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1.
Epidemiol Psychiatr Sci ; 29: e166, 2020 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-32895076

RESUMO

Since its discovery in 1997, the default mode network (DMN) and its components have been extensively studied in both healthy individuals and psychiatric patients. Several studies have investigated possible DMN alterations in specific mental conditions such as bipolar disorder (BD). In this review, we describe current evidence from resting-state functional magnetic resonance imaging studies with the aim to understand possible changes in the functioning of the DMN in BD. Overall, several types of analyses including seed-based and independent component have been conducted on heterogeneous groups of patients highlighting different results. Despite the differences, findings seem to indicate that BD is associated with alterations in both frontal and posterior DMN structures, mainly in the prefrontal, posterior cingulate and inferior parietal cortices. We conclude this review by suggesting possible future research directions.


Assuntos
Transtorno Bipolar/diagnóstico por imagem , Mapeamento Encefálico/métodos , Encéfalo/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Rede Nervosa/fisiologia , Vias Neurais/diagnóstico por imagem , Transtorno Bipolar/fisiopatologia , Humanos
2.
PLoS One ; 15(8): e0237032, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32790683

RESUMO

The behavioral activation system (BAS) and the behavioral inhibition system (BIS) have been proposed to relate to stable traits that predict inter-individual differences in motivation. Prior reports point dopamine (DA) pathways, mainly including ventral tegmental area (VTA) and substantia nigra (SN), implicate in subserving reward-related functions associated with BAS and inhibitory functions related with BIS. However, as an important factor that affects DA releasing, it remains an open question whether the ovarian hormones may also be related to BIS/BAS. Here, to investigate effects of the estradiol (E2) and progesterone (PROG) on BIS/BAS and related DA pathways, we employed a BIS/BAS scale and the resting-state functional magnetic resonance imaging (fMRI) during the late follicular phase (FP) and the mid-luteal phase (LP). On the behavioral level, when women had high PROG levels, their E2 levels were found positively correlated with BIS scores, but those women whose PROG levels were low, their E2 levels were negative correlation with BIS scores. On the neural level, we demonstrated BAS was related with the VTA pathway, included brain reward regions of nucleus accumbens (NAc) and orbitofrontal cortex (OFC). Meanwhile, the BIS was correlated with the SN-dorsolateral prefrontal cortex (dlPFC) pathway. ROI-based resting-state functional connectivity (RSFC) analyses further revealed that, RSFC between the SN and dlPFC was modulated by ovarian hormones. With higher PROG levels, increased E2 levels among women were accompanied by stronger RSFC of the SN-dlPFC, but when PROG levels were low, E2 levels were negatively correlated with the SN-dlPFC RSFC. These findings revealed a combined enhancement effect of E2 and PROG on BIS, and the SN-dlPFC pathway was mainly involved in this process.


Assuntos
Encéfalo/fisiologia , Dopamina/fisiologia , Inibição Psicológica , Motivação/fisiologia , Ovário/fisiologia , Adulto , Afeto/fisiologia , Encéfalo/diagnóstico por imagem , Neurônios Dopaminérgicos/fisiologia , Estradiol/fisiologia , Feminino , Neuroimagem Funcional , Humanos , Imagem por Ressonância Magnética , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiologia , Córtex Pré-Frontal/diagnóstico por imagem , Córtex Pré-Frontal/fisiologia , Progesterona/fisiologia , Psicofisiologia , Substância Negra/diagnóstico por imagem , Substância Negra/fisiologia , Área Tegmentar Ventral/diagnóstico por imagem , Área Tegmentar Ventral/fisiologia , Adulto Jovem
3.
Neuron ; 107(3): 580-589.e6, 2020 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-32778224

RESUMO

To induce brain plasticity in humans, we casted the dominant upper extremity for 2 weeks and tracked changes in functional connectivity using daily 30-min scans of resting-state functional MRI (rs-fMRI). Casting caused cortical and cerebellar regions controlling the disused extremity to functionally disconnect from the rest of the somatomotor system, while internal connectivity within the disused sub-circuit was maintained. Functional disconnection was evident within 48 h, progressed throughout the cast period, and reversed after cast removal. During the cast period, large, spontaneous pulses of activity propagated through the disused somatomotor sub-circuit. The adult brain seems to rely on regular use to maintain its functional architecture. Disuse-driven spontaneous activity pulses may help preserve functionally disconnected sub-circuits.


Assuntos
Córtex Motor/diagnóstico por imagem , Plasticidade Neuronal/fisiologia , Restrição Física , Atividades Cotidianas , Moldes Cirúrgicos , Feminino , Lateralidade Funcional , Neuroimagem Funcional , Humanos , Imagem por Ressonância Magnética , Masculino , Córtex Motor/fisiologia , Destreza Motora/fisiologia , Força Muscular/fisiologia , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiologia , Extremidade Superior
4.
PLoS One ; 15(6): e0232570, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32484832

RESUMO

In the last years, there has been a considerable increase of research into the neuroimaging correlates of inter-individual temperament and character variability-an endeavour for which the term 'personality neuroscience' was coined. Among other neuroimaging modalities and approaches, substantial work focuses on functional connectivity in resting state (rs-FC) functional magnetic resonance imaging data. In the current paper, we set out to independently query the questions asked in a highly cited study that reported a range of functional connectivity correlates of personality dimensions assessed by the widely used 'Big Five' Personality Inventory. Using a larger sample (84 subjects) and an equivalent data analysis pipeline, we obtained widely disagreeing results compared to the original study. Overall, the results were in line with the hypotheses of no relation between functional connectivity and personality, when more precise permutation-based multiple testing procedures were applied. The results demonstrate that as with other neuroimaging studies, great caution should be applied when interpreting the findings, among other reasons due to multiple testing problem involved at several levels in many neuroimaging studies. Of course, the current study results can not ultimately disprove the existence of some link between personality and brain's intrinsic functional architecture, but clearly shows that its form is very likely different and much more subtle and elusive than was previously reported.


Assuntos
Encéfalo/fisiologia , Personalidade/fisiologia , Adulto , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiologia , Testes de Personalidade , Descanso
5.
Neuron ; 107(2): 257-273.e5, 2020 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-32392471

RESUMO

The brain's complex microconnectivity underlies its computational abilities and vulnerability to injury and disease. It has been challenging to illuminate the features of this synaptic network due to the small size and dense packing of its elements. Here, we describe a rapid, accessible super-resolution imaging and analysis workflow-SEQUIN-that quantifies central synapses in human tissue and animal models, characterizes their nanostructural and molecular features, and enables volumetric imaging of mesoscale synaptic networks without the production of large histological arrays. Using SEQUIN, we identify cortical synapse loss resulting from diffuse traumatic brain injury, a highly prevalent connectional disorder. Similar synapse loss is observed in three murine models of Alzheimer-related neurodegeneration, where SEQUIN mesoscale mapping identifies regional synaptic vulnerability. These results establish an easily implemented and robust nano-to-mesoscale synapse quantification and characterization method. They furthermore identify a shared mechanism-synaptopathy-between Alzheimer neurodegeneration and its best-established epigenetic risk factor, brain trauma.


Assuntos
Lesões Encefálicas Traumáticas/patologia , Sistema Nervoso Central/diagnóstico por imagem , Nanoestruturas/ultraestrutura , Vias Neurais/diagnóstico por imagem , Vias Neurais/ultraestrutura , Neuroimagem/métodos , Sinapses/ultraestrutura , Animais , Mapeamento Encefálico , Sistema Nervoso Central/ultraestrutura , Córtex Cerebral/patologia , Humanos , Mamíferos , Camundongos
6.
J Clin Neurosci ; 77: 55-61, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32409218

RESUMO

It is commonly known that brain metastases usually have clear boundaries in magnetic resonance imaging. However, little is known regarding the trajectory of white matter fibers around the tumors, especially using the fiber dissection technique. Here, we focused on the anatomical interaction between white matter fibers and the tumor, using the fiber dissection in a postmortem brain with metastatic tumor and compared the findings with those of diffusion tensor imaging (DTI) tractography. One postmortem human brain hemisphere with metastatic adenocarcinoma in the Broca's area was dissected using fiber dissection following the Klingler's method. In order to compare the in vitro and in vivo results, additional brains from 15 patients with metastatic adenocarcinomas, the volumes of which were comparable to that of the adenocarcinoma in the brain used for fiber dissection, were analyzed using DTI tractographic reconstruction. Morphological findings of white matter bundles running around the tumor were compared between the two techniques. In the fiber dissection technique, the superior longitudinal fascicle, arcuate fascicle, and frontal aslant tract could be dissected, and the white matter bundles were curved and retracted to avoid the tumor. In all the cases analyzed, white matter fibers or streamlines surrounding the tumor avoided the lesion. Using the fiber dissection technique, this is the first direct evidence to elucidate the anatomy of white matter fibers affected by a metastatic brain. This suggests that brain metastatic adenocarcinoma is an intra-axial neoplasm with extra-axial white matter structures.


Assuntos
Adenocarcinoma/diagnóstico por imagem , Neoplasias Encefálicas/diagnóstico por imagem , Imagem de Tensor de Difusão/métodos , Microdissecção/métodos , Fibras Nervosas Mielinizadas , Substância Branca/diagnóstico por imagem , Adenocarcinoma/patologia , Adenocarcinoma/cirurgia , Adulto , Idoso , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Encéfalo/cirurgia , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/cirurgia , Dissecação/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fibras Nervosas Mielinizadas/patologia , Vias Neurais/diagnóstico por imagem , Vias Neurais/patologia , Vias Neurais/cirurgia , Substância Branca/patologia , Substância Branca/cirurgia
7.
Proc Natl Acad Sci U S A ; 117(20): 11068-11075, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32358193

RESUMO

The projection targets of a neuronal population are a key feature of its anatomical characteristics. Historically, tissue sectioning, confocal microscopy, and manual scoring of specific regions of interest have been used to generate coarse summaries of mesoscale projectomes. We present here TrailMap, a three-dimensional (3D) convolutional network for extracting axonal projections from intact cleared mouse brains imaged by light-sheet microscopy. TrailMap allows region-based quantification of total axon content in large and complex 3D structures after registration to a standard reference atlas. The identification of axonal structures as thin as one voxel benefits from data augmentation but also requires a loss function that tolerates errors in annotation. A network trained with volumes of serotonergic axons in all major brain regions can be generalized to map and quantify axons from thalamocortical, deep cerebellar, and cortical projection neurons, validating transfer learning as a tool to adapt the model to novel categories of axonal morphology. Speed of training, ease of use, and accuracy improve over existing tools without a need for specialized computing hardware. Given the recent emphasis on genetically and functionally defining cell types in neural circuit analysis, TrailMap will facilitate automated extraction and quantification of axons from these specific cell types at the scale of the entire mouse brain, an essential component of deciphering their connectivity.


Assuntos
Axônios , Encéfalo/anatomia & histologia , Encéfalo/diagnóstico por imagem , Imageamento Tridimensional/métodos , Animais , Mapeamento Encefálico/métodos , Processamento de Imagem Assistida por Computador , Camundongos , Camundongos Endogâmicos C57BL , Rede Nervosa/anatomia & histologia , Rede Nervosa/diagnóstico por imagem , Redes Neurais de Computação , Vias Neurais/anatomia & histologia , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiologia , Neurônios
8.
Ann Neurol ; 87(6): 962-975, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32239535

RESUMO

OBJECTIVE: Subthalamic nucleus deep brain stimulation (STN-DBS) in Parkinson's disease (PD) not only stimulates focal target structures but also affects distributed brain networks. The impact this network modulation has on non-motor DBS effects is not well-characterized. By focusing on the affective domain, we systematically investigate the impact of electrode placement and associated structural connectivity on changes in depressive symptoms following STN-DBS, which have been reported to improve, worsen, or remain unchanged. METHODS: Depressive symptoms before and after STN-DBS surgery were documented in 116 patients with PD from 3 DBS centers (Berlin, Queensland, and Cologne). Based on individual electrode reconstructions, the volumes of tissue activated (VTAs) were estimated and combined with normative connectome data to identify structural connections passing through VTAs. Berlin and Queensland cohorts formed a training and cross-validation dataset used to identify structural connectivity explaining change in depressive symptoms. The Cologne data served as the test-set for which depressive symptom change was predicted. RESULTS: Structural connectivity was linked to depressive symptom change under STN-DBS. An optimal connectivity map trained on the Berlin cohort could predict changes in depressive symptoms in Queensland patients and vice versa. Furthermore, the joint training-set map predicted changes in depressive symptoms in the independent test-set. Worsening of depressive symptoms was associated with left prefrontal connectivity. INTERPRETATION: Fibers connecting the electrode with left prefrontal areas were associated with worsening of depressive symptoms. Our results suggest that for the left STN-DBS lead, placement impacting fibers to left prefrontal areas should be avoided to maximize improvement of depressive symptoms. ANN NEUROL 2020;87:962-975.


Assuntos
Estimulação Encefálica Profunda/efeitos adversos , Depressão/etiologia , Depressão/psicologia , Vias Neurais/diagnóstico por imagem , Córtex Pré-Frontal/diagnóstico por imagem , Núcleo Subtalâmico , Afeto , Idoso , Mapeamento Encefálico , Conectoma , Depressão/diagnóstico por imagem , Eletrodos Implantados , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Neuroimagem , Doença de Parkinson/complicações , Doença de Parkinson/psicologia , Doença de Parkinson/terapia , Estudos Retrospectivos , Núcleo Subtalâmico/diagnóstico por imagem , Tomografia Computadorizada por Raios X
9.
JAMA Netw Open ; 3(3): e201184, 2020 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-32186744

RESUMO

Importance: Developmental coordination disorder (DCD) is a motor impairment that significantly interferes with activities of daily living. Little is known about the cause of DCD and how it develops, making it difficult to understand why children with DCD struggle in learning motor skills and to determine the best intervention to optimize function. Objective: To characterize white matter differences using diffusion tensor imaging in children with and without DCD. Design, Setting, and Participants: This cross-sectional study collected diffusion tensor imaging data at BC Children's Hospital Research Institute in Vancouver, British Columbia, Canada, from September 2014 to January 2017. Using a sample of convenience, children with DCD and children without DCD aged 8 to 12 years underwent magnetic resonance imaging. Data analysis was conducted from January 2017 to January 2020. Main Outcomes and Measures: The main outcome measures were diffusion parameters, including fractional anisotropy and mean, axial, and radial diffusivity, which are thought to provide an indirect measure of white matter microstructure. Tract-based spatial statistics, a voxelwise statistical analysis of diffusion parameters, were conducted using a 2-group comparison design matrix with age and attention as covariates. Results: Thirty children without DCD (mean [SD] age, 9.9 [1.4] years; 21 [70%] boys) and 31 children with DCD (mean [SD] age, 10.1 [1.2] years; 26 [84%] boys) were included in the study. Compared with children without DCD, children with DCD were characterized by significantly lower fractional anisotropy and axial diffusivity in regions of white matter pathways associated with motor and sensorimotor processing, including the corticospinal tract (fractional anisotropy: mean [SD], 0.54 [0.03] vs 0.51 [0.03]; P < .001; axial diffusivity: mean [SD], 0.13 [0.98] vs 0.12 [0.46]; P = .01), posterior thalamic radiation at the retrolenticular part of the internal capsule (axial diffusivity: mean [SD], 0.14 [0.57] vs 0.14 [0.44]; P = .01), and cerebellar pathways (eg, superior cerebellar peduncle, fractional anisotropy: mean [SD], 0.49 [0.05] vs 0.46 [0.03]; P = .03; axial diffusivity: mean [SD], 0.14 [0.66] vs 0.14 [0.63]; P = .009). There were no significant differences in mean diffusivity and radial diffusivity between children with and without DCD. Conclusions and Relevance: These findings suggest that children with DCD show significant brain differences in motor and sensorimotor white matter pathways compared with children without DCD. The pattern of diffusion parameters in children with DCD suggests that axonal development may be disrupted in this neurodevelopmental disorder.


Assuntos
Imagem de Tensor de Difusão , Transtornos das Habilidades Motoras/patologia , Substância Branca/patologia , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Colúmbia Britânica , Criança , Estudos Transversais , Feminino , Humanos , Masculino , Transtornos das Habilidades Motoras/diagnóstico por imagem , Transtornos das Habilidades Motoras/fisiopatologia , Vias Neurais/diagnóstico por imagem , Vias Neurais/patologia , Vias Neurais/fisiopatologia , Córtex Sensório-Motor/diagnóstico por imagem , Córtex Sensório-Motor/patologia , Córtex Sensório-Motor/fisiopatologia , Substância Branca/diagnóstico por imagem , Substância Branca/fisiopatologia
11.
Am J Psychiatry ; 177(6): 537-547, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32212855

RESUMO

OBJECTIVE: Schizophrenia has recently been associated with widespread white matter microstructural abnormalities, but the functional effects of these abnormalities remain unclear. Widespread heterogeneity of results from studies published to date preclude any definitive characterization of the relationship between white matter and cognitive performance in schizophrenia. Given the relevance of deficits in cognitive function to predicting social and functional outcomes in schizophrenia, the authors carried out a meta-analysis of available data through the ENIGMA Consortium, using a common analysis pipeline, to elucidate the relationship between white matter microstructure and a measure of general cognitive performance, IQ, in patients with schizophrenia and healthy participants. METHODS: The meta-analysis included 760 patients with schizophrenia and 957 healthy participants from 11 participating ENIGMA Consortium sites. For each site, principal component analysis was used to calculate both a global fractional anisotropy component (gFA) and a fractional anisotropy component for six long association tracts (LA-gFA) previously associated with cognition. RESULTS: Meta-analyses of regression results indicated that gFA accounted for a significant amount of variation in cognition in the full sample (effect size [Hedges' g]=0.27, CI=0.17-0.36), with similar effects sizes observed for both the patient (effect size=0.20, CI=0.05-0.35) and healthy participant groups (effect size=0.32, CI=0.18-0.45). Comparable patterns of association were also observed between LA-gFA and cognition for the full sample (effect size=0.28, CI=0.18-0.37), the patient group (effect size=0.23, CI=0.09-0.38), and the healthy participant group (effect size=0.31, CI=0.18-0.44). CONCLUSIONS: This study provides robust evidence that cognitive ability is associated with global structural connectivity, with higher fractional anisotropy associated with higher IQ. This association was independent of diagnosis; while schizophrenia patients tended to have lower fractional anisotropy and lower IQ than healthy participants, the comparable size of effect in each group suggested a more general, rather than disease-specific, pattern of association.


Assuntos
Cognição/fisiologia , Inteligência , Esquizofrenia/diagnóstico por imagem , Psicologia do Esquizofrênico , Substância Branca/diagnóstico por imagem , Adulto , Anisotropia , Encéfalo/diagnóstico por imagem , Estudos de Casos e Controles , Imagem de Tensor de Difusão , Análise Fatorial , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Vias Neurais/diagnóstico por imagem , Análise de Componente Principal , Esquizofrenia/fisiopatologia , Escalas de Wechsler
12.
World Neurosurg ; 138: e66-e71, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32014546

RESUMO

OBJECTIVE: Measuring functional connectivity (FC) and resting state networks (RSNs) using resting state functional magnetic resonance imaging is a method of preoperative planning in patients with brain tumors. However, the baseline FC and RSNs are altered in patients with brain tumors. In this study, we examined changes in inter-network FC in patients with brain tumors. METHODS: We performed region of interest (ROI) analysis of FC in 34 patients with supratentorial gliomas and 14 healthy subjects. We performed bivariate correlation analyses at the level of each subject. Resulting correlations were Fischer Z-transformed. The used nodes included 132 ROIs from the automated anatomical labeling atlas in addition to 32 ROIs representing the different functional brain networks. We investigated second-level effects by contrasting dummy encoded covariates representing the effects of group membership on functional connectivity. The significant 2-sided P value with corrected false discovery rate was set to 0.05. We set the t contrast between the group of patients with brain tumors and the group of healthy subjects to detect the effects of tumors on inter-network connectivity. RESULTS: Overall, the inter-network FC was significantly higher in patients with brain tumors compared with healthy subjects. The anterior and posterior cerebellar networks, as well as the supratentorial network, showed significantly higher connectivity in patients with brain tumors than in healthy subjects. CONCLUSION: Although brain tumors affect the FC and RSNs, the current study showed higher baseline inter-network connectivity in patients with brain tumors, which could indicate an intrinsic neural compensatory mechanism.


Assuntos
Glioma/fisiopatologia , Vias Neurais/fisiopatologia , Neoplasias Supratentoriais/fisiopatologia , Adolescente , Adulto , Idoso , Feminino , Glioma/diagnóstico por imagem , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Vias Neurais/diagnóstico por imagem , Descanso , Estudos Retrospectivos , Neoplasias Supratentoriais/diagnóstico por imagem , Adulto Jovem
13.
Brain Cogn ; 140: 105532, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32007789

RESUMO

Early language exposure and shared parent-child reading, as assessed by maternal reading ability and fluency, affect the child's future language and cognitive abilities. The aim of the current study was to explore the association between maternal reading ability and fluency and diffusion properties of language- and cognition-related white matter tracts in their pre-school age children using diffusion tensor imaging (DTI). DTI data were acquired from fifteen girls (mean age: 3.83 ± 0.49 years). Reading ability and fluency were assessed in their mothers. Effects of hemisphere and node on diffusion properties were measured at 100 points along white matter tracts related to language and cognitive abilities. Significant positive correlations were found between maternal reading ability and fractional anisotropy in left and right dorsal and ventral language and executive functions-related tracts, while maternal reading fluency was associated with higher fractional anisotropy in ventral tracts, mainly in the left hemisphere. Fractional Anisotropy was significantly higher in the left compared to the right arcuate, cingulum cingulate, and inferior longitudinal fasciculus and higher in the right compared to the left superior longitudinal fasciculus. Our results signify the importance of maternal reading as a facilitator of the child's future language and cognitive abilities.


Assuntos
Alfabetização , Mães , Leitura , Substância Branca/anatomia & histologia , Pré-Escolar , Imagem de Tensor de Difusão , Feminino , Humanos , Vias Neurais/anatomia & histologia , Vias Neurais/diagnóstico por imagem , Substância Branca/diagnóstico por imagem
14.
Brain Connect ; 10(2): 72-82, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32056450

RESUMO

Hierarchical organization of brain function has been an established concept in the neuroscience field for a long time, however, it has been rarely demonstrated how such hierarchical macroscale functional networks are actually organized in the human brain. In this study, to answer this question, we propose a novel methodology to provide an evidence of hierarchical organization of functional brain networks. This article introduces the hybrid spatiotemporal deep learning (HSDL), by jointly using deep belief networks (DBNs) and deep least absolute shrinkage and selection operator (LASSO) to reveal the temporal hierarchical features and spatial hierarchical maps of brain networks based on the Human Connectome Project 900 functional magnetic resonance imaging (fMRI) data sets. Briefly, the key idea of HSDL is to extract the weights between two adjacent layers of DBNs, which are then treated as the hierarchical dictionaries for deep LASSO to identify the corresponding hierarchical spatial maps. Our results demonstrate that both spatial and temporal aspects of dozens of functional networks exhibit multiscale properties that can be well characterized and interpreted based on existing computational tools and neuroscience knowledge. Our proposed novel hybrid deep model is used to provide the first insightful opportunity to reveal the potential hierarchical organization of time series and functional brain networks, using task-based fMRI signals of human brain.


Assuntos
Encéfalo/diagnóstico por imagem , Conectoma/métodos , Aprendizado Profundo , Imagem por Ressonância Magnética/métodos , Encéfalo/fisiologia , Emoções/fisiologia , Humanos , Idioma , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiologia , Análise Espaço-Temporal
15.
Brain Connect ; 10(2): 95-104, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32079409

RESUMO

Research suggests that disruption of brain networks might explain cognitive deficits in multiple sclerosis (MS). The reliability and effectiveness of graph theoretic network metrics as measures of cognitive performance were tested in 37 people with MS and 23 controls. Specifically, relationships with cognitive performance (linear regression against the paced auditory serial addition test-3 seconds [PASAT-3], symbol digit modalities test [SDMT], and attention network test) and 1-month reliability (using the intraclass correlation coefficient [ICC]) of network metrics were measured using both resting-state functional and diffusion magnetic resonance imaging data. Cognitive impairment was directly related to measures of brain network segregation and inversely related to network integration (prediction of PASAT-3 by small worldness, modularity, characteristic path length, R2 = 0.55; prediction of SDMT by small worldness, global efficiency, and characteristic path length, R2 = 0.60). Reliability of the measures for 1 month in a subset of nine participants was mostly rated as good (ICC >0.6) for both controls and MS patients in both functional and diffusion data, but was highly dependent on the chosen parcellation and graph density, with the 0.2-0.5 density range being the most reliable. This suggests that disrupted network organization predicts cognitive impairment in MS and its measurement is reliable for a 1-month period. These new findings support the hypothesis of network disruption as a major determinant of cognitive deficits in MS and the future possibility of the application of derived metrics as surrogate outcomes in trials of therapies for cognitive impairment.


Assuntos
Encéfalo/diagnóstico por imagem , Conectoma/métodos , Imagem por Ressonância Magnética/métodos , Esclerose Múltipla/diagnóstico por imagem , Adulto , Encéfalo/fisiopatologia , Cognição , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/tratamento farmacológico , Esclerose Múltipla/fisiopatologia , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiopatologia , Testes Neuropsicológicos , Reprodutibilidade dos Testes
16.
AJNR Am J Neuroradiol ; 41(3): 508-514, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32054614

RESUMO

BACKGROUND AND PURPOSE: Deep brain stimulation is a well-established treatment for generalized dystonia, but outcomes remain variable. Establishment of an imaging marker to guide device targeting and programming could possibly impact the efficacy of deep brain stimulation in dystonia, particularly in the absence of acute clinical markers to indicate benefit. We hypothesize that the stimulation-based functional and structural connectivity using resting-state fMRI and DTI can predict therapeutic outcomes in patients with generalized dystonia and deep brain stimulation. MATERIALS AND METHODS: We performed a retrospective analysis of 39 patients with inherited or idiopathic-isolated generalized dystonia who underwent bilateral globus pallidus internus deep brain stimulation. After electrode localization, the volumes of tissue activated were modeled and used as seed regions for functional and structural connectivity measures using a normative data base. Resulting connectivity maps were correlated with postoperative improvement in the Unified Dystonia Rating Scale score. RESULTS: Structural connectivity between the volumes of tissue activated and the primary sensorimotor cortex was correlated with Unified Dystonia Rating Scale improvement, while more anterior prefrontal connectivity was inversely correlated with Unified Dystonia Rating Scale improvement. Functional connectivity between the volumes of tissue activated and primary sensorimotor regions, motor thalamus, and cerebellum was most correlated with Unified Dystonia Rating Scale improvement; however, an inverse correlation with Unified Dystonia Rating Scale improvement was seen in the supplemental motor area and premotor cortex. CONCLUSIONS: Functional and structural connectivity with multiple nodes of the motor network is associated with motor improvement in patients with generalized dystonia undergoing deep brain stimulation. Results from this study may serve as a basis for future development of clinical markers to guide deep brain stimulation targeting and programming in dystonia.


Assuntos
Estimulação Encefálica Profunda/métodos , Distonia/diagnóstico por imagem , Distonia/terapia , Vias Neurais/diagnóstico por imagem , Resultado do Tratamento , Adulto , Distonia/fisiopatologia , Feminino , Globo Pálido/cirurgia , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Vias Neurais/fisiopatologia , Estudos Retrospectivos
19.
J Neurosci ; 40(9): 1909-1919, 2020 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-31959699

RESUMO

Memory consolidation is hypothesized to involve the distribution and restructuring of memory representations across hippocampal and cortical regions. Theories suggest that, through extended hippocampal-cortical interactions, cortical ensembles come to represent more integrated, or overlapping, memory traces that prioritize commonalities across related memories. Sleep processes, particularly fast sleep spindles, are thought to support consolidation, but evidence for this relationship has been mostly limited to memory retention benefits. Whether fast spindles provide a mechanism for neural changes hypothesized to support consolidation, including the strengthening of hippocampal-cortical networks and integration across memory representations, remains unclear, as does the specificity of regions involved. Using functional connectivity analyses of human fMRI data (both sexes), we show that fast spindle density during overnight sleep is related to enhanced hippocampal-cortical functional connectivity the next day, when restudying information learned before sleep. Spindle density modulated connectivity in distinct hippocampal-cortical networks depending on the category of the consolidated stimuli. Specifically, spindle density correlated with functional connectivity between anterior hippocampus and ventromedial prefrontal cortex (vmPFC) for object-word pairs, and posterior hippocampus and posteromedial cortex for scene-word pairs. Using multivariate pattern analyses, we also show that fast spindle density during postlearning sleep is associated with greater pattern similarity, or representational overlap, across individual object-word memories in vmPFC the next day. Further, the relationship between fast spindle density and representational overlap in vmPFC was mediated by the degree of anterior hippocampal-vmPFC functional connectivity. Together, these results suggest that fast spindles support the network distribution of memory traces, potentially restructuring memory representations in vmPFC.SIGNIFICANCE STATEMENT How new experiences are transformed into long-term memories remains a fundamental question for neuroscience research. Theories suggest that memories are stabilized as they are reorganized in the brain, a process thought to be supported by sleep oscillations, particularly sleep spindles. Although sleep spindles have been associated with benefits in memory retention, it is not well understood how spindles modify neural memory traces. This study found that spindles during overnight sleep correlate with changes in neural memory traces, including enhanced functional connectivity in distinct hippocampal-cortical networks and increased pattern similarity among memories in the cortex. The results provide critical evidence that spindles during overnight sleep may act as a physiological mechanism for the restructuring of neural memory traces.


Assuntos
Hipocampo/fisiologia , Consolidação da Memória/fisiologia , Vias Neurais/fisiologia , Córtex Pré-Frontal/fisiologia , Fases do Sono/fisiologia , Adolescente , Adulto , Mapeamento Encefálico , Feminino , Hipocampo/diagnóstico por imagem , Humanos , Imagem por Ressonância Magnética , Masculino , Memória de Longo Prazo/fisiologia , Rememoração Mental/fisiologia , Vias Neurais/diagnóstico por imagem , Polissonografia , Córtex Pré-Frontal/diagnóstico por imagem , Sono/fisiologia , Adulto Jovem
20.
Neurology ; 94(7): e699-e704, 2020 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-31969462

RESUMO

OBJECTIVE: To determine if Alzheimer disease (AD) is associated with aphasic rather than amnestic dementias in certain circumstances related in part to perturbations in different networks. METHODS: Three groups were investigated: 14 participants suspected of having the neuropathology of AD based on clinically diagnosed amnestic dementia of the Alzheimer type (DAT), 26 individuals with primary progressive aphasia (PPA) with either a positive 18F-florbetapir amyloid PET scan or confirmed AD at autopsy, and 26 neurologically intact controls. The groups were compared using rs-fMRI. Seeds included the left hemisphere inferior frontal gyrus (IFG) for the language network, the left hippocampus for the episodic memory network, and the left posterior cingulate for the default mode network (DMN). RESULTS: Greater connectivity perturbations were found from the hippocampus for the DAT group and from the IFG for the PPA group. Furthermore, connectivity alterations in the PPA group were more asymmetric and favored the language-dominant left hemisphere. Loss of connectivity from the DMN seed was of a similar magnitude in the PPA and DAT groups. CONCLUSIONS: Despite the presumptive common underlying neuropathology of amyloid plaques and neurofibrillary tangles, the 2 groups displayed 2 different patterns of network perturbation, each concordant with the clinical presentation and the anatomy of neurodegeneration.


Assuntos
Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/fisiopatologia , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Idoso , Doença de Alzheimer/psicologia , Amnésia/diagnóstico por imagem , Amnésia/fisiopatologia , Compostos de Anilina , Afasia/diagnóstico por imagem , Afasia/fisiopatologia , Cognição/fisiologia , Etilenoglicóis , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiopatologia , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos , Descanso
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