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1.
Nat Neurosci ; 22(11): 1751-1760, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31611705

RESUMO

Cognition and behavior emerge from brain network interactions, such that investigating causal interactions should be central to the study of brain function. Approaches that characterize statistical associations among neural time series-functional connectivity (FC) methods-are likely a good starting point for estimating brain network interactions. Yet only a subset of FC methods ('effective connectivity') is explicitly designed to infer causal interactions from statistical associations. Here we incorporate best practices from diverse areas of FC research to illustrate how FC methods can be refined to improve inferences about neural mechanisms, with properties of causal neural interactions as a common ontology to facilitate cumulative progress across FC approaches. We further demonstrate how the most common FC measures (correlation and coherence) reduce the set of likely causal models, facilitating causal inferences despite major limitations. Alternative FC measures are suggested to immediately start improving causal inferences beyond these common FC measures.


Assuntos
Encéfalo/fisiologia , Neuroimagem Funcional/métodos , Modelos Neurológicos , Vias Neurais/fisiologia , Animais , Humanos , Estudos de Validação como Assunto
2.
World Neurosurg ; 132: 251-252, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31520765

RESUMO

During functional-based resection under awake conditions of a left frontal isocitrate dehydrogenase-wildtype glioblastoma, the initial intralesional debulking performed to alleviate mass effect unmasked the right hemibody negative motor networks that were identified on the neocortex by direct electric stimulation. As compared with preoperative evaluation, the 3-month postoperative functional magnetic resonance imaging (MRI) confirmed unmasked cortical clusters for the right hemibody that were absent preoperatively using the same functional MRI parameters; language clusters were also better seen. The glioma-induced mass effect can mask eloquent brain areas, and surgical decompression can unmask intraoperatively eloquent brain areas.


Assuntos
Neoplasias Encefálicas/cirurgia , Procedimentos Cirúrgicos de Citorredução , Descompressão Cirúrgica , Glioblastoma/cirurgia , Linguagem , Movimento , Neocórtex/fisiologia , Adulto , Mapeamento Encefálico , Estimulação Elétrica , Feminino , Neuroimagem Funcional , Humanos , Monitorização Neurofisiológica Intraoperatória , Imagem por Ressonância Magnética , Neocórtex/diagnóstico por imagem , Procedimentos Neurocirúrgicos
3.
Postgrad Med ; 131(7): 501-508, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31483196

RESUMO

Objectives: Aiginition Longitudinal Biomarker Investigation Of Neurodegeneration (ALBION) is a longitudinal ongoing study initiated in 2018 that takes place in the Cognitive Disorders Clinic of Aiginition Hospital of the National and Kapodistrian University of Athens. Its aim is to address several research questions concerning the preclinical and prodromal stage of Alzheimer's disease and explore potential markers for early detection, prediction, and primary prevention of dementia. Methods: We here present the design and the preliminary baseline characteristics of ALBION. The sample of our study consists of people aged over 50 who are concerned about their memory but are cognitively normal (CN) or have mild cognitive deficits. Each participant undergoes an extensive assessment including several demographic, medical, social, environmental, clinical, nutritional, neuropsychological determinants and lifestyle activities. Furthermore, we are collecting data from portable devices, neuroimaging techniques and biological samples (blood, stools, CSF). All participants are assessed annually for a period of 10 years. Results: In total, 47 participants have completed the initial evaluation up to date and are divided in two groups, CN individuals (N = 26) and MCI patients (N = 21), based on their cognitive status. The participants are, on average, 64 years old, 46.3% of the sample is male with an average of 12.73 years of education. MCI patients report more comorbidities and have a lower score in the MMSE test. Regarding APOE status, 2 participants are ε4 homozygotes and 10 ε4 heterozygotes. CSF analyses (Aß42, Τ-tau, P-tau) revealed no differences between the two groups. Conclusion: The ALBION study offers an opportunity to explore preclinical dementia and identify new and tailored markers, particularly relating to lifestyle. Further investigation of these populations may provide a wider profile of the changes taking place in the preclinical phase of dementia, leading to potentially effective therapeutic and preventive strategies.


Assuntos
Doença de Alzheimer/prevenção & controle , Disfunção Cognitiva/metabolismo , Prevenção Primária , Sintomas Prodrômicos , Idoso , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/metabolismo , Doença de Alzheimer/fisiopatologia , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Apolipoproteínas E/genética , Biomarcadores , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/fisiopatologia , Diagnóstico Precoce , Eletroencefalografia , Feminino , Neuroimagem Funcional , Grécia , Humanos , Estudos Longitudinais , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Fragmentos de Peptídeos/líquido cefalorraquidiano , Dados Preliminares , Proteínas tau/líquido cefalorraquidiano
4.
Postgrad Med ; 131(7): 523-532, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31478421

RESUMO

Objectives: Many people affected by multiple sclerosis (MS) experience cognitive impairment, especially decreases in information processing speed (PS). Neural disconnection is thought to represent the neural marker of this symptom, although the role played by alterations of specific functional brain networks still remains unclear. The aim is to investigate and compare patterns of association between PS-demanding cognitive performance and functional connectivity across two MS phenotypes. Methods: Forty patients with relapsing-remitting MS (RRMS) and 25 with secondary progressive MS (SPMS) had neuropsychological and MRI assessments. Multiple regression models were used to investigate the relationship between performance on tests of visuomotor and verbal PS, and on the verbal fluency tests, and functional connectivity of four cognitive networks, i.e. left and right frontoparietal, salience and default-mode, and two control networks, i.e. visual and sensorimotor. Results: Patients with SPMS were older and had longer disease history than patients with RRMS and presented with worse overall clinical conditions: higher disease severity, total lesion volume, and cognitive impairment rates. However, in both patient samples, cognitive performance across tests was negatively correlated with functional connectivity of the salience and default-mode networks, and positively with connectivity of the left frontoparietal network. Only the visuomotor PS scores of the RRMS group were also associated with connectivity of the sensorimotor network. Conclusions: PS-demanding cognitive performance in patients with MS appears mainly associated with strength of functional connectivity of frontal networks involved in the evaluation and manipulation of information, as well as the default mode network. These results are in line with the hypothesis that multiple neural networks are needed to support normal cognitive performance across MS phenotypes. However, different PS measures showed partially different patterns of association with functional connectivity. Therefore, further investigations are needed to clarify the contribution of inter-network communication to specific cognitive deficits due to MS.


Assuntos
Encéfalo/diagnóstico por imagem , Esclerose Múltipla Crônica Progressiva/diagnóstico por imagem , Esclerose Múltipla Recidivante-Remitente/diagnóstico por imagem , Adulto , Idoso , Encéfalo/fisiopatologia , Cerebelo/diagnóstico por imagem , Cerebelo/fisiopatologia , Feminino , Lobo Frontal/diagnóstico por imagem , Lobo Frontal/fisiopatologia , Neuroimagem Funcional , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/diagnóstico por imagem , Esclerose Múltipla/fisiopatologia , Esclerose Múltipla/psicologia , Esclerose Múltipla Crônica Progressiva/fisiopatologia , Esclerose Múltipla Crônica Progressiva/psicologia , Esclerose Múltipla Recidivante-Remitente/fisiopatologia , Esclerose Múltipla Recidivante-Remitente/psicologia , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiopatologia , Testes Neuropsicológicos , Lobo Parietal/diagnóstico por imagem , Lobo Parietal/fisiopatologia , Desempenho Psicomotor
5.
World Neurosurg ; 132: 93-98, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31491580

RESUMO

BACKGROUND: Focal cortical dysplasias (FCDs) are highly epileptogenic and frequently associated with medically refractory focal epilepsy. FCDs are frequently located in the frontal lobe, making its complete resection highly challenging when in proximity to the motor cortex. CASE DESCRIPTION: We report a case of a 25-year-old woman with medically refractory epilepsy secondary to a focal cortical dysplasia in the motor cortex and extending deeply into the subcortical white matter. A detailed presurgical evaluation and invasive electroencephalographic monitoring performed at our epilepsy monitoring unit, along with the use of motor mapping, functional magnetic resonance imaging, diffusion tensor imaging, and the Stealth navigation system resulted in the complete resection of the lesion without a permanent postoperative motor deficit. The patient remained seizure-free at a 63-month follow-up while being maintained on a single antiepileptic drug. CONCLUSION: A detailed presurgical evaluation, accurate mapping of the functional and dysplastic cortex, and a well-planned tailored and complete surgical resection of the cortical dysplasia can result in a favorable outcome with relatively little risk of postoperative neurologic deficit.


Assuntos
Epilepsia Resistente a Medicamentos/cirurgia , Epilepsia/cirurgia , Malformações do Desenvolvimento Cortical do Grupo I/cirurgia , Córtex Motor/cirurgia , Procedimentos Neurocirúrgicos/métodos , Substância Branca/cirurgia , Adulto , Mapeamento Encefálico , Imagem de Tensor de Difusão , Epilepsia Resistente a Medicamentos/etiologia , Epilepsia/complicações , Feminino , Neuroimagem Funcional , Humanos , Imagem por Ressonância Magnética , Malformações do Desenvolvimento Cortical do Grupo I/complicações
6.
Nat Commun ; 10(1): 3675, 2019 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-31417075

RESUMO

Math and reading involve distributed brain networks and have both shared (e.g. encoding of visual stimuli) and dissociated (e.g. quantity processing) cognitive components. Yet, to date, the shared vs. dissociated gray and white matter substrates of the math and reading networks are unknown. Here, we define these networks and evaluate the structural properties of their fascicles using functional MRI, diffusion MRI, and quantitative MRI. Our results reveal that there are distinct gray matter regions which are preferentially engaged in either math (adding) or reading, and that the superior longitudinal and arcuate fascicles are shared across the math and reading networks. Strikingly, within these fascicles, reading- and math-related tracts are segregated into parallel sub-bundles and show structural differences related to myelination. These findings open a new avenue of research that examines the contribution of sub-bundles within fascicles to specific behaviors.


Assuntos
Substância Cinzenta/diagnóstico por imagem , Matemática , Leitura , Substância Branca/diagnóstico por imagem , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Imagem de Difusão por Ressonância Magnética , Feminino , Neuroimagem Funcional , Substância Cinzenta/fisiologia , Humanos , Imagem por Ressonância Magnética , Masculino , Fibras Nervosas Mielinizadas , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiologia , Substância Branca/fisiologia , Adulto Jovem
7.
Neuropsychology ; 33(6): 760-780, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31448945

RESUMO

OBJECTIVE: Alcohol use disorder (AUD) is a complex, dynamic condition that waxes and wanes with unhealthy drinking episodes and varies in drinking patterns and effects on brain structure and function with age. Its excessive use renders chronically heavy drinkers vulnerable to direct alcohol toxicity and a variety of comorbidities attributable to nonalcohol drug misuse, viral infections, and accelerated or premature aging. AUD affects widespread brain systems, commonly, frontolimbic, frontostriatal, and frontocerebellar networks. METHOD AND RESULTS: Multimodal assessment using selective neuropsychological testing and whole-brain neuroimaging provides evidence for AUD-related specific brain structure-function relations established with double dissociations. Longitudinal study using noninvasive imaging provides evidence for brain structural and functional improvement with sustained sobriety and further decline with relapse. Functional imaging suggests the possibility that some alcoholics in recovery can compensate for impairment by invoking brain systems typically not used for a target task but that can enable normal-level performance. CONCLUSIONS: Evidence for AUD-aging interactions, indicative of accelerated aging, together with increasing alcohol consumption in middle-age and older adults, put aging drinkers at special risk for developing cognitive decline and possibly dementia. (PsycINFO Database Record (c) 2019 APA, all rights reserved).


Assuntos
Envelhecimento/psicologia , Alcoolismo/psicologia , Encéfalo/diagnóstico por imagem , Alcoolismo/diagnóstico por imagem , Alcoolismo/epidemiologia , Alcoolismo/fisiopatologia , Encéfalo/fisiopatologia , Disfunção Cognitiva/epidemiologia , Disfunção Cognitiva/psicologia , Comorbidade , Demência/epidemiologia , Neuroimagem Funcional , Humanos , Estudos Longitudinais , Imagem por Ressonância Magnética , Testes Neuropsicológicos
8.
Neuropsychology ; 33(6): 781-794, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31448946

RESUMO

OBJECTIVE: This article provides an overview of the scientific literature pertaining to the effects of alcohol on neural correlates of cognitive and emotional functioning, including reward processing and cue-reactivity, in adolescence and young adulthood. METHOD: Peer-reviewed, original research articles that included a neuroimaging assessment of alcohol effects on subsequent cognitive or emotional processing in adolescent or young adult samples were searched (through November 2018) and summarized in the review. RESULTS: Cross-sectional studies provided early evidence of alcohol-related differences in neural processing across a number of cognitive domains. Longitudinal studies have identified neural abnormalities that predate drinking within most domains of cognitive functioning, while a few neural alterations have been observed within the domains of visual working memory, inhibitory control, reward processing, and cue-reactivity that appear to be related to the neurotoxic effect of alcohol use during adolescence. In contrast, neural correlates of emotion functioning appear to be relatively stable to the effects of alcohol. CONCLUSIONS: Larger prospective studies are greatly needed to disentangle premorbid factors from neural consequences associated with drinking, and to detect subsets of youth who may be particularly vulnerable to alcohol's effects on cognitive and emotional functioning. (PsycINFO Database Record (c) 2019 APA, all rights reserved).


Assuntos
Encéfalo/diagnóstico por imagem , Cognição , Emoções , Consumo de Álcool por Menores/psicologia , Adolescente , Consumo de Bebidas Alcoólicas/psicologia , Neuroimagem Funcional , Humanos , Memória de Curto Prazo , Neuroimagem , Recompensa
9.
Neurol Neurochir Pol ; 53(4): 304-310, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31441496

RESUMO

DESIGN: Migraine is regarded as a complex brain dysfunction of sensory and modulatory networks with the secondary sensitisation of the trigeminal system as well as the affected brain area's activities. The particular role of the hippocampus and the brainstem in the first phase of the attack, the disrupted cognitive network, and the activation of the limbic and visual systems, are the main discoveries in the field of migraine imaging that have been achieved using functional techniques. Thus advanced neuroimaging has been widely employed to study the pathogenesis of migraine. OBJECTIVE: The evaluation of fMRI BOLD images of migraine patients with or without aura, with particular attention to the interictal phase. SUBJECTS AND METHODS: The aim of this study was to compare brain activity during visual stimuli by fMRI BOLD in the interictal phase (black and white checkerboard tests, static or flickering) of 16 migraine patients, eight with aura and eight without. RESULTS: We demonstrated differences in the right part of the brainstem, the left part of the cerebellum, and in the right middle temporal gyrus. However, the bilateral brain activation in the occipital and frontal lobe remained similar. CONCLUSIONS: Results of our preliminary study suggest that migraine with aura and migraine without aura might be separate disorders, and this requires further investigation.


Assuntos
Epilepsia , Enxaqueca com Aura , Enxaqueca sem Aura , Encéfalo , Neuroimagem Funcional , Humanos , Imagem por Ressonância Magnética , Enxaqueca com Aura/diagnóstico por imagem , Enxaqueca sem Aura/diagnóstico por imagem
10.
PLoS Comput Biol ; 15(8): e1007263, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31433810

RESUMO

A major tenet in theoretical neuroscience is that cognitive and behavioral processes are ultimately implemented in terms of the neural system dynamics. Accordingly, a major aim for the analysis of neurophysiological measurements should lie in the identification of the computational dynamics underlying task processing. Here we advance a state space model (SSM) based on generative piecewise-linear recurrent neural networks (PLRNN) to assess dynamics from neuroimaging data. In contrast to many other nonlinear time series models which have been proposed for reconstructing latent dynamics, our model is easily interpretable in neural terms, amenable to systematic dynamical systems analysis of the resulting set of equations, and can straightforwardly be transformed into an equivalent continuous-time dynamical system. The major contributions of this paper are the introduction of a new observation model suitable for functional magnetic resonance imaging (fMRI) coupled to the latent PLRNN, an efficient stepwise training procedure that forces the latent model to capture the 'true' underlying dynamics rather than just fitting (or predicting) the observations, and of an empirical measure based on the Kullback-Leibler divergence to evaluate from empirical time series how well this goal of approximating the underlying dynamics has been achieved. We validate and illustrate the power of our approach on simulated 'ground-truth' dynamical systems as well as on experimental fMRI time series, and demonstrate that the learnt dynamics harbors task-related nonlinear structure that a linear dynamical model fails to capture. Given that fMRI is one of the most common techniques for measuring brain activity non-invasively in human subjects, this approach may provide a novel step toward analyzing aberrant (nonlinear) dynamics for clinical assessment or neuroscientific research.


Assuntos
Imagem por Ressonância Magnética/estatística & dados numéricos , Modelos Neurológicos , Rede Nervosa/fisiologia , Algoritmos , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Biologia Computacional , Neuroimagem Funcional/estatística & dados numéricos , Humanos , Dinâmica não Linear , Análise de Sistemas
11.
Int J Radiat Oncol Biol Phys ; 105(4): 773-783, 2019 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-31408667

RESUMO

PURPOSE: We used quantitative magnetic resonance imaging to prospectively analyze the association between microstructural damage to memory-associated structures within the medial temporal lobe and longitudinal memory performance after brain radiation therapy (RT). METHODS AND MATERIALS: Patients with a primary brain tumor receiving fractionated brain RT were enrolled on a prospective trial (n = 27). Patients underwent high-resolution volumetric brain magnetic resonance imaging, diffusion-weighted imaging, and neurocognitive testing before and 3, 6, and 12 months post-RT. Medial temporal lobe regions (hippocampus; entorhinal, parahippocampal, and temporal pole white matter [WM]) were autosegmented, quantifying volume and diffusion biomarkers of WM integrity (mean diffusivity [MD]; fractional anisotropy [FA]). Reliable change indices measured changes in verbal (Hopkins Verbal Learning Test-Revised) and visuospatial (Brief Visuospatial Memory Test-Revised [BVMT-R]) memory. Linear mixed-effects models assessed longitudinal associations between imaging parameters and memory. RESULTS: Visuospatial memory significantly declined at 6 months post-RT (mean reliable change indices, -1.3; P = .012). Concurrent chemotherapy and seizures trended toward a significant association with greater decline in visuospatial memory (P = .053 and P = .054, respectively). Higher mean dose to the left temporal pole WM was significantly associated with decreased FA (r = -0.667; P = .002). Over all time points, smaller right hippocampal volume (P = .021), lower right entorhinal FA (P = .023), greater right entorhinal MD (P = .047), and greater temporal pole MD (BVMT-R total recall, P = .003; BVMT-R delayed recall, P = .042) were associated with worse visuospatial memory. The interaction between right entorhinal MD (BVMT-R total recall, P = .021; BVMT-R delayed recall, P = .004) and temporal pole FA (BVMT-R delayed recall, P = .024) significantly predicted visuospatial memory performance. CONCLUSIONS: Brain tumor patients exhibited visuospatial memory decline post-RT. Microstructural damage to critical memory regions, including the hippocampus and medial temporal lobe WM, were associated with post-RT memory decline. The integrity of medial temporal lobe structures is critical to memory performance post-RT, representing possible avoidance targets for memory preservation.


Assuntos
Neoplasias Encefálicas/radioterapia , Irradiação Craniana/efeitos adversos , Transtornos da Memória/etiologia , Memória/efeitos da radiação , Lesões por Radiação/complicações , Lobo Temporal/efeitos da radiação , Adulto , Idoso , Agnosia/diagnóstico , Agnosia/etiologia , Anisotropia , Antineoplásicos/efeitos adversos , Neoplasias Encefálicas/tratamento farmacológico , Irradiação Craniana/métodos , Imagem de Difusão por Ressonância Magnética/métodos , Fracionamento da Dose de Radiação , Córtex Entorrinal/diagnóstico por imagem , Córtex Entorrinal/efeitos da radiação , Feminino , Neuroimagem Funcional , Hipocampo/diagnóstico por imagem , Hipocampo/efeitos da radiação , Humanos , Masculino , Transtornos da Memória/diagnóstico , Rememoração Mental/efeitos dos fármacos , Rememoração Mental/efeitos da radiação , Pessoa de Meia-Idade , Testes Neuropsicológicos , Estudos Prospectivos , Convulsões/complicações , Substância Branca/diagnóstico por imagem , Substância Branca/efeitos da radiação , Adulto Jovem
12.
BMC Neurosci ; 20(1): 37, 2019 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-31366391

RESUMO

BACKGROUND: Cardiovascular conditions contribute to brain volume loss, reduced cerebrovascular health, and increased dementia risk in aging adults. Altered hippocampal connectivity has also been observed in individuals with cardiovascular conditions, yet the functional consequences of these changes remain unclear. In the present study, we collected functional magnetic resonance imaging data during memory encoding and used a psychophysiological interaction analysis to examine whether cardiovascular burden, indexed using the Framingham risk score, was associated with encoding-related hippocampal connectivity and task performance in cognitively-intact older adults between 65 and 85 years of age. Our goal was to better understand the early functional consequences of vascular and metabolic dysfunction in those at risk for cognitive decline. RESULTS: High Framingham risk scores were associated with lower total brain volumes. In addition, those with high Framingham risk scores showed an altered relationship between left hippocampal-medial prefrontal coupling and task performance compared to those with low Framingham risk scores. Specifically, we found a significant interaction of Framingham risk and learning on connectivity between the left hippocampus and primarily left midline prefrontal regions comprising the left ventral anterior cingulate cortex and medial prefrontal cortex. Those with lower Framingham risk scores showed a pattern of weaker connectivity between left hippocampal and medial prefrontal regions associated with better task performance. Those with higher Framingham risk scores showed the opposite pattern; stronger connectivity was associated with better performance. CONCLUSIONS: Findings from the current study show that amongst older adults with cardiovascular conditions, higher Framingham risk is associated with lower brain volume and altered left hippocampal-medial prefrontal coupling during task performance compared to those with lower Framingham risk scores. This may reflect a compensatory mechanism in support of memory function and suggests that older adults with elevated cardiovascular risk are vulnerable to early Alzheimer disease-like dysfunction within the episodic memory system.


Assuntos
Doenças Cardiovasculares/fisiopatologia , Doenças Cardiovasculares/psicologia , Hipocampo/fisiopatologia , Córtex Pré-Frontal/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Neuroimagem Funcional , Humanos , Imagem por Ressonância Magnética , Masculino , Memória/fisiologia , Vias Neurais/fisiologia , Fatores de Risco
13.
Brain Cogn ; 135: 103581, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31301590

RESUMO

Anatomic and molecular sex differences exist in the brain, which suggests there may be functional differences. The present functional magnetic resonance imaging (fMRI) investigation aimed to identify the similarities and differences in brain activity between females and males during item memory. During encoding, abstract shapes were presented to the left or right of fixation. During retrieval, old and new shapes were presented at fixation and participants made "old-left", "old-right", or "new" judgments. Item memory was isolated by contrasting correct "old" responses to old items (with incorrect spatial memory responses; item memory hits) and "new" responses to old items (item memory misses). For both sexes, item memory produced activity in regions associated with visual long-term memory including the prefrontal cortex, parietal cortex, and visual processing regions. A sex by accuracy interaction analysis within each sub-region of activity produced largely null results, supporting common patterns of brain activity. However, there was sex-specific (male > female) activity within default network regions, which suggests males may have been less engaged in the task, and there was evidence for greater activity for females than males in language processing cortex. The present findings indicate that females and males employ similar patterns of brain activity during item memory.


Assuntos
Encéfalo/diagnóstico por imagem , Memória Espacial/fisiologia , Adolescente , Mapeamento Encefálico , Feminino , Neuroimagem Funcional , Humanos , Imagem por Ressonância Magnética , Masculino , Estimulação Luminosa/métodos , Fatores Sexuais , Adulto Jovem
14.
Neuropsychology ; 33(6): 893-910, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31192652

RESUMO

OBJECTIVE: Functional brain networks converge on areas of heteromodal processing such as lateral posterior parietal cortex (PPC). Traumatic brain injury (TBI) alters global connectivity patterns secondary to both focal and diffuse damage, but little is known about how it impacts regional environments. We examined local PPC functioning in individuals with moderate-severe TBI and controls during resting-state functional magnetic resonance imaging (rs-fMRI). METHOD: Eighteen individuals with moderate-severe TBI and 19 healthy controls underwent rs-fMRI and neurocognitive testing. Seed-based analyses characterized remote connectivity of PPC subregions. Voxelwise graph theoretical approaches were used to probe local PPC connectivity and modularity within and between groups, and to examine relationships between local functioning and cognition. RESULTS: Seed-based findings included increased connectivity from left and right hemispheric subregions to right-lateralized default mode and frontoparietal control networks in TBI compared to controls. Graph theoretical analyses revealed increased connection strength within right PPC relative to the contralateral region in TBI. Across groups, right PPC also showed decreased betweenness centrality compared with left PPC. Groups did not differ in the extent of modularity within left or right PPC, but there was less interindividual variability in modular structure within the TBI group. Right PPC modularity significantly predicted individual differences in cognitive performance. CONCLUSIONS: Our findings substantiate hyperconnectivity on both local and global levels after TBI and propose a special role for local right hemispheric functioning in supporting cognition independent of neurologic status. Hyperconnectivity does not appear to result from breakdown in local modular organization and may reflect shared responses to neurologic disruption among those with TBI. (PsycINFO Database Record (c) 2019 APA, all rights reserved).


Assuntos
Lesões Encefálicas Traumáticas/fisiopatologia , Lobo Parietal/fisiopatologia , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Lesões Encefálicas Traumáticas/diagnóstico por imagem , Estudos de Casos e Controles , Cognição , Feminino , Neuroimagem Funcional , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiopatologia , Testes Neuropsicológicos , Lobo Parietal/diagnóstico por imagem , Adulto Jovem
15.
Nat Commun ; 10(1): 2401, 2019 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-31160580

RESUMO

Neurotechnology attempts to develop supernumerary limbs, but can the human brain deal with the complexity to control an extra limb and yield advantages from it? Here, we analyzed the neuromechanics and manipulation abilities of two polydactyly subjects who each possess six fingers on their hands. Anatomical MRI of the supernumerary finger (SF) revealed that it is actuated by extra muscles and nerves, and fMRI identified a distinct cortical representation of the SF. In both subjects, the SF was able to move independently from the other fingers. Polydactyly subjects were able to coordinate the SF with their other fingers for more complex movements than five fingered subjects, and so carry out with only one hand tasks normally requiring two hands. These results demonstrate that a body with significantly more degrees-of-freedom can be controlled by the human nervous system without causing motor deficits or impairments and can instead provide superior manipulation abilities.


Assuntos
Córtex Cerebral/diagnóstico por imagem , Dedos/diagnóstico por imagem , Movimento/fisiologia , Músculo Esquelético/diagnóstico por imagem , Polidactilia/diagnóstico por imagem , Adolescente , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Córtex Cerebral/fisiologia , Feminino , Dedos/fisiologia , Neuroimagem Funcional , Mãos/diagnóstico por imagem , Mãos/fisiologia , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/fisiologia , Polidactilia/fisiopatologia
16.
Nat Commun ; 10(1): 2372, 2019 05 30.
Artigo em Inglês | MEDLINE | ID: mdl-31147546

RESUMO

Only a minority of individuals experiencing trauma subsequently develop post-traumatic stress disorder (PTSD). However, whether differences in vulnerability to PTSD result from a predisposition or trauma exposure remains unclear. A major challenge in differentiating these possibilities is that clinical studies focus on individuals already exposed to trauma without pre-trauma conditions. Here, using the predator scent model of PTSD in rats and a longitudinal design, we measure pre-trauma brain-wide neural circuit functional connectivity, behavioral and corticosterone responses to trauma exposure, and post-trauma anxiety. Freezing during predator scent exposure correlates with functional connectivity in a set of neural circuits, indicating pre-existing circuit function can predispose animals to differential fearful responses to threats. Counterintuitively, rats with lower freezing show more avoidance of the predator scent, a prolonged corticosterone response, and higher anxiety long after exposure. This study provides a framework of pre-existing circuit function that determines threat responses, which might directly relate to PTSD-like behaviors.


Assuntos
Comportamento Animal , Encéfalo/fisiopatologia , Corticosterona/metabolismo , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Animais , Ansiedade/diagnóstico por imagem , Ansiedade/metabolismo , Ansiedade/fisiopatologia , Aprendizagem da Esquiva , Encéfalo/diagnóstico por imagem , Modelos Animais de Doenças , Reação de Congelamento Cataléptica , Neuroimagem Funcional , Estudos Longitudinais , Imagem por Ressonância Magnética , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiopatologia , Odorantes , Trauma Psicológico/diagnóstico por imagem , Trauma Psicológico/metabolismo , Trauma Psicológico/fisiopatologia , Ratos , Transtornos de Estresse Pós-Traumáticos/diagnóstico por imagem , Transtornos de Estresse Pós-Traumáticos/metabolismo
17.
Neural Plast ; 2019: 9693109, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31198419

RESUMO

Dance and music are expressive art forms. Previous behavioural studies have reported that dancers/musicians show a better sensorimotor ability and emotional representation of others. However, the neural mechanism behind this phenomenon is not completely understood. Recently, intensive researches have identified that the insula is highly enrolled in the empathic process. Thus, to expand the knowledge of insular function associated with empathy under the dance/music training background, we mapped the insular network and its associated brain regions in 21 dancers, 20 musicians, and 24 healthy controls using resting-state functional connectivity (FC) analysis. Whole brain voxel-based analysis was performed using seeds from the posterior insula (PI), the ventral anterior insula (vAI), and the dorsal anterior insula (dAI). The training effects of dance and music on insular subnetworks were then evaluated using one-way analysis of variance ANOVA. Increased insular FC with those seeds was found in dancers/musicians, including PI and anterior cingulated cortex (ACC), vAI and middle temporal gyrus (MTG) and middle cingulated cortex (MCC), and dAI and ACC and MTG. In addition, significant associations were found between discrepant insular FC patterns and empathy scores in dancers and musicians. These results indicated that dance/music training might enhance insular subnetwork function, which would facilitate integration of intero/exteroceptive information and result in better affective sensitivity. Those changes might finally facilitate the subjects' empathic ability.


Assuntos
Córtex Cerebral/diagnóstico por imagem , Dança/psicologia , Empatia/fisiologia , Música/psicologia , Rede Nervosa/diagnóstico por imagem , Adolescente , Mapeamento Encefálico , Dança/fisiologia , Feminino , Neuroimagem Funcional , Humanos , Imagem por Ressonância Magnética , Masculino , Adulto Jovem
18.
Neural Plast ; 2019: 8527203, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31178905

RESUMO

Patients with multiple sclerosis (PwMS) frequently suffer from fatigue, but this debilitating symptom is not yet fully understood. We propose that self-control can be conceptually and mechanistically linked to the fatigue concept and might help explain some of the diversity on how PwMS who suffer from fatigue deal with this symptom. To test this claim, we first assessed how cortical oxygenation and measures of motor and cognitive state fatigue change during a strenuous physical task, and then we tested the predictive validity of trait fatigue and trait self-control in explaining the observed changes. A sample of N = 51 PwMS first completed a test battery to collect trait measures of fatigue and self-control. PwMS then performed an isometric hand contraction task at 10% of their maximum voluntary contraction until exhaustion while we repeatedly assessed ratings of perceived cognitive and motor exertion. In addition, we continuously measured oxygenation of the prefrontal cortex (PFC) using functional near-infrared spectroscopy. Linear mixed-effect models revealed significant increases in perceived motor and cognitive exertion, as well as increases in PFC oxygenation. Hierarchical stepwise regression analyses showed that higher trait self-control predicted a less steep increase in PFC oxygenation and perceived cognitive exertion, while trait fatigue did not predict change in any dependent variable. These results provide preliminary evidence for the suggested link between self-control and fatigue. As self-control can be enhanced with training, this finding possibly has important implications for devising nonpharmacological interventions to help patients deal with symptoms of fatigue.


Assuntos
Fadiga/psicologia , Contração Isométrica/fisiologia , Esclerose Múltipla/psicologia , Córtex Pré-Frontal/fisiopatologia , Autocontrole , Adulto , Cognição/fisiologia , Fadiga/diagnóstico por imagem , Fadiga/fisiopatologia , Feminino , Neuroimagem Funcional , Humanos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/diagnóstico por imagem , Esclerose Múltipla/fisiopatologia , Consumo de Oxigênio/fisiologia , Córtex Pré-Frontal/diagnóstico por imagem , Autorrelato , Espectroscopia de Luz Próxima ao Infravermelho
19.
Nat Commun ; 10(1): 2536, 2019 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-31182714

RESUMO

Optical fiber-mediated optogenetic activation and neuronal Ca2+ recording in combination with fMRI provide a multi-modal fMRI platform. Here, we developed an MRI-guided robotic arm (MgRA) as a flexible positioning system with high precision to real-time assist optical fiber brain intervention for multi-modal animal fMRI. Besides the ex vivo precision evaluation, we present the highly reliable brain activity patterns in the projected basal forebrain regions upon MgRA-driven optogenetic stimulation in the lateral hypothalamus. Also, we show the step-wise optical fiber targeting thalamic nuclei and map the region-specific functional connectivity with whole-brain fMRI accompanied by simultaneous calcium recordings to specify its circuit-specificity. The MgRA also guides the real-time microinjection to specific deep brain nuclei, which is demonstrated by an Mn-enhanced MRI method. The MgRA represents a clear advantage over the standard stereotaxic-based fiber implantation and opens a broad avenue to investigate the circuit-specific functional brain mapping with the multi-modal fMRI platform.


Assuntos
Imagem por Ressonância Magnética/instrumentação , Optogenética/instrumentação , Procedimentos Cirúrgicos Robóticos/instrumentação , Animais , Cálcio/metabolismo , Channelrhodopsins , Neuroimagem Funcional/instrumentação , Neuroimagem Funcional/métodos , Imagem por Ressonância Magnética/métodos , Masculino , Fibras Ópticas , Optogenética/métodos , Ratos Sprague-Dawley
20.
Nat Rev Dis Primers ; 5(1): 43, 2019 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-31249310

RESUMO

Conduct disorder (CD) is a common and highly impairing psychiatric disorder that usually emerges in childhood or adolescence and is characterized by severe antisocial and aggressive behaviour. It frequently co-occurs with attention-deficit/hyperactivity disorder (ADHD) and often leads to antisocial personality disorder in adulthood. CD affects ~3% of school-aged children and is twice as prevalent in males than in females. This disorder can be subtyped according to age at onset (childhood-onset versus adolescent-onset) and the presence or absence of callous-unemotional traits (deficits in empathy and guilt). The aetiology of CD is complex, with contributions of both genetic and environmental risk factors and different forms of interplay among the two (gene-environment interaction and correlation). In addition, CD is associated with neurocognitive impairments; smaller grey matter volume in limbic regions such as the amygdala, insula and orbitofrontal cortex, and functional abnormalities in overlapping brain circuits responsible for emotion processing, emotion regulation and reinforcement-based decision-making have been reported. Lower hypothalamic-pituitary-adrenal axis and autonomic reactivity to stress has also been reported. Management of CD primarily involves parent-based or family-based psychosocial interventions, although stimulants and atypical antipsychotics are sometimes used, especially in individuals with comorbid ADHD.


Assuntos
Transtorno da Conduta/diagnóstico , Transtorno da Conduta/terapia , Adolescente , Adulto , Criança , Comorbidade , Transtorno da Conduta/tratamento farmacológico , Feminino , Neuroimagem Funcional/métodos , Doenças Genéticas Inatas/epidemiologia , Humanos , Masculino , Programas de Rastreamento/métodos , Transtornos Mentais , Prevalência , Fatores de Risco
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