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1.
Basic Res Cardiol ; 2024 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-39120717

RESUMO

In the human organism, all functions are regulated and, therefore, require a feedback mechanism. This control involves a perception of the spatial tensile state of cardiac tissues. The presence and distribution of respective proprioceptive corpuscles have not been considered so far. Therefore, a comprehensive study of the entire human fibrous pericardium was conducted to describe the presence of proprioceptors, their density, and distribution patterns. Eight human pericardial specimens gained from our body donation program were used to create a three-dimensional map of proprioceptors in the pericardium based on their histological and immunohistochemical identification. The 3D map was generated as a volume-rendered 3D model based on magnetic resonance imaging of the pericardium, to which all identified receptors were mapped. To discover a systematic pattern in receptor distribution, statistical cluster analysis was conducted using the Scikit-learn library in Python. Ruffini-like corpuscles (RLCs) were found in all pericardia and assigned to three histological receptor localizations depending on the fibrous pericardium's layering, with no other corpuscular proprioceptors identified. Cluster analysis revealed that RLCs exhibit a specific topographical arrangement. The highest receptor concentrations occur at the ventricular bulges, where their size reaches its maximum in terms of diameter, and at the perivascular pericardial turn-up. The findings suggest that the pericardium is subject to proprioceptive control. RLCs record lateral shearing between the pericardial sublayers, and their distribution pattern enables the detection of distinct dilatation of the heart. Therefore, the pericardium might have an undiscovered function as a sensor with the RLCs as its anatomical correlate.

2.
Brain ; 146(8): 3319-3330, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-36795496

RESUMO

Structural grey and white matter changes precede the manifestation of clinical signs of Huntington's disease by many years. Conversion to clinically manifest disease therefore likely reflects not merely atrophy but a more widespread breakdown of brain function. Here, we investigated the structure-function relationship close to and after clinical onset, in important regional brain hubs, particularly caudate nucleus and putamen, which are central to maintaining normal motor behaviour. In two independent cohorts of patients with premanifest Huntington's disease close to onset and very early manifest Huntington's disease (total n = 84; n = 88 matched controls), we used structural and resting state functional MRI. We show that measures of functional activity and local synchronicity within cortical and subcortical regions remain normal in the premanifest Huntington's disease phase despite clear evidence of brain atrophy. In manifest Huntington's disease, homeostasis of synchronicity was disrupted in subcortical hub regions such as caudate nucleus and putamen, but also in cortical hub regions, for instance the parietal lobe. Cross-modal spatial correlations of functional MRI data with receptor/neurotransmitter distribution maps showed that Huntington's disease-specific alterations co-localize with dopamine receptors D1 and D2, as well as dopamine and serotonin transporters. Caudate nucleus synchronicity significantly improved models predicting the severity of the motor phenotype or predicting the classification into premanifest Huntington's disease or motor manifest Huntington's disease. Our data suggest that the functional integrity of the dopamine receptor-rich caudate nucleus is key to maintaining network function. The loss of caudate nucleus functional integrity affects network function to a degree that causes a clinical phenotype. These insights into what happens in Huntington's disease could serve as a model for what might be a more general relationship between brain structure and function in neurodegenerative diseases in which other brain regions are vulnerable.


Assuntos
Doença de Huntington , Humanos , Doença de Huntington/metabolismo , Núcleo Caudado/diagnóstico por imagem , Núcleo Caudado/metabolismo , Dopamina , Encéfalo/patologia , Atrofia/patologia , Imageamento por Ressonância Magnética , Fenótipo
3.
Neuroimage ; 283: 120403, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37865260

RESUMO

The mechanisms of cognitive decline and its variability during healthy aging are not fully understood, but have been associated with reorganization of white matter tracts and functional brain networks. Here, we built a brain network modeling framework to infer the causal link between structural connectivity and functional architecture and the consequent cognitive decline in aging. By applying in-silico interhemispheric degradation of structural connectivity, we reproduced the process of functional dedifferentiation during aging. Thereby, we found the global modulation of brain dynamics by structural connectivity to increase with age, which was steeper in older adults with poor cognitive performance. We validated our causal hypothesis via a deep-learning Bayesian approach. Our results might be the first mechanistic demonstration of dedifferentiation during aging leading to cognitive decline.


Assuntos
Envelhecimento Saudável , Substância Branca , Humanos , Idoso , Teorema de Bayes , Encéfalo , Envelhecimento/psicologia , Imageamento por Ressonância Magnética
4.
J Neurooncol ; 161(3): 643-654, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36750534

RESUMO

PURPOSE: In glioma patients, tumor development and multimodality therapy are associated with changes in health-related quality of life (HRQoL). It is largely unknown how different types and locations of tumor- and treatment-related brain lesions, as well as their relationship to white matter tracts and functional brain networks, affect HRQoL. METHODS: In 121 patients with pretreated gliomas of WHO CNS grades 3 or 4, structural MRI, O-(2-[18F]fluoroethyl)-L-tyrosine (FET) PET, resting-state functional MRI (rs-fMRI) and self-reported HRQoL questionnaires (EORTC QLQ-C30/BN20) were obtained. Resection cavities, T1-enhancing lesions, T2/FLAIR hyperintensities, and lesions with pathologically increased FET uptake were delineated. Effects of tumor lateralization, involvement of white matter tracts or resting-state network nodes by different types of lesions and within-network rs-fMRI connectivity were analyzed in terms of their interaction with HRQoL scores. RESULTS: Right hemisphere gliomas were associated with significantly less favorable outcomes in physical, role, emotional and social functioning, compared with left-sided tumors. Most functional HRQoL scores correlated significantly with right-sided white-matter tracts involvement by T2/FLAIR hyperintensities and with loss of within-network functional connectivity of right-sided nodes. Tumors of the left hemisphere caused significantly more communication deficits. CONCLUSION: In pretreated high-grade gliomas, right hemisphere lesions are associated with reduced HRQoL scores in most functional domains except communication ability, compared to tumors of the left hemisphere. These relationships are mainly observed for T2/FLAIR lesions involving structural and functional networks in the right hemisphere. The data suggest that sparing the right hemisphere from treatment-related tissue damage may improve HRQoL in glioma patients.


Assuntos
Neoplasias Encefálicas , Glioma , Humanos , Neoplasias Encefálicas/patologia , Imageamento por Ressonância Magnética , Qualidade de Vida , Tomografia por Emissão de Pósitrons , Glioma/patologia , Encéfalo/patologia , Organização Mundial da Saúde
5.
Eur J Neurol ; 30(5): 1174-1190, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36702775

RESUMO

BACKGROUND: White matter hyperintensities of presumed vascular origin (WMH) are frequent in cerebral magnetic resonance imaging of older people. They are promoted by vascular risk factors, especially hypertension, and are associated with cognitive deficits at the group level. It has been suggested that not only the severity, but also the location, of lesions might critically influence cognitive deficits and represent different pathologies. METHODS: In 560 participants (65.2 ± 7.5 years, 51.4% males) of the population-based 1000BRAINS study, we analyzed the association of regional WMH using Fazekas scoring separately for cerebral lobes, with hypertension and cognition. RESULTS: WMH most often affected the frontal lobe (83.7% score >0), followed by the parietal (75.8%), temporal (32.7%), and occipital lobe (7.3%). Higher Fazekas scores in the frontal, parietal, and temporal lobe were associated with higher blood pressure and antihypertensive treatment in unadjusted ordinal regression models and in models adjusted for age, sex, and vascular risk factors (e.g., age- and sex-adjusted odds ratio = 1.14, 95% confidence interval = 1.03-1.25 for the association of frontal lobe WMH Fazekas score with systolic blood pressure [SBP] [per 10 mm Hg]; 1.13 [1.02-1.23] for the association of parietal lobe score with SBP; 1.72 [1.19-2.48] for the association of temporal lobe score with antihypertensive medications). In linear regressions, higher frontal lobe scores were associated with lower performance in executive function and non-verbal memory, and higher parietal lobe scores were associated with lower performance in executive function, verbal-, and non-verbal memory. CONCLUSIONS: Hypertension promotes WMH in the frontal, parietal, and temporal lobe. WMH in the frontal and parietal lobe are associated with reduced executive function and memory.


Assuntos
Transtornos Cognitivos , Hipertensão , Substância Branca , Masculino , Humanos , Idoso , Feminino , Substância Branca/diagnóstico por imagem , Substância Branca/patologia , Anti-Hipertensivos , Cognição/fisiologia , Transtornos Cognitivos/patologia , Hipertensão/complicações , Hipertensão/diagnóstico por imagem , Imageamento por Ressonância Magnética
6.
Neuroimage ; 264: 119738, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36351560

RESUMO

Being on the bleeding edge of research requires the use of new and regularly updated software. The result is the occasional and inevitable occurrence of bugs. In the following work we present a case study where a feature request introduced a bug in a neuroimaging software package, which had consequences for the quality of results in a published article. We discuss the process of diagnosis, rectification and analysis replication.

7.
Neuroimage ; 260: 119453, 2022 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-35809885

RESUMO

The human insular cortex supports multifunctional integration including interoceptive, sensorimotor, cognitive and social-emotional processing. Different concepts of the underlying microstructure have been proposed over more than a century. However, a 3D map of the cytoarchitectonic segregation of the insula in standard reference space, that could be directly linked to neuroimaging experiments addressing different cognitive tasks, is not yet available. Here we analyzed the middle posterior and dorsal anterior insula with image analysis and a statistical mapping procedure to delineate cytoarchitectonic areas in ten human postmortem brains. 3D-probability maps of seven new areas with granular (Ig3, posterior), agranular (Ia1, posterior) and dysgranular (Id2-Id6, middle to dorsal anterior) cytoarchitecture have been calculated to represent the new areas in stereotaxic space. A hierarchical cluster analysis based on cytoarchitecture resulted in three distinct clusters in the superior posterior, inferior posterior and dorsal anterior insula, providing deeper insights into the structural organization of the insula. The maps are openly available to support future studies addressing relations between structure and function in the human insula.


Assuntos
Córtex Cerebral , Processamento de Imagem Assistida por Computador , Mapeamento Encefálico/métodos , Córtex Cerebral/diagnóstico por imagem , Humanos , Imageamento Tridimensional , Neuroimagem , Probabilidade
8.
Hum Brain Mapp ; 43(18): 5543-5561, 2022 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-35916531

RESUMO

In the normal aging process, the functional connectome restructures and shows a shift from more segregated to more integrated brain networks, which manifests itself in highly different cognitive performances in older adults. Underpinnings of this reorganization are not fully understood, but may be related to age-related differences in structural connectivity, the underlying scaffold for information exchange between regions. The structure-function relationship might be a promising factor to understand the neurobiological sources of interindividual cognitive variability, but remain unclear in older adults. Here, we used diffusion weighted and resting-state functional magnetic resonance imaging as well as cognitive performance data of 573 older subjects from the 1000BRAINS cohort (55-85 years, 287 males) and performed a partial least square regression on 400 regional functional and structural connectivity (FC and SC, respectively) estimates comprising seven resting-state networks. Our aim was to identify FC and SC patterns that are, together with cognitive performance, characteristic of the older adults aging process. Results revealed three different aging profiles prevalent in older adults. FC was found to behave differently depending on the severity of age-related SC deteriorations. A functionally highly interconnected system is associated with a structural connectome that shows only minor age-related decreases. Because this connectivity profile was associated with the most severe age-related cognitive decline, a more interconnected FC system in older adults points to a process of dedifferentiation. Thus, functional network integration appears to increase primarily when SC begins to decline, but this does not appear to mitigate the decline in cognitive performance.


Assuntos
Encéfalo , Conectoma , Masculino , Humanos , Idoso , Encéfalo/diagnóstico por imagem , Conectoma/métodos , Imageamento por Ressonância Magnética/métodos , Envelhecimento/patologia , Rede Nervosa/diagnóstico por imagem
9.
Hum Brain Mapp ; 43(1): 300-328, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-33615640

RESUMO

The Enhancing NeuroImaging Genetics through Meta-Analysis copy number variant (ENIGMA-CNV) and 22q11.2 Deletion Syndrome Working Groups (22q-ENIGMA WGs) were created to gain insight into the involvement of genetic factors in human brain development and related cognitive, psychiatric and behavioral manifestations. To that end, the ENIGMA-CNV WG has collated CNV and magnetic resonance imaging (MRI) data from ~49,000 individuals across 38 global research sites, yielding one of the largest studies to date on the effects of CNVs on brain structures in the general population. The 22q-ENIGMA WG includes 12 international research centers that assessed over 533 individuals with a confirmed 22q11.2 deletion syndrome, 40 with 22q11.2 duplications, and 333 typically developing controls, creating the largest-ever 22q11.2 CNV neuroimaging data set. In this review, we outline the ENIGMA infrastructure and procedures for multi-site analysis of CNVs and MRI data. So far, ENIGMA has identified effects of the 22q11.2, 16p11.2 distal, 15q11.2, and 1q21.1 distal CNVs on subcortical and cortical brain structures. Each CNV is associated with differences in cognitive, neurodevelopmental and neuropsychiatric traits, with characteristic patterns of brain structural abnormalities. Evidence of gene-dosage effects on distinct brain regions also emerged, providing further insight into genotype-phenotype relationships. Taken together, these results offer a more comprehensive picture of molecular mechanisms involved in typical and atypical brain development. This "genotype-first" approach also contributes to our understanding of the etiopathogenesis of brain disorders. Finally, we outline future directions to better understand effects of CNVs on brain structure and behavior.


Assuntos
Encéfalo , Variações do Número de Cópias de DNA , Imageamento por Ressonância Magnética , Transtornos Mentais , Transtornos do Neurodesenvolvimento , Neuroimagem , Encéfalo/diagnóstico por imagem , Encéfalo/crescimento & desenvolvimento , Encéfalo/patologia , Humanos , Transtornos Mentais/diagnóstico por imagem , Transtornos Mentais/genética , Transtornos Mentais/patologia , Estudos Multicêntricos como Assunto , Transtornos do Neurodesenvolvimento/diagnóstico por imagem , Transtornos do Neurodesenvolvimento/genética , Transtornos do Neurodesenvolvimento/patologia
10.
Neuroimage ; 231: 117779, 2021 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-33548459

RESUMO

The mammalian brain cortex is highly folded, with several developmental disorders affecting folding. On the extremes, lissencephaly, a lack of folds in humans, and polymicrogyria, an overly folded brain, can lead to severe mental retardation, short life expectancy, epileptic seizures, and tetraplegia. Not only a specific degree of folding, but also stereotyped patterns, are required for normal brain function. A quantitative model on how and why these folds appear during the development of the brain is the first step in understanding the cause of these conditions. In recent years, there have been various attempts to understand and model the mechanisms of brain folding. Previous works have shown that mechanical instabilities play a crucial role in the formation of brain folds, and that the geometry of the fetal brain is one of the main factors in dictating its folding characteristics. However, modeling higher-order folding, one of the main characteristics of the highly gyrencephalic brain, has not been fully tackled. The simulations presented in this work are used to study the effects of thickness inhomogeneity in the gyrogenesis of the mammalian brain in silico. Finite-element simulations of rectangular slabs are performed. These slabs are divided into two distinct regions, where the outer region mimicks the gray matter, and the inner region the underlying white matter. Differential growth is introduced by growing the top region tangentially, while keeping the underlying region untouched. The brain tissue is modeled as a neo-Hookean hyperelastic material. Simulations are performed with both homogeneous and inhomogeneous cortical thicknesses. Our results show that the homogeneous cortex folds into a single wavelength, as is common for bilayered materials, while the inhomogeneous cortex folds into more complex conformations. In the early stages of development of the inhomogeneous cortex, structures reminiscent of the deep sulci in the brain are obtained. As the cortex continues to develop, secondary undulations, which are shallower and more variable than the structures obtained in earlier gyrification stage emerge, reproducing well-known characteristics of higher-order folding in the mammalian, and particularly the human, brain.


Assuntos
Espessura Cortical do Cérebro , Córtex Cerebral/crescimento & desenvolvimento , Simulação por Computador , Modelos Anatômicos , Córtex Cerebral/diagnóstico por imagem , Humanos
11.
Neuroimage ; 235: 118006, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-33819611

RESUMO

A wide homology between human and macaque striatum is often assumed as in both the striatum is involved in cognition, emotion and executive functions. However, differences in functional and structural organization between human and macaque striatum may reveal evolutionary divergence and shed light on human vulnerability to neuropsychiatric diseases. For instance, dopaminergic dysfunction of the human striatum is considered to be a pathophysiological underpinning of different disorders, such as Parkinson's disease (PD) and schizophrenia (SCZ). Previous investigations have found a wide similarity in structural connectivity of the striatum between human and macaque, leaving the cross-species comparison of its functional organization unknown. In this study, resting-state functional connectivity (RSFC) derived striatal parcels were compared based on their homologous cortico-striatal connectivity. The goal here was to identify striatal parcels whose connectivity is human-specific compared to macaque parcels. Functional parcellation revealed that the human striatum was split into dorsal, dorsomedial, and rostral caudate and ventral, central, and caudal putamen, while the macaque striatum was divided into dorsal, and rostral caudate and rostral, and caudal putamen. Cross-species comparison indicated dissimilar cortico-striatal RSFC of the topographically similar dorsal caudate. We probed clinical relevance of the striatal clusters by examining differences in their cortico-striatal RSFC and gray matter (GM) volume between patients (with PD and SCZ) and healthy controls. We found abnormal RSFC not only between dorsal caudate, but also between rostral caudate, ventral, central and caudal putamen and widespread cortical regions for both PD and SCZ patients. Also, we observed significant structural atrophy in rostral caudate, ventral and central putamen for both PD and SCZ while atrophy in the dorsal caudate was specific to PD. Taken together, our cross-species comparative results revealed shared and human-specific RSFC of different striatal clusters reinforcing the complex organization and function of the striatum. In addition, we provided a testable hypothesis that abnormalities in a region with human-specific connectivity, i.e., dorsal caudate, might be associated with neuropsychiatric disorders.


Assuntos
Núcleo Caudado/fisiologia , Córtex Cerebral/fisiologia , Conectoma , Rede Nervosa/fisiologia , Doença de Parkinson , Putamen/fisiologia , Esquizofrenia , Adulto , Idoso , Animais , Núcleo Caudado/diagnóstico por imagem , Córtex Cerebral/diagnóstico por imagem , Conectoma/métodos , Conjuntos de Dados como Assunto , Feminino , Humanos , Macaca , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Rede Nervosa/diagnóstico por imagem , Doença de Parkinson/diagnóstico por imagem , Doença de Parkinson/patologia , Doença de Parkinson/fisiopatologia , Putamen/diagnóstico por imagem , Esquizofrenia/diagnóstico por imagem , Esquizofrenia/patologia , Esquizofrenia/fisiopatologia , Especificidade da Espécie , Adulto Jovem
12.
Mol Psychiatry ; 25(3): 692-695, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30705424

RESUMO

Prior to and following the publication of this article the authors noted that the complete list of authors was not included in the main article and was only present in Supplementary Table 1. The author list in the original article has now been updated to include all authors, and Supplementary Table 1 has been removed. All other supplementary files have now been updated accordingly. Furthermore, in Table 1 of this Article, the replication cohort for the row Close relative in data set, n (%) was incorrect. All values have now been corrected to 0(0%). The publishers would like to apologise for this error and the inconvenience it may have caused.

13.
Mol Psychiatry ; 25(3): 584-602, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-30283035

RESUMO

Carriers of large recurrent copy number variants (CNVs) have a higher risk of developing neurodevelopmental disorders. The 16p11.2 distal CNV predisposes carriers to e.g., autism spectrum disorder and schizophrenia. We compared subcortical brain volumes of 12 16p11.2 distal deletion and 12 duplication carriers to 6882 non-carriers from the large-scale brain Magnetic Resonance Imaging collaboration, ENIGMA-CNV. After stringent CNV calling procedures, and standardized FreeSurfer image analysis, we found negative dose-response associations with copy number on intracranial volume and on regional caudate, pallidum and putamen volumes (ß = -0.71 to -1.37; P < 0.0005). In an independent sample, consistent results were obtained, with significant effects in the pallidum (ß = -0.95, P = 0.0042). The two data sets combined showed significant negative dose-response for the accumbens, caudate, pallidum, putamen and ICV (P = 0.0032, 8.9 × 10-6, 1.7 × 10-9, 3.5 × 10-12 and 1.0 × 10-4, respectively). Full scale IQ was lower in both deletion and duplication carriers compared to non-carriers. This is the first brain MRI study of the impact of the 16p11.2 distal CNV, and we demonstrate a specific effect on subcortical brain structures, suggesting a neuropathological pattern underlying the neurodevelopmental syndromes.


Assuntos
Transtorno Autístico/genética , Gânglios da Base/patologia , Transtornos Cromossômicos/genética , Variações do Número de Cópias de DNA/genética , Deficiência Intelectual/genética , Adulto , Transtorno do Espectro Autista/genética , Encéfalo/patologia , Deleção Cromossômica , Duplicação Cromossômica , Cromossomos Humanos Par 16/genética , Bases de Dados Factuais , Feminino , Globo Pálido/patologia , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Transtornos do Neurodesenvolvimento/genética , Tamanho do Órgão/genética , Putamen/patologia , Esquizofrenia/genética
14.
Eur J Neurol ; 28(6): 1849-1858, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33686727

RESUMO

BACKGROUND AND PURPOSE: Cross-sectional studies showed an inverse association between serum 25-hydroxyvitamin D (25OHD) and white matter hyperintensities (WMHs) whereas the few longitudinal studies did not. The association between baseline 25OHD and WMHs at 10-year follow-up in the Heinz Nixdorf Recall Study plus 1000BRAINS was investigated. METHODS: Data of 505 participants (49% women, 56.2 ± 6.6 years) with 25OHD at baseline (2000-2003) and WMH volume and grade of WMHs using the Fazekas classification at 10-year follow-up were analysed. The association between deseasonalized 25OHD and the base-10 logarithm of WMH volume was evaluated by multiple linear regression, adjusted for age, sex, education, smoking, alcohol consumption, sports, diabetes mellitus, systolic blood pressure and total cholesterol. ß-estimators were transformed back (10ß ). Using multiple logistic regression, odds ratios (ORs) and 95% confidence intervals (95% CI) were calculated to evaluate the association between deseasonalized 25OHD and Fazekas grades (0, absence and 1, punctate foci vs. 2, beginning and 3, large confluence). RESULTS: Mean 25OHD was 17.0 ± 8.2 ng/ml, and mean deseasonalized 25OHD was 16.9 ± 7.5 ng/ml. Mean WMH volume was 16.6 ± 17.4 ml, range 1-132 ml. Most grade 2-3 WMHs were found to be periventricular (39% of the participants), parietal (32%) and frontal (31%) (temporal 6%, occipital 3%). The linear regression showed an inverse association between 25OHD and WMH volume. On average, a 25OHD increase of 1 ng/ml was associated with a reduced WMH volume by a factor of 0.99 (95% CI 0.98; 1.00) (fully adjusted). There was also some indication for an inverse association between 25OHD and extent of periventricular (OR 0.98 [95% CI 0.96; 1.01]), frontal (0.99 [0.97; 1.02]) and parietal (0.98 [0.95; 1.00]) WMHs according to the Fazekas classification. CONCLUSIONS: Lower 25OHD may be a risk factor for the occurrence of WMHs.


Assuntos
Leucoaraiose , Substância Branca , Estudos Transversais , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Vitamina D , Substância Branca/diagnóstico por imagem
15.
Brain ; 143(9): 2788-2802, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32851402

RESUMO

The hippocampus is a plastic region and highly susceptible to ageing and dementia. Previous studies explicitly imposed a priori models of hippocampus when investigating ageing and dementia-specific atrophy but led to inconsistent results. Consequently, the basic question of whether macrostructural changes follow a cytoarchitectonic or functional organization across the adult lifespan and in age-related neurodegenerative disease remained open. The aim of this cross-sectional study was to identify the spatial pattern of hippocampus differentiation based on structural covariance with a data-driven approach across structural MRI data of large cohorts (n = 2594). We examined the pattern of structural covariance of hippocampus voxels in young, middle-aged, elderly, mild cognitive impairment and dementia disease samples by applying a clustering algorithm revealing differentiation in structural covariance within the hippocampus. In all the healthy and in the mild cognitive impaired participants, the hippocampus was robustly divided into anterior, lateral and medial subregions reminiscent of cytoarchitectonic division. In contrast, in dementia patients, the pattern of subdivision was closer to known functional differentiation into an anterior, body and tail subregions. These results not only contribute to a better understanding of co-plasticity and co-atrophy in the hippocampus across the lifespan and in dementia, but also provide robust data-driven spatial representations (i.e. maps) for structural studies.


Assuntos
Bases de Dados Factuais/tendências , Demência/diagnóstico por imagem , Hipocampo/diagnóstico por imagem , Longevidade/fisiologia , Rede Nervosa/diagnóstico por imagem , Adulto , Idoso , Atrofia , Estudos de Coortes , Demência/patologia , Feminino , Hipocampo/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Rede Nervosa/patologia , Adulto Jovem
16.
Cereb Cortex ; 30(2): 801-811, 2020 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-31402375

RESUMO

Brain aging is highly variable and represents a challenge to delimit aging from disease processes. Moreover, genetic factors may influence both aging and disease. Here we focused on this issue and investigated effects of multiple genetic loci previously identified to be associated with late-onset Alzheimer's disease (AD) on brain structure of older adults from a population sample. We calculated a genetic risk score (GRS) using genome-wide significant single-nucleotide polymorphisms from genome-wide association studies of AD and tested its effect on cortical thickness (CT). We observed a common pattern of cortical thinning (right inferior frontal, left posterior temporal, medial occipital cortex). To identify CT changes by specific biological processes, we subdivided the GRS effect according to AD-associated pathways and performed follow-up analyses. The common pattern from the main analysis was further differentiated by pathway-specific effects yielding a more bilateral pattern. Further findings were located in the superior parietal and mid/anterior cingulate regions representing 2 unique pathway-specific patterns. All patterns, except the superior parietal pattern, were influenced by apolipoprotein E. Our step-wise approach revealed atrophy patterns that partially resembled imaging findings in early stages of AD. Our study provides evidence that genetic burden for AD contributes to structural brain variability in normal aging.


Assuntos
Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Encéfalo/patologia , Idoso , Doença de Alzheimer/diagnóstico por imagem , Atrofia/diagnóstico por imagem , Atrofia/patologia , Encéfalo/diagnóstico por imagem , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Masculino , Pessoa de Meia-Idade , Vias Neurais/diagnóstico por imagem , Vias Neurais/patologia , Polimorfismo de Nucleotídeo Único , Fatores de Risco
17.
Neuroimage ; 214: 116756, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32201326

RESUMO

Healthy aging has been associated with a decrease in functional network specialization. Importantly, variability of alterations of functional connectivity is especially high across older adults. Whole-brain functional network reorganization, though, and its impact on cognitive performance within particularly the older generation is still a matter of debate. We assessed resting state functional connectivity (RSFC) in 772 older adults (55-85 years, 421 males) using a graph-theoretical approach. Results show overall age-related increases of between- and decreases of within-network RSFC. With similar phenomena observed in young to middle-aged adults, i.e. that RSFC reorganizes towards more pronounced functional network integration, the current results amend such evidence for the old age. The results furthermore indicate that RSFC reorganization in older adults particularly pertain to early sensory networks (e.g. visual and sensorimotor network). Importantly, RSFC differences of these early sensory networks were found to be a relevant mediator in terms of the age-related cognitive performance differences. Further, we found systematic sex-related network differences with females showing patterns of more segregation (i.e. default mode and ventral attention network) and males showing a higher integrated network system (particularly for the sensorimotor network). These findings underpin the notion of sex-related connectivity differences, possibly facilitating sex-related behavioral functioning.


Assuntos
Encéfalo/fisiopatologia , Cognição/fisiologia , Conectoma , Envelhecimento Saudável/fisiologia , Rede Nervosa/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Imagem Ecoplanar , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Caracteres Sexuais
18.
Neuroimage ; 221: 117140, 2020 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-32650053

RESUMO

There has been an increasing interest in examining organisational principles of the cerebral cortex (and subcortical regions) using different MRI features such as structural or functional connectivity. Despite the widespread interest, introductory tutorials on the underlying technique targeted for the novice neuroimager are sparse in the literature. Articles that investigate various "neural gradients" (for example based on region studied "cortical gradients," "cerebellar gradients," "hippocampal gradients" etc … or feature of interest "functional gradients," "cytoarchitectural gradients," "myeloarchitectural gradients" etc …) have increased in popularity. Thus, we believe that it is opportune to discuss what is generally meant by "gradient analysis". We introduce basics concepts in graph theory, such as graphs themselves, the degree matrix, and the adjacency matrix. We discuss how one can think about gradients of feature similarity (the similarity between timeseries in fMRI, or streamline in tractography) using graph theory and we extend this to explore such gradients across the whole MRI scale; from the voxel level to the whole brain level. We proceed to introduce a measure for quantifying the level of similarity in regions of interest. We propose the term "the Vogt-Bailey index" for such quantification to pay homage to our history as a brain mapping community. We run through the techniques on sample datasets including a brain MRI as an example of the application of the techniques on real data and we provide several appendices that expand upon details. To maximise intuition, the appendices contain a didactic example describing how one could use these techniques to solve a particularly pernicious problem that one may encounter at a wedding. Accompanying the article is a tool, available in both MATLAB and Python, that enables readers to perform the analysis described in this article on their own data. We refer readers to the graphical abstract as an overview of the analysis pipeline presented in this work.


Assuntos
Encéfalo/fisiologia , Conectoma/métodos , Imageamento por Ressonância Magnética/métodos , Modelos Teóricos , Rede Nervosa/fisiologia , Adulto , Encéfalo/diagnóstico por imagem , Humanos , Rede Nervosa/diagnóstico por imagem
19.
Int J Geriatr Psychiatry ; 35(10): 1219-1227, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32510658

RESUMO

OBJECTIVE: Subjective cognitive decline (SCD) was frequently investigated for memory in healthy aging or in relation to diseases like dementia. It was found to be related to sociodemographic and psychological variables as well as cognitive abilities. The prevalence of SCD in other cognitive domains and their relation to these variables is largely unknown to date. The present study aimed to fill this gap. METHODS: A total of 807 subjects (18-85 years of age, M = 57.8 years, female: 43%) completed the Juelich Questionnaire on Subjective Cognitive Decline, to investigate SCD in memory, attention, language, motor, and executive functions. Logistic regression analyses were used to estimate association of depressive symptomatology, emotionality, and general cognitive performance as well as age, gender, and educational attainment with domain-specific SCD. RESULTS: The highest prevalence rate was obtained for the memory domain (65.9%), followed by the attention (54.6%), motor (52.9%), executive (39.7%), and language domain (31.5%). Of the psychosocial factors, only age, depressive symptomatology and emotionality were consistently and strongly associated with domain-specific SCD prevalence. CONCLUSIONS: SCD is prevalent not only in the memory domain, but also in other major cognitive domains. Our results also suggest that the suspicion from previous research, that subjective memory decline might be more strongly associated with depressive symptomatology and emotionality than with actual decline of cognitive performance, might also apply to the attention, motor, executive, and language domain. Further investigations using neuropsychological testing for specific cognitive functions and employing longitudinal designs are required for substantiating this suspicion.


Assuntos
Disfunção Cognitiva , Cognição , Disfunção Cognitiva/epidemiologia , Estudos de Coortes , Feminino , Alemanha/epidemiologia , Humanos , Testes Neuropsicológicos , Prevalência
20.
Cereb Cortex ; 29(3): 1305-1327, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30561508

RESUMO

Human posterior intraparietal sulcus (pIPS) and adjacent posterior wall of parieto-occipital sulcus (POS) are functionally diverse, serving higher motor, visual and cognitive functions. Its microstructural basis, though, is still largely unknown. A similar or even more pronounced architectonical complexity, as described in monkeys, could be assumed. We cytoarchitectonically mapped the pIPS/POS in 10 human postmortem brains using an observer-independent, quantitative parcellation. 3D-probability maps were generated within MNI reference space and used for functional decoding and meta-analytic coactivation modeling based on the BrainMap database to decode the general structural-functional organization of the areas. Seven cytoarchitectonically distinct areas were identified: five within human pIPS, three on its lateral (hIP4-6) and two on its medial wall (hIP7-8); and two (hPO1, hOc6) in POS. Mediocaudal areas (hIP7, hPO1) were predominantly involved in visual processing, whereas laterorostral areas (hIP4-6, 8) were associated with higher cognitive functions, e.g. counting. This shift was mirrored by systematic changes in connectivity, from temporo-occipital to premotor and prefrontal cortex, and in cytoarchitecture, from prominent Layer IIIc pyramidal cells to homogeneous neuronal distribution. This architectonical mosaic within human pIPS/POS represents a structural basis of its functional and connectional heterogeneity. The new 3D-maps of the areas enable dedicated assessments of structure-function relationships.


Assuntos
Cognição/fisiologia , Lobo Occipital/citologia , Lobo Occipital/fisiologia , Lobo Parietal/citologia , Lobo Parietal/fisiologia , Desempenho Psicomotor/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Imageamento Tridimensional , Masculino , Pessoa de Meia-Idade , Vias Neurais/citologia , Vias Neurais/diagnóstico por imagem , Lobo Occipital/diagnóstico por imagem , Lobo Parietal/diagnóstico por imagem
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