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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.
J Neuroinflammation ; 21(1): 105, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38649885

RESUMO

BACKGROUND: NADPH oxidase (NOX), a primary source of endothelial reactive oxygen species (ROS), is considered a key event in disrupting the integrity of the blood-retinal barrier. Abnormalities in neurovascular-coupled immune signaling herald the loss of ganglion cells in glaucoma. Persistent microglia-driven inflammation and cellular innate immune system dysregulation often lead to deteriorating retinal degeneration. However, the crosstalk between NOX and the retinal immune environment remains unresolved. Here, we investigate the interaction between oxidative stress and neuroinflammation in glaucoma by genetic defects of NOX2 or its regulation via gp91ds-tat. METHODS: Ex vivo cultures of retinal explants from wildtype C57BL/6J and Nox2 -/- mice were subjected to normal and high hydrostatic pressure (Pressure 60 mmHg) for 24 h. In vivo, high intraocular pressure (H-IOP) was induced in C57BL/6J mice for two weeks. Both Pressure 60 mmHg retinas and H-IOP mice were treated with either gp91ds-tat (a NOX2-specific inhibitor). Proteomic analysis was performed on control, H-IOP, and treatment with gp91ds-tat retinas to identify differentially expressed proteins (DEPs). The study also evaluated various glaucoma phenotypes, including IOP, retinal ganglion cell (RGC) functionality, and optic nerve (ON) degeneration. The superoxide (O2-) levels assay, blood-retinal barrier degradation, gliosis, neuroinflammation, enzyme-linked immunosorbent assay (ELISA), western blotting, and quantitative PCR were performed in this study. RESULTS: We found that NOX2-specific deletion or activity inhibition effectively attenuated retinal oxidative stress, immune dysregulation, the internal blood-retinal barrier (iBRB) injury, neurovascular unit (NVU) dysfunction, RGC loss, and ON axonal degeneration following H-IOP. Mechanistically, we unveiled for the first time that NOX2-dependent ROS-driven pro-inflammatory signaling, where NOX2/ROS induces endothelium-derived endothelin-1 (ET-1) overexpression, which activates the ERK1/2 signaling pathway and mediates the shift of microglia activation to a pro-inflammatory M1 phenotype, thereby triggering a neuroinflammatory outburst. CONCLUSIONS: Collectively, we demonstrate for the first time that NOX2 deletion or gp91ds-tat inhibition attenuates iBRB injury and NVU dysfunction to rescue glaucomatous RGC loss and ON axon degeneration, which is associated with inhibition of the ET-1/ERK1/2-transduced shift of microglial cell activation toward a pro-inflammatory M1 phenotype, highlighting NOX2 as a potential target for novel neuroprotective therapies in glaucoma management.


Assuntos
Barreira Hematorretiniana , Pressão Intraocular , Camundongos Endogâmicos C57BL , NADPH Oxidase 2 , Doenças Neuroinflamatórias , Animais , NADPH Oxidase 2/metabolismo , NADPH Oxidase 2/genética , Camundongos , Barreira Hematorretiniana/patologia , Barreira Hematorretiniana/metabolismo , Pressão Intraocular/fisiologia , Doenças Neuroinflamatórias/metabolismo , Doenças Neuroinflamatórias/patologia , Camundongos Knockout , Proliferação de Células/fisiologia , Sistema de Sinalização das MAP Quinases/fisiologia , Neuroglia/metabolismo , Neuroglia/patologia , Hipertensão Ocular/patologia , Hipertensão Ocular/metabolismo , Glaucoma/patologia , Glaucoma/metabolismo , Estresse Oxidativo/fisiologia
3.
Cereb Cortex ; 33(11): 6862-6871, 2023 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-36682884

RESUMO

The dynamic relationship between the neural representation of action word semantics and specific sensorimotor experience remains controversial. Here, we temporarily altered human subjects' sensorimotor experience in a 15-day head-down tilt bed rest setting, a ground-based analog of microgravity that disproportionally affects sensorimotor experiences of the lower limbs, and examined whether such effector-dependent activity deprivation specifically affected the neural processes of comprehending verbs of lower-limb actions (e.g. to kick) relative to upper-limb ones (e.g. to pinch). Using functional magnetic resonance imaging, we compared the multivoxel neural patterns for such action words prior to and after bed rest. We found an effector-specific (lower vs. upper limb) experience modulation in subcortical sensorimotor-related and anterior temporal regions. The neural action semantic representations in other effector-specific verb semantic regions (e.g. left lateral posterior temporal cortex) and motor execution regions were robust against such experience alterations. These effector-specific, sensorimotor-experience-sensitive and experience-independent patterns of verb neural representation highlight the multidimensional and dynamic nature of semantic neural representation, and the broad influence of microgravity (hence gravity) environment on cognition.


Assuntos
Mapeamento Encefálico , Semântica , Humanos , Mapeamento Encefálico/métodos , Cognição , Lobo Temporal , Imageamento por Ressonância Magnética
4.
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
5.
Cereb Cortex ; 33(18): 10036-10046, 2023 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-37491998

RESUMO

Speech comprehension is a complex process involving multiple stages, such as decoding of phonetic units, recognizing words, and understanding sentences and passages. In this study, we identify cortical networks beyond basic phonetic processing using a novel passage learning paradigm. Participants learn to comprehend a story composed of syllables of their native language, but containing unfamiliar vocabulary and syntax. Three learning methods are employed, each resulting in some degree of learning within a 12-min learning session. Functional magnetic resonance imaging results reveal that, when listening to the same story, the classic temporal-frontal language network is significantly enhanced by learning. Critically, activation of the left anterior and posterior temporal lobe correlates with the learning outcome that is assessed behaviorally through, e.g. word recognition and passage comprehension tests. This study demonstrates that a brief learning session is sufficient to induce neural plasticity in the left temporal lobe, which underlies the transformation from phonetic units to the units of meaning, such as words and sentences.


Assuntos
Percepção da Fala , Vocabulário , Humanos , Aprendizagem , Idioma , Fala , Fonética , Percepção da Fala/fisiologia , Imageamento por Ressonância Magnética/métodos , Compreensão/fisiologia , Mapeamento Encefálico
6.
Int J Mol Sci ; 24(17)2023 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-37686017

RESUMO

Glaucoma is a leading cause of irreversible blindness worldwide. While intraocular pressure (IOP) presents a major risk factor, the underlying pathophysiology still remains largely unclear. The correlation between vascular abnormalities and glaucoma has been deliberated for decades. Evidence for a role played by vascular factors in the pathogenesis of glaucomatous neurodegeneration has already been postulated. In addition, the fact that glaucoma causes both structural and functional changes to retinal blood vessels has been described. This review aims to investigate the published evidence concerning the relationship between vascular abnormalities and glaucoma, and to provide an overview of the "chicken or egg" dilemma in glaucoma. In this study, several biomarkers of glaucoma progression from a vascular perspective, including endothelin-1 (ET-1), nitric oxide, vascular endothelial growth factor (VEGF), and matrix metalloproteinases (MMPs), were identified and subsequently assessed for their potential as pharmacological intervention targets.


Assuntos
Glaucoma , Fator A de Crescimento do Endotélio Vascular , Humanos , Glaucoma/etiologia , Pressão Intraocular , Cegueira , Endotelina-1
7.
Psychol Sci ; 32(10): 1617-1635, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34546824

RESUMO

Humans primarily rely on language to communicate, on the basis of a shared understanding of the basic building blocks of communication: words. Do we mean the same things when we use the same words? Although cognitive neural research on semantics has revealed the common principles of word-meaning representation, the factors underlying the potential individual variations in word meanings are unknown. Here, we empirically characterized the intersubject consistency of 90 words across 20 adult subjects (10 female) using both behavioral measures (rating-based semantic-relationship patterns) and neuroimaging measures (word-evoked brain activity patterns). Across both the behavioral and neuroimaging experiments, we showed that the magnitude of individual disagreements on word meanings could be modeled on the basis of how much language or sensory experience is associated with a word and that this variation increases with word abstractness. Uncovering the cognitive and neural origins of word-meaning disagreements across individuals has implications for potential mechanisms to modulate such disagreements.


Assuntos
Individualidade , Semântica , Adulto , Feminino , Humanos , Idioma
8.
PLoS Biol ; 16(4): e2003993, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29624578

RESUMO

Object conceptual processing has been localized to distributed cortical regions that represent specific attributes. A challenging question is how object semantic space is formed. We tested a novel framework of representing semantic space in the pattern of white matter (WM) connections by extending the representational similarity analysis (RSA) to structural lesion pattern and behavioral data in 80 brain-damaged patients. For each WM connection, a neural representational dissimilarity matrix (RDM) was computed by first building machine-learning models with the voxel-wise WM lesion patterns as features to predict naming performance of a particular item and then computing the correlation between the predicted naming score and the actual naming score of another item in the testing patients. This correlation was used to build the neural RDM based on the assumption that if the connection pattern contains certain aspects of information shared by the naming processes of these two items, models trained with one item should also predict naming accuracy of the other. Correlating the neural RDM with various cognitive RDMs revealed that neural patterns in several WM connections that connect left occipital/middle temporal regions and anterior temporal regions associated with the object semantic space. Such associations were not attributable to modality-specific attributes (shape, manipulation, color, and motion), to peripheral picture-naming processes (picture visual similarity, phonological similarity), to broad semantic categories, or to the properties of the cortical regions that they connected, which tended to represent multiple modality-specific attributes. That is, the semantic space could be represented through WM connection patterns across cortical regions representing modality-specific attributes.


Assuntos
Dano Encefálico Crônico/fisiopatologia , Rede Nervosa/fisiologia , Lobo Occipital/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Semântica , Lobo Temporal/fisiologia , Substância Branca/fisiologia , Adulto , Idoso , Dano Encefálico Crônico/diagnóstico por imagem , Dano Encefálico Crônico/patologia , Estudos de Casos e Controles , Feminino , Humanos , Aprendizado de Máquina , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Rede Nervosa/anatomia & histologia , Rede Nervosa/diagnóstico por imagem , Testes Neuropsicológicos , Lobo Occipital/anatomia & histologia , Lobo Occipital/diagnóstico por imagem , Lobo Temporal/anatomia & histologia , Lobo Temporal/diagnóstico por imagem , Substância Branca/anatomia & histologia , Substância Branca/diagnóstico por imagem
9.
Graefes Arch Clin Exp Ophthalmol ; 258(2): 289-296, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31838707

RESUMO

PURPOSE: To study the retinal and choroidal microvascular parameters in children with nephrotic syndrome (NS). METHODS: This is a cross-sectional study. Optical coherence tomography angiography was used to evaluate the changes of retinal and choroidal microvessels in patients with NS. Thirty NS children and 20 normal controls were included in this study. The macular vessel density (VD) of the superficial capillary plexus (SCP), deep capillary plexus (DCP), choroid capillary plexus (CCP), and foveal avascular zone (FAZ) area of the SCP and DCP was quantitatively calculated. Clinical data including serum protein, blood lipid, uric acid, urea, serum creatinine, urinary protein concentration, urinary creatinine, 24-h urine volume, 24-h urinary total protein, 24-h creatinine clearance rate, and urinary albumin to creatinine ratio were collected. RESULTS: The VDs of the DCP and CCP in children with NS were significantly lower than those in controls (59.35 ± 2.45 vs. 61.15 ± 1.53, p = 0.002, 66.34 ± 1.43 vs. 67.16 ± 1.23, p = 0.042, respectively). The VD of the SCP in children with NS had a tendency to decrease compared with that in controls, but there were no significant differences. There were also no significant differences in FAZ area between the two groups. The VD of the SCP was positively correlated with serum total protein (ρ = 0.446, p = 0.014), serum albumin (ρ = 0.431, p = 0.017), and 24-h urine volume (ρ = 0.389, p = 0.034) but negatively correlated with triglyceride (ρ = - 0.450, p = 0.013), low-density lipoprotein cholesterol (ρ = -0.432, p = 0.017), urinary protein concentration (ρ = - 0.606, p < 0.001), and 24-h urinary total protein (ρ = - 0.517, p = 0.004). The VDs of the SCP, DCP, and CCP were negatively correlated with the urinary albumin to creatinine ratio (ρ = - 0.473, p = 0.008, ρ = - 0.438, p = 0.015, ρ = -0.467, p = 0.009, respectively). CONCLUSIONS: Retinal and choroidal VDs were decreased in children with NS and paralleled the severity of kidney disease. Optical coherence tomography angiography can be used as a noninvasive method for evaluating renal injury in patients with NS.


Assuntos
Corioide/irrigação sanguínea , Angiofluoresceinografia/métodos , Macula Lutea/patologia , Síndrome Nefrótica/diagnóstico , Vasos Retinianos/patologia , Tomografia de Coerência Óptica/métodos , Capilares/patologia , Criança , Pré-Escolar , Estudos Transversais , Feminino , Fundo de Olho , Humanos , Lactente , Recém-Nascido , Masculino , Projetos Piloto , Estudos Retrospectivos
10.
Angew Chem Int Ed Engl ; 59(47): 21049-21057, 2020 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-32767727

RESUMO

Here, we describe a fluorination strategy for semiconducting polymers for the development of highly bright second near-infrared region (NIR-II) probes. Tetrafluorination yielded a fluorescence QY of 3.2 % for the polymer dots (Pdots), over a 3-fold enhancement compared to non-fluorinated counterparts. The fluorescence enhancement was attributable to a nanoscale fluorous effect in the Pdots that maintained the molecular planarity and minimized the structure distortion between the excited state and ground state, thus reducing the nonradiative relaxations. By performing through-skull and through-scalp imaging of the brain vasculature of live mice, we quantitatively analyzed the vascular morphology of transgenic brain tumors in terms of the vessel lengths, vessel branches, and vessel symmetry, which showed statistically significant differences from the wild type animals. The bright NIR-II Pdots obtained through fluorination chemistry provide insightful information for precise diagnosis of the malignancy of the brain tumor.


Assuntos
Neoplasias Encefálicas/diagnóstico por imagem , Fluorescência , Corantes Fluorescentes/química , Imagem Óptica , Polímeros/química , Pontos Quânticos/química , Animais , Halogenação , Camundongos , Camundongos Endogâmicos C57BL , Estrutura Molecular , Tamanho da Partícula , Semicondutores , Propriedades de Superfície
11.
J Neurosci ; 38(13): 3303-3317, 2018 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-29476016

RESUMO

Concepts can be related in many ways. They can belong to the same taxonomic category (e.g., "doctor" and "teacher," both in the category of people) or be associated with the same event context (e.g., "doctor" and "stethoscope," both associated with medical scenarios). How are these two major types of semantic relations coded in the brain? We constructed stimuli from three taxonomic categories (people, manmade objects, and locations) and three thematic categories (school, medicine, and sports) and investigated the neural representations of these two dimensions using representational similarity analyses in human participants (10 men and nine women). In specific regions of interest, the left anterior temporal lobe (ATL) and the left temporoparietal junction (TPJ), we found that, whereas both areas had significant effects of taxonomic information, the taxonomic relations had stronger effects in the ATL than in the TPJ ("doctor" and "teacher" closer in ATL neural activity), with the reverse being true for thematic relations ("doctor" and "stethoscope" closer in TPJ neural activity). A whole-brain searchlight analysis revealed that widely distributed regions, mainly in the left hemisphere, represented the taxonomic dimension. Interestingly, the significant effects of the thematic relations were only observed after the taxonomic differences were controlled for in the left TPJ, the right superior lateral occipital cortex, and other frontal, temporal, and parietal regions. In summary, taxonomic grouping is a primary organizational dimension across distributed brain regions, with thematic grouping further embedded within such taxonomic structures.SIGNIFICANCE STATEMENT How are concepts organized in the brain? It is well established that concepts belonging to the same taxonomic categories (e.g., "doctor" and "teacher") share neural representations in specific brain regions. How concepts are associated in other manners (e.g., "doctor" and "stethoscope," which are thematically related) remains poorly understood. We used representational similarity analyses to unravel the neural representations of these different types of semantic relations by testing the same set of words that could be differently grouped by taxonomic categories or by thematic categories. We found that widely distributed brain areas primarily represented taxonomic categories, with the thematic categories further embedded within the taxonomic structure.


Assuntos
Mapeamento Encefálico , Semântica , Adolescente , Adulto , Córtex Cerebral/fisiologia , Feminino , Humanos , Masculino , Reconhecimento Visual de Modelos
12.
Hum Brain Mapp ; 40(16): 4759-4776, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31379052

RESUMO

The anterior temporal lobe (ATL) is engaged in various types of semantic dimensions. One consistently reported dimension is social information, with abstract words describing social behaviors inducing stronger activations in the ATL than nonsocial words. One potential factor that has been systematically confounded in this finding is emotional valence, given that abstract social words tend to be associated with emotional feelings. We investigated which factors drove the ATL sensitivity using a 2 (social/nonsocial) × 2 (valenced/neutral) factorial design in an fMRI study with relatively high spatial resolutions. We found that sociality and valence were processed in different ATL regions without significant interactions: The social effect was found in the left anterior superior temporal sulcus (aSTS), whereas the valence effect activated small clusters in the bilateral temporal poles (TP). In the left ATL, the social- and valence-related clusters were distinct from another superior ATL area that exhibited a general "abstractness" effect with little modulation of sociality or valence. These subregions exhibited distinct whole-brain functional connectivity patterns during the resting state, with the social cluster functionally connected to the default mode network, the valence cluster connected to the adjacent temporal regions and amygdala, and the abstractness cluster connected to a distributed network including a set of language-related regions. These results of activation profiles and connectivity patterns together indicate that the way in which the left ATL supports semantic processing is highly fine-grained, with the neural substrate for social semantic effects dissociated from those for emotional valence and abstractness.


Assuntos
Emoções , Semântica , Comportamento Social , Lobo Temporal/fisiologia , Adulto , Mapeamento Encefálico , Feminino , Humanos , Idioma , Imageamento por Ressonância Magnética , Masculino , Tempo de Reação , Lobo Temporal/diagnóstico por imagem , Adulto Jovem
13.
Cereb Cortex ; 28(8): 2699-2710, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-28633369

RESUMO

Neuroimaging studies have consistently indicated that semantic processing involves a brain network consisting of multimodal cortical regions distributed in the frontal, parietal, and temporal lobes. However, little is known about how semantic information is organized and processed within the network. Some recent studies have indicated that sensory-motor semantic information modulates the activation of this network. Other studies have indicated that this network responds more to social semantic information than to other information. Using fMRI, we collectively investigated the brain activations evoked by social and sensory-motor semantic information by manipulating the sociality and imageability of verbs in a word comprehension task. We detected 2 subgroups of brain regions within the network showing sociality and imageability effects, respectively. The 2 subgroups of regions are distinct but overlap in bilateral angular gyri and adjacent middle temporal gyri. A follow-up analysis of resting-state functional connectivity showed that dissociation of the 2 subgroups of regions is partially associated with their intrinsic functional connectivity differences. Additionally, an interaction effect of sociality and imageability was observed in the left anterior temporal lobe. Our findings indicate that the multimodal cortical semantic network has fine subdivisions that process and integrate social and sensory-motor semantic information.


Assuntos
Córtex Cerebral/fisiologia , Imaginação/fisiologia , Vias Neurais/fisiologia , Semântica , Comportamento Social , Teoria da Mente , Adulto , Mapeamento Encefálico , Córtex Cerebral/diagnóstico por imagem , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/diagnóstico por imagem , Oxigênio/sangue , Web Semântica , Adulto Jovem
14.
Cereb Cortex ; 28(12): 4305-4318, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-29186345

RESUMO

words constitute nearly half of the human lexicon and are critically associated with human abstract thoughts, yet little is known about how they are represented in the brain. We tested the neural basis of 2 classical cognitive notions of abstract meaning representation: by linguistic contexts and by semantic features. We collected fMRI BOLD responses for 360 abstract words and built theoretical representational models from state-of-the-art corpus-based natural language processing models and behavioral ratings of semantic features. Representational similarity analyses revealed that both linguistic contextual and semantic feature similarity affected the representation of abstract concepts, but in distinct neural levels. The corpus-based similarity was coded in the high-level linguistic processing system, whereas semantic feature information was reflected in distributed brain regions and in the principal component space derived from whole-brain activation patterns. These findings highlight the multidimensional organization and the neural dissociation between linguistic contextual and featural aspects of abstract concepts.


Assuntos
Encéfalo/fisiologia , Semântica , Adolescente , Adulto , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Modelos Neurológicos , Vias Neurais/fisiologia , Psicolinguística , Adulto Jovem
15.
Sheng Li Xue Bao ; 71(1): 117-126, 2019 Feb 25.
Artigo em Zh | MEDLINE | ID: mdl-30778510

RESUMO

Words denoting abstract concepts constitute nearly half of human lexicon and serve as building blocks of the human culture. Since the advent of non-invasive neuroimaging techniques, great progress has been made in revealing the neurobiological foundation of concrete object and action concepts, yet it remains unclear how abstract concepts are stored and processed in the brain. Here we review recent development in this field, focusing on both theoretical perspectives and neuroimaging findings. We found that abstract concepts can be represented via linguistic and experiential information; the neural correlates of abstract concepts are partly in line with such a theoretical framework. Future studies are warranted to uncover the cognitive and neural mechanisms of language and experience in abstract word representation, which will help to deepen our understanding of general computational principles of the human conceptual system and to promote the development of the brain-like artificial intelligence.


Assuntos
Encéfalo/fisiologia , Cognição , Formação de Conceito , Idioma , Semântica , Humanos
16.
Hum Brain Mapp ; 37(10): 3685-97, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27218306

RESUMO

The representation of object categories is a classical question in cognitive neuroscience and compelling evidence has identified specific brain regions showing preferential activation to categories of evolutionary significance. However, the potential contributions to category processing by tuning the connectivity patterns are largely unknown. Adopting a continuous multicategory paradigm, we obtained whole-brain functional connectivity (FC) patterns of each of four categories (faces, scenes, animals and tools) in healthy human adults and applied multivariate connectivity pattern classification analyses. We found that the whole-brain FC patterns made high-accuracy predictions of which category was being viewed. The decoding was successful even after the contributions of regions showing classical category-selective activations were excluded. We further identified the discriminative network for each category, which span way beyond the classical category-selective regions. Together, these results reveal novel mechanisms about how categorical information is represented in large-scale FC patterns, with general implications for the interactive nature of distributed brain areas underlying high-level cognition. Hum Brain Mapp 37:3685-3697, 2016. © 2016 Wiley Periodicals, Inc.


Assuntos
Encéfalo/fisiologia , Pensamento/fisiologia , Percepção Visual/fisiologia , Adulto , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico/métodos , Circulação Cerebrovascular/fisiologia , Cognição/fisiologia , Feminino , Humanos , Modelos Lineares , Imageamento por Ressonância Magnética , Masculino , Análise Multivariada , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiologia , Testes Neuropsicológicos , Oxigênio/sangue , Reprodutibilidade dos Testes , Descanso , Máquina de Vetores de Suporte , Adulto Jovem
17.
Cereb Cortex ; 25(9): 2416-26, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24642423

RESUMO

The placement and development of the visual word form area (VWFA) have commonly been assumed to depend, in part, on its connections with language regions. In this study, we specifically examined the effects of auditory speech experience deprivation in shaping the VWFA by investigating its location distribution, activation strength, and functional connectivity pattern in congenitally deaf participants. We found that the location and activation strength of the VWFA in congenitally deaf participants were highly comparable with those of hearing controls. Furthermore, while the congenitally deaf group showed reduced resting-state functional connectivity between the VWFA and the auditory speech area in the left anterior superior temporal gyrus, its intrinsic functional connectivity pattern between the VWFA and a fronto-parietal network was similar to that of hearing controls. Taken together, these results suggest that auditory speech experience has consequences for aspects of the word form-speech sound correspondence network, but that such experience does not significantly modulate the VWFA's placement or response strength. This is consistent with the view that the role of the VWFA might be to provide a representation that is suitable for mapping visual word forms onto language-specific gestures without the need to construct an aural representation.


Assuntos
Mapeamento Encefálico , Córtex Cerebral/fisiopatologia , Surdez/patologia , Surdez/fisiopatologia , Leitura , Fala , Adolescente , Análise de Variância , Córtex Cerebral/irrigação sanguínea , Feminino , Lateralidade Funcional , Humanos , Processamento de Imagem Assistida por Computador , Idioma , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/irrigação sanguínea , Vias Neurais/fisiopatologia , Oxigênio/sangue , Estimulação Luminosa , Descanso , Vocabulário , Adulto Jovem
18.
Cortex ; 174: 241-255, 2024 05.
Artigo em Inglês | MEDLINE | ID: mdl-38582629

RESUMO

Shape is a property that could be perceived by vision and touch, and is classically considered to be supramodal. While there is mounting evidence for the shared cognitive and neural representation space between visual and tactile shape, previous research tended to rely on dissimilarity structures between objects and had not examined the detailed properties of shape representation in the absence of vision. To address this gap, we conducted three explicit object shape knowledge production experiments with congenitally blind and sighted participants, who were asked to produce verbal features, 3D clay models, and 2D drawings of familiar objects with varying levels of tactile exposure, including tools, large nonmanipulable objects, and animals. We found that the absence of visual experience (i.e., in the blind group) led to stronger differences in animals than in tools and large objects, suggesting that direct tactile experience of objects is essential for shape representation when vision is unavailable. For tools with rich tactile/manipulation experiences, the blind produced overall good shapes comparable to the sighted, yet also showed intriguing differences. The blind group had more variations and a systematic bias in the geometric property of tools (making them stubbier than the sighted), indicating that visual experience contributes to aligning internal representations and calibrating overall object configurations, at least for tools. Taken together, the object shape representation reflects the intricate orchestration of vision, touch and language.


Assuntos
Cegueira , Percepção do Tato , Humanos , Cegueira/psicologia , Visão Ocular , Tato
19.
Elife ; 122023 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-37162200

RESUMO

One signature of the human brain is its ability to derive knowledge from language inputs, in addition to nonlinguistic sensory channels such as vision and touch. How does human language experience modulate the mechanism by which semantic knowledge is stored in the human brain? We investigated this question using a unique human model with varying amounts and qualities of early language exposure: early deaf adults who were born to hearing parents and had reduced early exposure and delayed acquisition of any natural human language (speech or sign), with early deaf adults who acquired sign language from birth as the control group that matches on nonlinguistic sensory experiences. Neural responses in a semantic judgment task with 90 written words that were familiar to both groups were measured using fMRI. The deaf group with reduced early language exposure, compared with the deaf control group, showed reduced semantic sensitivity, in both multivariate pattern (semantic structure encoding) and univariate (abstractness effect) analyses, in the left dorsal anterior temporal lobe (dATL). These results provide positive, causal evidence that language experience drives the neural semantic representation in the dATL, highlighting the roles of language in forming human neural semantic structures beyond nonverbal sensory experiences.


Humans are the only known species where much of knowledge learning happens symbolically through language, in addition to information received directly from the senses. For example, humans can learn about the color of some rose flowers from the popular expression "roses are red" without needing to see any red roses ­ allowing them to accumulate knowledge beyond the constraints of their own senses. Recent work suggests that a region of the brain known as the dorsal anterior temporal lobe represents knowledge acquired from language instead of sensory experiences. However, these studies were based on volunteers deprived of sensory experiences rather than those with reduced language exposure. Therefore, it was not clear whether this brain structure represents knowledge derived specifically from language and the importance of language in shaping non-sensory knowledge. To address this question, Wang et al. studied the brain activity of deaf adult volunteers in a word meaning judgement task. Volunteers were either born deaf or lost their hearing as toddlers, and all primarily used Chinese Sign Language for communication. One group of volunteers had been exposed to sign language from birth, giving them similar exposure to language as hearing individuals. The other group had less exposure to language in their early years and only learned sign language later in childhood. The task included 90 written words that were familiar to the volunteers. They included a mixture of object words ­ related to material objects ­ such as "shoulder" and "hammer" and abstract words ­ which are not linked to physical objects ­ such as "cause" and "violence". The volunteers were shown each word in turn and asked to think about the word's meaning. Brain scans revealed that the left dorsal anterior temporal lobes of the volunteers with reduced early language exposure were less sensitive to the meaning of the words compared with those of the other volunteers. The findings demonstrate that the dorsal anterior temporal lobe specifically supports meaning derived from a person's experience of language as opposed to sensory experience, providing a new angle to understand the mechanism of knowledge representations. Increased understanding of how language supports knowledge will help to uncover the human-specific ways of representing and creating knowledge in the brain.


Assuntos
Idioma , Semântica , Adulto , Humanos , Língua de Sinais , Lobo Temporal/fisiologia , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Imageamento por Ressonância Magnética , Mapeamento Encefálico
20.
Nat Commun ; 14(1): 5693, 2023 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-37709736

RESUMO

In recent years, numerous 1,2-R shift (R = aliphatic or aryl) based on tetracoordinate boron species have been well investigated. In the contrary, the corresponding radical migrations, especially 1,2-boryl radical shift for the construction of organoborons is still in its infancy. Given the paucity and significance of such strategies in boron chemistry, it is urgent to develop other efficient and alternative synthetic protocols to enrich these underdeveloped radical 1,2-boron migrations, before their fundamental potential applications could be fully explored at will. Herein, we have demonstrated a visible-light-induced photoredox neutral decarboxylative radical cross-coupling reaction, which undergoes a radical 1,2-boron shift to give a translocated C-radical for further capture of versatile radical acceptors. The mild reaction conditions, good functional-group tolerance, and broad ß-boryl NHPI esters scope as well as versatile radical acceptors make this protocol applicable in modification of bioactive molecules. It can be expected that this methodology will be a very useful tool and an alternative strategy for the construction of primary organoborons via a novel radical 1,2-boron shift mode.

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