Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Cereb Cortex ; 34(2)2024 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-38365271

RESUMO

Sense of agency (SoA) is the sensation that self-actions lead to ensuing perceptual consequences. The prospective mechanism emphasizes that SoA arises from motor prediction and its comparison with actual action outcomes, while the reconstructive mechanism stresses that SoA emerges from retrospective causal processing about the action outcomes. Consistent with the prospective mechanism, motor planning regions were identified by neuroimaging studies using the temporal binding (TB) effect, a behavioral measure often linked to implicit SoA. Yet, TB also occurs during passive observation of another's action, lending support to the reconstructive mechanism, but its neural correlates remain unexplored. Here, we employed virtual reality (VR) to modulate such observation-based SoA and examined it with functional magnetic resonance imaging (fMRI). After manipulating an avatar hand in VR, participants passively observed an avatar's "action" and showed a significant increase in TB. The binding effect was associated with the right angular gyrus and inferior parietal lobule, which are critical nodes for inferential and agency processing. These results suggest that the experience of controlling an avatar may potentiate inferential processing within the right inferior parietal cortex and give rise to the illusionary SoA without voluntary action.


Assuntos
Ilusões , Realidade Virtual , Humanos , Desempenho Psicomotor , Estudos Retrospectivos , Lobo Parietal
2.
Cereb Cortex ; 33(4): 997-1013, 2023 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-35332914

RESUMO

A critical way for humans to acquire information is through language, yet whether and how language experience drives specific neural semantic representations is still poorly understood. We considered statistical properties captured by 3 different computational principles of language (simple co-occurrence, network-(graph)-topological relations, and neural-network-vector-embedding relations) and tested the extent to which they can explain the neural patterns of semantic representations, measured by 2 functional magnetic resonance imaging experiments that shared common semantic processes. Distinct graph-topological word relations, and not simple co-occurrence or neural-network-vector-embedding relations, had unique explanatory power for the neural patterns in the anterior temporal lobe (capturing graph-common-neighbors), inferior frontal gyrus, and posterior middle/inferior temporal gyrus (capturing graph-shortest-path). These results were relatively specific to language: they were not explained by sensory-motor similarities and the same computational relations of visual objects (based on visual image database) showed effects in the visual cortex in the picture naming experiment. That is, different topological properties within language and the same topological computations (common-neighbors) for language and visual inputs are captured by different brain regions. These findings reveal the specific neural semantic representations along graph-topological properties of language, highlighting the information type-specific and statistical property-specific manner of semantic representations in the human brain.


Assuntos
Mapeamento Encefálico , Encéfalo , Humanos , Mapeamento Encefálico/métodos , Idioma , Semântica , Lobo Temporal/patologia , Imageamento por Ressonância Magnética/métodos
3.
Brain Struct Funct ; 227(5): 1683-1695, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35184222

RESUMO

Events are typically composed of at least actions and entities. Both actions and entities have been shown to be represented by neural structures respecting domain organizations in the brain, including those of social/animate (face and body; person-directed action) versus inanimate (man-made object or tool; object-directed action) concepts. It is unclear whether the brain combines actions and entities into events in a (relative) domain-specific fashion or via domain-general mechanisms in regions that have been shown to support semantic and syntactic composition. We tested these hypotheses in a functional magnetic resonance imaging experiment where two domains of verb-noun event phrases (social-person versus manipulation-artifact, e.g., "hug mother" versus "fold napkin") and their component words were contrasted. We found a series of brain region supporting social-composition effects more strongly than the manipulation phrase composition-the bilateral inferior occipital gyrus (IOG), inferior temporal gyrus (ITG) and anterior temporal lobe (ATL)-which either showed stronger activation strength tested by univariate contrast, stronger content representation tested by representation similarity analysis, or stronger relationship between the neural activation patterns of phrases and synthesis (additive and multiplication) of the neural activity patterns of the word constituents. No regions were observed showing evidence of phrase composition for both domains or stronger effects of manipulation phrases. These findings highlight the roles of the visual cortex and ATL in social event compositions, suggesting a domain-preferring, rather than domain-general, mechanisms of verbal event composition.


Assuntos
Mapeamento Encefálico , Semântica , Compreensão/fisiologia , Humanos , Idioma , Imageamento por Ressonância Magnética , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/fisiologia
4.
Cereb Cortex ; 32(21): 4913-4933, 2022 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-35059712

RESUMO

In high-level visual areas in the human brain, preference for inanimate objects is observed regardless of stimulation modality (visual/auditory/tactile) and individual's visual experience (sighted/blind) whereas preference for animate entities seems robust mainly in the visual modality. Here, we test a hypothesis explaining this domain difference: Object representations can be activated through nonvisual stimulation when their shapes are systematically related to action system representations, a quality typical of most inanimate objects but of only specific animate entities. We studied functional magnetic resonance imaging activations in congenitally blind and sighted individuals listening to animal, object, and human sounds. In blind individuals, the typical location of the fusiform face area preferentially responded to human facial expression sounds clearly related to specific facial actions and resulting face shapes but not to speech or animal sounds. No univariate preference for any sound category was observed in the fusiform gyrus in sighted individuals, but the expected multivoxel effects were present. We conclude that nonvisual signals can activate shape representations of those stimuli-inanimate or animate-for which shape and action computations are transparently related. However, absence of potentially competing visual inputs seems necessary for this effect to be clearly detectable in the case of animate representation.


Assuntos
Mapeamento Encefálico , Lobo Temporal , Humanos , Som , Imageamento por Ressonância Magnética/métodos , Percepção Auditiva/fisiologia
5.
Sci Rep ; 10(1): 21200, 2020 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-33273681

RESUMO

Visual perception of actions and objects has been shown to activate different cortical systems: action perception system spanning more dorsally, across parietal, frontal, and dorsal temporal regions; object perception relying more strongly the ventral occipitotemporal cortex (VOTC). Compared to the well-established object-domain structure (e.g., faces vs. artifacts) in VOTC, it is less known whether the action perception system is constrained by similar domain principle and whether it communicates with the ventral object recognition system in a domain-specific manner. In a fMRI long-block experiment designed to evaluate both regional activity and task-based functional connectivity (FC) patterns, participants viewed animated videos of a human performing two domains of actions to the same set of meaningless shapes without object-domain information: social-communicative-actions (e.g., waving) and manipulation-actions (e.g., folding). We observed action-domain-specific activations, with the superior temporal sulcus and the right precentral region responding more strongly during social-communicative-action perception; the supramarginal gyrus, inferior and superior parietal lobe, and precentral gyrus during manipulation-action perception. The two domains of action perception systems communicated with VOTC in domain-specific manners: FC between the social-communicative-action system and the bilateral fusiform face area was enhanced during social-communicative-action perception; FC between the manipulation-action system and the left tool-preferring lateral occipitoptemporal cortex was enhanced during manipulation-action perception. There was a significant correlation between the FC-with-action-system and the local activity strength across VOTC voxels. Our findings highlight social- and manipulation-domains of human interaction as an overarching principle of both object and action perception systems, with domain-based functional communication across systems.


Assuntos
Percepção Visual/fisiologia , Adolescente , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Desempenho Psicomotor/fisiologia , Adulto Jovem
6.
Molecules ; 25(20)2020 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-33096843

RESUMO

Using antibiotics as feed additives have been successively banned worldwide from 1986; therefore, it is an urgent task to finding safe and effective alternatives. As natural products of plant origin, essential oils (EOs) are an outstanding option due to their reported bioactivity. In this research, ten EOs of Labiatae species were extracted by steam distillation and its chemical constituents were identified by gas chromatography-mass spectrometry (GC-MS). A total of 123 chemical compounds, including alkenes, phenols, aldehydes and ketones, were identified. The results of antioxidant activity carried out through DPPH free radical scavenging (DPPH) and ferric reducing antioxidant power (FRAP), showing that EOs of Ocimum basilicum Linn. (ObEO), Thymus mongolicus Ronn. (TmEO), Origanum vulgare Linn. (OvEO) and Mosla chinensis Maxim. (McEO) have strong antioxidant activities. Their 50%-inhibitory concentration (IC50) value was <1.00, 1.42, 1.47 and 1.92 µg/mL, respectively; and their FRAP value was 1536.67 ± 24.22, 271.84 ± 4.93, 633.71 ± 13.14 and 480.66 ± 29.90, respectively. The results of filter paper diffusion showing that McEO, OvEO and TmEO inhibition zone diameter (IZD) are all over 30 mm. The results of two-fold dilution method showed that McEO, OvEO and TmEO have strong antibacterial activities against Staphylococcus aureus (S. aureus) and their minimal inhibitory concentrations (MIC) value was 1 µL/mL, 2 µL/mL, and 2 µL/mL, respectively. In conclusion, the results in this work demonstrate the possibility for development and application of EOs as potential feed additives.


Assuntos
Antibacterianos/farmacologia , Antioxidantes/farmacologia , Compostos de Bifenilo/antagonistas & inibidores , Lamiaceae/química , Óleos Voláteis/química , Picratos/antagonistas & inibidores , Staphylococcus aureus/efeitos dos fármacos , Aldeídos/química , Aldeídos/isolamento & purificação , Aldeídos/farmacologia , Alcenos/química , Alcenos/isolamento & purificação , Alcenos/farmacologia , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antioxidantes/química , Antioxidantes/isolamento & purificação , Cetonas/química , Cetonas/isolamento & purificação , Cetonas/farmacologia , Testes de Sensibilidade Microbiana , Fenóis/química , Fenóis/isolamento & purificação , Fenóis/farmacologia
7.
Brain Struct Funct ; 225(3): 995-1008, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32140848

RESUMO

Neuroimaging studies have indicated that a brain network distributed in the supramodal cortical regions of the frontal, temporal, and parietal lobes plays a central role in conceptual processing. The activation of this network is modulated by two orthogonal dimensions in conceptual processing-the semantic features of individual concepts and the meaningfulness of conceptual combinations-but it remains unclear how the network is functionally organized along these two dimensions. In this fMRI study, we focused on two specific factors, i.e. the social semantic richness of words and the semantic plausibility of word combinations, along the two dimensions. In literature, the distributions of the effects of the two factors are very similar, but have not been rigorously compared in one study. We orthogonally manipulated the two factors in a phrase comprehension task and found a clear dissociation between their effects. The combination of these results with our previous findings reveals three adjacently distributed subnetworks of the supramodal semantic network, associated with the sociality effect, imageability effect, and semantic plausibility effect, respectively. Further analysis of the resting-state functional connectivity data indicated that the functional dissociation among the three subnetworks is associated with their underlying intrinsic connectivity structures.


Assuntos
Encéfalo/fisiologia , Formação de Conceito/fisiologia , Semântica , Comportamento Social , Adulto , Mapeamento Encefálico , Compreensão/fisiologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/fisiologia , Adulto Jovem
8.
Neuropsychologia ; 133: 107187, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31499047

RESUMO

A variety of objects are made to serve social functions. The use of these objects has greatly enriched and expanded our social behaviors. How do our brains represent the social knowledge of inanimate objects such as coins, telephones, and handcuffs? According to a recent version of the grounded theory, social knowledge of inanimate objects might be grounded in the mentalizing network, as the social functions of inanimate objects are closely associated with the intentions of the people using them. However, there is also evidence that the mentalizing network may only get activated when a human/mental agent is detected. Using fMRI, we explored the neural correlates of social knowledge of inanimate objects by comparing the brain activation evoked by high-sociality object nouns (e.g., banknote) with that evoked by low-sociality object nouns (e.g., battery). The left anterior superior temporal sulcus, a classic part of the mentalizing network, showed higher activation for the high-sociality inanimate object nouns than for the low-sociality ones in the whole-brain analysis. Several other areas of the mentalizing network showed sensitivity to object sociality in small volume correction and/or region-of-interest analyses. Our findings indicate that social knowledge of inanimate objects is supported by brain areas in the mentalizing network.


Assuntos
Encéfalo/fisiologia , Formação de Conceito/fisiologia , Mentalização/fisiologia , Adolescente , Encéfalo/diagnóstico por imagem , Feminino , Neuroimagem Funcional , Giro do Cíngulo/diagnóstico por imagem , Giro do Cíngulo/fisiologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Córtex Pré-Frontal/diagnóstico por imagem , Córtex Pré-Frontal/fisiologia , Tempo de Reação , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/fisiologia , Adulto Jovem
9.
Front Microbiol ; 10: 1666, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31396184

RESUMO

Pyropia yezoensis is commercially the most important edible red alga in China, and red rot disease is viewed as one of the major constraints for its cultivation. Microbes within the oomycetic genus Pythium have been reported as the causative agents for this disease; however, little is known about the interactions between the disease and the epiphytic and planktonic bacterial communities. In the present study, bacterial communities associated with uninfected, locally infected, and seriously infected thalli collected from cultivation farms, and within seawater adjacent to the thalli, were investigated using in-depth 16S ribosomal RNA (rRNA) gene sequencing in conjunction with assessing multiple environmental factors. For both thalli and seawater, uninfected and infected communities were significantly different though alpha diversity was similar. Phylogenetic differences between epiphytic bacterial communities associated with P. yezoensis were mainly reflected by the relative changes in the dominant operational taxonomic units (OTUs) assigned as genus Flavirhabdus, genus Sulfitobacter, and family Rhodobacteraceae. The prevalent OTUs in seawater also differed in relative abundance across the communities and were affiliated with diverse taxa, including the phyla Actinobacteria, Verrucomicrobia, and Bacteroidetes, and the classes Alpha- and Gamma-proteobacteria. The differentiation of bacterial communities associated with P. yezoensis and seawater was primarily shaped by reactive silicate (RS) content and salinity, respectively. In particular, 14 potential indicators (two OTUs on P. yezoensis and twelve OTUs in seawater) were identified that significantly differentiated P. yezoensis health statuses and correlated with environmental changes. Overall, the present study provides insights into the alterations of bacterial communities associated with P. yezoensis and surrounding seawater co-occurring with red rot disease. Observed changes were closely associated with health status of algal host, and highlight the potential of using community differentiation to forecast disease occurrence.

10.
Brain Lang ; 175: 29-41, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28926795

RESUMO

The processing mechanism of verbs-actions and nouns-objects is a central topic of language research, with robust evidence for behavioral dissociation. The neural basis for these two major word and/or conceptual classes, however, remains controversial. Two experiments were conducted to study this question from the network perspective. Experiment 1 found that nodes of the same class, obtained through task-evoked brain imaging meta-analyses, were more strongly connected with each other than nodes of different classes during resting-state, forming segregated network modules. Experiment 2 examined the behavioral relevance of these intrinsic networks using data from 88 brain-damaged patients, finding that across patients the relative strength of functional connectivity of the two networks significantly correlated with the noun-object vs. verb-action relative behavioral performances. In summary, we found that verbs-actions and nouns-objects are supported by separable intrinsic functional networks and that the integrity of such networks accounts for the relative noun-object- and verb-action-selective deficits.


Assuntos
Encéfalo/fisiologia , Idioma , Adulto , Encéfalo/fisiopatologia , Lesões Encefálicas/patologia , Lesões Encefálicas/fisiopatologia , Mapeamento Encefálico , Feminino , Voluntários Saudáveis , Humanos , Imageamento por Ressonância Magnética , Masculino , Adulto Jovem
11.
Front Aging Neurosci ; 9: 243, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28798683

RESUMO

Cognitive impairment, functional decline and behavioral symptoms that characterize Alzheimer's disease (AD) are associated with perturbations of the neuronal network. The typical electroencephalographic (EEG) features in AD patients are increased delta or theta rhythm and decreased alpha or beta rhythm activities. However, considering the role of cross-frequency couplings in cognition, the alternation of cross-frequency couplings in AD patients is still obscure. This study aims to explore the interaction dynamics between different EEG oscillations in AD patients. We recorded the resting eye-closed EEG signals in 8 AD patients and 12 healthy volunteers. By analyzing the wavelet power spectrum and bicoherence of EEG, we found enhanced gamma rhythm power in AD patients in addition to the increased delta and decreased alpha power. Furthermore, an enhancement of the cross-frequency coupling strength between the beta/gamma and low-frequency bands was observed in AD patients compared to healthy controls (HCs). We propose that the pathological increase of ongoing gamma-band power might result from the disruption of the GABAergic interneuron network in AD patients. Furthermore, the cross-frequency overcouplings, which reflect the enhanced synchronization, might indicate the attenuated complexity of the neuronal network, and AD patients have to use more neural resources to maintain the resting brain state. Overall, our findings provide new evidence of the disturbance of the brain oscillation network in AD and further deepen our understanding of the central mechanisms of AD.

12.
Zhonghua Xin Xue Guan Bing Za Zhi ; 37(4): 352-7, 2009 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-19791473

RESUMO

OBJECTIVE: To investigate the effects of simvastatin (SIM)on cardiac hypertrophy and association with calcium channel modulation in rats with myocardial hypertrophy. METHODS: Myocardial hypertrophy was induced by abdominal aortic constriction (AAC) in adult SD rats. Following groups were studied (n=8 each): sham group, AAC group, AAC+ verapamil group (10 mg x kg(-1) x d(-1) per gavage for 4 weeks), AAC +SIM group (10 mg x kg(-1) x d(-1) per gavage for 4 weeks) AAC + SIM + mevalonic acid (50 mg x kg(-1) x d(-1) per gavage for 4 weeks) group. Systolic blood pressure (SBP), echocardiography, heart weight/body weight (HW/BW) and left ventricle weight/body weight (LVW/BW) ratios were measured. The protein and mRNA expressions of L-type calcium channel subunit alpha1 C and T-type calcium channel subunit alpha1 G and alpha1 H were detected by Western blot and RT-PCR respectively. RESULTS: SBP, HW/BW, LVW/BW, IVS and LVPW thickness, left ventricular weights were significantly increased in AAC rats and these effects could be significantly reduced by verapamil and SIM. The protein and mRNA expressions of alpha1 G and alpha1 H were significantly increased in AAC rats which could also be significantly inhibited by SIM or verapamil. The effects of SIM could be blocked by cotreatment with mevalonic acid. Protein and mRNA expressions of L-type calcium channel alpha1 C were similar among groups. CONCLUSION: Similar as verapamil, SIM could prevent AAC induced cardiac hypertrophy, possibly via inhibiting T-type calcium channel subunit alpha1 G and alpha1 H re-expression.


Assuntos
Canais de Cálcio Tipo L/metabolismo , Canais de Cálcio Tipo T/metabolismo , Cardiomegalia/prevenção & controle , Miocárdio/metabolismo , Sinvastatina/uso terapêutico , Animais , Cardiomegalia/metabolismo , Masculino , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Sinvastatina/farmacologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...