tamaño de los ÓrganosRESUMEN
Despite their distinct embryonic origins, the skull and brain are highly integrated. Understanding the covariation between the skull and brain can shed light on anatomical, cognitive, and behavioral traits in extant and extinct species. Domestic dogs offer a unique opportunity to investigate skull-brain covariation due to their diverse skull morphologies and neural anatomy. To assess this question, we examined T2-weighted MRI studies of 62 dogs from 33 breeds, plus an additional 17 dogs of mixed or unknown breeds. Scans were opportunistically collected from a veterinary teaching hospital of dogs that were referred for neurological examination but did not have grossly observable structural brain abnormalities. As the neurocrania of dogs become broader and shorter, there is a significant decrease in the gray matter volume of the right olfactory bulb, frontal cortex, marginal gyrus, and cerebellum. On the other hand, as the neurocrania of dogs become narrower and longer, there is a significant decrease in the gray matter volume of the olfactory bulb, frontal cortex, temporal cortex, amygdala, hypothalamus, hippocampus, periaqueductal gray, cerebellum, and brainstem. Selective breeding for specific skull shapes may impact canine brain anatomy and function.
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Encéfalo , Imagen por Resonancia Magnética , Cráneo , Animales , Perros/anatomía & histología , Encéfalo/anatomía & histología , Cráneo/anatomía & histología , Cráneo/diagnóstico por imagen , Masculino , Femenino , Sustancia Gris/anatomía & histología , Sustancia Gris/diagnóstico por imagenRESUMEN
Large biobanks have dramatically advanced our understanding of genetic influences on human brain anatomy. However, most studies have combined rather than compared male and female participants. Here we screen for sex differences in the common genetic architecture of over 1000 neuroanatomical phenotypes in the UK Biobank and establish a general concordance between male and female participants in heritability estimates, genetic correlations, and variant-level effects. Notable exceptions include higher mean heritability in the female group for regional volume and surface area phenotypes; between-sex genetic correlations that are significantly below 1 in the insula and parietal cortex; and a common variant with stronger effect in male participants mapping to RBFOX1 - a gene linked to multiple neuropsychiatric disorders more common in men. This work suggests that common variant influences on human brain anatomy are largely consistent between males and females, with a few exceptions that will guide future research in growing datasets.
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Encéfalo , Humanos , Masculino , Femenino , Encéfalo/anatomía & histología , Encéfalo/diagnóstico por imagen , Factores de Empalme de ARN/genética , Fenotipo , Persona de Mediana Edad , Caracteres Sexuales , Reino Unido , Imagen por Resonancia Magnética , Bancos de Muestras Biológicas , Anciano , Polimorfismo de Nucleótido Simple , Factores Sexuales , Adulto , Estudio de Asociación del Genoma CompletoRESUMEN
With brain structure and function undergoing complex changes throughout childhood and adolescence, age is a critical consideration in neuroimaging studies, particularly for those of individuals with neurodevelopmental conditions. However, despite the increasing use of large, consortium-based datasets to examine brain structure and function in neurotypical and neurodivergent populations, it is unclear whether age-related changes are consistent between datasets and whether inconsistencies related to differences in sample characteristics, such as demographics and phenotypic features, exist. To address this, we built models of age-related changes of brain structure (regional cortical thickness and regional surface area; N = 1218) and function (resting-state functional connectivity strength; N = 1254) in two neurodiverse datasets: the Province of Ontario Neurodevelopmental Network and the Healthy Brain Network. We examined whether deviations from these models differed between the datasets, and explored whether these deviations were associated with demographic and clinical variables. We found significant differences between the two datasets for measures of cortical surface area and functional connectivity strength throughout the brain. For regional measures of cortical surface area, the patterns of differences were associated with race/ethnicity, while for functional connectivity strength, positive associations were observed with head motion. Our findings highlight that patterns of age-related changes in the brain may be influenced by demographic and phenotypic characteristics, and thus future studies should consider these when examining or controlling for age effects in analyses.
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Conjuntos de Datos como Asunto , Imagen por Resonancia Magnética , Humanos , Femenino , Masculino , Niño , Adolescente , Adulto Joven , Adulto , Trastornos del Neurodesarrollo/diagnóstico por imagen , Trastornos del Neurodesarrollo/fisiopatología , Trastornos del Neurodesarrollo/patología , Conectoma , Encéfalo/diagnóstico por imagen , Encéfalo/crecimiento & desarrollo , Encéfalo/anatomía & histología , Corteza Cerebral/diagnóstico por imagen , Corteza Cerebral/crecimiento & desarrollo , Corteza Cerebral/anatomía & histología , Envejecimiento/fisiologíaRESUMEN
Felix Vicq-d'Azyr (1748-1794) was a distinguished eighteenth-century scientist, personal physician to Queen Marie Antoinette and secretary of the Royal Society of Medicine, who made significant contributions to theoretical and practical medicine, most notably to neuroanatomy. His descriptions of the brain were among the most accurate of the time, and his «Traité d'Anatomie et de Physiologie¼ is one of the best neuroanatomical works. Vicq-d'Azyr was the first to use lithography in neuroanatomy, as well as the founder of the technique for dissecting fixed brain matter. The scientist first described a number of neuroanatomical structures, including the central sulcus (almost 50 years before Rolando), the insula, the red nucleus and the substantia nigra. The mammillothalamic fasciculus («bundle of Vicq-d'Azyr¼) are named after him; it was he who called the relief elements of the cerebral cortex «gyri¼. He carefully studied and described the internal structures of the brain, in particular, the corpus callosum, the fornix, which connects the hippocampus with the hypothalamus and the right hemisphere with the left, the anterior perforated substance, the gray matter inside the hemispheres (striatum), and communication pathways between the ventricles of the brain. Despite the fact that Vicq-d'Azyr lived a short life and did not have time to publish his anatomical works in the intended volume, he left a rich scientific heritage, and his discoveries were a significant impetus for the development of neuroanatomy.
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Neuroanatomía , Neuroanatomía/historia , Humanos , Historia del Siglo XVIII , Encéfalo/anatomía & histologíaRESUMEN
Surface-based cortical registration is an important topic in medical image analysis and facilitates many downstream applications. Current approaches for cortical registration are mainly driven by geometric features, such as sulcal depth and curvature, and often assume that registration of folding patterns leads to alignment of brain function. However, functional variability of anatomically corresponding areas across subjects has been widely reported, particularly in higher-order cognitive areas. In this work, we present JOSA, a novel cortical registration framework that jointly models the mismatch between geometry and function while simultaneously learning an unbiased population-specific atlas. Using a semi-supervised training strategy, JOSA achieves superior registration performance in both geometry and function to the state-of-the-art methods but without requiring functional data at inference. This learning framework can be extended to any auxiliary data to guide spherical registration that is available during training but is difficult or impossible to obtain during inference, such as parcellations, architectonic identity, transcriptomic information, and molecular profiles. By recognizing the mismatch between geometry and function, JOSA provides new insights into the future development of registration methods using joint analysis of brain structure and function.
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Imagen por Resonancia Magnética , Humanos , Imagen por Resonancia Magnética/métodos , Encéfalo/diagnóstico por imagen , Encéfalo/anatomía & histología , Algoritmos , Imagenología Tridimensional/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Atlas como AsuntoRESUMEN
Although the impact of occupation on cognitive skills has been extensively studied, there is limited research examining if genetically predicted cognitive score may influence occupation. We examined the association between Cognitive Polygenic Index (PGI) and occupation, including the role of brain measures. Participants were recruited for the Reference Ability Neural Network and the Cognitive Reserve studies. Occupational complexity ratings for Data, People, or Things came from the Dictionary of Occupational Titles. A previously-created Cognitive PGI and linear regression models were used for the analyses. Age, sex, education, and the first 20 genetic Principal Components (PCs) of the sample were covariates. Total cortical thickness and total gray matter volume were further covariates. We included 168 white-ethnicity participants, 20-80 years old. After initial adjustment, higher Cognitive PGI was associated with higher Data complexity (B=-0.526, SE = 0.227, Beta= -0.526 p = 0.022, R2 = 0.259) (lower score implies higher complexity). Associations for People or Things were not significant. After adding brain measures, association for Data remained significant (B=-0.496, SE: 0.245, Beta= -0.422, p = 0.045, R2 = 0.254). Similarly, for a further, fully-adjusted analysis including all the three occupational complexity measures (B=-0.568, SE = 0.237, Beta= -0.483, p = 0.018, R2 = 0.327). Cognitive genes were associated with occupational complexity over and above brain morphometry. Working with Data occupational complexity probably acquires higher cognitive status, which can be significantly genetically predetermined.
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Encéfalo , Cognición , Herencia Multifactorial , Ocupaciones , Humanos , Femenino , Masculino , Persona de Mediana Edad , Herencia Multifactorial/genética , Adulto , Anciano , Encéfalo/diagnóstico por imagen , Encéfalo/anatomía & histología , Anciano de 80 o más Años , Reserva Cognitiva , Adulto Joven , Imagen por Resonancia Magnética , Sustancia Gris/diagnóstico por imagenRESUMEN
A large range of sophisticated brain image analysis tools have been developed by the neuroscience community, greatly advancing the field of human brain mapping. Here we introduce the Computational Anatomy Toolbox (CAT)-a powerful suite of tools for brain morphometric analyses with an intuitive graphical user interface but also usable as a shell script. CAT is suitable for beginners, casual users, experts, and developers alike, providing a comprehensive set of analysis options, workflows, and integrated pipelines. The available analysis streams-illustrated on an example dataset-allow for voxel-based, surface-based, and region-based morphometric analyses. Notably, CAT incorporates multiple quality control options and covers the entire analysis workflow, including the preprocessing of cross-sectional and longitudinal data, statistical analysis, and the visualization of results. The overarching aim of this article is to provide a complete description and evaluation of CAT while offering a citable standard for the neuroscience community.
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Encéfalo , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Programas Informáticos , Imagen por Resonancia Magnética/métodos , Humanos , Encéfalo/diagnóstico por imagen , Encéfalo/anatomía & histología , Procesamiento de Imagen Asistido por Computador/métodos , Mapeo Encefálico/métodos , Biología Computacional/métodos , Neuroimagen/métodosRESUMEN
While brain size in primates and their relatives within Euarchontoglires is well-studied, less research has examined brain shape, or the allometric trajectories that underlie the relationship between size and shape. Defining these patterns is key to understanding evolutionary trends. 3D geometric morphometric analyses of endocranial shape were performed on 140 species of extant euarchontoglirans using digital cranial endocasts. Principal component analyses on Procrustes shape variables show a clear phylogenetic pattern in endocranial shape, supported by an ANOVA which identified significant differences in shape among several groups (e.g., Platyrrhini, Strepsirrhini, Scandentia, Rodentia, and Lagomorpha). ANOVAs of shape and size also indicate that allometry has a small but significant impact on endocranial shape across Euarchontoglires, with homogeneity of slopes tests finding significant differences in the scaling relationship between shape and size among these same groups. While most of these clades possess a distinct endocranial morphotype, the highly derived platyrrhines display the strongest relationship between size and shape. Rodents show the most diversity in endocranial shape, potentially attributed to their comparatively weak relationship between shape and size. These results suggest fundamental differences in how shape and size covary among Euarchontoglires, which may have facilitated the adaptive radiations that characterize members of this group.
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Evolución Biológica , Filogenia , Cráneo , Animales , Cráneo/anatomía & histología , Fósiles/anatomía & histología , Análisis de Componente Principal , Encéfalo/anatomía & histología , Primates/anatomía & histologíaRESUMEN
Streamline tractography locally traces peak directions extracted from fiber orientation distribution (FOD) functions, lacking global information about the trend of the whole fiber bundle. Therefore, it is prone to producing erroneous tracks while missing true positive connections. In this work, we propose a new bundle-specific tractography (BST) method based on a bundle-specific tractogram distribution (BTD) function, which directly reconstructs the fiber trajectory from the start region to the termination region by incorporating the global information in the fiber bundle mask. A unified framework for any higher-order streamline differential equation is presented to describe the fiber bundles with disjoint streamlines defined based on the diffusion vectorial field. At the global level, the tractography process is simplified as the estimation of BTD coefficients by minimizing the energy optimization model, and is used to characterize the relations between BTD and diffusion tensor vector under the prior guidance by introducing the tractogram bundle information to provide anatomic priors. Experiments are performed on simulated Hough, Sine, Circle data, ISMRM 2015 Tractography Challenge data, FiberCup data, and in vivo data from the Human Connectome Project (HCP) for qualitative and quantitative evaluation. Results demonstrate that our approach reconstructs complex fiber geometry more accurately. BTD reduces the error deviation and accumulation at the local level and shows better results in reconstructing long-range, twisting, and large fanning tracts.
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Encéfalo , Conectoma , Imagen de Difusión Tensora , Humanos , Imagen de Difusión Tensora/métodos , Conectoma/métodos , Encéfalo/diagnóstico por imagen , Encéfalo/anatomía & histología , Procesamiento de Imagen Asistido por Computador/métodos , Algoritmos , Vías Nerviosas/anatomía & histología , Vías Nerviosas/diagnóstico por imagen , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/anatomía & histologíaRESUMEN
Domestication has long been considered the most powerful evolutionary engine behind dramatic reductions in brain size in several taxa, and the dog (Canis familiaris) is considered as a typical example that shows a substantial decrease in brain size relative to its ancestor, the grey wolf (Canis lupus). However, to make the case for exceptional evolution of reduced brain size under domestication requires an interspecific approach in a phylogenetic context that can quantify the extent by which domestication reduces brain size in comparison to closely related non-domesticated species responding to different selection factors in the wild. Here, we used a phylogenetic method to identify evolutionary singularities to test if the domesticated dog stands out in terms of relative brain size from other species of canids. We found that the dog does not present unambiguous signature of evolutionary singularity with regard to its small brain size, as the results were sensitive to the considerations about the ancestral trait values upon domestication. However, we obtained strong evidence for the hibernating common raccoon dog (Nyctereutes procyonoides) being an evolutionary outlier for its brain size. Therefore, domestication is not necessarily an exceptional case concerning evolutionary reductions in brain size in an interspecific perspective.
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Evolución Biológica , Encéfalo , Canidae , Domesticación , Filogenia , Animales , Encéfalo/anatomía & histología , Perros/anatomía & histología , Tamaño de los Órganos , Canidae/anatomía & histología , Lobos/anatomía & histología , Especificidad de la Especie , Perros Mapache/anatomía & histologíaRESUMEN
BACKGROUND: Stereotaxic surgery is a cornerstone in brain research for the precise positioning of electrodes and probes, but its application is limited to species with available brain atlases and tailored stereotaxic frames. Addressing this limitation, we introduce an alternative technique for small animal brain surgery that requires neither an aligned brain atlas nor a stereotaxic frame. NEW METHOD: The new method requires an ex-vivo high-contrast MRI brain scan of one specimen and access to a micro-CT scanner. The process involves attaching miniature markers to the skull, followed by CT scanning of the head. Subsequently, MRI and CT images are co-registered using standard image processing software and the targets for brain recordings are marked in the MRI image. During surgery, the animal's head is stabilized in any convenient orientation, and the probe's 3D position and angle are tracked using a multi-camera system. We have developed a software that utilizes the on-skull markers as fiducial points to align the CT/MRI 3D model with the surgical positioning system, and in turn instructs the surgeon how to move the probe to reach the targets within the brain. RESULTS: Our technique allows the execution of insertion tracks connecting two points in the brain. We successfully applied this method for neuropixels probe positioning in owls, quails, and mice, demonstrating its versatility. COMPARISON WITH EXISTING METHODS: We present an alternative to traditional stereotaxic brain surgeries that does not require established stereotaxic tools. Thus, this method is especially of advantage for research in non-standard and novel animal models.
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Encéfalo , Imagen por Resonancia Magnética , Técnicas Estereotáxicas , Animales , Técnicas Estereotáxicas/instrumentación , Encéfalo/diagnóstico por imagen , Encéfalo/cirugía , Encéfalo/anatomía & histología , Imagen por Resonancia Magnética/métodos , Microtomografía por Rayos X/métodos , Atlas como Asunto , Programas Informáticos , Ratones , Imagenología Tridimensional/métodos , Procedimientos Neuroquirúrgicos/métodosRESUMEN
Modern birds possess highly encephalized brains that evolved from non-avian dinosaurs. Evolutionary shifts in developmental timing, namely juvenilization of adult phenotypes, have been proposed as a driver of head evolution along the dinosaur-bird transition, including brain morphology. Testing this hypothesis requires a sufficient developmental sampling of brain morphology in non-avian dinosaurs. In this study, we harness brain endocasts of a postnatal growth series of the ornithischian dinosaur Psittacosaurus and several other immature and mature non-avian dinosaurs to investigate how evolutionary changes to brain development are implicated in the origin of the avian brain. Using three-dimensional characterization of neuroanatomical shape across archosaurian reptiles, we demonstrate that (i) the brain of non-avian dinosaurs underwent a distinct developmental trajectory compared to alligators and crown birds; (ii) ornithischian and non-avialan theropod dinosaurs shared a similar developmental trajectory, suggesting that their derived trajectory evolved in their common ancestor; and (iii) the evolutionary shift in developmental trajectories is partly consistent with paedomorphosis underlying overall brain shape evolution along the dinosaur-bird transition; however, the heterochronic signal is not uniform across time and neuroanatomical region suggesting a highly mosaic acquisition of the avian brain form.
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Evolución Biológica , Aves , Encéfalo , Dinosaurios , Fósiles , Cráneo , Animales , Dinosaurios/anatomía & histología , Dinosaurios/crecimiento & desarrollo , Encéfalo/anatomía & histología , Encéfalo/crecimiento & desarrollo , Aves/anatomía & histología , Aves/crecimiento & desarrollo , Cráneo/anatomía & histología , Cráneo/crecimiento & desarrollo , Filogenia , Caimanes y Cocodrilos/anatomía & histología , Caimanes y Cocodrilos/crecimiento & desarrolloRESUMEN
Structural neuroimaging data have been used to compute an estimate of the biological age of the brain (brain-age) which has been associated with other biologically and behaviorally meaningful measures of brain development and aging. The ongoing research interest in brain-age has highlighted the need for robust and publicly available brain-age models pre-trained on data from large samples of healthy individuals. To address this need we have previously released a developmental brain-age model. Here we expand this work to develop, empirically validate, and disseminate a pre-trained brain-age model to cover most of the human lifespan. To achieve this, we selected the best-performing model after systematically examining the impact of seven site harmonization strategies, age range, and sample size on brain-age prediction in a discovery sample of brain morphometric measures from 35,683 healthy individuals (age range: 5-90 years; 53.59% female). The pre-trained models were tested for cross-dataset generalizability in an independent sample comprising 2101 healthy individuals (age range: 8-80 years; 55.35% female) and for longitudinal consistency in a further sample comprising 377 healthy individuals (age range: 9-25 years; 49.87% female). This empirical examination yielded the following findings: (1) the accuracy of age prediction from morphometry data was higher when no site harmonization was applied; (2) dividing the discovery sample into two age-bins (5-40 and 40-90 years) provided a better balance between model accuracy and explained age variance than other alternatives; (3) model accuracy for brain-age prediction plateaued at a sample size exceeding 1600 participants. These findings have been incorporated into CentileBrain (https://centilebrain.org/#/brainAGE2), an open-science, web-based platform for individualized neuroimaging metrics.
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Envejecimiento , Encéfalo , Imagen por Resonancia Magnética , Humanos , Adolescente , Femenino , Anciano , Adulto , Niño , Adulto Joven , Masculino , Encéfalo/diagnóstico por imagen , Encéfalo/anatomía & histología , Encéfalo/crecimiento & desarrollo , Anciano de 80 o más Años , Preescolar , Persona de Mediana Edad , Envejecimiento/fisiología , Imagen por Resonancia Magnética/métodos , Neuroimagen/métodos , Neuroimagen/normas , Tamaño de la MuestraRESUMEN
Behavioral differences between men and women have been studied extensively, as have differences in brain anatomy. However, most studies have focused on differences in gray matter, while white matter has been much less studied. We conducted a comprehensive study of 77 deep white matter tracts to analyze their volumetric and microstructural variability between men and women in the full Human Connectome Project (HCP) cohort of 1065 healthy individuals aged 22-35 years. We found a significant difference in total brain volume between men and women (+ 12.6% in men), consistent with the literature. 16 tracts showed significant volumetric differences between men and women, one of which stood out due to a larger effect size: the corpus callosum genu, which was larger in women (+ 7.3% in women, p = 5.76 × 10-19). In addition, we found several differences in microstructural parameters between men and women, both using standard Diffusion Tensor Imaging (DTI) parameters and more complex microstructural parameters from the Neurite Orientation Dispersion and Density Imaging (NODDI) model, with the tracts showing the greatest differences belonging to motor (cortico-spinal tracts, cortico-cerebellar tracts) or limbic (cingulum, fornix, thalamo-temporal radiations) systems. These microstructural differences may be related to known behavioral differences between the sexes in timed motor performance, aggressiveness/impulsivity, and social cognition.
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Encéfalo , Conectoma , Imagen de Difusión Tensora , Caracteres Sexuales , Sustancia Blanca , Humanos , Sustancia Blanca/anatomía & histología , Sustancia Blanca/diagnóstico por imagen , Masculino , Femenino , Adulto , Adulto Joven , Encéfalo/anatomía & histología , Encéfalo/diagnóstico por imagen , Estudios de Cohortes , Vías Nerviosas/anatomía & histología , Vías Nerviosas/diagnóstico por imagenRESUMEN
Brain development is a highly complex process regulated by numerous genes at the molecular and cellular levels. Brain tissue exhibits serial microstructural changes during the development process. High-resolution diffusion magnetic resonance imaging (dMRI) affords a unique opportunity to probe these changes in the developing brain non-destructively. In this study, we acquired multi-shell dMRI datasets at 32 µm isotropic resolution to investigate the tissue microstructure alterations, which we believe to be the highest spatial resolution dMRI datasets obtained for postnatal mouse brains. We adapted the Allen Developing Mouse Brain Atlas (ADMBA) to integrate quantitative MRI metrics and spatial transcriptomics. Diffusion tensor imaging (DTI), diffusion kurtosis imaging (DKI), and neurite orientation dispersion and density imaging (NODDI) metrics were used to quantify brain development at different postnatal days. We demonstrated that the differential evolutions of fiber orientation distributions contribute to the distinct development patterns in white matter (WM) and gray matter (GM). Furthermore, the genes enriched in the nervous system that regulate brain structure and function were expressed in spatial correlation with age-matched dMRI. This study is the first one providing high-resolution dMRI, including DTI, DKI, and NODDI models, to trace mouse brain microstructural changes in WM and GM during postnatal development. This study also highlighted the genotype-phenotype correlation of spatial transcriptomics and dMRI, which may improve our understanding of brain microstructure changes at the molecular level.
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Encéfalo , Imagen de Difusión por Resonancia Magnética , Transcriptoma , Animales , Ratones , Encéfalo/crecimiento & desarrollo , Encéfalo/diagnóstico por imagen , Encéfalo/anatomía & histología , Imagen de Difusión por Resonancia Magnética/métodos , Imagen de Difusión Tensora/métodos , Sustancia Blanca/crecimiento & desarrollo , Sustancia Blanca/diagnóstico por imagen , Sustancia Gris/crecimiento & desarrollo , Sustancia Gris/diagnóstico por imagen , Sustancia Gris/anatomía & histología , Ratones Endogámicos C57BL , Masculino , FemeninoRESUMEN
OBJECTIVES: To investigate potential effects of heading on the neurocognitive performance and the white matter (WM) of the brain in high-level adult male football players. DESIGN: Prospective longitudinal. METHODS: Football players engaging in the highest football leagues in Germany were included. Neurocognitive performance tests and diffusion tensor imaging (DTI) were executed before and after the observation period. Video recordings of each training session and each match play during the observation period were analyzed regarding heading exposure and characteristics. Four DTI measures from tract-based spatial statistics (fractional anisotropy, mean, axial, and radial diffusivity) were investigated. Associations between heading variables and DTI and neurocognitive parameters were tested subsequently. RESULTS: 8052 headers of 22 players (19.9⯱â¯2.7â¯years) were documented in a median of 16.9â¯months. The individual total heading number ranged from 57 to 943 (median: 320.5). Header characteristics differed between training sessions and matches. Neurocognitive performance (nâ¯=â¯22) and DTI measures (nâ¯=â¯14) showed no significant differences from pre- to post-test. After correction for multiple comparisons, no significant correlations with the total heading number were found. However, the change in fractional anisotropy in the splenium of the corpus callosum correlated significantly with the total amount of long-distance headers (Pearson's râ¯=â¯-0.884; pâ¯<â¯0.0001). CONCLUSIONS: Over the median observation period of 16.9â¯months, DTI measures and neurocognitive performance remained unchanged. To elucidate the meaning of the association between individual change in fractional anisotropy and long-distance headers further investigations with larger samples, longer observations, and various cohorts regarding age and level of play are required.
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Imagen de Difusión Tensora , Fútbol , Sustancia Blanca , Humanos , Masculino , Estudios Prospectivos , Adulto Joven , Fútbol/fisiología , Estudios Longitudinales , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/anatomía & histología , Sustancia Blanca/fisiología , Adolescente , Cognición/fisiología , Encéfalo/diagnóstico por imagen , Encéfalo/fisiología , Encéfalo/anatomía & histología , Alemania , Pruebas Neuropsicológicas , Adulto , Anisotropía , Cuerpo Calloso/diagnóstico por imagen , Cuerpo Calloso/anatomía & histología , Cuerpo Calloso/fisiología , Fútbol Americano/fisiologíaRESUMEN
Examining underlying neurostructural correlates of specific cognitive abilities is practically and theoretically complicated by the existence of the positive manifold (all cognitive tests positively correlate): if a brain structure is associated with a cognitive task, how much of this is uniquely related to the cognitive domain, and how much is due to covariance with all other tests across domains (captured by general cognitive functioning, also known as general intelligence, or 'g')? We quantitatively address this question by examining associations between brain structural and diffusion MRI measures (global tissue volumes, white matter hyperintensities, global white matter diffusion fractional anisotropy and mean diffusivity, and FreeSurfer processed vertex-wise cortical volumes, smoothed at 20mm fwhm) with g and cognitive domains (processing speed, crystallised ability, memory, visuospatial ability). The cognitive domains were modelled using confirmatory factor analysis to derive both hierarchical and bifactor solutions using 13 cognitive tests in 697 participants from the Lothian Birth Cohort 1936 study (mean age 72.5 years; SD = .7). Associations between the extracted cognitive factor scores for each domain and g were computed for each brain measure covarying for age, sex and intracranial volume, and corrected for false discovery rate. There were a range of significant associations between cognitive domains and global MRI brain structural measures (r range .008 to .269, p < .05). Regions implicated by vertex-wise regional cortical volume included a widespread number of medial and lateral areas of the frontal, temporal and parietal lobes. However, at both global and regional level, much of the domain-MRI associations were shared (statistically accounted for by g). Removing g-related variance from cognitive domains attenuated association magnitudes with global brain MRI measures by 27.9-59.7% (M = 46.2%), with only processing speed retaining all significant associations. At the regional cortical level, g appeared to account for the majority (range 22.1-88.4%; M = 52.8% across cognitive domains) of regional domain-specific associations. Crystallised and memory domains had almost no unique cortical correlates, whereas processing speed and visuospatial ability retained limited cortical volumetric associations. The greatest spatial overlaps across cognitive domains (as denoted by g) were present in the medial and lateral temporal, lateral parietal and lateral frontal areas.
Asunto(s)
Encéfalo , Cognición , Inteligencia , Humanos , Femenino , Inteligencia/fisiología , Masculino , Anciano , Encéfalo/diagnóstico por imagen , Encéfalo/anatomía & histología , Cognición/fisiología , Pruebas Neuropsicológicas , Cohorte de Nacimiento , Sustancia Blanca/diagnóstico por imagen , Imagen de Difusión por Resonancia Magnética/métodos , Imagen por Resonancia Magnética/métodos , Persona de Mediana Edad , Estudios de CohortesRESUMEN
Alzheimer's disease is the leading cause of dementia worldwide, but the cellular pathways that underlie its pathological progression across brain regions remain poorly understood1-3. Here we report a single-cell transcriptomic atlas of six different brain regions in the aged human brain, covering 1.3 million cells from 283 post-mortem human brain samples across 48 individuals with and without Alzheimer's disease. We identify 76 cell types, including region-specific subtypes of astrocytes and excitatory neurons and an inhibitory interneuron population unique to the thalamus and distinct from canonical inhibitory subclasses. We identify vulnerable populations of excitatory and inhibitory neurons that are depleted in specific brain regions in Alzheimer's disease, and provide evidence that the Reelin signalling pathway is involved in modulating the vulnerability of these neurons. We develop a scalable method for discovering gene modules, which we use to identify cell-type-specific and region-specific modules that are altered in Alzheimer's disease and to annotate transcriptomic differences associated with diverse pathological variables. We identify an astrocyte program that is associated with cognitive resilience to Alzheimer's disease pathology, tying choline metabolism and polyamine biosynthesis in astrocytes to preserved cognitive function late in life. Together, our study develops a regional atlas of the ageing human brain and provides insights into cellular vulnerability, response and resilience to Alzheimer's disease pathology.
Asunto(s)
Enfermedad de Alzheimer , Encéfalo , Perfilación de la Expresión Génica , Análisis de la Célula Individual , Anciano de 80 o más Años , Animales , Femenino , Humanos , Masculino , Ratones , Envejecimiento/metabolismo , Envejecimiento/patología , Enfermedad de Alzheimer/patología , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/metabolismo , Astrocitos/clasificación , Astrocitos/citología , Astrocitos/metabolismo , Astrocitos/patología , Autopsia , Encéfalo/anatomía & histología , Encéfalo/citología , Encéfalo/metabolismo , Encéfalo/patología , Estudios de Casos y Controles , Colina/metabolismo , Cognición/fisiología , Redes Reguladoras de Genes , Interneuronas/clasificación , Interneuronas/citología , Interneuronas/metabolismo , Interneuronas/patología , Proteínas del Tejido Nervioso/metabolismo , Proteínas del Tejido Nervioso/genética , Inhibición Neural , Neuronas/clasificación , Neuronas/citología , Neuronas/metabolismo , Neuronas/patología , Poliaminas/metabolismo , Proteína Reelina , Transducción de Señal , Tálamo/citología , Tálamo/metabolismo , Tálamo/patología , TranscriptomaRESUMEN
Diffusion-weighted Magnetic Resonance Imaging (dMRI) is increasingly used to study the fetal brain in utero. An important computation enabled by dMRI is streamline tractography, which has unique applications such as tract-specific analysis of the brain white matter and structural connectivity assessment. However, due to the low fetal dMRI data quality and the challenging nature of tractography, existing methods tend to produce highly inaccurate results. They generate many false streamlines while failing to reconstruct the streamlines that constitute the major white matter tracts. In this paper, we advocate for anatomically constrained tractography based on an accurate segmentation of the fetal brain tissue directly in the dMRI space. We develop a deep learning method to compute the segmentation automatically. Experiments on independent test data show that this method can accurately segment the fetal brain tissue and drastically improve the tractography results. It enables the reconstruction of highly curved tracts such as optic radiations. Importantly, our method infers the tissue segmentation and streamline propagation direction from a diffusion tensor fit to the dMRI data, making it applicable to routine fetal dMRI scans. The proposed method can facilitate the study of fetal brain white matter tracts with dMRI.