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1.
Hum Brain Mapp ; 44(15): 5125-5138, 2023 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-37608591

RESUMEN

While animal models indicate altered brain dopaminergic neurotransmission after premature birth, corresponding evidence in humans is scarce due to missing molecular imaging studies. To overcome this limitation, we studied dopaminergic neurotransmission changes in human prematurity indirectly by evaluating the spatial co-localization of regional alterations in blood oxygenation fluctuations with the distribution of adult dopaminergic neurotransmission. The study cohort comprised 99 very premature-born (<32 weeks of gestation and/or birth weight below 1500 g) and 107 full-term born young adults, being assessed by resting-state functional MRI (rs-fMRI) and IQ testing. Normative molecular imaging dopamine neurotransmission maps were derived from independent healthy control groups. We computed the co-localization of local (rs-fMRI) activity alterations in premature-born adults with respect to term-born individuals to different measures of dopaminergic neurotransmission. We performed selectivity analyses regarding other neuromodulatory systems and MRI measures. In addition, we tested if the strength of the co-localization is related to perinatal measures and IQ. We found selectively altered co-localization of rs-fMRI activity in the premature-born cohort with dopamine-2/3-receptor availability in premature-born adults. Alterations were specific for the dopaminergic system but not for the used MRI measure. The strength of the co-localization was negatively correlated with IQ. In line with animal studies, our findings support the notion of altered dopaminergic neurotransmission in prematurity which is associated with cognitive performance.


Asunto(s)
Cognición , Dopamina , Imágenes Dopaminérgicas , Recien Nacido Extremadamente Prematuro , Nacimiento Prematuro , Transmisión Sináptica , Dopamina/fisiología , Nacimiento Prematuro/diagnóstico por imagen , Nacimiento Prematuro/psicología , Humanos , Masculino , Femenino , Lactante , Adulto Joven , Imagen por Resonancia Magnética , Saturación de Oxígeno , Pruebas de Inteligencia
2.
Neuroimage ; 264: 119750, 2022 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-36379421

RESUMEN

The myelin concentration and the degree of myelination of nerve fibers can provide valuable information on the integrity of human brain tissue. Magnetic resonance imaging (MRI) of myelin-sensitive parameters can help to non-invasively evaluate demyelinating diseases such as multiple sclerosis (MS). Several different myelin-sensitive MRI methods have been proposed to determine measures of the degree of myelination, in particular the g-ratio. However, variability in underlying physical principles and different biological models influence measured myelin concentrations, and consequently g-ratio values. We therefore investigated similarities and differences between five different myelin-sensitive MRI measures and their effects on g-ratio mapping in the brains of both MS patients and healthy volunteers. We compared two different estimates of the myelin water fraction (MWF) as well as the inhomogeneous magnetization transfer ratio (ihMTR), magnetization transfer saturation (MTsat), and macromolecular tissue volume (MTV) in 13 patients with MS and 14 healthy controls. In combination with diffusion-weighted imaging, we derived g-ratio parameter maps for each of the five different myelin measures. The g-ratio values calculated from different myelin measures varied strongly, especially in MS lesions. While, compared to normal-appearing white matter, MTsat and one estimate of the MWF resulted in higher g-ratio values within lesions, ihMTR, MTV, and the second MWF estimate resulted in lower lesion g-ratio values. As myelin-sensitive measures provide rough estimates of myelin content rather than absolute myelin concentrations, resulting g-ratio values strongly depend on the utilized myelin measure and model used for g-ratio mapping. When comparing g-ratio values, it is, thus, important to utilize the same MRI methods and models or to consider methodological differences. Particular caution is necessary in pathological tissue such as MS lesions.


Asunto(s)
Esclerosis Múltiple , Sustancia Blanca , Humanos , Vaina de Mielina/patología , Esclerosis Múltiple/diagnóstico por imagen , Esclerosis Múltiple/patología , Imagen por Resonancia Magnética/métodos , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología , Agua
3.
Cereb Cortex ; 31(12): 5549-5559, 2021 10 22.
Artículo en Inglés | MEDLINE | ID: mdl-34171095

RESUMEN

Several observations suggest an impact of prematurity on the claustrum. First, the claustrum's development appears to depend on transient subplate neurons of intra-uterine brain development, which are affected by prematurity. Second, the claustrum is the most densely connected region of the mammalian forebrain relative to its volume; due to its effect on pre-oligodendrocytes, prematurity impacts white matter connections and thereby the development of sources and targets of such connections, potentially including the claustrum. Third, due to its high connection degree, the claustrum contributes to general cognitive functioning (e.g., selective attention and task switching/maintaining); general cognitive functioning, however, is at risk in prematurity. Thus, we hypothesized altered claustrum structure after premature birth, with these alterations being associated with impaired general cognitive performance in premature born persons. Using T1-weighted and diffusion-weighted magnetic resonance imaging in 70 very preterm/very low-birth-weight (VP/VLBW) born adults and 87 term-born adults, we found specifically increased mean diffusivity in the claustrum of VP/VLBW adults, associated both with low birth weight and at-trend with reduced IQ. This result demonstrates altered claustrum microstructure after premature birth. Data suggest aberrant claustrum development, which is potentially related with aberrant subplate neuron and forebrain connection development of prematurity.


Asunto(s)
Claustro , Nacimiento Prematuro , Sustancia Blanca , Encéfalo/patología , Imagen de Difusión por Resonancia Magnética , Femenino , Humanos , Recien Nacido Extremadamente Prematuro , Recién Nacido , Recién Nacido de muy Bajo Peso/fisiología , Imagen por Resonancia Magnética , Embarazo , Nacimiento Prematuro/patología , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología
4.
Eur J Neurosci ; 53(10): 3362-3377, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33764572

RESUMEN

Visual information processing requires an efficient visual attention system. The neural theory of visual attention (TVA) proposes that visual processing speed depends on the coordinated activity between frontoparietal and occipital brain areas. Previous research has shown that the coordinated activity between (i.e., functional connectivity and "inter-FC") cingulo-opercular (COn) and right-frontoparietal (RFPn) networks is linked to visual processing speed. However, how inter-FC of COn and RFPn with visual networks links to visual processing speed has not been directly addressed yet. Forty-eight healthy adult participants (27 females) underwent resting-state (rs-)fMRI and performed a whole-report psychophysical task. To obtain inter-FC, we analyzed the entire frequency range available in our rs-fMRI data (i.e., 0.01-0.4 Hz) to avoid discarding neural information. Following previous approaches, we analyzed the data across frequency bins (Hz): Slow-5 (0.01-0.027), Slow-4 (0.027-0.073), Slow-3 (0.073-0.198), and Slow-2 (0.198-0.4). We used the mathematical TVA framework to estimate an individual, latent-level visual processing speed parameter. We found that visual processing speed was negatively associated with inter-FC between RFPn and visual networks in Slow-5 and Slow-2, with no corresponding significant association for inter-FC between COn and visual networks. These results provide the first empirical evidence that links inter-FC between RFPn and visual networks with the visual processing speed parameter. These findings suggest that direct connectivity between occipital and right frontoparietal, but not frontoinsular, regions support visual processing speed.


Asunto(s)
Mapeo Encefálico , Percepción Visual , Adulto , Encéfalo , Cognición , Femenino , Humanos , Imagen por Resonancia Magnética , Vías Nerviosas/diagnóstico por imagen
5.
Hum Brain Mapp ; 42(18): 5862-5872, 2021 12 15.
Artículo en Inglés | MEDLINE | ID: mdl-34520080

RESUMEN

In the last two decades, neuroscience has produced intriguing evidence for a central role of the claustrum in mammalian forebrain structure and function. However, relatively few in vivo studies of the claustrum exist in humans. A reason for this may be the delicate and sheet-like structure of the claustrum lying between the insular cortex and the putamen, which makes it not amenable to conventional segmentation methods. Recently, Deep Learning (DL) based approaches have been successfully introduced for automated segmentation of complex, subcortical brain structures. In the following, we present a multi-view DL-based approach to segment the claustrum in T1-weighted MRI scans. We trained and evaluated the proposed method in 181 individuals, using bilateral manual claustrum annotations by an expert neuroradiologist as reference standard. Cross-validation experiments yielded median volumetric similarity, robust Hausdorff distance, and Dice score of 93.3%, 1.41 mm, and 71.8%, respectively, representing equal or superior segmentation performance compared to human intra-rater reliability. The leave-one-scanner-out evaluation showed good transferability of the algorithm to images from unseen scanners at slightly inferior performance. Furthermore, we found that DL-based claustrum segmentation benefits from multi-view information and requires a sample size of around 75 MRI scans in the training set. We conclude that the developed algorithm allows for robust automated claustrum segmentation and thus yields considerable potential for facilitating MRI-based research of the human claustrum. The software and models of our method are made publicly available.


Asunto(s)
Claustro/anatomía & histología , Claustro/diagnóstico por imagen , Aprendizaje Profundo , Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética/métodos , Neuroimagen/métodos , Humanos
6.
Neuroimage ; 208: 116438, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-31811902

RESUMEN

Premature birth bears an increased risk for aberrant brain development concerning its structure and function. Cortical complexity (CC) expresses the fractal dimension of the brain surface and changes during neurodevelopment. We hypothesized that CC is altered after premature birth and associated with long-term cognitive development. One-hundred-and-one very premature-born adults (gestational age <32 weeks and/or birth weight <1500 â€‹g) and 111 term-born adults were assessed by structural MRI and cognitive testing at 26 years of age. CC was measured based on MRI by vertex-wise estimation of fractal dimension. Cognitive performance was measured based on Griffiths-Mental-Development-Scale (at 20 months) and Wechsler-Adult-Intelligence-Scales (at 26 years). In premature-born adults, CC was decreased bilaterally in large lateral temporal and medial parietal clusters. Decreased CC was associated with lower gestational age and birth weight. Furthermore, decreased CC in the medial parietal cortices was linked with reduced full-scale IQ of premature-born adults and mediated the association between cognitive development at 20 months and IQ in adulthood. Results demonstrate that CC is reduced in very premature-born adults in temporoparietal cortices, mediating the impact of prematurity on impaired cognitive development. These data indicate functionally relevant long-term alterations in the brain's basic geometry of cortical organization in prematurity.


Asunto(s)
Corteza Cerebral/anatomía & histología , Corteza Cerebral/crecimiento & desarrollo , Desarrollo Humano/fisiología , Recien Nacido Prematuro/crecimiento & desarrollo , Inteligencia/fisiología , Adulto , Peso al Nacer/fisiología , Corteza Cerebral/diagnóstico por imagen , Femenino , Estudios de Seguimiento , Fractales , Edad Gestacional , Humanos , Recién Nacido , Imagen por Resonancia Magnética , Masculino , Escalas de Wechsler
7.
Neuroimage ; 208: 116440, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-31841682

RESUMEN

Aging impacts both visual short-term memory (vSTM) capacity and thalamo-cortical connectivity. According to the Neural Theory of Visual Attention, vSTM depends on the structural connectivity between posterior thalamus and visual occipital cortices (PT-OC). We tested whether aging modifies the association between vSTM capacity and PT-OC structural connectivity. To do so, 66 individuals aged 20-77 years were assessed by diffusion-weighted imaging used for probabilistic tractography and performed a psychophysical whole-report task of briefly presented letter arrays, from which vSTM capacity estimates were derived. We found reduced vSTM capacity, and aberrant PT-OC connection probability in aging. Critically, age modified the relationship between vSTM capacity and PT-OC connection probability: in younger adults, vSTM capacity was negatively correlated with PT-OC connection probability while in older adults, this association was positive. Furthermore, age modified the microstructure of PT-OC tracts suggesting that the inversion of the association between PT-OC connection probability and vSTM capacity with aging might reflect age-related changes in white-matter properties. Accordingly, our results demonstrate that age-related differences in vSTM capacity links with the microstructure and connectivity of PT-OC tracts.


Asunto(s)
Envejecimiento/patología , Envejecimiento/fisiología , Atención/fisiología , Memoria a Corto Plazo/fisiología , Red Nerviosa/anatomía & histología , Lóbulo Occipital/anatomía & histología , Tálamo/anatomía & histología , Percepción Visual/fisiología , Adulto , Anciano , Imagen de Difusión Tensora , Femenino , Humanos , Masculino , Persona de Mediana Edad , Red Nerviosa/diagnóstico por imagen , Lóbulo Occipital/diagnóstico por imagen , Tálamo/diagnóstico por imagen , Adulto Joven
8.
Hum Brain Mapp ; 41(17): 4952-4963, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32820839

RESUMEN

Cortical thickness (CTh) reflects cortical properties such as dendritic complexity and synaptic density, which are not only vulnerable to developmental disturbances caused by premature birth but also highly relevant for cognitive performance. We tested the hypotheses whether CTh in young adults is altered after premature birth and whether these aberrations are relevant for general cognitive abilities. We investigated CTh based on brain structural magnetic resonance imaging and surface-based morphometry in a large and prospectively collected cohort of 101 very premature-born adults (<32 weeks of gestation and/or birth weight [BW] below 1,500 g) and 111 full-term controls at 26 years of age. Cognitive performance was assessed by full-scale intelligence quotient (IQ) using the Wechsler Adult Intelligence Scale. CTh was reduced in frontal, parietal, and temporal associative cortices predominantly in the left hemisphere in premature-born adults compared to controls. We found a significant positive association of CTh with both gestational age and BW, particularly in the left hemisphere, and a significant negative association between CTh and intensity of neonatal treatment within limited regions bilaterally. Full-scale IQ and CTh in the left hemisphere were positively correlated. Furthermore, CTh in the left hemisphere acted as a mediator on the association between premature birth and full-scale IQ. Results provide evidence that premature born adults have widespread reduced CTh that is relevant for their general cognitive performance. Data suggest lasting reductions in cortical microstructure subserving CTh after premature birth.


Asunto(s)
Peso al Nacer/fisiología , Corteza Cerebral/patología , Cognición/fisiología , Recien Nacido Prematuro/fisiología , Inteligencia/fisiología , Adulto , Corteza Cerebral/diagnóstico por imagen , Femenino , Edad Gestacional , Humanos , Recien Nacido Extremadamente Prematuro/fisiología , Recién Nacido , Estudios Longitudinales , Imagen por Resonancia Magnética , Masculino
9.
Hum Brain Mapp ; 41(18): 5215-5227, 2020 12 15.
Artículo en Inglés | MEDLINE | ID: mdl-32845045

RESUMEN

Reduced global hippocampus volumes have been demonstrated in premature-born individuals, from newborns to adults; however, it is unknown whether hippocampus subfield (HCSF) volumes are differentially affected by premature birth and how relevant they are for cognitive performance. To address these questions, we investigated magnetic resonance imaging (MRI)-derived HCSF volumes in very premature-born adults, and related them with general cognitive performance in adulthood. We assessed 103 very premature-born (gestational age [GA] <32 weeks and/or birth weight <1,500 g) and 109 term-born individuals with cognitive testing and structural MRI at 26 years of age. HCSFs were automatically segmented based on three-dimensional T1- and T2-weighted sequences and studied both individually and grouped into three functional units, namely hippocampus proper (HP), subicular complex (SC), and dentate gyrus (DG). Cognitive performance was measured using the Wechsler-Adult-Intelligence-Scale (full-scale intelligence quotient [FS-IQ]) at 26 years. We observed bilateral volume reductions for almost all HCSF volumes in premature-born adults and associations with GA and neonatal treatment intensity but not birth weight. Left-sided HP, SC, and DG volumes were associated with adult FS-IQ. Furthermore, left DG volume was a mediator of the association between GA and adult FS-IQ in premature-born individuals. Results demonstrate nonspecifically reduced HCSF volumes in premature-born adults; but specific associations with cognitive outcome highlight the importance of the left DG. Data suggest that specific interventions toward hippocampus function might be promising to lower adverse cognitive effects of prematurity.


Asunto(s)
Peso al Nacer/fisiología , Lateralidad Funcional/fisiología , Hipocampo/anatomía & histología , Recién Nacido de Bajo Peso/fisiología , Recien Nacido Prematuro/fisiología , Inteligencia/fisiología , Adulto , Giro Dentado/anatomía & histología , Giro Dentado/diagnóstico por imagen , Femenino , Edad Gestacional , Hipocampo/diagnóstico por imagen , Humanos , Interpretación de Imagen Asistida por Computador , Recien Nacido Extremadamente Prematuro/fisiología , Recién Nacido , Estudios Longitudinales , Imagen por Resonancia Magnética , Masculino , Escalas de Wechsler
10.
Brain ; 142(5): 1255-1269, 2019 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-31032850

RESUMEN

Gyrification is a hallmark of human brain development, starting in the second half of gestation in primary cortices, followed by unimodal and then transmodal associative cortices. Alterations in gyrification have been noted in premature-born newborns and children, suggesting abnormal cortical folding to be a permanent feature of prematurity. Furthermore, both gyrification and prematurity are tightly linked with cognitive performance, indicating a link between prematurity, gyrification, and cognitive performance. To investigate this triangular relation, we tested the following two hypotheses: (i) gyrification is aberrant in premature-born adults; and (ii) aberrant gyrification contributes to the impact of prematurity on adult cognitive performance. One hundred and one very premature-born adults (i.e. adults born before 32 weeks of gestation, and/or with birth weight <1500 g) and 111 mature-born adults were assessed by structural MRI and cognitive testing at 27 years of age. Gyrification was measured by local cortical absolute mean curvature (AMC), evaluated through structural MRI. Cognitive performance was assessed by the Wechsler Adult Intelligence Scale, full-scale IQ test. Two-sample t-tests, regression and mediation analyses were used to assess AMC group differences and the relation between AMC, birth-related variables, and full-scale IQ. Three key findings were identified. First, local AMC was widely increased in fronto-temporo-parietal primary and associative cortices of very premature-born adults. Increase of AMC was inversely associated with gestational age and birth weight and positively associated with medical complications at birth, respectively. Second, increased AMC of temporal associative cortices specifically contributed to the association between prematurity and reduced adult IQ (two-path mediation), indicating that aberrant gyrification of temporal associative cortices is critical for impaired cognitive performance after premature birth. Finally, further investigation of the relationship of gyrification between the early folding postcentral cortices and associative temporal cortices, folding later during neurodevelopment, revealed that the effect of gyrification abnormalities in associative temporal cortices on adult IQ is influenced itself by gyrification abnormalities occurring in the early folding postcentral cortices (three-path mediation). These results indicate that gyrification development across cortical areas in the brain conveys prematurity effects on adult IQ. Overall, these results provide evidence that premature birth leads to permanently aberrant gyrification patterns suggesting an altered neurodevelopmental trajectory. Statistical mediation modelling suggests that both aberrant gyrification itself as well as its propagation across the cortex express aspects of impaired neurodevelopment after premature birth and lead to reduced cognitive performance in adulthood. Thus, markers of gyrification appear as potential candidates for prognosis and treatment of prematurity effects.


Asunto(s)
Corteza Cerebral/anomalías , Corteza Cerebral/diagnóstico por imagen , Edad Gestacional , Inteligencia/fisiología , Nacimiento Prematuro/diagnóstico por imagen , Nacimiento Prematuro/psicología , Adulto , Femenino , Estudios de Seguimiento , Humanos , Recién Nacido , Estudios Longitudinales , Masculino , Escalas de Wechsler
11.
J Neurosci ; 38(20): 4655-4665, 2018 05 16.
Artículo en Inglés | MEDLINE | ID: mdl-29712788

RESUMEN

The axon guidance cue receptor DCC (deleted in colorectal cancer) plays a critical role in the organization of mesocorticolimbic pathways in rodents. To investigate whether this occurs in humans, we measured (1) anatomical connectivity between the substantia nigra/ventral tegmental area (SN/VTA) and forebrain targets, (2) striatal and cortical volumes, and (3) putatively associated traits and behaviors. To assess translatability, morphometric data were also collected in Dcc-haploinsufficient mice. The human volunteers were 20 DCC+/- mutation carriers, 16 DCC+/+ relatives, and 20 DCC+/+ unrelated healthy volunteers (UHVs; 28 females). The mice were 11 Dcc+/- and 16 wild-type C57BL/6J animals assessed during adolescence and adulthood. Compared with both control groups, the human DCC+/- carriers exhibited the following: (1) reduced anatomical connectivity from the SN/VTA to the ventral striatum [DCC+/+: p = 0.0005, r(effect size) = 0.60; UHV: p = 0.0029, r = 0.48] and ventral medial prefrontal cortex (DCC+/+: p = 0.0031, r = 0.53; UHV: p = 0.034, r = 0.35); (2) lower novelty-seeking scores (DCC+/+: p = 0.034, d = 0.82; UHV: p = 0.019, d = 0.84); and (3) reduced striatal volume (DCC+/+: p = 0.0009, d = 1.37; UHV: p = 0.0054, d = 0.93). Striatal volumetric reductions were also present in Dcc+/- mice, and these were seen during adolescence (p = 0.0058, d = 1.09) and adulthood (p = 0.003, d = 1.26). Together these findings provide the first evidence in humans that an axon guidance gene is involved in the formation of mesocorticolimbic circuitry and related behavioral traits, providing mechanisms through which DCC mutations might affect susceptibility to diverse neuropsychiatric disorders.SIGNIFICANCE STATEMENT Opportunities to study the effects of axon guidance molecules on human brain development have been rare. Here, the identification of a large four-generational family that carries a mutation to the axon guidance molecule receptor gene, DCC, enabled us to demonstrate effects on mesocorticolimbic anatomical connectivity, striatal volumes, and personality traits. Reductions in striatal volumes were replicated in DCC-haploinsufficient mice. Together, these processes might influence mesocorticolimbic function and susceptibility to diverse neuropsychiatric disorders.


Asunto(s)
Receptor DCC/genética , Sistema Límbico/fisiopatología , Vías Nerviosas/fisiopatología , Corteza Prefrontal/fisiopatología , Adulto , Envejecimiento/psicología , Animales , Axones , Conducta Exploratoria , Femenino , Heterocigoto , Humanos , Sistema Límbico/diagnóstico por imagen , Imagen por Resonancia Magnética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Persona de Mediana Edad , Vías Nerviosas/diagnóstico por imagen , Trastornos de la Personalidad/genética , Trastornos de la Personalidad/psicología , Corteza Prefrontal/diagnóstico por imagen , Trastornos Relacionados con Sustancias/genética , Trastornos Relacionados con Sustancias/psicología , Sustancia Negra/diagnóstico por imagen , Sustancia Negra/fisiopatología , Área Tegmental Ventral/diagnóstico por imagen , Área Tegmental Ventral/fisiopatología , Adulto Joven
12.
Neuroimage ; 195: 67-77, 2019 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-30928688

RESUMEN

In the theory of visual attention (TVA), it is suggested that objects in a visual scene compete for representation in a visual short-term memory (vSTM) store. The race towards the store is assumed to be biased by top-down controlled weighting of the objects according to their task relevance. Only objects that reach the store before its capacity limitation is reached are represented consciously in a given instant. TVA-based computational modeling of participants' performance in whole- and partial-report tasks permits independent parameters of individual efficiency of top-down control α and vSTM storage capacity K to be extracted. The neural interpretation of the TVA proposes recurrent loops between the posterior thalamus and posterior visual cortices to be relevant for generating attentional weights for competing objects and for maintaining selected objects in vSTM. Accordingly, we tested whether structural connectivity between posterior thalamus and occipital cortices (PT-OC) is associated with estimates of top-down control and vSTM capacity. We applied whole- and partial-report tasks and probabilistic tractography in a sample of 37 healthy adults. We found vSTM capacity K to be associated with left PT-OC structural connectivity and a trend-wise relation between top-down control α and right PT-OC structural connectivity. These findings support the assumption of the relevance of thalamic structures and their connections to visual cortex for top-down control and vSTM capacity.


Asunto(s)
Atención/fisiología , Memoria a Corto Plazo/fisiología , Lóbulo Occipital/fisiología , Tálamo/fisiología , Adulto , Imagen de Difusión Tensora/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Vías Nerviosas/fisiología , Adulto Joven
13.
Hum Brain Mapp ; 40(14): 4058-4071, 2019 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-31179600

RESUMEN

The dorsal attention network (DAN), including frontal eye fields and posterior parietal cortices, and its link with the posterior thalamus, contribute to visual-spatial abilities. Very premature birth impairs both visual-spatial abilities and cortico-thalamic structural connectivity. We hypothesized that impaired structural DAN-pulvinar connectivity mediates the effect of very premature birth on adult visual-spatial abilities. Seventy very premature (median age 26.6 years) and 57 mature born adults (median age 26.6 years) were assessed with cognitive tests and diffusion tensor imaging. Perceptual organization (PO) index of the Wechsler Adult Intelligence Scale-III was used as a proxy for visual-spatial abilities, and connection probability maps in the thalamus, derived from probabilistic tractography from the DAN, were used as a proxy for DAN-thalamic connectivity. Premature born adults showed decreases in both PO-index and connection probability from DAN into the pulvinar, with both changes being positively correlated. Moreover, path analysis revealed that DAN-pulvinar connectivity mediates the relationship between very premature birth and PO-index. Results provide evidence for long-term effects of very premature birth on structural DAN-pulvinar connectivity, mediating the effect of prematurity on adult visual-spatial impairments. Data suggest DAN-pulvinar connectivity as a specific target of prognostic and diagnostic procedures for visual-spatial abilities after premature birth.


Asunto(s)
Encéfalo/fisiopatología , Recien Nacido Prematuro , Vías Nerviosas/fisiopatología , Trastornos de la Percepción/fisiopatología , Navegación Espacial/fisiología , Percepción Visual/fisiología , Adulto , Imagen de Difusión Tensora , Femenino , Humanos , Recién Nacido , Masculino , Trastornos de la Percepción/etiología
14.
Neuroimage ; 150: 68-76, 2017 04 15.
Artículo en Inglés | MEDLINE | ID: mdl-28188917

RESUMEN

Preterm birth is associated with an increased risk for lasting changes in both the cortico-thalamic system and attention; however, the link between cortico-thalamic and attention changes is as yet little understood. In preterm newborns, cortico-cortical and cortico-thalamic structural connectivity are distinctively altered, with increased local clustering for cortico-cortical and decreased integrity for cortico-thalamic connectivity. In preterm-born adults, among the various attention functions, visual short-term memory (vSTM) capacity is selectively impaired. We hypothesized distinct associations between vSTM capacity and the structural integrity of cortico-thalamic and cortico-cortical connections, respectively, in preterm-born adults. A whole-report paradigm of briefly presented letter arrays based on the computationally formalized Theory of Visual Attention (TVA) was used to quantify parameter vSTM capacity in 26 preterm- and 21 full-term-born adults. Fractional anisotropy (FA) of posterior thalamic radiations and the splenium of the corpus callosum obtained by diffusion tensor imaging were analyzed by tract-based spatial statistics and used as proxies for cortico-thalamic and cortico-cortical structural connectivity. The relationship between vSTM capacity and cortico-thalamic and cortico-cortical connectivity, respectively, was significantly modified by prematurity. In full-term-born adults, the higher FA in the right posterior thalamic radiation the higher vSTM capacity; in preterm-born adults this FA-vSTM-relationship was inversed. In the splenium, higher FA was correlated with higher vSTM capacity in preterm-born adults, whereas no significant relationship was evident in full-term-born adults. These results indicate distinct associations between cortico-thalamic and cortico-cortical integrity and vSTM capacity in preterm-and full-term-born adults. Data suggest compensatory cortico-cortical fiber re-organization for attention deficits after preterm delivery.


Asunto(s)
Cuerpo Calloso/patología , Trastornos de la Memoria/patología , Vías Nerviosas/patología , Nacimiento Prematuro/patología , Tálamo/patología , Adulto , Atención/fisiología , Imagen de Difusión Tensora , Femenino , Humanos , Interpretación de Imagen Asistida por Computador , Estudios Longitudinales , Masculino , Trastornos de la Memoria/etiología , Memoria a Corto Plazo/fisiología , Embarazo , Percepción Visual/fisiología
15.
Artículo en Inglés | MEDLINE | ID: mdl-35276405

RESUMEN

BACKGROUND: Microscopic studies in newborns and animal models indicate impaired myelination after premature birth, particularly for cortical myelination; however, it remains unclear whether such myelination impairments last into adulthood and, if so, are relevant for impaired cognitive performance. It has been suggested that the ratio of T1-weighted (T1w) and T2-weighted (T2w) magnetic resonance imaging signal intensity (T1w/T2w ratio) is a proxy for myelin content. We hypothesized altered gray matter (GM) T1w/T2w ratio in premature-born adults, which is associated with lower cognitive performance after premature birth. METHODS: We analyzed GM T1w/T2w ratio in 101 adults born very premature (VP) and/or at very low birth weight (VLBW) (<32 weeks of gestation and/or birth weight <1500 g) and 109 full-term control subjects at 26 years of age, controlled for voxelwise volume alterations. Cognitive performance was assessed by verbal, performance, and full scale IQ using the Wechsler Adult Intelligence Scale. RESULTS: Significantly higher T1w/T2w ratio in VP/VLBW subjects was found bilaterally in widespread cortical areas, particularly in frontal, parietal, and temporal cortices, and in putamen and pallidum. In these areas, T1w/T2w ratio was not related to birth variables, such as gestational age, or IQ scores. In contrast, significantly lower T1w/T2w ratio in VP/VLBW subjects was found in bilateral clusters in superior temporal gyrus, which was associated with birth weight in the VP/VLBW group. Furthermore, lower T1w/T2w ratio in left superior temporal gyrus was associated with lower full scale and verbal IQ. CONCLUSIONS: Results demonstrate GM T1w/T2w ratio alterations in premature-born adults and suggest altered GM myelination development after premature birth with lasting and functionally relevant effects into early adulthood.


Asunto(s)
Sustancia Gris , Nacimiento Prematuro , Humanos , Femenino , Sustancia Gris/patología , Nacimiento Prematuro/patología , Imagen por Resonancia Magnética/métodos , Peso al Nacer
16.
Neuroimage Clin ; 37: 103286, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36516730

RESUMEN

The human claustrum is a gray matter structure in the white matter between insula and striatum. Previous analysis found altered claustrum microstructure in very preterm-born adults associated with lower cognitive performance. As the claustrum development is related to hypoxia-ischemia sensitive transient cell populations being at-risk in premature birth, we hypothesized that claustrum structure is already altered in preterm-born neonates. We studied anatomical and diffusion-weighted MRIs of 83 preterm- and 83 term-born neonates at term-equivalent age. Additionally, claustrum development was analyzed both in a spectrum of 377 term-born neonates and longitudinally in 53 preterm-born subjects. Data was provided by the developing Human Connectome Project. Claustrum development showed increasing volume, increasing fractional anisotropy (FA), and decreasing mean diffusivity (MD) around term both across term- and preterm-born neonates. Relative to term-born ones, preterm-born neonates had (i) increased absolute and relative claustrum volumes, both indicating increased cellular and/or extracellular matter and being in contrast to other subcortical gray matter regions of decreased volumes such as thalamus; (ii) lower claustrum FA and higher claustrum MD, pointing at increased extracellular matrix and impaired axonal integrity; and (iii) aberrant covariance between claustrum FA and MD, respectively, and that of distributed gray matter regions, hinting at relatively altered claustrum microstructure. Results together demonstrate specifically aberrant claustrum structure in preterm-born neonates, suggesting altered claustrum development in prematurity, potentially relevant for later cognitive performance.


Asunto(s)
Claustro , Nacimiento Prematuro , Sustancia Blanca , Recién Nacido , Adulto , Embarazo , Femenino , Humanos , Encéfalo , Imagen de Difusión Tensora/métodos , Imagen por Resonancia Magnética , Recien Nacido Prematuro , Sustancia Blanca/diagnóstico por imagen
17.
Brain Commun ; 5(1): fcac341, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36632185

RESUMEN

A universal allometric scaling law has been proposed to describe cortical folding of the mammalian brain as a function of the product of cortical surface area and the square root of cortical thickness across different mammalian species, including humans. Since these cortical properties are vulnerable to developmental disturbances caused by preterm birth in humans and since these alterations are related to cognitive impairments, we tested (i) whether cortical folding in preterm-born adults follows this cortical scaling law and (ii) the functional relevance of potential scaling aberrances. We analysed the cortical scaling relationship in a large and prospectively collected cohort of 91 very premature-born adults (<32 weeks of gestation and/or birthweight <1500 g, very preterm and/or very low birth weight) and 105 full-term controls at 26 years of age based on the total surface area, exposed surface area and average cortical thickness measured with structural magnetic resonance imaging and surface-based morphometry. We found that the slope of the log-transformed cortical scaling relationship was significantly altered in adults (very preterm and/or very low birth weight: 1.24, full-term: 1.14, P = 0.018). More specifically, the slope was significantly altered in male adults (very preterm and/or very low birth weight: 1.24, full-term: 1.00, P = 0.031), while there was no significant difference in the slope of female adults (very preterm and/or very low birth weight: 1.27, full-term: 1.12, P = 0.225). Furthermore, offset was significantly lower compared with full-term controls in both male (very preterm and/or very low birth weight: -0.546, full-term: -0.538, P = 0.001) and female adults (very preterm and/or very low birth weight: -0.545, full-term: -0.538, P = 0.023), indicating a systematic shift of the regression line after preterm birth. Gestational age had a significant effect on the slope in very preterm and/or very low birth weight adults and more specifically in male very preterm and/or very low birth weight adults, indicating that the difference in slope is specifically related to preterm birth. The shape or tension term of the scaling law had no significant effect on cognitive performance, while the size of the cortex did. Results demonstrate altered scaling of cortical surface and cortical thickness in very premature-born adults. Data suggest altered mechanical forces acting on the cortex after preterm birth.

18.
CNS Neurosci Ther ; 29(11): 3199-3211, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37365964

RESUMEN

AIMS: To investigate cortical organization in brain magnetic resonance imaging (MRI) of preterm-born adults using percent contrast of gray-to-white matter signal intensities (GWPC), which is an in vivo proxy measure for cortical microstructure. METHODS: Using structural MRI, we analyzed GWPC at different percentile fractions across the cortex (0%, 10%, 20%, 30%, 40%, 50%, and 60%) in a large and prospectively collected cohort of 86 very preterm-born (<32 weeks of gestation and/or birth weight <1500 g, VP/VLBW) adults and 103 full-term controls at 26 years of age. Cognitive performance was assessed by full-scale intelligence quotient (IQ) using the Wechsler Adult Intelligence Scale. RESULTS: GWPC was significantly decreased in VP/VLBW adults in frontal, parietal, and temporal associative cortices, predominantly in the right hemisphere. Differences were pronounced at 20%, 30%, and 40%, hence, in middle cortical layers. GWPC was significantly increased in right paracentral lobule in VP/VLBW adults. GWPC in frontal and temporal cortices was positively correlated with birth weight, and negatively with duration of ventilation (p < 0.05). Furthermore, GWPC in right paracentral lobule was negatively correlated with IQ (p < 0.05). CONCLUSIONS: Widespread aberrant gray-to-white matter contrast suggests lastingly altered cortical microstructure after preterm birth, mainly in middle cortical layers, with differential effects on associative and primary cortices.


Asunto(s)
Nacimiento Prematuro , Sustancia Blanca , Femenino , Humanos , Adulto , Recién Nacido , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología , Peso al Nacer , Recién Nacido de muy Bajo Peso , Nacimiento Prematuro/diagnóstico por imagen , Nacimiento Prematuro/patología , Sustancia Gris/diagnóstico por imagen , Sustancia Gris/patología , Encéfalo/diagnóstico por imagen , Imagen por Resonancia Magnética
19.
Front Psychiatry ; 13: 925476, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36203848

RESUMEN

For decades, aberrant dopamine transmission has been proposed to play a central role in schizophrenia pathophysiology. These theories are supported by human in vivo molecular imaging studies of dopamine transmission, particularly positron emission tomography. However, there are several downsides to such approaches, for example limited spatial resolution or restriction of the measurement to synaptic processes of dopaminergic neurons. To overcome these limitations and to measure complementary aspects of dopamine transmission, magnetic resonance imaging (MRI)-based approaches investigating the macrostructure, metabolism, and connectivity of dopaminergic nuclei, i.e., substantia nigra pars compacta and ventral tegmental area, can be employed. In this scoping review, we focus on four dopamine MRI methods that have been employed in patients with schizophrenia so far: neuromelanin MRI, which is thought to measure long-term dopamine function in dopaminergic nuclei; morphometric MRI, which is assumed to measure the volume of dopaminergic nuclei; diffusion MRI, which is assumed to measure fiber-based structural connectivity of dopaminergic nuclei; and resting-state blood-oxygenation-level-dependent functional MRI, which is thought to measure functional connectivity of dopaminergic nuclei based on correlated blood oxygenation fluctuations. For each method, we describe the underlying signal, outcome measures, and downsides. We present the current state of research in schizophrenia and compare it to other disorders with either similar (psychotic) symptoms, i.e., bipolar disorder and major depressive disorder, or dopaminergic abnormalities, i.e., substance use disorder and Parkinson's disease. Finally, we discuss overarching issues and outline future research questions.

20.
Clin Neuroradiol ; 32(3): 665-676, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35072752

RESUMEN

PURPOSE: Intrauterine claustrum and subplate neuron development have been suggested to overlap. As premature birth typically impairs subplate neuron development, neonatal claustrum might indicate a specific prematurity impact; however, claustrum identification usually relies on expert knowledge due to its intricate structure. We established automated claustrum segmentation in newborns. METHODS: We applied a deep learning-based algorithm for segmenting the claustrum in 558 T2-weighted neonatal brain MRI of the developing Human Connectome Project (dHCP) with transfer learning from claustrum segmentation in T1-weighted scans of adults. The model was trained and evaluated on 30 manual bilateral claustrum annotations in neonates. RESULTS: With only 20 annotated scans, the model yielded median volumetric similarity, robust Hausdorff distance and Dice score of 95.9%, 1.12 mm and 80.0%, respectively, representing an excellent agreement between the automatic and manual segmentations. In comparison with interrater reliability, the model achieved significantly superior volumetric similarity (p = 0.047) and Dice score (p < 0.005) indicating stable high-quality performance. Furthermore, the effectiveness of the transfer learning technique was demonstrated in comparison with nontransfer learning. The model can achieve satisfactory segmentation with only 12 annotated scans. Finally, the model's applicability was verified on 528 scans and revealed reliable segmentations in 97.4%. CONCLUSION: The developed fast and accurate automated segmentation has great potential in large-scale study cohorts and to facilitate MRI-based connectome research of the neonatal claustrum. The easy to use models and codes are made publicly available.


Asunto(s)
Claustro , Adulto , Humanos , Procesamiento de Imagen Asistido por Computador , Recién Nacido , Aprendizaje Automático , Imagen por Resonancia Magnética , Neuroimagen , Reproducibilidad de los Resultados
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