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1.
Nat Commun ; 11(1): 5004, 2020 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-33020473

RESUMO

Adaptive brain function requires that sensory impressions of the social and natural milieu are dynamically incorporated into intrinsic brain activity. While dynamic switches between brain states have been well characterised in resting state acquisitions, the remodelling of these state transitions by engagement in naturalistic stimuli remains poorly understood. Here, we show that the temporal dynamics of brain states, as measured in fMRI, are reshaped from predominantly bistable transitions between two relatively indistinct states at rest, toward a sequence of well-defined functional states during movie viewing whose transitions are temporally aligned to specific features of the movie. The expression of these brain states covaries with different physiological states and reflects subjectively rated engagement in the movie. In sum, a data-driven decoding of brain states reveals the distinct reshaping of functional network expression and reliable state transitions that accompany the switch from resting state to perceptual immersion in an ecologically valid sensory experience.


Assuntos
Encéfalo/fisiologia , Filmes Cinematográficos , Adulto , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Feminino , Frequência Cardíaca/fisiologia , Humanos , Imagem por Ressonância Magnética , Masculino , Filmes Cinematográficos/classificação , Filmes Cinematográficos/estatística & dados numéricos , Percepção/fisiologia , Pupila/fisiologia , Descanso/fisiologia , Inquéritos e Questionários , Adulto Jovem
2.
Proc Natl Acad Sci U S A ; 117(38): 23904-23913, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32868436

RESUMO

Adult brains are functionally flexible, a unique characteristic that is thought to contribute to cognitive flexibility. While tools to assess cognitive flexibility during early infancy are lacking, we aimed to assess the spatiotemporal developmental features of "neural flexibility" during the first 2 y of life. Fifty-two typically developing children 0 to 2 y old were longitudinally imaged up to seven times during natural sleep using resting-state functional MRI. Using a sliding window approach, MR-derived neural flexibility, a quantitative measure of the frequency at which brain regions change their allegiance from one functional module to another during a given time period, was used to evaluate the temporal emergence of neural flexibility during early infancy. Results showed that neural flexibility of whole brain, motor, and high-order brain functional networks/regions increased significantly with age, while visual regions exhibited a temporally stable pattern, suggesting spatially and temporally nonuniform developmental features of neural flexibility. Additionally, the neural flexibility of the primary visual network at 3 mo of age was significantly and negatively associated with cognitive ability evaluated at 5/6 y of age. The "flexible club," comprising brain regions with neural flexibility significantly higher than whole-brain neural flexibility, were consistent with brain regions known to govern cognitive flexibility in adults and exhibited unique characteristics when compared to the functional hub and diverse club regions. Thus, MR-derived neural flexibility has the potential to reveal the underlying neural substrates for developing a cognitively flexible brain during early infancy.


Assuntos
Encéfalo/crescimento & desenvolvimento , Encéfalo/fisiologia , Encéfalo/diagnóstico por imagem , Pré-Escolar , Cognição/fisiologia , Feminino , Humanos , Lactente , Recém-Nascido , Imagem por Ressonância Magnética , Masculino , Descanso/fisiologia
3.
PLoS One ; 15(9): e0238946, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32956397

RESUMO

BACKGROUND: The origin of low frequency cerebral hemodynamic fluctuations (CHF) in the resting state remains unknown. Breath-by breath O2-CO2 exchange ratio (bER) has been reported to correlate with the cerebrovascular response to brief breath hold challenge at the frequency range of 0.008-0.03Hz in healthy adults. bER is defined as the ratio of the change in the partial pressure of oxygen (ΔPO2) to that of carbon dioxide (ΔPCO2) between end inspiration and end expiration. In this study, we aimed to investigate the contribution of respiratory gas exchange (RGE) metrics (bER, ΔPO2 and ΔPCO2) to low frequency CHF during spontaneous breathing. METHODS: Twenty-two healthy adults were included. We used transcranial Doppler sonography to evaluate CHF by measuring the changes in cerebral blood flow velocity (ΔCBFv) in bilateral middle cerebral arteries. The regional CHF were mapped with blood oxygenation level dependent (ΔBOLD) signal changes using functional magnetic resonance imaging. Temporal features and frequency characteristics of RGE metrics during spontaneous breathing were examined, and the simultaneous measurements of RGE metrics and CHF (ΔCBFv and ΔBOLD) were studied for their correlation. RESULTS: We found that the time courses of ΔPO2 and ΔPCO2 were interdependent but not redundant. The oscillations of RGE metrics were coherent with resting state CHF at the frequency range of 0.008-0.03Hz. Both bER and ΔPO2 were superior to ΔPCO2 in association with CHF while CHF could correlate more strongly with bER than with ΔPO2 in some brain regions. Brain regions with the strongest coupling between bER and ΔBOLD overlapped with many areas of default mode network including precuneus and posterior cingulate. CONCLUSION: Although the physiological mechanisms underlying the strong correlation between bER and CHF are unclear, our findings suggest the contribution of bER to low frequency resting state CHF, providing a novel insight of brain-body interaction via CHF and oscillations of RGE metrics.


Assuntos
Circulação Cerebrovascular/fisiologia , Taxa Respiratória/fisiologia , Adulto , Velocidade do Fluxo Sanguíneo/fisiologia , Encéfalo/fisiologia , Dióxido de Carbono/sangue , Feminino , Voluntários Saudáveis , Hemodinâmica/fisiologia , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Artéria Cerebral Média/fisiologia , Oxigênio/sangue , Pressão Parcial , Respiração , Descanso/fisiologia , Ultrassonografia Doppler Transcraniana/métodos , Vasodilatação/fisiologia
4.
Proc Natl Acad Sci U S A ; 117(34): 20890-20897, 2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32817467

RESUMO

Multimodal evidence suggests that brain regions accumulate information over timescales that vary according to anatomical hierarchy. Thus, these experimentally defined "temporal receptive windows" are longest in cortical regions that are distant from sensory input. Interestingly, spontaneous activity in these regions also plays out over relatively slow timescales (i.e., exhibits slower temporal autocorrelation decay). These findings raise the possibility that hierarchical timescales represent an intrinsic organizing principle of brain function. Here, using resting-state functional MRI, we show that the timescale of ongoing dynamics follows hierarchical spatial gradients throughout human cerebral cortex. These intrinsic timescale gradients give rise to systematic frequency differences among large-scale cortical networks and predict individual-specific features of functional connectivity. Whole-brain coverage permitted us to further investigate the large-scale organization of subcortical dynamics. We show that cortical timescale gradients are topographically mirrored in striatum, thalamus, and cerebellum. Finally, timescales in the hippocampus followed a posterior-to-anterior gradient, corresponding to the longitudinal axis of increasing representational scale. Thus, hierarchical dynamics emerge as a global organizing principle of mammalian brains.


Assuntos
Mapeamento Encefálico/métodos , Encéfalo/fisiologia , Vias Neurais/fisiologia , Adulto , Córtex Cerebral/fisiologia , Corpo Estriado/fisiologia , Bases de Dados Factuais , Feminino , Substância Cinzenta/fisiologia , Hipocampo/fisiologia , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Descanso/fisiologia , Fatores de Tempo
5.
PLoS One ; 15(7): e0236423, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32735611

RESUMO

BACKGROUND: Use of functional MRI (fMRI) in pre-surgical planning is a non-invasive method for pre-operative functional mapping for patients with brain tumors, especially tumors located near eloquent cortex. Currently, this practice predominantly involves task-based fMRI (T-fMRI). Resting state fMRI (RS-fMRI) offers an alternative with several methodological advantages. Here, we compare group-level analyses of RS-fMRI vs. T-fMRI as methods for language localization. PURPOSE: To contrast RS-fMRI vs. T-fMRI as techniques for localization of language function. METHODS: We analyzed data obtained in 35 patients who had both T-fMRI and RS-fMRI scans during the course of pre-surgical evaluation. The RS-fMRI data were analyzed using a previously trained resting-state network classifier. The T-fMRI data were analyzed using conventional techniques. Group-level results obtained by both methods were evaluated in terms of two outcome measures: (1) inter-subject variability of response magnitude and (2) sensitivity/specificity analysis of response topography, taking as ground truth previously reported maps of the language system based on intraoperative cortical mapping as well as meta-analytic maps of language task fMRI responses. RESULTS: Both fMRI methods localized major components of the language system (areas of Broca and Wernicke) although not with equal inter-subject consistency. Word-stem completion T-fMRI strongly activated Broca's area but also several task-general areas not specific to language. RS-fMRI provided a more specific representation of the language system. CONCLUSION: We demonstrate several advantages of classifier-based mapping of language representation in the brain. Language T-fMRI activated task-general (i.e., not language-specific) functional systems in addition to areas of Broca and Wernicke. In contrast, classifier-based analysis of RS-fMRI data generated maps confined to language-specific regions of the brain.


Assuntos
Encéfalo/diagnóstico por imagem , Área de Broca/patologia , Glioblastoma/diagnóstico , Imagem por Ressonância Magnética , Adulto , Idoso , Atenção/fisiologia , Mapeamento Encefálico/métodos , Área de Broca/diagnóstico por imagem , Feminino , Lobo Frontal/diagnóstico por imagem , Lobo Frontal/patologia , Lateralidade Funcional/fisiologia , Glioblastoma/diagnóstico por imagem , Glioblastoma/patologia , Humanos , Idioma , Masculino , Pessoa de Meia-Idade , Descanso/fisiologia , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/patologia , Adulto Jovem
6.
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
7.
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
8.
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
9.
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
10.
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
11.
J Electromyogr Kinesiol ; 53: 102429, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32505088

RESUMO

Unfused tetanic contractions evoked in fast motor units exhibit extra-efficient force production at the onset of contraction, an effect called "boost". Boost is diminished in subsequent contractions if there is a short rest period between contractions, but can be re-established with a longer period of rest. We tested the hypothesis that contractile activity and rest could enhance boost-related metrics. Two sets of 3 unfused tetani were evoked 3 min apart in fast fatigable (FF) and fast fatigue-resistant (FR) motor units of the rat medial gastrocnemius. The greatest changes occurred in the first unfused tetanic contractions. Relative to the first contraction in the first set, the first contraction in the second set exhibited higher peak force during boost in a subset of motor units (76% of FF and 48% of FR). Enhanced force during boost was influenced by interaction of slowing of twitch contraction time (up to 20% and 25%, for FF and FR motor units, respectively), half-relaxation time (up to 37% and 49% for FF and FR motor units, respectively), and potentiation of the first twitch (up to 13% and 5% for FF and FR motor units, respectively). Examination of twitches evoked between sets suggested opportunity for greater enhancement of boost with shorter intervening rest periods. The phenomenon of enhanced boost following motor unit activity may interest sports scientists.


Assuntos
Contração Muscular/fisiologia , Fadiga Muscular/fisiologia , Músculo Esquelético/fisiologia , Recrutamento Neurofisiológico/fisiologia , Descanso/fisiologia , Animais , Estimulação Elétrica/métodos , Feminino , Neurônios Motores/fisiologia , Ratos , Ratos Wistar , Fatores de Tempo
12.
Sci Rep ; 10(1): 9411, 2020 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-32523060

RESUMO

Reverse-transcription quantitative real-time polymerase chain reaction (RT-qPCR) is widely used for mRNA quantification. To accurately measure changing gene transcript levels under different experimental conditions, the use of appropriate reference gene transcripts is instrumental. In T cell immunology, suitable reference genes have been reported for bulk CD4+ and CD8+ T cells. However, many CD4+ and CD8+ T cell subsets have been described in the past. Although they respond differently to given activation stimuli, proper validation of suitable reference genes in these subsets is lacking. In this study, we evaluated twelve commonly used reference gene products in human naïve (NV) and effector memory (EM) CD8+ T cells under non-activated and activated (2 h, 10 h and 20 h) conditions. We used five different statistical approaches for data analysis. Our results show that a number of widely used reference transcripts become differentially expressed under activating conditions. Using them as references markedly alters results as exemplified with IFNG mRNA expression. The only candidate reference gene products that remained stable during the activation process were 18S rRNA and SDHA mRNA, encouraging their usage as reference gene products for RT-qPCR experiments, when quantifying mRNA levels in human NV and EM CD8+ T cells.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Memória Imunológica/imunologia , Descanso/fisiologia , Adolescente , Adulto , Linfócitos T CD4-Positivos/imunologia , Feminino , Perfilação da Expressão Gênica/métodos , Humanos , Interferon gama/imunologia , Masculino , RNA Mensageiro/imunologia , Reação em Cadeia da Polimerase em Tempo Real/métodos , Padrões de Referência , Adulto Jovem
13.
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
14.
J Sports Sci ; 38(17): 2021-2034, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32552580

RESUMO

Heart rate (HR), when combined with accelerometry, can dramatically improve estimates of energy expenditure and sleep. Advancements in technology, via the development and introduction of small, low-cost photoplethysmography devices embedded within wrist-worn consumer wearables, have made the collection of heart rate (HR) under free-living conditions more feasible. This systematic review and meta-analysis compared the validity of wrist-worn HR estimates to a criterion measure of HR (electrocardiography ECG or chest strap). Searches of PubMed/Medline, Web of Science, EBSCOhost, PsycINFO, and EMBASE resulted in a total of 44 articles representing 738 effect sizes across 15 different brands. Multi-level random effects meta-analyses resulted in a small mean difference (beats per min, bpm) of -0.40 bpm (95 confidence interval (CI) -1.64 to 0.83) during sleep, -0.01 bpm (-0.02 to 0.00) during rest, -0.51 bpm (-1.60 to 0.58) during treadmill activities (walking to running), while the mean difference was larger during resistance training (-7.26 bpm, -10.46 to -4.07) and cycling (-4.55 bpm, -7.24 to -1.87). Mean difference increased by 3 bpm (2.5 to 3.5) per 10 bpm increase of HR for resistance training. Wrist-worn devices that measure HR demonstrate acceptable validity compared to a criterion measure of HR for most common activities.


Assuntos
Frequência Cardíaca/fisiologia , Fotopletismografia/instrumentação , Dispositivos Eletrônicos Vestíveis , Acelerometria , Atividades Cotidianas , Ciclismo/fisiologia , Metabolismo Energético/fisiologia , Humanos , Reprodutibilidade dos Testes , Treinamento de Resistência , Descanso/fisiologia , Corrida/fisiologia , Sono/fisiologia , Caminhada/fisiologia , Punho
15.
Obesity (Silver Spring) ; 28(7): 1283-1291, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32510870

RESUMO

OBJECTIVE: This study aimed to investigate regional neural activity and regulation of patterns in the reorganized neural network of obesity and explore the correlation between brain activities and eating behavior. METHODS: A total of 23 individuals with obesity and 23 controls with normal weight were enrolled. Functional magnetic resonance imaging (fMRI) data were acquired using 3.0-T MRI. Amplitude of low-frequency fluctuation and functional connectivity (FC) analyses were conducted using Data Processing Assistant for resting-state fMRI and Resting-State fMRI Data Analysis Toolkit (REST). RESULTS: The group with obesity showed increased amplitude of low-frequency values in left fusiform gyrus/amygdala, inferior temporal gyrus (ITG), hippocampus/parahippocampal gyrus, and bilateral caudate but decreased values in right superior temporal gyrus. The group with obesity showed increased FC between left caudate and right superior temporal gyrus, left fusiform gyrus/amygdala and left ITG, right caudate and left fusiform gyrus/amygdala, and right caudate and left hippocampus/parahippocampal gyrus. Dutch Eating Behavior Questionnaire-Emotional scores were positively correlated with FC between left hippocampus/parahippocampal gyrus and right caudate but negatively correlated with FC between left fusiform gyrus/amygdala and left ITG. CONCLUSIONS: The study indicated the reorganized neural network presented as a bilateral cross-regulation pattern across hemispheres between reward and various appetite-related functional processing, thus affecting emotional and external eating behavior. These results could provide further evidence for neuropsychological underpinnings of food intake and their neuromodulatory therapeutic potential in obesity.


Assuntos
Regulação do Apetite/fisiologia , Encéfalo/diagnóstico por imagem , Transtornos da Alimentação e da Ingestão de Alimentos/diagnóstico , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/patologia , Obesidade/psicologia , Adolescente , Adulto , Encéfalo/patologia , Encéfalo/fisiopatologia , Mapeamento Encefálico/métodos , Estudos de Casos e Controles , Comportamento Alimentar/fisiologia , Comportamento Alimentar/psicologia , Transtornos da Alimentação e da Ingestão de Alimentos/complicações , Transtornos da Alimentação e da Ingestão de Alimentos/fisiopatologia , Transtornos da Alimentação e da Ingestão de Alimentos/psicologia , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Obesidade/complicações , Obesidade/diagnóstico , Obesidade/fisiopatologia , Descanso/fisiologia , Descanso/psicologia , Adulto Jovem
16.
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
17.
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
18.
Am J Hum Genet ; 106(6): 764-778, 2020 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-32386560

RESUMO

Sudden cardiac death is responsible for half of all deaths from cardiovascular disease. The analysis of the electrophysiological substrate for arrhythmias is crucial for optimal risk stratification. A prolonged T-peak-to-Tend (Tpe) interval on the electrocardiogram is an independent predictor of increased arrhythmic risk, and Tpe changes with heart rate are even stronger predictors. However, our understanding of the electrophysiological mechanisms supporting these risk factors is limited. We conducted genome-wide association studies (GWASs) for resting Tpe and Tpe response to exercise and recovery in ∼30,000 individuals, followed by replication in independent samples (∼42,000 for resting Tpe and ∼22,000 for Tpe response to exercise and recovery), all from UK Biobank. Fifteen and one single-nucleotide variants for resting Tpe and Tpe response to exercise, respectively, were formally replicated. In a full dataset GWAS, 13 further loci for resting Tpe, 1 for Tpe response to exercise and 1 for Tpe response to exercise were genome-wide significant (p ≤ 5 × 10-8). Sex-specific analyses indicated seven additional loci. In total, we identify 32 loci for resting Tpe, 3 for Tpe response to exercise and 3 for Tpe response to recovery modulating ventricular repolarization, as well as cardiac conduction and contraction. Our findings shed light on the genetic basis of resting Tpe and Tpe response to exercise and recovery, unveiling plausible candidate genes and biological mechanisms underlying ventricular excitability.


Assuntos
Eletrocardiografia , Exercício Físico/fisiologia , Estudo de Associação Genômica Ampla , Função Ventricular/genética , Adulto , Idoso , Feminino , Loci Gênicos/genética , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Descanso/fisiologia , Caracteres Sexuais , Reino Unido , Função Ventricular/fisiologia
19.
Clin Exp Hypertens ; 42(7): 595-600, 2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-32249609

RESUMO

OBJECTIVE: Isometric resistance training may reduce resting blood pressure (BP); however, the magnitude of this effect varies among individual subjects and few studies attempted to predict it. This study aimed to investigate the potential hypotensive effects of isometric training and their association with cardiovascular reactivity to acute isometric exercise and muscle strength in young women. METHODS: In this randomized trial, twenty young women were randomly assigned to either the training (n = 10) or control (n = 10) group. Women from the training group performed unilateral isometric handgrip sessions for 8 weeks (4 × 2 min at 25% of maximal voluntary contraction [MVC]; 3 days/week). Cardiovascular reactivity to acute isometric exercise and MVC were measured at baseline. Resting BP was assessed during and after the intervention. RESULTS: Resting systolic BP significantly lowered only in the training group. The change in resting systolic BP following an 8-week intervention was significantly associated with the systolic BP and diastolic BP reactivity to the acute exercise at baseline during set 3 and 4 (P <.05). The handgrip MVC was associated with changes in systolic BP (r = 0.79, P =.007), diastolic BP (r = 0.68, P =.032), and mean arterial pressure (r = 0.79, P =.006). These results indicated that high cardiovascular reactivity and strength attenuate the hypotensive effects following isometric training in young women. CONCLUSIONS: The hypotensive effects following isometric training may be identified by BP reactivity to acute isometric exercise or handgrip strength in young women.


Assuntos
Pressão Sanguínea , Exercício Físico/fisiologia , Força da Mão/fisiologia , Contração Isométrica/fisiologia , Treinamento de Resistência , Adolescente , Feminino , Humanos , Descanso/fisiologia , Adulto Jovem
20.
J Interv Cardiol ; 2020: 9813038, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32265599

RESUMO

Background: A patent foramen ovale (PFO) is a rare cause of hypoxemia and clinical symptoms of dyspnea. Due to a right-to-left shunt, desaturated blood enters the systemic circulation in a subset of patients resulting in dyspnea and a subsequent reduction in quality of life (QoL). Percutaneous closure of PFO is the treatment of choice. Objectives: This retrospective multicentre study evaluates short- and long-term results of percutaneous closure of PFO in patients with dyspnea and/or reduced oxygen saturation. Methods: Patients with respiratory symptoms were selected from databases containing all patients percutaneously closed between January 2000 and September 2018. Improvement in dyspnea, oxygenation, and QoL was investigated using pre- and postprocedural lung function parameters and two postprocedural questionnaires (SF-36 and PFSDQ-M). Results: The average follow-up period was 36 [12-43] months, ranging from 0 months to 14 years. Percutaneous closure was successful in 15 of the 16 patients. All patients reported subjective improvement in dyspnea immediately after device deployment, consistent with their improvement in oxygen saturation (from 90 ± 6% to 94 [92-97%] on room air and in upright position) (p < 0.05). Both questionnaires also indicated an improvement of dyspnea and QoL after closure. The two early and two late deaths were unrelated to the procedure. Conclusion: PFO-related dyspnea and/or hypoxemia can be treated successfully with a percutaneous intervention with long-lasting benefits on oxygen saturation, dyspnea, and QoL.


Assuntos
Dispneia , Forame Oval Patente , Hipóxia , Efeitos Adversos de Longa Duração , Qualidade de Vida , Adulto , Cateterismo Cardíaco/métodos , Dispneia/etiologia , Dispneia/psicologia , Dispneia/terapia , Exercício Físico/fisiologia , Feminino , Forame Oval Patente/diagnóstico , Forame Oval Patente/metabolismo , Forame Oval Patente/psicologia , Forame Oval Patente/cirurgia , Humanos , Hipóxia/etiologia , Hipóxia/psicologia , Hipóxia/terapia , Efeitos Adversos de Longa Duração/diagnóstico , Efeitos Adversos de Longa Duração/psicologia , Efeitos Adversos de Longa Duração/cirurgia , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio , Implantação de Prótese/métodos , Descanso/fisiologia , Estudos Retrospectivos , Dispositivo para Oclusão Septal , Resultado do Tratamento
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