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1.
Int J Mol Sci ; 22(11)2021 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-34072450

RESUMO

Obesity currently represents a major societal and health challenge worldwide. Its prevalence has reached epidemic proportions and trends continue to rise, reflecting the need for more effective preventive measures. Hypothalamic circuits that control energy homeostasis in response to food intake are interesting targets for body-weight management, for example, through interventions that reinforce the gut-to-brain nutrient signalling, whose malfunction contributes to obesity. Gut microbiota-diet interactions might interfere in nutrient sensing and signalling from the gut to the brain, where the information is processed to control energy homeostasis. This gut microbiota-brain crosstalk is mediated by metabolites, mainly short chain fatty acids, secondary bile acids or amino acids-derived metabolites and subcellular bacterial components. These activate gut-endocrine and/or neural-mediated pathways or pass to systemic circulation and then reach the brain. Feeding time and dietary composition are the main drivers of the gut microbiota structure and function. Therefore, aberrant feeding patterns or unhealthy diets might alter gut microbiota-diet interactions and modify nutrient availability and/or microbial ligands transmitting information from the gut to the brain in response to food intake, thus impairing energy homeostasis. Herein, we update the scientific evidence supporting that gut microbiota is a source of novel dietary and non-dietary biological products that may beneficially regulate gut-to-brain communication and, thus, improve metabolic health. Additionally, we evaluate how the feeding time and dietary composition modulate the gut microbiota and, thereby, the intraluminal availability of these biological products with potential effects on energy homeostasis. The review also identifies knowledge gaps and the advances required to clinically apply microbiome-based strategies to improve the gut-brain axis function and, thus, combat obesity.


Assuntos
Encéfalo/fisiologia , Metabolismo Energético , Microbioma Gastrointestinal/fisiologia , Trato Gastrointestinal/fisiologia , Homeostase , Microbiota/fisiologia , Ritmo Circadiano , Dieta , Suscetibilidade a Doenças , Ingestão de Alimentos , Comportamento Alimentar , Humanos , Micronutrientes , Nutrientes , Obesidade/etiologia , Obesidade/metabolismo
2.
Nat Commun ; 12(1): 3294, 2021 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-34078892

RESUMO

Experimental manipulation of gut microbes in animal models alters fear behavior and relevant neurocircuitry. In humans, the first year of life is a key period for brain development, the emergence of fearfulness, and the establishment of the gut microbiome. Variation in the infant gut microbiome has previously been linked to cognitive development, but its relationship with fear behavior and neurocircuitry is unknown. In this pilot study of 34 infants, we find that 1-year gut microbiome composition (Weighted Unifrac; lower abundance of Bacteroides, increased abundance of Veillonella, Dialister, and Clostridiales) is significantly associated with increased fear behavior during a non-social fear paradigm. Infants with increased richness and reduced evenness of the 1-month microbiome also display increased non-social fear. This study indicates associations of the human infant gut microbiome with fear behavior and possible relationships with fear-related brain structures on the basis of a small cohort. As such, it represents an important step in understanding the role of the gut microbiome in the development of human fear behaviors, but requires further validation with a larger number of participants.


Assuntos
Bacteroides/genética , Clostridiales/genética , Medo/psicologia , Microbioma Gastrointestinal/genética , Veillonella/genética , Veillonellaceae/genética , Adulto , Bacteroides/classificação , Bacteroides/isolamento & purificação , Encéfalo/fisiologia , Aleitamento Materno , Clostridiales/classificação , Clostridiales/isolamento & purificação , Fezes/microbiologia , Feminino , Humanos , Lactente , Fórmulas Infantis , Estudos Longitudinais , Masculino , Projetos Piloto , RNA Ribossômico 16S/genética , Veillonella/classificação , Veillonella/isolamento & purificação , Veillonellaceae/classificação , Veillonellaceae/isolamento & purificação
3.
Nat Commun ; 12(1): 3435, 2021 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-34103511

RESUMO

To understand the underlying mechanisms of progressive neurophysiological phenomena, neural interfaces should interact bi-directionally with brain circuits over extended periods of time. However, such interfaces remain limited by the foreign body response that stems from the chemo-mechanical mismatch between the probes and the neural tissues. To address this challenge, we developed a multifunctional sensing and actuation platform consisting of multimaterial fibers intimately integrated within a soft hydrogel matrix mimicking the brain tissue. These hybrid devices possess adaptive bending stiffness determined by the hydration states of the hydrogel matrix. This enables their direct insertion into the deep brain regions, while minimizing tissue damage associated with the brain micromotion after implantation. The hydrogel hybrid devices permit electrophysiological, optogenetic, and behavioral studies of neural circuits with minimal foreign body responses and tracking of stable isolated single neuron potentials in freely moving mice over 6 months following implantation.


Assuntos
Técnicas Biossensoriais , Hidrogéis/química , Sondas Moleculares/química , Neurônios/fisiologia , Potenciais de Ação/fisiologia , Animais , Comportamento Animal , Bioensaio , Encéfalo/fisiologia , Fenômenos Eletrofisiológicos , Reação a Corpo Estranho/fisiopatologia , Masculino , Camundongos Endogâmicos C57BL , Optogenética , Estresse Mecânico , Fatores de Tempo
4.
Nat Commun ; 12(1): 2643, 2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-33976118

RESUMO

Prediction of future sensory input based on past sensory information is essential for organisms to effectively adapt their behavior in dynamic environments. Humans successfully predict future stimuli in various natural settings. Yet, it remains elusive how the brain achieves effective prediction despite enormous variations in sensory input rate, which directly affect how fast sensory information can accumulate. We presented participants with acoustic sequences capturing temporal statistical regularities prevalent in nature and investigated neural mechanisms underlying predictive computation using MEG. By parametrically manipulating sequence presentation speed, we tested two hypotheses: neural prediction relies on integrating past sensory information over fixed time periods or fixed amounts of information. We demonstrate that across halved and doubled presentation speeds, predictive information in neural activity stems from integration over fixed amounts of information. Our findings reveal the neural mechanisms enabling humans to robustly predict dynamic stimuli in natural environments despite large sensory input rate variations.


Assuntos
Adaptação Fisiológica/fisiologia , Algoritmos , Encéfalo/fisiologia , Modelos Neurológicos , Rede Nervosa/fisiologia , Sensação/fisiologia , Estimulação Acústica , Adulto , Encéfalo/citologia , Feminino , Humanos , Magnetoencefalografia/métodos , Masculino , Neurônios/fisiologia , Desempenho Psicomotor/fisiologia , Adulto Jovem
5.
Nat Commun ; 12(1): 2698, 2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-33976215

RESUMO

Gut microbiome profoundly affects many aspects of host physiology and behaviors. Here we report that gut microbiome modulates aggressive behaviors in Drosophila. We found that germ-free males showed substantial decrease in inter-male aggression, which could be rescued by microbial re-colonization. These germ-free males are not as competitive as wild-type males for mating with females, although they displayed regular levels of locomotor and courtship behaviors. We further found that Drosophila microbiome interacted with diet during a critical developmental period for the proper expression of octopamine and manifestation of aggression in adult males. These findings provide insights into how gut microbiome modulates specific host behaviors through interaction with diet during development.


Assuntos
Agressão/fisiologia , Drosophila melanogaster/fisiologia , Microbioma Gastrointestinal/fisiologia , Octopamina/metabolismo , Comportamento Sexual Animal/fisiologia , Animais , Bactérias/classificação , Bactérias/genética , Encéfalo/citologia , Encéfalo/metabolismo , Encéfalo/fisiologia , Drosophila melanogaster/metabolismo , Drosophila melanogaster/microbiologia , Feminino , Microbioma Gastrointestinal/genética , Masculino , Atividade Motora/fisiologia , Neurônios/metabolismo , Neurônios/fisiologia , RNA Ribossômico 16S/genética , Transdução de Sinais/fisiologia , Organismos Livres de Patógenos Específicos
6.
Best Pract Res Clin Anaesthesiol ; 35(2): 231-240, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34030807

RESUMO

In patients undergoing craniotomy, general anesthesia should be addressed to warrant good hypnosis, immobility, and analgesia, to ensure systemic and cerebral physiological status and provide the best possible surgical field. Regarding craniotomies, it is unclear if there are substantial differences in providing general anesthesia using total intravenous anesthesia (TIVA) or balanced anesthesia (BA) accomplished using the third generation halogenates. New evidence highlighted that the last generation of halogenated agents has possible advantages compared with intravenous drugs: rapid induction, minimal absorption and metabolization, reproducible pharmacokinetic, faster recovery, cardioprotective effect, and opioid spare analgesia. This review aims to report evidence related to the use of the latest halogenated agents in patients undergoing craniotomy and to present available clinical evidence on their effects: cerebral and systemic hemodynamic, neurophysiological monitoring, and timing and quality of recovery after anesthesia.


Assuntos
Período de Recuperação da Anestesia , Anestesia Geral/métodos , Anestesia por Inalação/métodos , Procedimentos Neurocirúrgicos/métodos , Anestesia Geral/efeitos adversos , Anestesia por Inalação/efeitos adversos , Encéfalo/efeitos dos fármacos , Encéfalo/fisiologia , Desflurano/administração & dosagem , Hemodinâmica/efeitos dos fármacos , Hemodinâmica/fisiologia , Humanos
8.
Nat Commun ; 12(1): 2519, 2021 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-33947867

RESUMO

Transcranial focused ultrasound (tFUS) is a promising neuromodulation technique, but its mechanisms remain unclear. We hypothesize that if tFUS parameters exhibit distinct modulation effects in different neuron populations, then the mechanism can be understood through identifying unique features in these neuron populations. In this work, we investigate the effect of tFUS stimulation on different functional neuron types in in vivo anesthetized rodent brains. Single neuron recordings were separated into regular-spiking and fast-spiking units based on their extracellular spike shapes acquired through intracranial electrophysiological recordings, and further validated in transgenic optogenetic mice models of light-excitable excitatory and inhibitory neurons. We show that excitatory and inhibitory neurons are intrinsically different in response to ultrasound pulse repetition frequency (PRF). The results suggest that we can preferentially target specific neuron types noninvasively by tuning the tFUS PRF. Chemically deafened rats and genetically deafened mice were further tested for validating the directly local neural effects induced by tFUS without potential auditory confounds.


Assuntos
Mapeamento Encefálico/métodos , Encéfalo/citologia , Encéfalo/efeitos da radiação , Potenciais Somatossensoriais Evocados/fisiologia , Potenciais Somatossensoriais Evocados/efeitos da radiação , Neurônios/citologia , Ultrassonografia/métodos , Animais , Encéfalo/fisiologia , Eletrofisiologia , Masculino , Camundongos , Camundongos Transgênicos , Neurônios/fisiologia , Neurônios/efeitos da radiação , Optogenética , Ratos , Ratos Wistar
9.
Nat Commun ; 12(1): 2744, 2021 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-33980860

RESUMO

Understanding the neurophysiology underlying neonatal responses to noxious stimulation is central to improving early life pain management. In this neonatal multimodal MRI study, we use resting-state and diffusion MRI to investigate inter-individual variability in noxious-stimulus evoked brain activity. We observe that cerebral haemodynamic responses to experimental noxious stimulation can be predicted from separately acquired resting-state brain activity (n = 18). Applying this prediction model to independent Developing Human Connectome Project data (n = 215), we identify negative associations between predicted noxious-stimulus evoked responses and white matter mean diffusivity. These associations are subsequently confirmed in the original noxious stimulation paradigm dataset, validating the prediction model. Here, we observe that noxious-stimulus evoked brain activity in healthy neonates is coupled to resting-state activity and white matter microstructure, that neural features can be used to predict responses to noxious stimulation, and that the dHCP dataset could be utilised for future exploratory research of early life pain system neurophysiology.


Assuntos
Encéfalo/fisiologia , Nociceptividade/fisiologia , Encéfalo/diagnóstico por imagem , Encéfalo/crescimento & desenvolvimento , Conectoma , Imagem de Difusão por Ressonância Magnética , Feminino , Humanos , Recém-Nascido , Imageamento por Ressonância Magnética , Masculino , Modelos Neurológicos , Rede Nervosa , Acoplamento Neurovascular , Dor/fisiopatologia , Descanso/fisiologia , Substância Branca/diagnóstico por imagem , Substância Branca/fisiologia
10.
Nat Commun ; 12(1): 2930, 2021 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-34006884

RESUMO

The neural mechanisms underlying conscious recognition remain unclear, particularly the roles played by the prefrontal cortex, deactivated brain areas and subcortical regions. We investigated neural activity during conscious object recognition using 7 Tesla fMRI while human participants viewed object images presented at liminal contrasts. Here, we show both recognized and unrecognized images recruit widely distributed cortical and subcortical regions; however, recognized images elicit enhanced activation of visual, frontoparietal, and subcortical networks and stronger deactivation of the default-mode network. For recognized images, object category information can be decoded from all of the involved cortical networks but not from subcortical regions. Phase-scrambled images trigger strong involvement of inferior frontal junction, anterior cingulate cortex and default-mode network, implicating these regions in inferential processing under increased uncertainty. Our results indicate that content-specific activity in both activated and deactivated cortical networks and non-content-specific subcortical activity support conscious recognition.


Assuntos
Encéfalo/fisiologia , Córtex Cerebral/fisiologia , Estado de Consciência/fisiologia , Reconhecimento Psicológico/fisiologia , Córtex Visual/fisiologia , Adulto , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Córtex Cerebral/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiologia , Estimulação Luminosa/métodos , Córtex Visual/diagnóstico por imagem , Adulto Jovem
11.
Nat Commun ; 12(1): 3095, 2021 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-34035249

RESUMO

The analysis of biomedical signals for clinical studies and therapeutic applications can benefit from embedded devices that can process these signals locally and in real-time. An example is the analysis of intracranial EEG (iEEG) from epilepsy patients for the detection of High Frequency Oscillations (HFO), which are a biomarker for epileptogenic brain tissue. Mixed-signal neuromorphic circuits offer the possibility of building compact and low-power neural network processing systems that can analyze data on-line in real-time. Here we present a neuromorphic system that combines a neural recording headstage with a spiking neural network (SNN) processing core on the same die for processing iEEG, and show how it can reliably detect HFO, thereby achieving state-of-the-art accuracy, sensitivity, and specificity. This is a first feasibility study towards identifying relevant features in iEEG in real-time using mixed-signal neuromorphic computing technologies.


Assuntos
Encéfalo/fisiologia , Eletrocorticografia/métodos , Rede Nervosa/fisiologia , Neurônios/fisiologia , Potenciais de Ação/fisiologia , Algoritmos , Encéfalo/citologia , Eletrocorticografia/instrumentação , Humanos , Modelos Neurológicos , Convulsões/fisiopatologia , Lobo Temporal/fisiopatologia
12.
Science ; 372(6544)2021 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-34016753

RESUMO

To make effective decisions, people need to consider the relationship between actions and outcomes. These are often separated by time and space. The neural mechanisms by which disjoint actions and outcomes are linked remain unknown. One promising hypothesis involves neural replay of nonlocal experience. Using a task that segregates direct from indirect value learning, combined with magnetoencephalography, we examined the role of neural replay in human nonlocal learning. After receipt of a reward, we found significant backward replay of nonlocal experience, with a 160-millisecond state-to-state time lag, which was linked to efficient learning of action values. Backward replay and behavioral evidence of nonlocal learning were more pronounced for experiences of greater benefit for future behavior. These findings support nonlocal replay as a neural mechanism for solving complex credit assignment problems during learning.


Assuntos
Encéfalo/fisiologia , Aprendizagem Baseada em Problemas , Reforço Psicológico , Feminino , Humanos , Masculino , Estimulação Luminosa , Recompensa , Adulto Jovem
13.
Nat Commun ; 12(1): 3112, 2021 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-34035303

RESUMO

Sleep is thought to support memory consolidation via reactivation of prior experiences, with particular electrophysiological sleep signatures (slow oscillations (SOs) and sleep spindles) gating the information flow between relevant brain areas. However, empirical evidence for a role of endogenous memory reactivation (i.e., without experimentally delivered memory cues) for consolidation in humans is lacking. Here, we devised a paradigm in which participants acquired associative memories before taking a nap. Multivariate decoding was then used to capture endogenous memory reactivation during non-rapid eye movement (NREM) sleep in surface EEG recordings. Our results reveal reactivation of learning material during SO-spindle complexes, with the precision of SO-spindle coupling predicting reactivation strength. Critically, reactivation strength (i.e. classifier evidence in favor of the previously studied stimulus category) in turn predicts the level of consolidation across participants. These results elucidate the memory function of sleep in humans and emphasize the importance of SOs and spindles in clocking endogenous consolidation processes.


Assuntos
Encéfalo/fisiologia , Aprendizagem/fisiologia , Consolidação da Memória/fisiologia , Memória/fisiologia , Sono/fisiologia , Sinais (Psicologia) , Eletroencefalografia/métodos , Feminino , Humanos , Masculino , Estimulação Luminosa , Polissonografia/métodos , Desempenho Psicomotor/fisiologia , Adulto Jovem
14.
Epidemiol Psychiatr Sci ; 30: e29, 2021 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-33820592

RESUMO

According to the social brain hypothesis, the human brain includes a network designed for the processing of social information. This network includes several brain regions that elaborate social cues, interactions and contexts, i.e. prefrontal paracingulate and parietal cortices, amygdala, temporal lobes and the posterior superior temporal sulcus. While current literature suggests the importance of this network from both a psychological and evolutionary perspective, little is known about its neurobiological bases. Specifically, only a paucity of studies explored the neural underpinnings of constructs that are ascribed to the social brain network functioning, i.e. objective social isolation and perceived loneliness. As such, this review aimed to overview neuroimaging studies that investigated social isolation in healthy subjects. Social isolation correlated with both structural and functional alterations within the social brain network and in other regions that seem to support mentalising and social processes (i.e. hippocampus, insula, ventral striatum and cerebellum). However, results are mixed possibly due to the heterogeneity of methods and study design. Future neuroimaging studies with longitudinal designs are needed to measure the effect of social isolation in experimental v. control groups and to explore its relationship with perceived loneliness, ultimately helping to clarify the neural correlates of the social brain.


Assuntos
Encéfalo , Neuroimagem , Isolamento Social , Encéfalo/fisiologia , Humanos
15.
Nutrients ; 13(3)2021 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-33803651

RESUMO

Malnutrition represents a major problem in the clinical management of the inflammatory bowel disease (IBD). Presently, our understanding of the cross-link between eating behavior and intestinal inflammation is still in its infancy. Crohn's disease patients with active disease exhibit strong hedonic desires for food and emotional eating patterns possibly to ameliorate feelings of low mood, anxiety, and depression. Impulsivity traits seen in IBD patients may predispose them to palatable food intake as an immediate reward rather than concerns for future health. The upregulation of enteroendocrine cells (EEC) peptide response to food intake has been described in ileal inflammation, which may lead to alterations in gut-brain signaling with implications for appetite and eating behavior. In summary, a complex interplay of gut peptides, psychological, cognitive factors, disease-related symptoms, and inflammatory burden may ultimately govern eating behavior in intestinal inflammation.


Assuntos
Encéfalo/fisiologia , Ingestão de Alimentos/fisiologia , Comportamento Alimentar/fisiologia , Doenças Inflamatórias Intestinais/fisiopatologia , Intestinos/fisiologia , Regulação do Apetite/fisiologia , Doença de Crohn/fisiopatologia , Ingestão de Alimentos/psicologia , Células Enteroendócrinas/metabolismo , Comportamento Alimentar/psicologia , Humanos , Inflamação , Doenças Inflamatórias Intestinais/psicologia , Recompensa
16.
Int J Behav Nutr Phys Act ; 18(1): 47, 2021 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-33789683

RESUMO

BACKGROUND: Physical activity (PA) may positively stimulate the brain, cognition and mental health during adolescence, a period of dynamic neurobiological development. High-intensity interval training (HIIT) or vigorous PA interventions are time-efficient, scalable and can be easily implemented in existing school curricula, yet their effects on cognitive, academic and mental health outcomes are unclear. The primary aim of the Fit to Study trial was to investigate whether a pragmatic and scalable HIIT-style VPA intervention delivered during school physical education (PE) could improve attainment in maths. The primary outcome has previously been reported and was null. Here, we report the effect of the intervention on prespecified secondary outcomes, including cardiorespiratory fitness, cognitive performance, and mental health in young adolescents. METHODS: The Fit to Study cluster randomised controlled trial included Year 8 pupils (n = 18,261, aged 12-13) from 104 secondary state schools in South/Mid-England. Schools were randomised into an intervention condition (n = 52), in which PE teachers delivered an additional 10 min of VPA per PE lesson for one academic year (2017-2018), or into a "PE as usual" control condition. Secondary outcomes included assessments of cardiorespiratory fitness (20-m shuttle run), cognitive performance (executive functions, relational memory and processing speed) and mental health (Strength and Difficulties Questionnaire and self-esteem measures). The primary intention-to-treat (ITT) analysis used linear models and structural equation models with cluster-robust standard errors to test for intervention effects. A complier-average causal effect (CACE) was estimated using a two-stage least squares procedure. RESULTS: The HIIT-style VPA intervention did not significantly improve cardiorespiratory fitness, cognitive performance (executive functions, relational memory or processed speed), or mental health (all p > 0.05). Subgroup analyses showed no significant moderation of intervention effects by sex, socioeconomic status or baseline fitness levels. Changes in cardiorespiratory fitness were not significantly related to changes in cognitive or mental health outcomes. The trial was marked by high drop-out and low intervention compliance. Findings from the CACE analysis were in line with those from the ITT analysis. CONCLUSION: The one-academic year HIIT-style VPA intervention delivered during regular school PE did not significantly improve fitness, cognitive performance or mental health, but these findings should be interpreted with caution given low implementation fidelity and high drop-out. Well-controlled, large-scale, school-based trials that examine the effectiveness of HIIT-style interventions to enhance cognitive and mental health outcomes are warranted. TRIAL REGISTRATION: ISRCTN registry, 15,730,512 . Trial protocol and analysis plan for primary outcome prospectively registered on 30th March 2017. ClinicalTrials.gov , NCT03286725 . Secondary measures (focus of current manuscript) retrospectively registered on 18 September 2017.


Assuntos
Desempenho Acadêmico , Aptidão Cardiorrespiratória , Exercício Físico , Matemática , Saúde Mental , Processos Mentais , Adolescente , Encéfalo/fisiologia , Cognição , Inglaterra , Função Executiva , Treinamento Intervalado de Alta Intensidade , Humanos , Masculino , Educação Física e Treinamento
17.
Nutrients ; 13(4)2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33916974

RESUMO

Gut-brain signaling controls food intake and energy homeostasis, and its activity is thought to be dysregulated in obesity. We will explore new studies that suggest the endocannabinoid (eCB) system in the upper gastrointestinal tract plays an important role in controlling gut-brain neurotransmission carried by the vagus nerve and the intake of palatable food and other reinforcers. A focus will be on studies that reveal both indirect and direct interactions between eCB signaling and vagal afferent neurons. These investigations identify (i) an indirect mechanism that controls nutrient-induced release of peptides from the gut epithelium that directly interact with corresponding receptors on vagal afferent neurons, and (ii) a direct mechanism via interactions between eCBs and cannabinoid receptors expressed on vagal afferent neurons. Moreover, the impact of diet-induced obesity on these pathways will be considered.


Assuntos
Encéfalo/fisiologia , Ingestão de Alimentos/fisiologia , Endocanabinoides/metabolismo , Trato Gastrointestinal/fisiologia , Obesidade/fisiopatologia , Animais , Endocanabinoides/química , Humanos , Transmissão Sináptica/fisiologia
18.
Nutrients ; 13(5)2021 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-33919044

RESUMO

The mouth is the first part of the gastrointestinal tract. During mastication sensory signals from the mouth, so-called oro-sensory exposure, elicit physiological signals that affect satiation and food intake. It has been established that a longer duration of oro-sensory exposure leads to earlier satiation. In addition, foods with more intense sweet or salty taste induce earlier satiation compared to foods that are equally palatable, but with lower taste intensity. Oro-sensory exposure to food affects satiation by direct signaling via the brainstem to higher cortical regions involved in taste and reward, including the nucleus accumbens and the insula. There is little evidence that oro-sensory exposure affects satiation indirectly through either hormone responses or gastric signals. Critical brain areas for satiation, such as the brainstem, should be studied more intensively to better understand the neurophysiological mechanisms underlying the process of satiation. Furthermore, it is essential to increase the understanding of how of highly automated eating behaviors, such as oral processing and eating rate, are formed during early childhood. A better understanding of the aforementioned mechanisms provides fundamental insight in relation to strategies to prevent overconsumption and the development of obesity in future generations.


Assuntos
Encéfalo/fisiologia , Boca/fisiologia , Saciação/fisiologia , Sensação/fisiologia , Animais , Humanos , Modelos Biológicos , Paladar/fisiologia
19.
Nutrients ; 13(4)2021 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-33806218

RESUMO

Brain structure and function depend on a constant and sufficient supply with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) by blood. Blood levels of EPA and DHA reflect dietary intake and other variables and are preferably assessed as percentage in erythrocytes with a well-documented and standardized analytical method (HS-Omega-3 Index®). Every human being has an Omega-3 Index between 2 and 20%, with an optimum of 8-11%. Compared to an optimal Omega-3 Index, a lower Omega-3 Index was associated with increased risk for total mortality and ischemic stroke, reduced brain volume, impaired cognition, accelerated progression to dementia, psychiatric diseases, compromises of complex brain functions, and other brain issues in epidemiologic studies. Most intervention trials, and their meta-analyses considered EPA and DHA as drugs with good bioavailability, a design tending to produce meaningful results in populations characterized by low baseline blood levels (e.g., in major depression), but otherwise responsible for many neutral results and substantial confusion. When trial results were evaluated using blood levels of EPA and DHA measured, effects were larger than comparing EPA and DHA to placebo groups, and paralleled epidemiologic findings. This indicates future trial design, and suggests a targeted use EPA and DHA, based on the Omega-3 Index.


Assuntos
Encéfalo/anatomia & histologia , Encéfalo/fisiologia , Ácidos Docosa-Hexaenoicos/sangue , Ácido Eicosapentaenoico/sangue , Encéfalo/efeitos dos fármacos , Ácidos Docosa-Hexaenoicos/administração & dosagem , Ácidos Docosa-Hexaenoicos/farmacologia , Ácido Eicosapentaenoico/administração & dosagem , Ácido Eicosapentaenoico/farmacologia , Humanos
20.
Molecules ; 26(9)2021 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-33924992

RESUMO

The stress response in the brain is not fully understood, although stress is one of the risk factors for developing mental disorders. On the other hand, the stimulation of the olfactory system can influence stress levels, and a certain smell has been empirically known to have a stress-suppressing effect, indeed. In this review, we first outline what stress is and previous studies on stress-responsive biomarkers (stress markers) in the brain. Subsequently, we confirm the olfactory system and review previous studies on the relationship between smell and stress response by species, such as humans, rats, and mice. Numerous studies demonstrated the stress-suppressing effects of aroma. There are also investigations showing the effects of odor that induce stress in experimental animals. In addition, we introduce recent studies on the effects of aroma of coffee beans and essential oils, such as lavender, cypress, α-pinene, and thyme linalool on the behavior and the expression of stress marker candidates in the brain. The transfer of volatile components into the brain is also discussed while using the results of thyme linalool as an example. These studies may provide a good opportunity to connect chemical research at the molecular level with neuropharmacological approaches in the future.


Assuntos
Encéfalo/fisiologia , Percepção Olfatória , Estresse Fisiológico , Estresse Psicológico , Animais , Biomarcadores , Encéfalo/efeitos dos fármacos , Conectoma , Humanos , Neurofarmacologia , Olfato
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