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1.
Nat Commun ; 11(1): 3480, 2020 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-32661242

RESUMO

Researchers have observed large-scale neural meta-state transitions that align to narrative events during movie-viewing. However, group or training-derived priors have been needed to detect them. Here, we introduce methods to sample transitions without any priors. Transitions detected by our methods predict narrative events, are similar across task and rest, and are correlated with activation of regions associated with spontaneous thought. Based on the centrality of semantics to thought, we argue these transitions serve as general, implicit neurobiological markers of new thoughts, and that their frequency, which is stable across contexts, approximates participants' mentation rate. By enabling observation of idiosyncratic transitions, our approach supports many applications, including phenomenological access to the black box of resting cognition. To illustrate the utility of this access, we regress resting fMRI transition rate and movie-viewing transition conformity against trait neuroticism, thereby providing a first neural confirmation of mental noise theory.


Assuntos
Encéfalo/fisiologia , Neuroticismo/fisiologia , Adulto , Mapeamento Encefálico , Cognição/fisiologia , Neurociência Cognitiva/métodos , Intervalos de Confiança , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Análise de Componente Principal , Descanso/fisiologia
2.
Rev Mal Respir ; 37(7): 608-612, 2020 09.
Artigo em Francês | MEDLINE | ID: mdl-32600900
3.
PLoS One ; 15(7): e0236025, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32658929

RESUMO

BACKGROUND: The need to control for the potential influence of menstrual cycle phase on resting metabolism (RMR) places a burden on research participants who must self-report onset of menstruation and researchers who must schedule metabolic testing accordingly. PURPOSE: To systematically review and analyze existing research to determine the effect of menstrual cycle on RMR. METHODS: We searched PubMed, CINAHL, MEDLINE, SPORTDiscus, and Scopus databases using the search terms "menstrual cycle and metabolic rate" and "menstrual cycle and energy expenditure." Eligibility criteria were English language, single-group repeated measures design, and RMR as either a primary or secondary outcome. Risk of bias was assessed based on study sample, measurement, and control of confounders. Differences between the follicular and luteal phases of the menstrual cycle were analyzed using the standardized mean difference in effect size. RESULTS: Thirty English-language studies published between 1930 and December 2019 were included in the systematic review, and 26 studies involving 318 women were included in the meta-analysis. Overall, there was a small but significant effect favoring increased RMR in the luteal phase (ES = 0.33; 95% CI = 0.17, 0.49, p < 0.001). DISCUSSION: Limitations include risk of bias regarding measurement of both menstrual cycle and RMR. Sample sizes were small and studies did not report control of potential confounders. Sub-group analysis demonstrated that in more recent studies published since 2000, the effect of menstrual phase was reduced and not statistically significant (ES = 0.23; 95% CI = -0.00, 0.47; p = 0.055). Until larger and better designed studies are available, based on our current findings, researchers should be aware of the potential confounding influence of the menstrual cycle and control for it by testing consistently in one phase of the cycle when measuring RMR in pre-menopausal women.


Assuntos
Metabolismo Basal , Ciclo Menstrual , Descanso/fisiologia , Feminino , Humanos
5.
PLoS Biol ; 18(7): e3000789, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32614823

RESUMO

In the absence of any task, both the brain and spinal cord exhibit spontaneous intrinsic activity organised in a set of functionally relevant neural networks. However, whether such resting-state networks (RSNs) are interconnected across the brain and spinal cord is unclear. Here, we used a unique scanning protocol to acquire functional images of both brain and cervical spinal cord (CSC) simultaneously and examined their spatiotemporal correspondence in humans. We show that the brain and spinal cord activities are strongly correlated during rest periods, and specific spinal cord regions are functionally linked to consistently reported brain sensorimotor RSNs. The functional organisation of these networks follows well-established anatomical principles, including the contralateral correspondence between the spinal hemicords and brain hemispheres as well as sensory versus motor segregation of neural pathways along the brain-spinal cord axis. Thus, our findings reveal a unified functional organisation of sensorimotor networks in the entire central nervous system (CNS) at rest.


Assuntos
Encéfalo/fisiologia , Descanso/fisiologia , Medula Espinal/fisiologia , Adulto , Mapeamento Encefálico , Córtex Cerebral/fisiologia , Feminino , Humanos , Masculino , Rede Nervosa/fisiologia
6.
PLoS Biol ; 18(7): e3000733, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32649707

RESUMO

Recent resting-state functional MRI (fMRI) studies have revealed that the global signal (GS) exhibits a nonuniform spatial distribution across the gray matter. Whether this topography is informative remains largely unknown. We therefore tested rest-task modulation of GS topography by analyzing static GS correlation and dynamic coactivation patterns in a large sample of an fMRI dataset (n = 837) from the Human Connectome Project. The GS topography in the resting state and in seven different tasks was first measured by correlating the GS with the local time series (GSCORR). In the resting state, high GSCORR was observed mainly in the primary sensory and motor regions, whereas low GSCORR was seen in the association brain areas. This pattern changed during the seven tasks, with mainly decreased GSCORR in sensorimotor cortex. Importantly, this rest-task modulation of GSCORR could be traced to transient coactivation patterns at the peak period of GS (GS-peak). By comparing the topography of GSCORR and respiration effects, we observed that the topography of respiration mimicked the topography of GS in the resting state, whereas both differed during the task states; because of such partial dissociation, we assume that GSCORR could not be equated with a respiration effect. Finally, rest-task modulation of GS topography could not be exclusively explained by other sources of physiological noise. Together, we here demonstrate the informative nature of GS topography by showing its rest-task modulation, the underlying dynamic coactivation patterns, and its partial dissociation from respiration effects during task states.


Assuntos
Mapeamento Encefálico , Imagem por Ressonância Magnética , Descanso/fisiologia , Processamento de Sinais Assistido por Computador , Análise e Desempenho de Tarefas , Adulto , Conectoma , Feminino , Humanos , Masculino , Prosencéfalo/fisiologia , Reprodutibilidade dos Testes , Respiração , Fatores de Tempo , Adulto Jovem
7.
Medicine (Baltimore) ; 99(28): e21125, 2020 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-32664139

RESUMO

OBJECTIVE: The aim of this study was to characterize the capability of detection of the resting state networks (RSNs) with functional magnetic resonance imaging (fMRI) in healthy subjects using a 1.5T scanner in a middle-income country. MATERIALS AND METHODS: Ten subjects underwent a complete blood-oxygen-level dependent imaging (BOLD) acquisition on a 1.5T scanner. For the imaging analysis, we used the spatial independent component analysis (sICA). We designed a computer tool for 1.5 T (or above) scanners for imaging processing. We used it to separate and delineate the different components of the RSNs of the BOLD signal. The sICA was also used to differentiate the RSNs from noise artifact generated by breathing and cardiac cycles. RESULTS: For each subject, 20 independent components (IC) were computed from the sICA (a total of 200 ICs). From these ICs, a spatial pattern consistent with RSNs was identified in 161 (80.5%). From the 161, 131 (65.5%) were fit for study. The networks that were found in all subjects were: the default mode network, the right executive control network, the medial visual network, and the cerebellar network. In 90% of the subjects, the left executive control network and the sensory/motor network were observed. The occipital visual network was present in 80% of the subjects. In 39 (19.5%) of the images, no any neural network was identified. CONCLUSIONS: Reproduction and differentiation of the most representative RSNs was achieved using a 1.5T scanner acquisitions and sICA processing of BOLD imaging in healthy subjects.


Assuntos
Encéfalo/diagnóstico por imagem , Processamento de Imagem Assistida por Computador , Imagem por Ressonância Magnética/instrumentação , Rede Nervosa/diagnóstico por imagem , Descanso/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Mapeamento Encefálico/métodos , Desenho de Equipamento , Feminino , Seguimentos , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Estudos Retrospectivos
8.
Nat Protoc ; 15(7): 2186-2202, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32514178

RESUMO

Functional magnetic resonance imaging (fMRI) is a standard tool to investigate the neural correlates of cognition. fMRI noninvasively measures brain activity, allowing identification of patterns evoked by tasks performed during scanning. Despite the long history of this technique, the idiosyncrasies of each dataset have led to the use of ad-hoc preprocessing protocols customized for nearly every different study. This approach is time consuming, error prone and unsuitable for combining datasets from many sources. Here we showcase fMRIPrep (http://fmriprep.org), a robust tool to prepare human fMRI data for statistical analysis. This software instrument addresses the reproducibility concerns of the established protocols for fMRI preprocessing. By leveraging the Brain Imaging Data Structure to standardize both the input datasets (MRI data as stored by the scanner) and the outputs (data ready for modeling and analysis), fMRIPrep is capable of preprocessing a diversity of datasets without manual intervention. In support of the growing popularity of fMRIPrep, this protocol describes how to integrate the tool in a task-based fMRI investigation workflow.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Imagem por Ressonância Magnética , Animais , Encéfalo/diagnóstico por imagem , Humanos , Processamento de Imagem Assistida por Computador/normas , Padrões de Referência , Descanso/fisiologia , Fluxo de Trabalho
9.
World Neurosurg ; 138: 672-679, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32545020

RESUMO

OBJECTIVE: In this study, we considered the treatment of cognitive characteristics of Parkinson's subtypes under resting magnetic resonance imaging scans, and used magnetic resonance imaging to analyze brain activity characteristics of patients with Parkinson's subtypes at rest. METHODS: In this study, patients with neurological Parkinson's disease subtypes were selected: 27 patients in the tremor group, 33 patients in the orthostatic gastric instability group, and 3 patients with mild cognitive impairment and neuropathic Parkinson's disease. Scientific treatment was adopted. RESULTS: Nineteen patients had mild cognitive dysfunction tremor and unstable posture, and 23 of them had mild cognitive dysfunction. Fifteen healthy controls were subjected to resting state functional magnetic resonance imaging by plane echo imaging sequence scanning. Neurological diseases-Regional consistency analysis of brain regions in patients with Parkinson's disease increased, including the right lower lobe, while regional consistency analysis of brain regions decreased, including the right frontal gyrus, right middle anterior gyrus, and lateral cerebellum. CONCLUSIONS: The experimental results show that the local consistency analysis method based on resting magnetic resonance imaging scan can effectively detect the differences in early neural activity in patients with Parkinson's disease subtype cognitive impairment, and can effectively reflect the brain characteristics of Parkinson's disease.


Assuntos
Encéfalo/diagnóstico por imagem , Disfunção Cognitiva/diagnóstico por imagem , Doença de Parkinson/diagnóstico por imagem , Idoso , Estudos de Casos e Controles , Cognição , Disfunção Cognitiva/fisiopatologia , Disfunção Cognitiva/psicologia , Feminino , Neuroimagem Funcional , Transtornos Neurológicos da Marcha/fisiopatologia , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/fisiopatologia , Doença de Parkinson/psicologia , Descanso , Tremor/fisiopatologia
10.
PLoS One ; 15(6): e0235074, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32569326

RESUMO

OBJECTIVES: It is commonly accepted that motor imagery (MI), i.e. the mental simulation of a movement, leads to an increased size of cortical motor evoked potentials (MEPs), although the magnitude of this effect differs between studies. Its impact on the spinal level is even more variable in the literature. Such discrepancies may be explained by many different experimental approaches. Therefore, the question of the optimal stimulation parameters to assess both spinal and corticospinal excitabilities remains open. METHODS: H-reflexes and MEPs of the triceps surae were evoked in 11 healthy subjects during MI, weak voluntary contraction (CON) and rest (REST). In each condition, the full recruitment curve from the response threshold to maximal potential was investigated. RESULTS: At stimulation intensities close to the maximal response, MEP amplitude was increased by CON compared to REST on the triceps surae. No effect of the different conditions was found on the H-reflex recruitment curve, except a small variation beyond maximal H-reflex in the soleus muscle. CONCLUSION: Based on our results, we recommend to assess corticospinal excitability between 70% and 100% of maximal MEP intensity instead of the classical use of a percentage of the motor threshold and to elicit H-reflexes on the ascending part of the recruitment curve.


Assuntos
Imagens, Psicoterapia , Contração Muscular/fisiologia , Tratos Piramidais/fisiologia , Descanso , Medula Espinal/fisiologia , Estimulação Magnética Transcraniana , Adulto , Potencial Evocado Motor/fisiologia , Feminino , Humanos , Masculino , Projetos Piloto
11.
J Sports Med Phys Fitness ; 60(7): 992-998, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32597616

RESUMO

BACKGROUND: The rest interval between sets can affect the responses to resistance training. Thus, the purpose of this study was to compare the effects of different rest intervals (RI) on volume, density, and rating of perceived exertion (RPE) when adopting a crescent pyramid (CP) system. METHODS: Twenty young women (21.1±2.6 years, 1.59±0.06 m, 58.5±9.3 kg) participated in this study. All participants performed three experimental sessions of the leg press exercise in 5 sets until voluntary muscular failure at 60%, 65%, 70%, 75%, and 80% of one-repetition maximum (1RM). A randomized and crossover design was used so that in each session one of three RI (RI-1 = 1 min, RI-2 = 2 min, and RI-3 = 3 min) was tested. RESULTS: The participants performed a significantly larger volume in the RI-3 (12820±3134 kg) when compared to RI-1 (10367±3053 kg) condition (P<0.05). The volume did not differ between RI-2 and RI-3 (P>0.05). The density was higher (P<0.05) in RI-1 (43.1±12.7 kg/s) when compared RI-2 (25.6±5.8 kg/s) and RI-3 (17.7±4.3 kg/s). The RI-2 presented higher density compared to RI-3 condition (P<0.05). The RPE was not different between the three conditions (P>0.05). CONCLUSIONS: The use of 2 minutes of rest between sets allowed the performance of a high volume-load and density of the session in young women. In addition, the three experimental sessions provided a high perception of effort.


Assuntos
Percepção/fisiologia , Esforço Físico/fisiologia , Treinamento de Resistência/métodos , Levantamento de Peso/fisiologia , Adulto , Estudos Cross-Over , Feminino , Humanos , Perna (Membro)/fisiologia , Descanso/fisiologia , Fatores de Tempo , Adulto Jovem
12.
Adv Exp Med Biol ; 1235: 35-52, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32488635

RESUMO

Functional connectivity magnetic resonance imaging (fcMRI), performed during resting wakefulness without tasks or stimulation, is a non-invasive technique to assess and visualise functional brain networks in vivo. Acquisition of resting-state imaging data has become increasingly common in longitudinal studies to investigate brain health and disease. However, the scanning protocols vary considerably across different institutions creating challenges for comparability especially for the interpretation of findings in patient cohorts and establishment of diagnostic or prognostic imaging biomarkers. The aim of this chapter is to discuss the effect of two experimental conditions (i.e. a low cognitive demand paradigm and a pure resting-state fcMRI) on the reproducibility of brain networks between a baseline and a follow-up session, 30 (±5) days later, acquired from 12 right-handed volunteers (29 ± 5 yrs). A novel method was developed and used for a direct statistical comparison of the test-retest reliability using 28 well-established functional brain networks. Overall, both scanning conditions produced good levels of test-retest reliability. While the pure resting-state condition showed higher test-retest reliability for 18 of the 28 analysed networks, the low cognitive demand paradigm produced higher test-retest reliability for 8 of the 28 brain networks (i.e. visual, sensorimotor and frontal areas); in 2 of the 28 brain networks no significant changes could be detected. These results are relevant to planning of longitudinal studies, as higher test-retest reliability generally increases statistical power. This work also makes an important contribution to neuroimaging where optimising fcMRI experimental scanning conditions, and hence data visualisation of brain function, remains an on-going topic of interest. In this chapter, we provide a full methodological explanation of the two paradigms and our analysis so that readers can apply them to their own scanning protocols.


Assuntos
Mapeamento Encefálico/normas , Encéfalo/fisiologia , Imagem por Ressonância Magnética/normas , Descanso/fisiologia , Humanos , Reprodutibilidade dos Testes
13.
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
14.
Clin Imaging ; 65: 47-53, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32353718

RESUMO

Resting state functional connectivity magnetic resonance imaging (rsfcMRI) has become a key component of investigations of neurocognitive and psychiatric behaviors. Over the past two decades, several methods and paradigms have been adopted to utilize and interpret data from resting-state fluctuations in the brain. These findings have increased our understanding of changes in many disease states. As the amount of resting state data available for research increases with big datasets and data-sharing projects, it is important to review the established traditional analysis methods and recognize areas where research methodology can be adapted to better accommodate the scale and complexity of rsfcMRI analysis. In this paper, we review established methods of analysis as well as areas that have been receiving increasing attention such as dynamic rsfcMRI, independent vector analysis, multiband rsfcMRI and network of networks.


Assuntos
Imagem por Ressonância Magnética/métodos , Adulto , Encéfalo/fisiopatologia , Mapeamento Encefálico/métodos , Feminino , Humanos , Masculino , Rede Nervosa/fisiopatologia , Descanso
15.
Med Sci Sports Exerc ; 52(6): 1437, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32427752
16.
PLoS One ; 15(5): e0233636, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32442227

RESUMO

This study assesses the respiratory dynamics related to stress parameters and resting time before slaughter, in the quality of surubim (Pseudopatystoma spp.) fillets. A completely randomized design was conducted using five treatments: resting time before slaughter of 0, 2, 4, 8 and 24 hours, with 15 fish sampled per treatment. Time 0 corresponded to the treatment without resting time, where the fish were slaughtered immediately after arriving at the processing plant. The resting time did not affect the electrolyte balance, hemoglobin, plasma, hepatic glycogen, myofibrillar fragmentation index (MFI) and water holding capacity (WHC) of surubins. However, with increased resting time, there was a significant decrease in muscle glycogen and an increase in blood pH and blood bicarbonate levels. Additionally, respiratory parameters showed an increase in pO2 and, consequently, in O2 saturation and a decrease in pCO2.The hematocrit and MCV values of the surubins after 24 hours of resting decreased significantly. In the first hours of resting, the highest values of erythrocytes and CHCM were observed. The lowest level of stress was observed for fish having 24 hours of resting. Fish having longer resting periods (8 and 24 hours) presented fillets with a higher pH (P <0.05) and the rigor mortis establishment time was shorter for the first 2 hours and 24 hours of resting time. There was a linear decrease in fillet lightness and an increase in the intensity of red (CIE a*) color up to 24 hours when resting was increased. In CIE b*, a linear decrease (P <0.05) of the yellow intensity of the fillets was observed as the surubim resting time increased. A resting time of 4 to 8 hours before slaughter is effective in reestablishing homeostasis after transporting surubim, providing fillets with higher quality and a greater length of the pre-rigor mortis period.


Assuntos
Peixes-Gato/metabolismo , Manipulação de Alimentos , Qualidade dos Alimentos , Alimentos Marinhos/análise , Animais , Cor , Homeostase , Concentração de Íons de Hidrogênio , Músculos/metabolismo , Descanso , Rigor Mortis
17.
Rev Med Suisse ; 16(692): 901-903, 2020 May 06.
Artigo em Francês | MEDLINE | ID: mdl-32374533

RESUMO

Patients with acquired brain injury often suffer from pathological fatigue that differs from "normal" fatigue in that it appears more quickly and during non-demanding tasks, and recovery is not complete despite rest. It limits physical and cognitive activities, interferes with rehabilitation and return to work. The underlying mechanisms are poorly understood but appear to involve dysfunction of brain interactions. Current management combining physical reconditioning, cognitive compensatory strategies, and treatment of associated factors often leads to significant clinical improvement and promotes socio-professional reintegration. However, the effect remains insufficient in some patients, which underlines the importance of developing new therapeutic approaches based on a better understanding of the underlying neuronal deficits.


Assuntos
Lesões Encefálicas/fisiopatologia , Lesões Encefálicas/reabilitação , Encéfalo/fisiopatologia , Fadiga/complicações , Fadiga/fisiopatologia , Lesões Encefálicas/complicações , Lesões Encefálicas/psicologia , Cognição , Humanos , Descanso
18.
Clin Sports Med ; 39(3): 589-596, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32446577

RESUMO

When more obvious and common causes of elbow pathology are ruled out, it is important to be aware of uncommon causes of elbow pain in throwers. The Lacertus syndrome can be a debilitating problem when overlooked; however, it can be easily diagnosed with a careful history and physical examination. If the description suggests a postexertional compartment-like problem, consider having the patient throw before the examination, and the diagnosis becomes easier to either confirm or rule out. Once the diagnosis is established treatment includes rest or fasciotomy. Recovery is uncomplicated and athletes can return to throwing within a month.


Assuntos
Artralgia/etiologia , Traumatismos em Atletas/diagnóstico , Traumatismos em Atletas/terapia , Síndromes Compartimentais/diagnóstico , Síndromes Compartimentais/terapia , Cotovelo/lesões , Traumatismos em Atletas/cirurgia , Síndromes Compartimentais/cirurgia , Fasciotomia , Humanos , Exame Físico , Descanso , Volta ao Esporte
19.
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