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1.
Nat Commun ; 12(1): 6114, 2021 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-34671042

RESUMO

In the hippocampal circuit CA3 input plays a critical role in the organization of CA1 population activity, both during learning and sleep. While integrated spatial representations have been observed across the two hemispheres of CA1, these regions lack direct connectivity and thus the circuitry responsible remains largely unexplored. Here we investigate the role of CA3 in organizing bilateral CA1 activity by blocking synaptic transmission at CA3 terminals through the inducible transgenic expression of tetanus toxin. Although the properties of single place cells in CA1 were comparable bilaterally, we find a decrease of ripple synchronization between left and right CA1 after silencing CA3. Further, during both exploration and rest, CA1 neuronal ensemble activity is less coordinated across hemispheres. This included degradation of the replay of previously explored spatial paths in CA1 during rest, consistent with the idea that CA3 bilateral projections integrate activity between left and right hemispheres and orchestrate bilateral hippocampal coding.


Assuntos
Região CA1 Hipocampal/fisiologia , Região CA3 Hipocampal/fisiologia , Lateralidade Funcional/fisiologia , Animais , Região CA1 Hipocampal/citologia , Região CA1 Hipocampal/metabolismo , Potenciais Pós-Sinápticos Excitadores/fisiologia , Camundongos , Vias Neurais/fisiologia , Células de Lugar/fisiologia , Descanso/fisiologia , Transmissão Sináptica/genética , Toxina Tetânica/genética , Vigília/fisiologia
2.
Nat Commun ; 12(1): 5713, 2021 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-34588439

RESUMO

Large, openly available datasets and current analytic tools promise the emergence of population neuroscience. The considerable diversity in personality traits and behaviour between individuals is reflected in the statistical variability of neural data collected in such repositories. Recent studies with functional magnetic resonance imaging (fMRI) have concluded that patterns of resting-state functional connectivity can both successfully distinguish individual participants within a cohort and predict some individual traits, yielding the notion of an individual's neural fingerprint. Here, we aim to clarify the neurophysiological foundations of individual differentiation from features of the rich and complex dynamics of resting-state brain activity using magnetoencephalography (MEG) in 158 participants. We show that akin to fMRI approaches, neurophysiological functional connectomes enable the differentiation of individuals, with rates similar to those seen with fMRI. We also show that individual differentiation is equally successful from simpler measures of the spatial distribution of neurophysiological spectral signal power. Our data further indicate that differentiation can be achieved from brain recordings as short as 30 seconds, and that it is robust over time: the neural fingerprint is present in recordings performed weeks after their baseline reference data was collected. This work, thus, extends the notion of a neural or brain fingerprint to fast and large-scale resting-state electrophysiological dynamics.


Assuntos
Encéfalo/fisiologia , Individualidade , Magnetoencefalografia/estatística & dados numéricos , Neurofisiologia/métodos , Descanso/fisiologia , Adolescente , Adulto , Artefatos , Conectoma , Fenômenos Eletrofisiológicos , Feminino , Humanos , Análise dos Mínimos Quadrados , Masculino , Pessoa de Meia-Idade , Adulto Jovem
3.
Sci Rep ; 11(1): 16288, 2021 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-34381127

RESUMO

Veterinary and human medicine are still seeking a conclusive explanation of the function of sleep, including the change in sleep behaviour over the course of an individual's lifetime. In human medicine, sleep disorders and abnormalities in the electroencephalogram are used for prognostic statements, therapeutic means and diagnoses. To facilitate such use in foal medicine, we monitored 10 foals polysomnographically for 48 h. Via 10 attached cup electrodes, brain waves were recorded by electroencephalography, eye movements by electrooculography and muscle activity by electromyography. Wireless polysomnographs allowed us to measure the foals in their home stables. In addition, each foal was simultaneously monitored with infrared video cameras. By combining the recorded data, we determined the time budgeting of the foals over 48 h, whereby the states of vigilance were divided into wakefulness, light sleep, slow-wave sleep and rapid-eye-movement sleep, and the body positions into standing, suckling, sternal recumbency and lateral recumbency. The results of the qualitative analyses showed that the brain waves of the foals differ in their morphology from those previously reported for adult horses. The quantitative data analyses revealed that foals suckle throughout all periods of the day, including night-time. The results of our combined measurements allow optimizing the daily schedule of the foals according to their sleep and activity times. We recommend that stall rest should begin no later than 9.00 p.m. and daily stable work should be done in the late afternoon.


Assuntos
Cavalos/fisiologia , Sono REM/fisiologia , Animais , Encéfalo/fisiologia , Eletroencefalografia/métodos , Eletromiografia/métodos , Eletroculografia/métodos , Estudos de Avaliação como Assunto , Movimentos Oculares/fisiologia , Polissonografia/métodos , Descanso/fisiologia , Vigília/fisiologia
4.
Sci Rep ; 11(1): 16930, 2021 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-34417487

RESUMO

Symptomatic overlap of depressive episodes in bipolar disorder (BD) and major depressive disorder (MDD) is a major diagnostic and therapeutic problem. Mania in medical history remains the only reliable distinguishing marker which is problematic given that episodes of depression compared to episodes of mania are more frequent and predominantly present at the beginning of BD. Resting-state functional magnetic resonance imaging (rs-fMRI) is a non-invasive, task-free, and well-tolerated method that may provide diagnostic markers acquired from spontaneous neural activity. Previous rs-fMRI studies focused on differentiating BD from MDD depression were inconsistent in their findings due to low sample power, heterogeneity of compared samples, and diversity of analytical methods. This meta-analysis investigated resting-state activity differences in BD and MDD depression using activation likelihood estimation. PubMed, Web of Science, Scopus and Google Scholar databases were searched for whole-brain rs-fMRI studies which compared MDD and BD currently depressed patients between Jan 2000 and August 2020. Ten studies were included, representing 234 BD and 296 MDD patients. The meta-analysis found increased activity in the left insula and adjacent area in MDD compared to BD. The finding suggests that the insula is involved in neural activity patterns during resting-state that can be potentially used as a biomarker differentiating both disorders.


Assuntos
Transtorno Bipolar/diagnóstico , Transtorno Bipolar/fisiopatologia , Encéfalo/fisiopatologia , Descanso/fisiologia , Adulto , Mapeamento Encefálico , Diagnóstico Diferencial , Feminino , Humanos , Masculino
5.
Clin Neurophysiol ; 132(10): 2540-2550, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34455312

RESUMO

OBJECTIVE: Resting-state functional connectivity reveals a promising way for the early detection of dementia. This study proposes a novel method to accurately classify Healthy Controls, Early Mild Cognitive Impairment, Late Mild Cognitive Impairment, and Alzheimer's Disease individuals. METHODS: A novel mapping function based on the B distribution has been developed to map correlation matrices to robust functional connectivity. The node2vec algorithm is applied to the functional connectivity to produce node embeddings. The concatenation of these embedding has been used to derive the patients' feature vectors for further feeding into the Support Vector Machine and Logistic Regression classifiers. RESULTS: The experimental results indicate promising results in the complex four-class classification problem with an accuracy rate of 97.73% and a quadratic kappa score of 96.86% for the Support Vector Machine. These values are 97.32% and 96.74% for Logistic Regression. CONCLUSION: This study presents an accurate automated method for dementia classification. Default Mode Network and Dorsal Attention Network have been found to demonstrate a significant role in the classification method. SIGNIFICANCE: A new mapping function is proposed in this study, the mapping function improves accuracy by 10-11% in the Alzheimer's Disease Neuroimaging Initiative (ADNI) database.


Assuntos
Doença de Alzheimer/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Disfunção Cognitiva/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Rede Nervosa/diagnóstico por imagem , Máquina de Vetores de Suporte , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Doença de Alzheimer/classificação , Doença de Alzheimer/fisiopatologia , Encéfalo/fisiologia , Disfunção Cognitiva/classificação , Disfunção Cognitiva/fisiopatologia , Bases de Dados Factuais , Feminino , Humanos , Imageamento por Ressonância Magnética/classificação , Masculino , Rede Nervosa/fisiologia , Descanso/fisiologia
6.
J Clin Invest ; 131(18)2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34264865

RESUMO

BACKGROUNDCertain components of rest-activity rhythms such as greater eveningness (delayed phase), physical inactivity (blunted amplitude), and shift work (irregularity) are associated with increased risk for drug use. Dopaminergic (DA) signaling has been hypothesized to mediate the associations, though clinical evidence is lacking.METHODSWe examined associations between rhythm components and striatal D1 (D1R) and D2/3 receptor (D2/3R) availability in 32 healthy adults (12 female, 20 male; age 42.40 ± 12.22 years) and its relationship to drug reward. Rest-activity rhythms were assessed by 1-week actigraphy combined with self-reports. [11C]NNC112 and [11C]raclopride positron emission tomography (PET) scans were conducted to measure D1R and D2/3R availability, respectively. Additionally, self-reported drug-rewarding effects of 60 mg oral methylphenidate were assessed.RESULTSWe found that delayed rhythm was associated with higher D1R availability in caudate, which was not attributable to sleep loss or so-called social jet lag, whereas physical inactivity was associated with higher D2/3R availability in nucleus accumbens (NAc). Delayed rest-activity rhythm, higher caudate D1R, and NAc D2/3R availability were associated with greater sensitivity to the rewarding effects of methylphenidate.CONCLUSIONThese findings reveal specific components of rest-activity rhythms associated with striatal D1R, D2/3R availability, and drug-rewarding effects. Personalized interventions that target rest-activity rhythms may help prevent and treat substance use disorders.TRIAL REGISTRATIONClinicalTrials.gov: NCT03190954.FUNDINGNational Institute on Alcohol Abuse and Alcoholism (ZIAAA000550).


Assuntos
Ritmo Circadiano/fisiologia , Receptores de Dopamina D1/fisiologia , Receptores de Dopamina D2/fisiologia , Recompensa , Transtornos Relacionados ao Uso de Substâncias/etiologia , Transtornos Relacionados ao Uso de Substâncias/fisiopatologia , Actigrafia , Adulto , Estimulantes do Sistema Nervoso Central/administração & dosagem , Corpo Estriado/fisiologia , Feminino , Humanos , Masculino , Metilfenidato/administração & dosagem , Pessoa de Meia-Idade , Atividade Motora/fisiologia , Tomografia por Emissão de Pósitrons , Descanso/fisiologia , Adulto Jovem
7.
Am J Cardiol ; 155: 45-51, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34284867

RESUMO

Resting heart rate (RHR) has been an established predictor for atrial fibrillation (AF). However, the association of visit-to-visit heart rate variability (VVHRV) with new-onset AF risk over long term remains unclear. Our study investigates the relation of VVHRV to new-onset AF in general population in the prospective study of the Kailuan cohort. A total of 46,126 individuals without arrhythmia were included. They underwent 3 health examinations from 2006 to 2010 and performed follow up. VVHRV was measured by coefficient of variation (CV), variability independent of the mean (VIM), and standard deviation (SD). Participants were separately divided into 5 categories by quintiles of visit-to-visit RHR-CV, RHR-VIM and RHR-SD. Multivariate Cox regression and restricted cubic spline models were performed to establish the association between VVHRV and new-onset AF. 241 new-onset AF occurred during a median follow-up of 7.54 years. The incidence of new-onset AF in the group of the lowest (Q1) and highest quintiles (Q5) of RHR-CV were higher than that in other groups. The HRs for the new-onset AF were 2.07 (95% CI, 1.34-3.21, p < 0.01), in the highest quintile group(Q5) compared with group Q2, and 1.89(95% CI, 1.20-2.97, p < 0.01) in the lowest quintile group(Q1) compared with group Q2. The risk for new-onset AF showed a similar trend using RHR-VIM (p < 0.01) and RHR-SD (p < 0.05) parameters. Further sensitivity analyses indicated the consistent results in subjects without prior cardiovascular disease and without taking beta blockers or CCB. To match the covariates, analyses were also performed by propensity score matching, and prominent trends were also found in RHR-SD and RHR-VIM. In conclusion, the study indicated that higher and lower VVHRV were associated with the increasing risk of new-onset AF, which supporting a U-shaped curve existence.


Assuntos
Fibrilação Atrial/epidemiologia , Frequência Cardíaca/fisiologia , Visita a Consultório Médico/estatística & dados numéricos , Vigilância da População , Descanso/fisiologia , Fibrilação Atrial/fisiopatologia , China/epidemiologia , Feminino , Seguimentos , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco
8.
Neuroimage ; 239: 118326, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34216772

RESUMO

Vocal flexibility is a hallmark of the human species, most particularly the capacity to speak and sing. This ability is supported in part by the evolution of a direct neural pathway linking the motor cortex to the brainstem nucleus that controls the larynx the primary sound source for communication. Early brain imaging studies demonstrated that larynx motor cortex at the dorsal end of the orofacial division of motor cortex (dLMC) integrated laryngeal and respiratory control, thereby coordinating two major muscular systems that are necessary for vocalization. Neurosurgical studies have since demonstrated the existence of a second larynx motor area at the ventral extent of the orofacial motor division (vLMC) of motor cortex. The vLMC has been presumed to be less relevant to speech motor control, but its functional role remains unknown. We employed a novel ultra-high field (7T) magnetic resonance imaging paradigm that combined singing and whistling simple melodies to localise the larynx motor cortices and test their involvement in respiratory motor control. Surprisingly, whistling activated both 'larynx areas' more strongly than singing despite the reduced involvement of the larynx during whistling. We provide further evidence for the existence of two larynx motor areas in the human brain, and the first evidence that laryngeal-respiratory integration is a shared property of both larynx motor areas. We outline explicit predictions about the descending motor pathways that give these cortical areas access to both the laryngeal and respiratory systems and discuss the implications for the evolution of speech.


Assuntos
Laringe/fisiologia , Imageamento por Ressonância Magnética/métodos , Córtex Motor/fisiologia , Vias Neurais/fisiologia , Respiração , Fala/fisiologia , Adulto , Feminino , Humanos , Análise dos Mínimos Quadrados , Masculino , Córtex Motor/diagnóstico por imagem , Mecânica Respiratória/fisiologia , Descanso/fisiologia , Canto/fisiologia , Adulto Jovem
9.
Sci Rep ; 11(1): 15059, 2021 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-34301967

RESUMO

Previous neuroimaging studies demonstrated that patients with strabismus or amblyopia can show significant functional and anatomical changes in the brain, but alterations of interhemispheric functional connectivity (FC) have not been well studied in this population. The current study analyzed whole-brain changes of interhemispheric FC in children with strabismus and amblyopia (CSA) using voxel-mirrored homotopic connectivity (VMHC).A total of 24 CSA (16 males and 8 females) and 24 normal controls (NCs) consisting of 16 and 8 age-, sex, and education-matched males and females, respectively, underwent functional magnetic resonance imaging (fMRI) scans in the resting state. According to Gaussian random field theory, changes in the resting state FC (rsFC) between hemispheres were evaluated using the VMHC method. The relationships between mean VMHC values in multiple brain regions and behavioral performance were evaluated by Pearson correlation analysis. In contrast to NCs, the CSA group showed significantly decreased VMHC values in the bilateral cerebellum, bilateral frontal superior orbital (frontal sup orb), bilateral temporal inferior(temporal inf),and bilateral frontal superior(frontal sup). CSA have abnormal interhemispheric FC in many brain regions, which may reflect dysfunction of eye movements and visual fusion. These findings might provide insight into the underlying pathogenetic mechanisms of CSA.


Assuntos
Ambliopia/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Neuroimagem Funcional , Imageamento por Ressonância Magnética , Estrabismo/diagnóstico por imagem , Adolescente , Ambliopia/fisiopatologia , Encéfalo/fisiopatologia , Mapeamento Encefálico , Cerebelo/diagnóstico por imagem , Cerebelo/fisiopatologia , Criança , Feminino , Humanos , Masculino , Descanso/fisiologia , Estrabismo/diagnóstico , Estrabismo/fisiopatologia
10.
Neuroimage ; 240: 118368, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34242786

RESUMO

This magnetoencephalography (MEG) study investigates how procedural sequence learning performance is related to prior brain resting-state functional connectivity (rsFC), and to what extent sequence learning induces rapid changes in brain rsFC in school-aged children. Procedural learning was assessed in 30 typically developing children (mean age ± SD: 9.99 years ± 1.35) using a serial reaction time task (SRTT). During SRTT, participants touched as quickly and accurately as possible a stimulus sequentially or randomly appearing in one of the quadrants of a touchscreen. Band-limited power envelope correlation (brain rsFC) was applied to MEG data acquired at rest pre- and post-learning. Correlation analyses were performed between brain rsFC and sequence-specific learning or response time indices. Stronger pre-learning interhemispheric rsFC between inferior parietal and primary somatosensory/motor areas correlated with better subsequent sequence learning performance and faster visuomotor response time. Faster response time was associated with post-learning decreased rsFC within the dorsal extra-striate visual stream and increased rsFC between temporo-cerebellar regions. In school-aged children, variations in functional brain architecture at rest within the sensorimotor network account for interindividual differences in sequence learning and visuomotor performance. After learning, rapid adjustments in functional brain architecture are associated with visuomotor performance but not sequence learning skills.


Assuntos
Encéfalo/fisiologia , Aprendizagem/fisiologia , Magnetoencefalografia/métodos , Rede Nervosa/fisiologia , Tempo de Reação/fisiologia , Descanso/fisiologia , Encéfalo/diagnóstico por imagem , Criança , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Rede Nervosa/diagnóstico por imagem , Estimulação Luminosa/métodos
11.
Neuroimage ; 241: 118409, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34293465

RESUMO

Classification of whole-brain functional connectivity MRI data with convolutional neural networks (CNNs) has shown promise, but the complexity of these models impedes understanding of which aspects of brain activity contribute to classification. While visualization techniques have been developed to interpret CNNs, bias inherent in the method of encoding abstract input data, as well as the natural variance of deep learning models, detract from the accuracy of these techniques. We introduce a stochastic encoding method in an ensemble of CNNs to classify functional connectomes by sex. We applied our method to resting-state and task data from the UK BioBank, using two visualization techniques to measure the salience of three brain networks involved in task- and resting-states, and their interaction. To regress confounding factors such as head motion, age, and intracranial volume, we introduced a multivariate balancing algorithm to ensure equal distributions of such covariates between classes in our data. We achieved a final AUROC of 0.8459. We found that resting-state data classifies more accurately than task data, with the inner salience network playing the most important role of the three networks overall in classification of resting-state data and connections to the central executive network in task data.


Assuntos
Encéfalo/fisiologia , Aprendizado Profundo , Rede Nervosa/fisiologia , Desempenho Psicomotor/fisiologia , Descanso/fisiologia , Caracteres Sexuais , Bancos de Espécimes Biológicos , Encéfalo/diagnóstico por imagem , Bases de Dados Factuais , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Rede Nervosa/diagnóstico por imagem , Reino Unido/epidemiologia
12.
Neuroimage ; 241: 118423, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34303794

RESUMO

Resting state functional magnetic resonance imaging (rsfMRI) data exhibits complex but structured patterns. However, the underlying origins are unclear and entangled in rsfMRI data. Here we establish a variational auto-encoder, as a generative model trainable with unsupervised learning, to disentangle the unknown sources of rsfMRI activity. After being trained with large data from the Human Connectome Project, the model has learned to represent and generate patterns of cortical activity and connectivity using latent variables. The latent representation and its trajectory represent the spatiotemporal characteristics of rsfMRI activity. The latent variables reflect the principal gradients of the latent trajectory and drive activity changes in cortical networks. Representational geometry captured as covariance or correlation between latent variables, rather than cortical connectivity, can be used as a more reliable feature to accurately identify subjects from a large group, even if only a short period of data is available in each subject. Our results demonstrate that VAE is a valuable addition to existing tools, particularly suited for unsupervised representation learning of resting state fMRI activity.


Assuntos
Encéfalo/diagnóstico por imagem , Conectoma/métodos , Individualidade , Imageamento por Ressonância Magnética/métodos , Descanso , Aprendizado de Máquina não Supervisionado , Encéfalo/fisiologia , Bases de Dados Factuais , Humanos , Descanso/fisiologia
13.
Neuroimage ; 241: 118419, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34302967

RESUMO

BACKGROUND: Metabolic disorders associated with obesity could lead to alterations in brain structure and function. Whether these changes can be reversed after weight loss is unclear. Bariatric surgery provides a unique opportunity to address these questions because it induces marked weight loss and metabolic improvements which in turn may impact the brain in a longitudinal fashion. Previous studies found widespread changes in grey matter (GM) and white matter (WM) after bariatric surgery. However, findings regarding changes in spontaneous neural activity following surgery, as assessed with the fractional amplitude of low frequency fluctuations (fALFF) and regional homogeneity of neural activity (ReHo), are scarce and heterogenous. In this study, we used a longitudinal design to examine the changes in spontaneous neural activity after bariatric surgery (comparing pre- to post-surgery), and to determine whether these changes are related to cardiometabolic variables. METHODS: The study included 57 participants with severe obesity (mean BMI=43.1 ± 4.3 kg/m2) who underwent sleeve gastrectomy (SG), biliopancreatic diversion with duodenal switch (BPD), or Roux-en-Y gastric bypass (RYGB), scanned prior to bariatric surgery and at follow-up visits of 4 months (N = 36), 12 months (N = 29), and 24 months (N = 14) after surgery. We examined fALFF and ReHo measures across 1022 cortical and subcortical regions (based on combined Schaeffer-Xiao parcellations) using a linear mixed effect model. Voxel-based morphometry (VBM) based on T1-weighted images was also used to measure GM density in the same regions. We also used an independent sample from the Human Connectome Project (HCP) to assess regional differences between individuals who had normal-weight (N = 46) or severe obesity (N = 46). RESULTS: We found a global increase in the fALFF signal with greater increase within dorsolateral prefrontal cortex, precuneus, inferior temporal gyrus, and visual cortex. This effect was more significant 4 months after surgery. The increase within dorsolateral prefrontal cortex, temporal gyrus, and visual cortex was more limited after 12 months and only present in the visual cortex after 24 months. These increases in neural activity measured by fALFF were also significantly associated with the increase in GM density following surgery. Furthermore, the increase in neural activity was significantly related to post-surgery weight loss and improvement in cardiometabolic variables, such as blood pressure. In the independent HCP sample, normal-weight participants had higher global and regional fALFF signals, mainly in dorsolateral/medial frontal cortex, precuneus and middle/inferior temporal gyrus compared to the obese participants. These BMI-related differences in fALFF were associated with the increase in fALFF 4 months post-surgery especially in regions involved in control, default mode and dorsal attention networks. CONCLUSIONS: Bariatric surgery-induced weight loss and improvement in metabolic factors are associated with widespread global and regional increases in neural activity, as measured by fALFF signal. These findings alongside the higher fALFF signal in normal-weight participants compared to participants with severe obesity in an independent dataset suggest an early recovery in the neural activity signal level after the surgery.


Assuntos
Cirurgia Bariátrica/tendências , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Imageamento por Ressonância Magnética/tendências , Obesidade/diagnóstico por imagem , Descanso/fisiologia , Adulto , Cirurgia Bariátrica/métodos , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Obesidade/fisiopatologia , Obesidade/cirurgia , Cuidados Pós-Operatórios/métodos , Cuidados Pré-Operatórios/métodos
14.
Neuroimage ; 241: 118425, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34303795

RESUMO

Cascading high-amplitude bursts in neural activity, termed avalanches, are thought to provide insight into the complex spatially distributed interactions in neural systems. In human neuroimaging, for example, avalanches occurring during resting-state show scale-invariant dynamics, supporting the hypothesis that the brain operates near a critical point that enables long range spatial communication. In fact, it has been suggested that such scale-invariant dynamics, characterized by a power-law distribution in these avalanches, are universal in neural systems and emerge through a common mechanism. While the analysis of avalanches and subsequent criticality is increasingly seen as a framework for using complex systems theory to understand brain function, it is unclear how the framework would account for the omnipresent cognitive variability, whether across individuals or tasks. To address this, we analyzed avalanches in the EEG activity of healthy humans during rest as well as two distinct task conditions that varied in cognitive demands and produced behavioral measures unique to each individual. In both rest and task conditions we observed that avalanche dynamics demonstrate scale-invariant characteristics, but differ in their specific features, demonstrating individual variability. Using a new metric we call normalized engagement, which estimates the likelihood for a brain region to produce high-amplitude bursts, we also investigated regional features of avalanche dynamics. Normalized engagement showed not only the expected individual and task dependent variability, but also scale-specificity that correlated with individual behavior. Our results suggest that the study of avalanches in human brain activity provides a tool to assess cognitive variability. Our findings expand our understanding of avalanche features and are supportive of the emerging theoretical idea that the dynamics of an active human brain operate close to a critical-like region and not a singular critical-state.


Assuntos
Potenciais de Ação/fisiologia , Encéfalo/fisiologia , Eletroencefalografia/métodos , Emoções/fisiologia , Desempenho Psicomotor/fisiologia , Descanso/fisiologia , Adulto , Feminino , Humanos , Masculino , Estimulação Luminosa/métodos
15.
Neuroimage ; 241: 118427, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34311069

RESUMO

The neural underpinnings of rumination can be characterized by its specific dynamic nature. Temporal stability is the stable and consistent representation of information by a distributed neural activity and connectivity pattern across brain regions. Although stability is a key feature of the brain's functional architecture, its profiles supporting rumination remain elusive. We characterized the stability of the whole-brain functional architecture during an induced, continuous rumination state and compared it with a well-constrained distraction state as the control condition in a group of healthy participants (N = 40). We further examined the relationship between stability in regions showing a significant effect on the rumination vs. distraction contrast and rumination traits. The variability of dynamic functional connectivities (FCs) among these regions was also explored to determine the potential coupling regions that drove the altered stability pattern during rumination. The results showed that rumination was characterized by a similar but altered stability profile compared with distraction and resting states. Comparison between rumination and distraction revealed that key regions of the default mode network (DMN), such as the medial prefrontal cortex (MPFC) and bilateral parahippocampal gyrus (PHG), which showed decreased stability while frontoparietal control network (FPCN) regions, including the inferior parietal lobule (IPL) and dorsal lateral prefrontal cortex (DLPFC), showed significantly enhanced stability in rumination compared with distraction. Additionally, stability in the MPFC and IPL was related to individual differences in rumination traits. Exploratory analysis of the variation in dynamic FCs suggested that higher stability in the IPL may be related to its less variable FCs with the PHG. Together, these findings implicated that rumination may be supported by the dissociated dynamic nature of hypostability in the DMN and hyperstability in the FPCN.


Assuntos
Rede de Modo Padrão/fisiologia , Imageamento por Ressonância Magnética/métodos , Rede Nervosa/fisiologia , Lobo Parietal/fisiologia , Córtex Pré-Frontal/fisiologia , Ruminação Cognitiva/fisiologia , Adolescente , Adulto , Rede de Modo Padrão/diagnóstico por imagem , Feminino , Humanos , Masculino , Rede Nervosa/diagnóstico por imagem , Lobo Parietal/diagnóstico por imagem , Córtex Pré-Frontal/diagnóstico por imagem , Descanso/fisiologia , Adulto Jovem
16.
Clin Neurophysiol ; 132(9): 2019-2031, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34284236

RESUMO

OBJECTIVES: The present study aims to compare early-onset Alzheimer's disease (EOAD) patients with healthy controls (HC), and late-onset Alzheimer's disease (LOAD) patients using resting-state delta, theta, alpha, and beta oscillations and provide a cut-off score of alpha/theta ratio to discriminate individuals with EOAD and young HC. METHODS: Forty-seven individuals with EOAD, 51 individuals with LOAD, and demographically-matched 49 young and 51 older controls were included in the study. Spectral-power analysis using Fast-Fourier Transformation (FFT) is performed on resting-state electroencephalography (EEG) data. Delta, theta, alpha, and beta oscillations compared between groups and Receiver Operating Characteristic (ROC) curve analysis was conducted. RESULTS: Compared to healthy controls individuals with EOAD showed an increase in slow frequency bands and a decrease in fast frequency bands. Frontal alpha/theta power ratio is the best discriminating value between EOAD and young HC with the sensitivity and specificity greater than 80% with area under the curve (AUC) 0.881. CONCLUSIONS: EOAD display more widespread and severe electrophysiological abnormalities than LOAD and HC which may reflect more pronounced pathological burden and cholinergic deficits in EOAD. Additionally, the alpha/theta ratio can discriminate EOAD and young HC successfully. SIGNIFICANCE: This study is the first to report that resting-state EEG power can be a promising marker for diagnostic accuracy between EOAD and healthy controls.


Assuntos
Ritmo alfa/fisiologia , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/fisiopatologia , Descanso/fisiologia , Ritmo Teta/fisiologia , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/psicologia , Eletroencefalografia/métodos , Eletroencefalografia/psicologia , Feminino , Voluntários Saudáveis/psicologia , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos
17.
Clin Neurophysiol ; 132(9): 2083-2090, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34284243

RESUMO

OBJECTIVE: Although about 1-2% of MRI examinations must be aborted due to anxiety, there is little research on how MRI-related anxiety affects BOLD signals in resting states. METHODS: We re-analyzed cardiac beat-to beat interval (RRI) and BOLD signals of 23 healthy fMRI participants in four resting states by calculation of phase-coupling in the 0.07-0.13 Hz band and determination of positive time delays (pTDs; RRI leading neural BOLD oscillations) and negative time delays (nTDs; RRI lagging behind vascular BOLD oscillations). State anxiety of each subject was assigned to either a low anxiety (LA) or a high anxiety (HA, with most participants exhibiting moderate anxiety symptoms) category based on the inside scanner assessed anxiety score. RESULTS: Although anxiety strongly differed between HA and LA categories, no significant difference was found for nTDs. In contrast, pTDs indicating neural BOLD oscillations exhibited a significant cumulation in the high anxiety category. CONCLUSIONS: Findings may suggest that vascular BOLD oscillations related to slow cerebral blood circulation are of about similar intensity during low/no and elevated anxiety. In contrast, neural BOLD oscillations, which might be associated with a central rhythm generating mechanism (pacemaker-like activity), appear to be significantly intensified during elevated anxiety. SIGNIFICANCE: The study provides evidence that fMRI-related anxiety can activate a central rhythm generating mechanism very likely located in the brain stem, associated with slow neural BOLD oscillation.


Assuntos
Ansiedade/fisiopatologia , Ondas Encefálicas/fisiologia , Encéfalo/fisiologia , Circulação Cerebrovascular/fisiologia , Frequência Cardíaca/fisiologia , Imageamento por Ressonância Magnética/métodos , Adulto , Ansiedade/diagnóstico por imagem , Ansiedade/psicologia , Encéfalo/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética/psicologia , Masculino , Estimulação Luminosa/métodos , Desempenho Psicomotor/fisiologia , Descanso/fisiologia , Descanso/psicologia , Adulto Jovem
18.
Clin Neurophysiol ; 132(9): 2101-2109, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34284245

RESUMO

OBJECTIVE: Homonymous visual field deficits (HFVDs) are frequent following brain lesions. Current restoration treatments aim at activating areas of residual vision through numerous stimuli, but show limited effect. Recent findings suggest that spontaneous neural α-band coupling is more efficient for enabling visual perception in healthy humans than task-induced activations. Here, we evaluated whether it is also associated with the severity of HFVD. METHODS: Ten patients with HFVDs after brain damage in the subacute to chronic stage and ten matched healthy controls underwent visual stimulation with alternating checkerboards and electroencephalography recordings of stimulation-induced power changes and of spontaneous neural interactions during rest. RESULTS: Visual areas of the affected hemisphere showed reduced event-related power decrease in α and ß frequency bands, but also reduced spontaneous α-band interactions during rest, as compared to contralesional areas and healthy controls. A multivariate stepwise regression retained the degree of disruption of spontaneous interactions, but not the reduced task-induced power changes as predictor for the severity of the visual deficit. CONCLUSIONS: Spontaneous α-band interactions of visual areas appear as a better marker for the severity of HFVDs than task-induced activations. SIGNIFICANCE: Treatment attempts of HFVDs should try to enhance spontaneous α-band coupling of structurally intact ipsilesional areas.


Assuntos
Ritmo alfa/fisiologia , Lesões Encefálicas/fisiopatologia , Descanso/fisiologia , Índice de Gravidade de Doença , Transtornos da Visão/fisiopatologia , Campos Visuais/fisiologia , Adulto , Lesões Encefálicas/complicações , Lesões Encefálicas/diagnóstico , Eletroencefalografia/métodos , Feminino , Hemianopsia/diagnóstico , Hemianopsia/etiologia , Hemianopsia/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Estimulação Luminosa/métodos , Transtornos da Visão/diagnóstico , Transtornos da Visão/etiologia , Percepção Visual/fisiologia , Adulto Jovem
19.
Neuroimage ; 241: 118408, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34284108

RESUMO

Functional connectivity (FC) networks are typically inferred from resting-state fMRI data using the Pearson correlation between BOLD time series from pairs of brain regions. However, alternative methods of estimating functional connectivity have not been systematically tested for their sensitivity or robustness to head motion artifact. Here, we evaluate the sensitivity of eight different functional connectivity measures to motion artifact using resting-state data from the Human Connectome Project. We report that FC estimated using full correlation has a relatively high residual distance-dependent relationship with motion compared to partial correlation, coherence, and information theory-based measures, even after implementing rigorous methods for motion artifact mitigation. This disadvantage of full correlation, however, may be offset by higher test-retest reliability, fingerprinting accuracy, and system identifiability. FC estimated by partial correlation offers the best of both worlds, with low sensitivity to motion artifact and intermediate system identifiability, with the caveat of low test-retest reliability and fingerprinting accuracy. We highlight spatial differences in the sub-networks affected by motion with different FC metrics. Further, we report that intra-network edges in the default mode and retrosplenial temporal sub-networks are highly correlated with motion in all FC methods. Our findings indicate that the method of estimating functional connectivity is an important consideration in resting-state fMRI studies and must be chosen carefully based on the parameters of the study.


Assuntos
Artefatos , Encéfalo/diagnóstico por imagem , Imageamento por Ressonância Magnética/normas , Movimento (Física) , Rede Nervosa/diagnóstico por imagem , Descanso , Encéfalo/fisiologia , Análise de Dados , Movimentos da Cabeça/fisiologia , Humanos , Imageamento por Ressonância Magnética/métodos , Rede Nervosa/fisiologia , Descanso/fisiologia
20.
Sci Rep ; 11(1): 13883, 2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34230580

RESUMO

The role of leukocyte inflammatory markers and toll like receptors (TLRs)2/4 in pathologies associated with elevated resting heart rate (RHR) levels in healthy obese (HO) individuals is not well elucidated. Herein, we investigated the relationship of RHR with expression of leukocyte-inflammatory markers and TLRs in HO individuals. 58-obese and 57-lean participants with no history of a major medical condition, were recruited in this study. In HO individuals, the elevated-RHR correlated positively with diastolic blood pressure, cholesterol, pro-inflammatory monocytes CD11b+CD11c+CD206- phenotype (r = 0.52, P = 0.0003) as well as with activated T cells CD8+HLA-DR+ phenotype (r = 0.27, P = 0.039). No association was found between RHR and the percentage of CD16+CD11b+ neutrophils. Interestingly, elevated RHR positively correlated with cells expressing TLR4 and TLR2 (CD14+TLR4+, r = 0.51, P ≤ 0.0001; and CD14+TLR2+, r = 0.42, P = 0.001). TLR4+ expressing cells also associated positively with the plasma concentrations of proinflammatory or vascular permeability/matrix modulatory markers including TNF-α (r = 0.36, P = 0.005), VEGF (r = 0.47, P = 0.0002), and MMP-9 (r = 0.53, P ≤ 0.0001). Multiple regression revealed that RHR is independently associated with CD14+TLR4+ monocytes and VEGF. We conclude that in HO individuals, increased CD14+TLR4+ monocytes and circulatory VEGF levels associated independently with RHR, implying that RHR monitoring could be used as a non-invasive clinical indicator to identify healthy obese individuals at an increased risk of developing inflammation and cardiovascular disease.


Assuntos
Doenças Cardiovasculares/fisiopatologia , Frequência Cardíaca/fisiologia , Inflamação/fisiopatologia , Obesidade/fisiopatologia , Descanso/fisiologia , Adulto , Biomarcadores/sangue , Doenças Cardiovasculares/sangue , Feminino , Humanos , Mediadores da Inflamação/metabolismo , Leucócitos/patologia , Modelos Lineares , Masculino , Monócitos/metabolismo , Obesidade/sangue , Fenótipo , Fatores de Risco
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