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Pelizaeus-Merzbacher disease (PMD) is a rare childhood hypomyelinating leukodystrophy. Quantification of the pronounced myelin deficit and delineation of subtle myelination processes are of high clinical interest. Quantitative magnetic resonance imaging (qMRI) techniques can provide in vivo insights into myelination status, its spatial distribution, and dynamics during brain maturation. They may serve as potential biomarkers to assess the efficacy of myelin-modulating therapies. However, registration techniques for image quantification and statistical comparison of affected pediatric brains, especially those of low or deviant image tissue contrast, with healthy controls are not yet established. This study aimed first to develop and compare postprocessing pipelines for atlas-based quantification of qMRI data in pediatric patients with PMD and evaluate their registration accuracy. Second, to apply an optimized pipeline to investigate spatial myelin deficiency using myelin water imaging (MWI) data from patients with PMD and healthy controls. This retrospective single-center study included five patients with PMD (mean age, 6 years ± 3.8) who underwent conventional brain MRI and diffusion tensor imaging (DTI), with MWI data available for a subset of patients. Three methods of registering PMD images to a pediatric template were investigated. These were based on (a) T1-weighted (T1w) images, (b) fractional anisotropy (FA) maps, and (c) a combination of T1w, T2-weighted, and FA images in a multimodal approach. Registration accuracy was determined by visual inspection and calculated using the structural similarity index method (SSIM). SSIM values for the registration approaches were compared using a t test. Myelin water fraction (MWF) was quantified from MWI data as an assessment of relative myelination. Mean MWF was obtained from two PMDs (mean age, 3.1 years ± 0.3) within four major white matter (WM) pathways of a pediatric atlas and compared to seven healthy controls (mean age, 3 years ± 0.2) using a Mann-Whitney U test. Our results show that visual registration accuracy estimation and computed SSIM were highest for FA-based registration, followed by multimodal, and T1w-based registration (SSIMFA = 0.67 ± 0.04 vs. SSIMmultimodal = 0.60 ± 0.03 vs. SSIMT1 = 0.40 ± 0.14). Mean MWF of patients with PMD within the WM pathways was significantly lower than in healthy controls MWFPMD = 0.0267 ± 0.021 vs. MWFcontrols = 0.1299 ± 0.039. Specifically, MWF was measurable in brain structures known to be myelinated at birth (brainstem) or postnatally (projection fibers) but was scarcely detectable in other brain regions (commissural and association fibers). Taken together, our results indicate that registration accuracy was highest with an FA-based registration pipeline, providing an alternative to conventional T1w-based registration approaches in the case of hypomyelinating leukodystrophies missing normative intrinsic tissue contrasts. The applied atlas-based analysis of MWF data revealed that the extent of spatial myelin deficiency in patients with PMD was most pronounced in commissural and association and to a lesser degree in brainstem and projection pathways.
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Atlas como Asunto , Imagen de Difusión Tensora , Vaina de Mielina , Enfermedad de Pelizaeus-Merzbacher , Humanos , Enfermedad de Pelizaeus-Merzbacher/diagnóstico por imagen , Enfermedad de Pelizaeus-Merzbacher/patología , Masculino , Niño , Femenino , Preescolar , Vaina de Mielina/patología , Imagen de Difusión Tensora/métodos , Estudios Retrospectivos , Imagen por Resonancia Magnética/métodos , Imagen por Resonancia Magnética/normas , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patologíaRESUMEN
Atypical social impairments (i.e., impaired social cognition and social communication) are vital manifestations of autism spectrum disorder (ASD) patients, and the incidence rate of ASD is significantly higher in males than in females. Characterizing the atypical brain patterns underlying social deficits of ASD is significant for understanding the pathogenesis. However, there are no robust imaging biomarkers that are specific to ASD, which may be due to neurobiological complexity and limitations of single-modality research. To describe the multimodal brain patterns related to social deficits in ASD, we highlighted the potential functional role of white matter (WM) and incorporated WM functional activity and gray matter structure into multimodal fusion. Gray matter volume (GMV) and fractional amplitude of low-frequency fluctuations of WM (WM-fALFF) were combined by fusion analysis model adopting the social behavior. Our results revealed multimodal spatial patterns associated with Social Responsiveness Scale multiple scores in ASD. Specifically, GMV exhibited a consistent brain pattern, in which salience network and limbic system were commonly identified associated with all multiple social impairments. More divergent brain patterns in WM-fALFF were explored, suggesting that WM functional activity is more sensitive to ASD's complex social impairments. Moreover, brain regions related to social impairment may be potentially interconnected across modalities. Cross-site validation established the repeatability of our results. Our research findings contribute to understanding the neural mechanisms underlying social disorders in ASD and affirm the feasibility of identifying biomarkers from functional activity in WM.
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Trastorno del Espectro Autista , Sustancia Gris , Imagen por Resonancia Magnética , Imagen Multimodal , Sustancia Blanca , Humanos , Trastorno del Espectro Autista/diagnóstico por imagen , Trastorno del Espectro Autista/fisiopatología , Trastorno del Espectro Autista/patología , Masculino , Sustancia Gris/diagnóstico por imagen , Sustancia Gris/patología , Adulto Joven , Adulto , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología , Adolescente , Conducta Social , Niño , Neuroimagen/métodos , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Encéfalo/fisiopatologíaRESUMEN
Structural connectivity (SC) between distant regions of the brain support synchronized function known as functional connectivity (FC) and give rise to the large-scale brain networks that enable cognition and behavior. Understanding how SC enables FC is important to understand how injuries to SC may alter brain function and cognition. Previous work evaluating whole-brain SC-FC relationships showed that SC explained FC well in unimodal visual and motor areas, but only weakly in association areas, suggesting a unimodal-heteromodal gradient organization of SC-FC coupling. However, this work was conducted in group-averaged SC/FC data. Thus, it could not account for inter-individual variability in the locations of cortical areas and white matter tracts. We evaluated the correspondence of SC and FC within three highly sampled healthy participants. For each participant, we collected 78 min of diffusion-weighted MRI for SC and 360 min of resting state fMRI for FC. We found that FC was best explained by SC in visual and motor systems, as well as in anterior and posterior cingulate regions. A unimodal-to-heteromodal gradient could not fully explain SC-FC coupling. We conclude that the SC-FC coupling of the anterior-posterior cingulate circuit is more similar to unimodal areas than to heteromodal areas.
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Encéfalo , Imagen por Resonancia Magnética , Vías Nerviosas , Humanos , Masculino , Encéfalo/fisiología , Encéfalo/diagnóstico por imagen , Adulto , Femenino , Imagen por Resonancia Magnética/métodos , Vías Nerviosas/fisiología , Vías Nerviosas/diagnóstico por imagen , Mapeo Encefálico/métodos , Adulto Joven , Imagen de Difusión por Resonancia Magnética , Descanso/fisiología , Sustancia Blanca/fisiología , Sustancia Blanca/diagnóstico por imagenRESUMEN
BACKGROUND AND OBJECTIVES: Markers of white matter (WM) injury on brain MRI are important indicators of brain health. Different patterns of WM atrophy, WM hyperintensities (WMHs), and microstructural integrity could reflect distinct pathologies and disease risks, but large-scale imaging studies investigating WM signatures are lacking. This study aims to identify distinct WM signatures using brain MRI in community-dwelling adults, determine underlying risk factor profiles, and assess risks of dementia, stroke, and mortality associated with each signature. METHODS: Between 2005 and 2016, we measured WMH volume, WM volume, fractional anisotropy (FA), and mean diffusivity (MD) using automated pipelines on structural and diffusion MRI in community-dwelling adults aged older than 45 years of the Rotterdam study. Continuous surveillance was conducted for dementia, stroke, and mortality. We applied hierarchical clustering to identify separate WM injury clusters and Cox proportional hazard models to determine their risk of dementia, stroke, and mortality. RESULTS: We included 5,279 participants (mean age 65.0 years, 56.0% women) and identified 4 distinct data-driven WM signatures: (1) above-average microstructural integrity and little WM atrophy and WMH; (2) above-average microstructural integrity and little WMH, but substantial WM atrophy; (3) poor microstructural integrity and substantial WMH, but little WM atrophy; and (4) poor microstructural integrity with substantial WMH and WM atrophy. Prevalence of cardiovascular risk factors, lacunes, and cerebral microbleeds was higher in clusters 3 and 4 than in clusters 1 and 2. During a median 10.7 years of follow-up, 291 participants developed dementia, 220 had a stroke, and 910 died. Compared with cluster 1, dementia risk was increased for all clusters, notably cluster 3 (hazard ratio [HR] 3.06, 95% CI 2.12-4.42), followed by cluster 4 (HR 2.31, 95% CI 1.58-3.37) and cluster 2 (HR 1.67, 95% CI 1.17-2.38). Compared with cluster 1, risk of stroke was higher only for clusters 3 (HR 1.55, 95% CI 1.02-2.37) and 4 (HR 1.94, 95% CI 1.30-2.89), whereas mortality risk was increased in all clusters (cluster 2: HR 1.27, 95% CI 1.06-1.53, cluster 3: HR 1.65, 95% CI 1.35-2.03, cluster 4: HR 1.76, 95% CI 1.44-2.15), compared with cluster 1. Models including clusters instead of an individual imaging marker showed a superior goodness of fit for dementia and mortality, but not for stroke. DISCUSSION: Clustering can derive WM signatures that are differentially associated with dementia, stroke, and mortality risk. Future research should incorporate spatial information of imaging markers.
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Demencia , Vida Independiente , Accidente Cerebrovascular , Sustancia Blanca , Humanos , Masculino , Femenino , Demencia/epidemiología , Demencia/patología , Demencia/diagnóstico por imagen , Demencia/mortalidad , Anciano , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología , Accidente Cerebrovascular/epidemiología , Accidente Cerebrovascular/mortalidad , Accidente Cerebrovascular/patología , Accidente Cerebrovascular/diagnóstico por imagen , Persona de Mediana Edad , Factores de Riesgo , Imagen por Resonancia Magnética , Análisis por Conglomerados , Atrofia/patologíaRESUMEN
Significant evidence links obesity and schizophrenia (SZ), but the brain associations are still largely unclear. 48 people with SZ were divided into two subgroups: patients with lower waist circumference (SZ-LWC: n = 24) and patients with higher waist circumference (SZ-HWC: n = 24). Healthy controls (HC) were included for comparison (HC: n = 27). Using tract-based spatial statistics, we compared fractional anisotropy (FA) of the whole-brain white matter skeleton between these three groups (SZ-LWC, SZ-HWC, HC). Using Free Surfer, we compared whole-brain cortical thickness and the selected subcortical volumes between the three groups. FA of widespread white matter and the mean cortical thickness in the right temporal lobe and insular cortex were significantly lower in the SZ-HWC group than in the HC group. The FA of regional white matter was significantly lower in the SZ-LWC group than in the HC group. There were no significant differences in mean subcortical volumes between the groups. Additionally, the cognitive performances were worse in the SZ-HWC group, who had more severe triglycerides elevation. This study provides evidence for microstructural abnormalities of white matter, cortical thickness and neurocognitive deficits in SZ patients with excessive abdominal obesity.
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Obesidad Abdominal , Esquizofrenia , Sustancia Blanca , Humanos , Esquizofrenia/diagnóstico por imagen , Esquizofrenia/patología , Masculino , Adulto , Femenino , Obesidad Abdominal/diagnóstico por imagen , Obesidad Abdominal/patología , Obesidad Abdominal/complicaciones , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología , Imagen de Difusión Tensora , Persona de Mediana Edad , Circunferencia de la Cintura , Encéfalo/patología , Encéfalo/diagnóstico por imagenRESUMEN
Telomere length (TL) is an important cellular marker of biological aging impacting the brain and heart. However, how it is related to the brain (e.g., cognitive function and neuroanatomic architecture), and how these relationships may vary by sex and reproductive status, is not well established. Here we assessed the association between leukocyte TL and memory circuitry regional brain volumes and memory performance in early midlife, in relation to sex and reproductive status. Participants (N = 198; 95 females, 103 males; ages 45-55) underwent structural MRI and neuropsychological assessments of verbal, associative, and working memory. Overall, shorter TL was associated with smaller white matter volume in the parahippocampal gyrus and dorsolateral prefrontal cortex. In males, shorter TL was associated with worse working memory performance and corresponding smaller white matter volumes in the parahippocampal gyrus, anterior cingulate cortex, and dorsolateral prefrontal cortex. In females, the impact of cellular aging was revealed over the menopausal transition. In postmenopausal females, shorter TL was associated with poor associative memory performance and smaller grey matter volume in the right hippocampus. In contrast, TL was not related to memory performance or grey and white matter volumes in any memory circuitry region in pre/perimenopausal females. Results demonstrated that shorter TL is associated with worse memory function and smaller volume in memory circuitry regions in early midlife, an association that differs by sex and reproductive status. Taken together, TL may serve as an early indicator of sex-dependent brain abnormalities in early midlife.
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Envejecimiento , Cognición , Leucocitos , Memoria , Menopausia , Humanos , Femenino , Persona de Mediana Edad , Masculino , Envejecimiento/fisiología , Leucocitos/fisiología , Cognición/fisiología , Menopausia/fisiología , Memoria/fisiología , Caracteres Sexuales , Imagen por Resonancia Magnética , Encéfalo/diagnóstico por imagen , Encéfalo/fisiología , Telómero/fisiología , Sustancia Gris/diagnóstico por imagen , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/fisiología , Pruebas NeuropsicológicasRESUMEN
Obsessive-compulsive disorder (OCD) is characterized by structural alteration within white matter tissues of cortico-striato-thalamo-cortical, temporal and occipital circuits. However, the presence of microstructural changes in the white matter tracts of unaffected first-degree relatives of patients with OCD as a vulnerability marker remains unclear. Therefore, here, diffusion-tensor magnetic resonance imaging (DTI) data were obtained from 29 first-degree relatives of patients with OCD and 59 healthy controls. We investigated the group differences in FA using whole-brain analysis (DTI analysis). For additional regions of interest (ROI) analysis, we focused on the posterior thalamic radiation and sagittal stratum, shown in recent meta-analysis of patients with OCD. In both whole-brain and ROI analyses, using a strict statistical threshold (family-wise error rate [FWE] corrected p<.05 for whole-brain analyses, and p<.0125 (0.05/4) with Bonferroni correction for ROI analyses), we found no significant group differences in FA. Subtle reductions were observed in the anterior corona radiata, forceps minor, cingulum bundle, and corpus callosum only when a lenient statistical was applied (FWE corrected p<.20). These findings suggest that alterations in the white matter microstructure of first-degree relatives, as potential vulnerability markers for OCD, are likely subtle.
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Imagen de Difusión Tensora , Familia , Trastorno Obsesivo Compulsivo , Sustancia Blanca , Humanos , Trastorno Obsesivo Compulsivo/diagnóstico por imagen , Trastorno Obsesivo Compulsivo/patología , Trastorno Obsesivo Compulsivo/genética , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología , Masculino , Adulto , Femenino , Imagen de Difusión Tensora/métodos , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Persona de Mediana Edad , Adulto JovenRESUMEN
Proprioceptive impairments occur in approximately 50-64% of people following stroke. While much is known about the grey matter structures underlying proprioception, our understanding of the white matter correlates of proprioceptive impairments is less well developed. It is recognised that behavioural impairments post-stroke are often the result of disconnection between wide-scale brain networks, however the disconnectome associated with proprioception post-stroke is unknown. In the current study, white matter disconnection was assessed in relation to performance on a robotic arm position matching (APM) task. Neuroimaging and robotic assessments of proprioception were collected for 203 stroke survivors, approximately 2-weeks post-stroke. The robotic assessment was performed in a KINARM Exoskeleton robotic device and consisted of a nine-target APM task. First, the relationship between white matter tract lesion load and performance on the APM task was assessed. Next, differences in the disconnectome between participants with and without impairments on the APM task were examined. Greater lesion load to the superior longitudinal fasciculus (SLF II and III), arcuate fasciculus (all segments) and fronto-insular tracts were associated with worse APM task performance. In those with APM task impairments, there was, additionally, disconnection of the posterior corpus callosum, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus and optic radiations. This study highlights an important perisylvian white matter network supporting proprioceptive processing in the human brain. It also identifies white matter tracts, important for relaying proprioceptive information from parietal and frontal brain regions, that are not traditionally considered proprioceptive in nature.
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Propiocepción , Accidente Cerebrovascular , Sustancia Blanca , Humanos , Sustancia Blanca/fisiopatología , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología , Propiocepción/fisiología , Masculino , Femenino , Persona de Mediana Edad , Accidente Cerebrovascular/fisiopatología , Accidente Cerebrovascular/complicaciones , Anciano , Adulto , RobóticaRESUMEN
Intravital 2P-microscopy enables the longitudinal study of brain tumor biology in superficial mouse cortex layers. Intravital microscopy of the white matter, an important route of glioblastoma invasion and recurrence, has not been feasible, due to low signal-to-noise ratios and insufficient spatiotemporal resolution. Here, we present an intravital microscopy and artificial intelligence-based analysis workflow (Deep3P) that enables longitudinal deep imaging of glioblastoma up to a depth of 1.2 mm. We find that perivascular invasion is the preferred invasion route into the corpus callosum and uncover two vascular mechanisms of glioblastoma migration in the white matter. Furthermore, we observe morphological changes after white matter infiltration, a potential basis of an imaging biomarker during early glioblastoma colonization. Taken together, Deep3P allows for a non-invasive intravital investigation of brain tumor biology and its tumor microenvironment at subcortical depths explored, opening up opportunities for studying the neuroscience of brain tumors and other model systems.
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Neoplasias Encefálicas , Glioblastoma , Microscopía Intravital , Microambiente Tumoral , Animales , Neoplasias Encefálicas/diagnóstico por imagen , Neoplasias Encefálicas/patología , Glioblastoma/diagnóstico por imagen , Glioblastoma/patología , Microscopía Intravital/métodos , Ratones , Humanos , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología , Cuerpo Calloso/diagnóstico por imagen , Cuerpo Calloso/patología , Línea Celular Tumoral , Microscopía de Fluorescencia por Excitación Multifotónica/métodos , Invasividad NeoplásicaRESUMEN
Multiple sclerosis (MS) is a leading cause of non-traumatic disability in young adults. The highly dynamic nature of MS lesions has made them difficult to study using traditional histopathology due to the specificity of current stains. This requires numerous stains to track and study demyelinating activity in MS. Thus, we utilized Fourier transform infrared (FTIR) spectroscopy to generate holistic biomolecular profiles of demyelinating activities in MS brain tissue. Multivariate analysis can differentiate MS tissue from controls. Analysis of the absorbance spectra shows profound reductions of lipids, proteins, and phosphate in white matter lesions. Changes in unsaturated lipids and lipid chain length indicate oxidative damage in MS brain tissue. Altered lipid and protein structures suggest changes in MS membrane structure and organization. Unique carbohydrate signatures are seen in MS tissue compared to controls, indicating altered metabolic activities. Cortical lesions had increased olefinic lipid content and abnormal membrane structure in normal appearing MS cortex compared to controls. Our results suggest that FTIR spectroscopy can further our understanding of lesion evolution and disease mechanisms in MS paving the way towards improved diagnosis, prognosis, and development of novel therapeutics.
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Encéfalo , Esclerosis Múltiple , Humanos , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Femenino , Masculino , Encéfalo/patología , Encéfalo/metabolismo , Esclerosis Múltiple/patología , Esclerosis Múltiple/metabolismo , Adulto , Persona de Mediana Edad , Sustancia Blanca/patología , Sustancia Blanca/metabolismoRESUMEN
Turner syndrome, caused by complete or partial loss of an X-chromosome, is often accompanied by specific cognitive challenges. Magnetic resonance imaging studies of adults and children with Turner syndrome suggest these deficits reflect differences in anatomical and functional connectivity. However, no imaging studies have explored connectivity in infants with Turner syndrome. Consequently, it is unclear when in development connectivity differences emerge. To address this gap, we compared functional connectivity and white matter microstructure of 1-year-old infants with Turner syndrome to typically developing 1-year-old boys and girls. We examined functional connectivity between the right precentral gyrus and five regions that show reduced volume in 1-year old infants with Turner syndrome compared to controls and found no differences. However, exploratory analyses suggested infants with Turner syndrome have altered connectivity between right supramarginal gyrus and left insula and right putamen. To assess anatomical connectivity, we examined diffusivity indices along the superior longitudinal fasciculus and found no differences. However, an exploratory analysis of 46 additional white matter tracts revealed significant group differences in nine tracts. Results suggest that the first year of life is a window in which interventions might prevent connectivity differences observed at later ages, and by extension, some of the cognitive challenges associated with Turner syndrome.
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Encéfalo , Vías Nerviosas , Síndrome de Turner , Sustancia Blanca , Humanos , Síndrome de Turner/patología , Síndrome de Turner/diagnóstico por imagen , Síndrome de Turner/fisiopatología , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología , Femenino , Lactante , Masculino , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Encéfalo/fisiopatología , Vías Nerviosas/diagnóstico por imagen , Vías Nerviosas/fisiopatología , Vías Nerviosas/patología , Imagen por Resonancia Magnética , Imagen de Difusión TensoraRESUMEN
PURPOSE: Anorexia nervosa (AN) is a mental health disorder characterized by significant weight loss and associated medical and psychological comorbidities. Conventional treatments for severe AN have shown limited effectiveness, leading to the exploration of novel interventional strategies, including deep brain stimulation (DBS). However, the neural mechanisms driving DBS interventions, particularly in psychiatric conditions, remain uncertain. This study aims to address this knowledge gap by examining changes in structural connectivity in patients with severe AN before and after DBS. METHODS: Sixteen participants, including eight patients with AN and eight controls, underwent baseline T1-weigthed and diffusion tensor imaging (DTI) acquisitions. Patients received DBS targeting either the subcallosal cingulate (DBS-SCC, N = 4) or the nucleus accumbens (DBS-NAcc, N = 4) based on psychiatric comorbidities and AN subtype. Post-DBS neuroimaging evaluation was conducted in four patients. Data analyses were performed to compare structural connectivity between patients and controls and to assess connectivity changes after DBS intervention. RESULTS: Baseline findings revealed that structural connectivity is significantly reduced in patients with AN compared to controls, mainly regarding callosal and subcallosal white matter (WM) tracts. Furthermore, pre- vs. post-DBS analyses in AN identified a specific increase after the intervention in two WM tracts: the anterior thalamic radiation and the superior longitudinal fasciculus-parietal bundle. CONCLUSIONS: This study supports that structural connectivity is highly compromised in severe AN. Moreover, this investigation preliminarily reveals that after DBS of the SCC and NAcc in severe AN, there are WM modifications. These microstructural plasticity adaptations may signify a mechanistic underpinning of DBS in this psychiatric disorder.
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Anorexia Nerviosa , Estimulación Encefálica Profunda , Imagen de Difusión Tensora , Giro del Cíngulo , Núcleo Accumbens , Humanos , Estimulación Encefálica Profunda/métodos , Anorexia Nerviosa/terapia , Anorexia Nerviosa/diagnóstico por imagen , Núcleo Accumbens/diagnóstico por imagen , Femenino , Giro del Cíngulo/diagnóstico por imagen , Adulto , Imagen de Difusión Tensora/métodos , Adulto Joven , Masculino , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología , Adolescente , Vías Nerviosas/diagnóstico por imagen , Vías Nerviosas/fisiopatologíaRESUMEN
BACKGROUND AND OBJECTIVES: The internal capsule is supplied by perforators originating from the internal carotid artery, middle cerebral artery, anterior choroidal artery and anterior cerebral artery. The aim of this study is to examine the vascular anatomy of the internal capsule, along with its related white matter anatomy, in order to prevent potential risks and complications during surgical interventions. METHODS: Twenty injected hemispheres prepared according to the Klingler method were dissected. Dissections were photographed at each stage. The findings obtained from the dissections were illustrated to make them more understandable. Additionally, the origins of the arteries involved in the vascularization of the internal capsule, their distances to bifurcations, and variations in supplying territories have been thoroughly examined. RESULTS: The insular cortex and the branches of the middle cerebral artery on the insula and operculum were observed. Following decortication of the insular cortex, the extreme capsule, claustrum, external capsule, putamen and globus pallidus structures were exposed. The internal capsule is shown together with the lenticulostriate arteries running on the anterior, genu and posterior limbs. Perforators supplying the internal capsule originated from the middle cerebral artery, anterior cerebral artery, internal carotid artery and anterior choroidal artery. The internal capsule's vascular supply varied, with the medial lenticulostriate arteries (MLA) and lateral lenticulostriate arteries (LLA) being the primary arteries. The anterior limb was most often supplied by the MLA, while the LLA and anterior choroidal artery dominated the genu and posterior limb. The recurrent artery of Heubner originated mostly from the A2 segment. The distance from the ICA bifurcation to the origin of the first LLA on M1 is 9.55 ± 2.32 mm, and to the first MLA on A1 is 5.35 ± 1.84 mm. MLA branching from A1 and proximal A2 ranged from 5 to 9, while LLA originating from the MCA ranged from 7 to 12. CONCLUSION: This study provides comprehensive understanding of the arterial supply to the internal capsule by combining white matter dissection. The insights gained from this study can help surgeons plan and execute procedures including oncological, psychosurgical, and vascular more accurately and safely. The illustrations derived from the dissections serve as valuable educational material for young neurosurgeons and other medical professionals.
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Cápsula Interna , Sustancia Blanca , Humanos , Cápsula Interna/anatomía & histología , Cápsula Interna/irrigación sanguínea , Sustancia Blanca/anatomía & histología , Sustancia Blanca/irrigación sanguínea , Arteria Cerebral Media/anatomía & histología , Arteria Cerebral Media/cirugía , Arteria Carótida Interna/anatomía & histología , Arterias Cerebrales/anatomía & histologíaRESUMEN
BACKGROUND: Material characterization of brain white matter (BWM) is difficult due to the anisotropy inherent to the three-dimensional microstructure and the various interactions between heterogeneous brain-tissue (axon, myelin, and glia). Developing full scale finite element models that accurately represent the relationship between the micro and macroscale BWM is however extremely challenging and computationally expensive. The anisotropic properties of the microstructure of BWM computed by building unit cells under frequency domain viscoelasticity comprises of 36 individual constants each, for the loss and storage moduli. Furthermore, the architecture of each unit cell is arbitrary in an infinite dataset. METHODS: In this study, we extend our previous work on developing representative volume elements (RVE) of the microstructure of the BWM in the frequency domain to develop 3D deep learning algorithms that can predict the anisotropic composite properties. The deep 3D convolutional neural network (CNN) algorithms utilizes a voxelization method to obtain geometry information from 3D RVEs. The architecture information encoded in the voxelized location is employed as input data while cross-referencing the RVEs' material properties (output data). We further develop methods by incorporating parallel pathways, Residual Neural Networks and inception modulus that improve the efficiency of deep learning algorithms. RESULTS: This paper presents different CNN algorithms in predicting the anisotropic composite properties of BWM. A quantitative analysis of the individual algorithms is presented with the view of identifying optimal strategies to interpret the combined measurements of brain MRE and DTI. SIGNIFICANCE: The proposed Multiscale 3D ResNet (M3DR) algorithm demonstrates high learning ability and performance over baseline CNN algorithms in predicting BWM tissue properties. The hybrid M3DR framework also overcomes the significant limitations encountered in modeling brain tissue using finite elements alone including those such as high computational cost, mesh and simulation failure. The proposed framework also provides an efficient and streamlined platform for implementing complex boundary conditions, modeling intrinsic material properties and imparting interfacial architecture information.
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Algoritmos , Análisis de Elementos Finitos , Redes Neurales de la Computación , Sustancia Blanca , Sustancia Blanca/diagnóstico por imagen , Humanos , Anisotropía , Encéfalo/diagnóstico por imagen , Encéfalo/fisiología , Imagenología Tridimensional/métodos , Aprendizaje ProfundoRESUMEN
Understanding the sequence of cellular responses and their contributions to pathomorphogical changes in spinal white matter injuries is a prerequisite for developing efficient therapeutic strategies for spinal cord injury (SCI) as well as neurodegenerative and inflammatory diseases of the spinal cord such as amyotrophic lateral sclerosis and multiple sclerosis. We have developed several types of surgical procedures suitable for acute one-time and chronic recurrent in vivo multiphoton microscopy of spinal white matter [1]. Sophisticated surgical procedures were combined with transgenic mouse technology to image spinal tissue labeled with up to four fluorescent proteins (FPs) in axons, astrocytes, microglia, and blood vessels. To clearly separate the simultaneously excited FPs, spectral unmixing including iterative procedures was performed after imaging the diversely labeled spinal white matter with a custom-made 4-channel two-photon laser-scanning microscope. In our longitudinal multicellular studies of injured spinal white matter, we imaged axonal dynamics and invasion of microglia and astrocytes for a time course of over 200 days after SCI. Our methods offer ideal platforms for investigating acute and chronic cellular dynamics, cell-cell interactions, and metabolite fluctuations in health and disease as well as pharmacological manipulations in vivo.
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Axones , Ratones Transgénicos , Traumatismos de la Médula Espinal , Sustancia Blanca , Animales , Sustancia Blanca/patología , Sustancia Blanca/metabolismo , Sustancia Blanca/diagnóstico por imagen , Traumatismos de la Médula Espinal/patología , Traumatismos de la Médula Espinal/metabolismo , Traumatismos de la Médula Espinal/diagnóstico por imagen , Axones/patología , Axones/metabolismo , Neuroglía/metabolismo , Neuroglía/patología , Ratones , Microscopía de Fluorescencia por Excitación Multifotónica/métodos , Médula Espinal/patología , Médula Espinal/metabolismo , Microglía/metabolismo , Microglía/patología , Astrocitos/metabolismo , Astrocitos/patologíaRESUMEN
Background: Essential tremor (ET) and dystonic tremor (DT) are movement disorders that cause debilitating symptoms, significantly impacting daily activities and quality of life. A poor understanding of their pathophysiology, as well as the mediators of clinical outcomes following deep brain stimulation (DBS), highlights the need for biomarkers to accurately characterise and optimally treat patients. Objectives: We assessed the white matter microstructure of pathways implicated in the pathophysiology and therapeutic intervention in a retrospective cohort of patients with DT (n = 17) and ET (n = 19). We aimed to identity associations between white matter microstructure, upper limb tremor severity, and tremor improvement following DBS. Methods: A fixel-based analysis pipeline was implemented to investigate white matter microstructural metrics in the whole brain, cerebello-thalamic pathways and tracts connected to stimulation volumes following DBS. Associations with preoperative and postoperative severity were analysed within each disorder group and across combined disorder groups. Results: DBS led to significant improvements in both groups. No group differences in stimulation positions were identified. When white matter microstructural data was aligned according to the maximally affected upper limb, increased fiber density, and combined fiber density & cross-section of fixels in the left cerebellum were associated with greater tremor severity across DT and ET patients. White matter microstructure did not show associations with postoperative changes in cerebello-thalamic pathways, or tracts connected to stimulation volumes. Discussion: Diffusion changes of the cerebellum are associated with the severity of upper limb tremor and appear to overlap in essential or dystonic tremor disorders.
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Estimulación Encefálica Profunda , Temblor Esencial , Sustancia Blanca , Humanos , Femenino , Masculino , Anciano , Persona de Mediana Edad , Temblor Esencial/terapia , Temblor Esencial/fisiopatología , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología , Estudios Retrospectivos , Trastornos Distónicos/terapia , Trastornos Distónicos/fisiopatología , Trastornos Distónicos/diagnóstico por imagen , Índice de Severidad de la Enfermedad , Temblor/terapia , Temblor/fisiopatología , Temblor/diagnóstico por imagen , Resultado del TratamientoRESUMEN
Dual decline in gait and cognition is associated with an increased risk of dementia, with combined gait and memory decline exhibiting the strongest association. To better understand the underlying pathology, we investigated the associations of baseline brain structure with dual decliners using three serial gait speed and cognitive assessments in memory, processing speed-attention, and verbal fluency. Participants (n=267) were categorized based on annual decline in gait speed and cognitive measures. Lower gray and white matter volume and higher white matter hyperintensity volume increased the risk of being a dual decliner in gait and both the memory and processing speed-attention groups (all p < 0.05). Lower hippocampal volume (p = 0.047) was only associated with dual decline in gait and memory group. No brain structures were correlated with dual decline in gait and verbal fluency. These results suggest that neurodegenerative pathology and white matter hyperintensities are involved in dual decline in gait and both memory and processing speed-attention. Smaller hippocampal volume may only contribute to dual decline in gait and memory.
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Encéfalo , Cognición , Marcha , Hipocampo , Memoria , Sustancia Blanca , Humanos , Masculino , Femenino , Anciano , Marcha/fisiología , Hipocampo/patología , Hipocampo/diagnóstico por imagen , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología , Tamaño de los Órganos , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Imagen por Resonancia Magnética , Anciano de 80 o más Años , Atención/fisiología , Riesgo , Demencia/etiología , Demencia/patología , Demencia/diagnóstico por imagen , Sustancia Gris/patología , Sustancia Gris/diagnóstico por imagenRESUMEN
Trunk control involves integration of sensorimotor information in the brain. Individuals with chronic low back pain (cLBP) have impaired trunk control and show differences in brain structure and function in sensorimotor areas compared with healthy controls (HC). However, the relationship between brain structure and trunk control in this group is not well understood. This cross-sectional study aimed to compare seated trunk control and sensorimotor white matter (WM) structure in people with cLBP and HC and explore relationships between WM properties and trunk control in each group. Thirty-two people with cLBP and 35 HC were tested sitting on an unstable chair to isolate trunk control; performance was measured using the 95% confidence ellipse area (CEA95) of center-of-pressure tracing. A WM network between cortical sensorimotor regions of interest was derived using probabilistic tractography. WM microstructure and anatomical connectivity between cortical sensorimotor regions were assessed. A mixed-model ANOVA showed that people with cLBP had worse trunk control than HC (F = 12.96; p < .001; ηp2 = .091). There were no differences in WM microstructure or anatomical connectivity between groups (p = 0.564 to 0.940). In the cLBP group, WM microstructure was moderately correlated (|r| = .456 to .565; p ≤ .009) with trunk control. Additionally, the cLBP group demonstrated stronger relationships between anatomical connectivity and trunk control (|r| = .377 to .618 p < .034) compared to the HC group. Unique to the cLBP group, WM connectivity between right somatosensory and left motor areas highlights the importance of interhemispheric information exchange for trunk control. Parietal areas associated with attention and spatial reference frames were also relevant to trunk control. These findings suggest that people with cLBP adopt a more cortically driven sensorimotor integration strategy for trunk control. Future research should replicate these findings and identify interventions to effectively modulate this strategy.
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Dolor de la Región Lumbar , Corteza Sensoriomotora , Sustancia Blanca , Humanos , Dolor de la Región Lumbar/fisiopatología , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/fisiopatología , Sustancia Blanca/patología , Masculino , Femenino , Adulto , Corteza Sensoriomotora/fisiopatología , Corteza Sensoriomotora/diagnóstico por imagen , Estudios Transversales , Persona de Mediana Edad , Torso/fisiopatología , Dolor Crónico/fisiopatología , Dolor Crónico/diagnóstico por imagen , Dolor Crónico/patología , Sedestación , Estudios de Casos y Controles , Imagen por Resonancia MagnéticaRESUMEN
Apolipoprotein E ε4 (APOE4) is a strong genetic risk factor of Alzheimer's disease and metabolic dysfunction. However, whether APOE4 and markers of metabolic dysfunction synergistically impact the deterioration of white matter (WM) integrity in older adults remains unknown. In the UK Biobank data, we conducted a multivariate analysis to investigate the interactions between APOE4 and 249 plasma metabolites (measured using nuclear magnetic resonance spectroscopy) with whole-brain WM integrity (measured by diffusion-weighted magnetic resonance imaging) in a cohort of 1917 older adults (aged 65.0-81.0 years; 52.4â¯% female). Although no main association was observed between either APOE4 or metabolites with WM integrity (adjusted P > 0.05), significant interactions between APOE4 and metabolites with WM integrity were identified. Among the examined metabolites, higher concentrations of low-density lipoprotein and very low-density lipoprotein were associated with a lower level of WM integrity (b=-0.12, CI=-0.14,-0.10) among APOE4 carriers. Conversely, among non-carriers, they were associated with a higher level of WM integrity (b=0.05, CI=0.04,0.07), demonstrating a significant moderation role of APOE4 (b =-0.18, CI=-0.20,-0.15, P<0.00001).
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Apolipoproteína E4 , Heterocigoto , Lipoproteínas LDL , Sustancia Blanca , Humanos , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología , Apolipoproteína E4/genética , Femenino , Masculino , Anciano , Lipoproteínas LDL/sangre , Anciano de 80 o más Años , Estudios de Cohortes , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/diagnóstico por imagen , Enfermedad de Alzheimer/sangre , Enfermedad de Alzheimer/patología , Imagen de Difusión por Resonancia Magnética , Espectroscopía de Resonancia Magnética , Factores de RiesgoRESUMEN
In the field of autism spectrum disorder (ASD), research on functional connectivity between gray matter and white matter remains under-researched. To address this gap, this study innovatively introduced a nested cross-validation method that integrates gray-white matter functional connectivity with an F-Score algorithm. This method calculates the correlation based on signals extracted from functional magnetic resonance imaging data using gray matter and white matter brain region templates. After applying the method to a New York University Langone Medical Center dataset consisting of 55 individuals with high-functioning ASD and 52 healthy subjects, we achieved a classification accuracy of 72.94%. This study found abnormal functional connectivity, primarily involving the left anterior prefrontal cortex and right superior corona radiata, left retrosplenial cortex and left superior corona radiata, as well as the left ventral anterior cingulate cortex and body of corpus callosum. Besides, we discovered that these abnormal connections are closely related to social impairment and restrictive and repetitive behaviors in ASD. In conclusion, this study provides a gray-white matter functional connectivity perspective for the diagnosis and understanding of ASD.