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1.
Nat Hum Behav ; 5(9): 1127-1144, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34545237

RESUMO

Human visual perception carves a scene at its physical joints, decomposing the world into objects, which are selectively attended, tracked and predicted as we engage our surroundings. Object representations emancipate perception from the sensory input, enabling us to keep in mind that which is out of sight and to use perceptual content as a basis for action and symbolic cognition. Human behavioural studies have documented how object representations emerge through grouping, amodal completion, proto-objects and object files. By contrast, deep neural network models of visual object recognition remain largely tethered to sensory input, despite achieving human-level performance at labelling objects. Here, we review related work in both fields and examine how these fields can help each other. The cognitive literature provides a starting point for the development of new experimental tasks that reveal mechanisms of human object perception and serve as benchmarks driving the development of deep neural network models that will put the object into object recognition.


Assuntos
Reconhecimento Visual de Modelos/fisiologia , Reconhecimento Psicológico/fisiologia , Percepção Visual/fisiologia , Humanos , Redes Neurais de Computação , Vias Visuais/fisiologia
2.
J Neural Eng ; 18(5)2021 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-34492637

RESUMO

Objective. Transient visual evoked potential (TVEP) can reflect the condition of the visual pathway and has been widely used in brain-computer interface. TVEP signals are typically obtained by averaging the time-locked brain responses across dozens or even hundreds of stimulations, in order to remove different kinds of interferences. However, this procedure increases the time needed to detect the brain status in realistic applications. Meanwhile, long repeated stimuli can vary the evoked potentials and discomfort the subjects. Therefore, a novel unsupervised framework was developed in this study to realize the fast extraction of single-channel TVEP signals with a high signal-to-noise ratio.Approach.Using the principle of nonlinear aperiodic FitzHugh-Nagumo (FHN) model, a fast extraction and signal restoration technology of TVEP waveform based on FHN stochastic resonance is proposed to achieve high-quality acquisition of signal features with less average times.Results:A synergistic effect produced by noise, aperiodic signal and nonlinear system can force the energy of noise to be transferred into TVEP and hence amplifying the useful P100 feature while suppressing multi-scale noise.Significance. Compared with the conventional average and average-singular spectrum analysis-independent component analysis(average-SSA-ICA) method, the average-FHN method has a shorter stimulation time which can greatly improve the comfort of patients in clinical TVEP detection and a better performance of TVEP waveform i.e. a higher accuracy of P100 latency. The FHN recovery method is not only highly correlated with the original signal, but also can better highlight the P100 amplitude, which has high clinical application value.


Assuntos
Potenciais Evocados Visuais , Vias Visuais , Humanos , Razão Sinal-Ruído
3.
Med Hypotheses ; 156: 110686, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34583308

RESUMO

Schizophrenia is a severe mental disease involving both neurological and psychiatric abnormalities. Previous studies mainly focus on damage to high-order cognitive dysfunction, which is related to high-level cortical regions such as the prefrontal and temporal lobes. Recent research reveals that impairment of low-level sensory processing occurs in the early stage of schizophrenia, which may be due to impairment of the subcortical magnocellular visual pathway. Moreover, the structure and function of some important nuclei in a subcortical visual pathway are reported to be abnormal in patients with schizophrenia. Inspired by the above evidence, we propose a hypothesis that impairment of the Superior Colliculus-Pulvinar-Amygdala subcortical visual pathway may be involved in the pathological mechanisms of early stages of schizophrenia. And we propose a possible method to detect dysfunction of this subcortical pathway through examining topological processing, which may help early diagnosis of schizophrenia.


Assuntos
Pulvinar , Esquizofrenia , Tonsila do Cerebelo , Humanos , Colículos Superiores , Vias Visuais
4.
Proc Natl Acad Sci U S A ; 118(39)2021 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-34556573

RESUMO

Many sensory systems utilize parallel ON and OFF pathways that signal stimulus increments and decrements, respectively. These pathways consist of ensembles or grids of ON and OFF detectors spanning sensory space. Yet, encoding by opponent pathways raises a question: How should grids of ON and OFF detectors be arranged to optimally encode natural stimuli? We investigated this question using a model of the retina guided by efficient coding theory. Specifically, we optimized spatial receptive fields and contrast response functions to encode natural images given noise and constrained firing rates. We find that the optimal arrangement of ON and OFF receptive fields exhibits a transition between aligned and antialigned grids. The preferred phase depends on detector noise and the statistical structure of the natural stimuli. These results reveal that noise and stimulus statistics produce qualitative shifts in neural coding strategies and provide theoretical predictions for the configuration of opponent pathways in the nervous system.


Assuntos
Modelos Neurológicos , Ruído , Retina/fisiologia , Campos Visuais/fisiologia , Vias Visuais/fisiologia , Animais , Humanos , Estimulação Luminosa , Retina/citologia , Razão Sinal-Ruído , Percepção Visual
5.
Nat Neurosci ; 24(9): 1280-1291, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34341586

RESUMO

Predictive motion encoding is an important aspect of visually guided behavior that allows animals to estimate the trajectory of moving objects. Motion prediction is understood primarily in the context of translational motion, but the environment contains other types of behaviorally salient motion correlation such as those produced by approaching or receding objects. However, the neural mechanisms that detect and predictively encode these correlations remain unclear. We report here that four of the parallel output pathways in the primate retina encode predictive motion information, and this encoding occurs for several classes of spatiotemporal correlation that are found in natural vision. Such predictive coding can be explained by known nonlinear circuit mechanisms that produce a nearly optimal encoding, with transmitted information approaching the theoretical limit imposed by the stimulus itself. Thus, these neural circuit mechanisms efficiently separate predictive information from nonpredictive information during the encoding process.


Assuntos
Percepção de Movimento/fisiologia , Células Ganglionares da Retina/fisiologia , Vias Visuais/fisiologia , Animais , Macaca , Estimulação Luminosa
6.
Nat Rev Neurosci ; 22(9): 573-583, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34345018

RESUMO

How does the brain encode information about the environment? Decades of research have led to the pervasive notion that the object-processing pathway in primate cortex consists of multiple areas that are each specialized to process different object categories (such as faces, bodies, hands, non-face objects and scenes). The anatomical consistency and modularity of these regions have been interpreted as evidence that these regions are innately specialized. Here, we propose that ventral-stream modules do not represent clusters of circuits that each evolved to process some specific object category particularly important for survival, but instead reflect the effects of experience on a domain-general architecture that evolved to be able to adapt, within a lifetime, to its particular environment. Furthermore, we propose that the mechanisms underlying the development of domains are both evolutionarily old and universal across cortex. Topographic maps are fundamental, governing the development of specializations across systems, providing a framework for brain organization.


Assuntos
Lobo Temporal/fisiologia , Vias Visuais/fisiologia , Animais , Mapeamento Encefálico , Humanos , Macaca mulatta , Neurônios/fisiologia , Estimulação Luminosa , Percepção Visual/fisiologia
7.
Invest Ophthalmol Vis Sci ; 62(10): 21, 2021 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-34410298

RESUMO

Purpose: To characterize the visual pathway integrity of five glaucoma animal models using diffusion tensor imaging (DTI). Methods: Two experimentally induced and three genetically determined models of glaucoma were evaluated. For inducible models, chronic IOP elevation was achieved via intracameral injection of microbeads or laser photocoagulation of the trabecular meshwork in adult rodent eyes. For genetic models, the DBA/2J mouse model of pigmentary glaucoma, the LTBP2 mutant feline model of congenital glaucoma, and the transgenic TBK1 mouse model of normotensive glaucoma were compared with their respective genetically matched healthy controls. DTI parameters, including fractional anisotropy, axial diffusivity, and radial diffusivity, were evaluated along the optic nerve and optic tract. Results: Significantly elevated IOP relative to controls was observed in each animal model except for the transgenic TBK1 mice. Significantly lower fractional anisotropy and higher radial diffusivity were observed along the visual pathways of the microbead- and laser-induced rodent models, the DBA/2J mice, and the LTBP2-mutant cats compared with their respective healthy controls. The DBA/2J mice also exhibited lower axial diffusivity, which was not observed in the other models examined. No apparent DTI change was observed in the transgenic TBK1 mice compared with controls. Conclusions: Chronic IOP elevation was accompanied by decreased fractional anisotropy and increased radial diffusivity along the optic nerve or optic tract, suggestive of disrupted microstructural integrity in both inducible and genetic glaucoma animal models. The effects on axial diffusivity differed between models, indicating that this DTI metric may represent different aspects of pathological changes over time and with severity.


Assuntos
Imagem de Tensor de Difusão/métodos , Glaucoma de Ângulo Aberto/diagnóstico , Substância Cinzenta/patologia , Pressão Intraocular/fisiologia , Nervo Óptico/patologia , Vias Visuais/patologia , Animais , Anisotropia , Gatos , Modelos Animais de Doenças , Glaucoma de Ângulo Aberto/fisiopatologia , Camundongos , Camundongos Endogâmicos DBA , Fibras Nervosas/patologia , Ratos , Ratos Sprague-Dawley
8.
Elife ; 102021 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-34342580

RESUMO

An important goal for vision science is to develop quantitative models of the representation of visual signals at post-receptoral sites. To this end, we develop the quadratic color model (QCM) and examine its ability to account for the BOLD fMRI response in human V1 to spatially uniform, temporal chromatic modulations that systematically vary in chromatic direction and contrast. We find that the QCM explains the same, cross-validated variance as a conventional general linear model, with far fewer free parameters. The QCM generalizes to allow prediction of V1 responses to a large range of modulations. We replicate the results for each subject and find good agreement across both replications and subjects. We find that within the LM cone contrast plane, V1 is most sensitive to L-M contrast modulations and least sensitive to L+M contrast modulations. Within V1, we observe little to no change in chromatic sensitivity as a function of eccentricity.


Assuntos
Percepção de Cores , Visão de Cores , Sensibilidades de Contraste , Modelos Neurológicos , Córtex Visual/fisiologia , Vias Visuais/fisiologia , Adulto , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Estimulação Luminosa , Reprodutibilidade dos Testes , Fatores de Tempo , Córtex Visual/diagnóstico por imagem , Vias Visuais/diagnóstico por imagem , Adulto Jovem
9.
Science ; 373(6553)2021 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-34437090

RESUMO

The ability to perceive and respond to environmental stimuli emerges in the absence of sensory experience. Spontaneous retinal activity prior to eye opening guides the refinement of retinotopy and eye-specific segregation in mammals, but its role in the development of higher-order visual response properties remains unclear. Here, we describe a transient window in neonatal mouse development during which the spatial propagation of spontaneous retinal waves resembles the optic flow pattern generated by forward self-motion. We show that wave directionality requires the same circuit components that form the adult direction-selective retinal circuit and that chronic disruption of wave directionality alters the development of direction-selective responses of superior colliculus neurons. These data demonstrate how the developing visual system patterns spontaneous activity to simulate ethologically relevant features of the external world and thereby instruct self-organization.


Assuntos
Fluxo Óptico , Retina/fisiologia , Células Ganglionares da Retina/fisiologia , Visão Ocular/fisiologia , Vias Visuais , Potenciais de Ação , Células Amácrinas/fisiologia , Animais , Animais Recém-Nascidos , Axônios/fisiologia , Proteínas do Citoesqueleto/genética , Camundongos , Movimento (Física) , Mutação , Piridazinas/farmacologia , Receptores de GABA-A/metabolismo , Retina/crescimento & desenvolvimento , Análise Espaço-Temporal , Colículos Superiores/fisiologia
10.
Neuron ; 109(18): 2928-2942.e8, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34390651

RESUMO

The ability to encode the direction of image motion is fundamental to our sense of vision. Direction selectivity along the four cardinal directions is thought to originate in direction-selective ganglion cells (DSGCs) because of directionally tuned GABAergic suppression by starburst cells. Here, by utilizing two-photon glutamate imaging to measure synaptic release, we reveal that direction selectivity along all four directions arises earlier than expected at bipolar cell outputs. Individual bipolar cells contained four distinct populations of axon terminal boutons with different preferred directions. We further show that this bouton-specific tuning relies on cholinergic excitation from starburst cells and GABAergic inhibition from wide-field amacrine cells. DSGCs received both tuned directionally aligned inputs and untuned inputs from among heterogeneously tuned glutamatergic bouton populations. Thus, directional tuning in the excitatory visual pathway is incrementally refined at the bipolar cell axon terminals and their recipient DSGC dendrites by two different neurotransmitters co-released from starburst cells.


Assuntos
Axônios/fisiologia , Conectoma/métodos , Estimulação Luminosa/métodos , Terminações Pré-Sinápticas/fisiologia , Células Bipolares da Retina/fisiologia , Vias Visuais/fisiologia , Animais , Axônios/química , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Terminações Pré-Sinápticas/química , Células Bipolares da Retina/química , Vias Visuais/química
11.
Int J Mol Sci ; 22(16)2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34445636

RESUMO

The Drosophila eye has been used extensively to study numerous aspects of biological systems, for example, spatio-temporal regulation of differentiation, visual signal transduction, protein trafficking and neurodegeneration. Right from the advent of fluorescent proteins (FPs) near the end of the millennium, heterologously expressed fusion proteins comprising FPs have been applied in Drosophila vision research not only for subcellular localization of proteins but also for genetic screens and analysis of photoreceptor function. Here, we summarize applications for FPs used in the Drosophila eye as part of genetic screens, to study rhodopsin expression patterns, subcellular protein localization, membrane protein transport or as genetically encoded biosensors for Ca2+ and phospholipids in vivo. We also discuss recently developed FPs that are suitable for super-resolution or correlative light and electron microscopy (CLEM) approaches. Illustrating the possibilities provided by using FPs in Drosophila photoreceptors may aid research in other sensory or neuronal systems that have not yet been studied as well as the Drosophila eye.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila/metabolismo , Proteínas Luminescentes/metabolismo , Células Fotorreceptoras de Invertebrados/metabolismo , Vias Visuais/metabolismo , Animais , Transporte Proteico
12.
Indian J Ophthalmol ; 69(9): 2328-2332, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34427213

RESUMO

Purpose: Visual evoked potentials (VEP) are used to determine the function of visual pathway from the optic nerve to visual cortex. Various factors may affect VEP response, viz., technical and environmental. The aim of this study is to obtain the normative value of VEP latency and amplitude parameters in adulthood in Indonesia, as well as the relationship of height, weight, body mass index (BMI), head circumference, and visual acuity with the variety of latency and amplitude values of VEP parameters. Methods: It is a cross-sectional study on 120 healthy subjects consisting of 60 males and 60 females between 18 and 65 years old. Height, weight, BMI, head circumference, and visual acuity were measured and continued with VEP examination using a 26' checkerboard pattern on the left and right eyes alternately. All data were collected and analyzed with the Shapiro-Wilk test using statistical software R version 3.5.2. Results: Mean value of P100 latency (interocular latency) of left and right eye were 104.6 ± 3.4 ms and 104.1 ± 3.4 ms, respectively, as well as 9.8 ± 4.7 µV and 10.3 ± 5.4 µV for the amplitude. There was no significant difference between the male and female group, as well as on the age group. Female significantly exhibited a higher P100 amplitude than male. The greater the age, the lower amplitude of P100 significantly. Conclusion: Gender and age do not affect the P100 latency value but only affect P100 amplitude. Height, weight, BMI, head circumference, and visual acuity also do not affect the P100 latency and amplitude.


Assuntos
Potenciais Evocados Visuais , Córtex Visual , Adolescente , Adulto , Idoso , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Acuidade Visual , Vias Visuais , Adulto Jovem
13.
Nat Commun ; 12(1): 4911, 2021 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-34389710

RESUMO

The mammalian sensory neocortex consists of hierarchically organized areas reciprocally connected via feedforward (FF) and feedback (FB) circuits. Several theories of hierarchical computation ascribe the bulk of the computational work of the cortex to looped FF-FB circuits between pairs of cortical areas. However, whether such corticocortical loops exist remains unclear. In higher mammals, individual FF-projection neurons send afferents almost exclusively to a single higher-level area. However, it is unclear whether FB-projection neurons show similar area-specificity, and whether they influence FF-projection neurons directly or indirectly. Using viral-mediated monosynaptic circuit tracing in macaque primary visual cortex (V1), we show that V1 neurons sending FF projections to area V2 receive monosynaptic FB inputs from V2, but not other V1-projecting areas. We also find monosynaptic FB-to-FB neuron contacts as a second motif of FB connectivity. Our results support the existence of FF-FB loops in primate cortex, and suggest that FB can rapidly and selectively influence the activity of incoming FF signals.


Assuntos
Biorretroalimentação Psicológica/fisiologia , Macaca fascicularis/fisiologia , Neurônios/fisiologia , Córtex Visual/fisiologia , Vias Visuais/fisiologia , Animais , Feminino , Corpos Geniculados/citologia , Corpos Geniculados/fisiologia , Modelos Neurológicos , Reflexo Monosináptico/fisiologia , Córtex Visual/citologia
14.
Neurosci Bull ; 37(10): 1454-1468, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34215969

RESUMO

Visual object recognition in humans and nonhuman primates is achieved by the ventral visual pathway (ventral occipital-temporal cortex, VOTC), which shows a well-documented object domain structure. An on-going question is what type of information is processed in the higher-order VOTC that underlies such observations, with recent evidence suggesting effects of certain visual features. Combining computational vision models, fMRI experiment using a parametric-modulation approach, and natural image statistics of common objects, we depicted the neural distribution of a comprehensive set of visual features in the VOTC, identifying voxel sensitivities with specific feature sets across geometry/shape, Fourier power, and color. The visual feature combination pattern in the VOTC is significantly explained by their relationships to different types of response-action computation (fight-or-flight, navigation, and manipulation), as derived from behavioral ratings and natural image statistics. These results offer a comprehensive visual feature map in the VOTC and a plausible theoretical explanation as a mapping onto different types of downstream response-action systems.


Assuntos
Mapeamento Encefálico , Vias Visuais , Animais , Humanos , Imageamento por Ressonância Magnética , Lobo Occipital , Reconhecimento Visual de Modelos , Estimulação Luminosa , Lobo Temporal , Vias Visuais/diagnóstico por imagem , Percepção Visual
15.
Exp Brain Res ; 239(9): 2725-2740, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34228165

RESUMO

Motion perception deficits in dyslexia show a large intersubjective variability, partly reflecting genetic factors influencing brain architecture development. In previous work, we have demonstrated that dyslexic carriers of a mutation of the DCDC2 gene have a very strong impairment in motion perception. In the present study, we investigated structural white matter alterations associated with the poor motion perception in a cohort of twenty dyslexics with a subgroup carrying the DCDC2 gene deletion (DCDC2d+) and a subgroup without the risk variant (DCDC2d-). We observed significant deficits in motion contrast sensitivity and in motion direction discrimination accuracy at high contrast, stronger in the DCDC2d+ group. Both motion perception impairments correlated significantly with the fractional anisotropy in posterior ventral and dorsal tracts, including early visual pathways both along the optic radiation and in proximity of occipital cortex, MT and VWFA. However, the DCDC2d+ group showed stronger correlations between FA and motion perception impairments than the DCDC2d- group in early visual white matter bundles, including the optic radiations, and in ventral pathways located in the left inferior temporal cortex. Our results suggest that the DCDC2d+ group experiences higher vulnerability in visual motion processing even at early stages of visual analysis, which might represent a specific feature associated with the genotype and provide further neurobiological support to the visual-motion deficit account of dyslexia in a specific subpopulation.


Assuntos
Dislexia , Percepção de Movimento , Substância Branca , Dislexia/diagnóstico por imagem , Dislexia/genética , Humanos , Proteínas Associadas aos Microtúbulos , Lobo Occipital , Vias Visuais , Percepção Visual , Substância Branca/diagnóstico por imagem
16.
eNeuro ; 8(4)2021.
Artigo em Inglês | MEDLINE | ID: mdl-34193509

RESUMO

Retinal ganglion cells (RGCs) project topographically to the superior colliculus (SC) and dorsal lateral geniculate nucleus (dLGN). Spontaneous activity plays a critical role in retinotopic mapping in both regions; however, the molecular mechanisms underlying activity-dependent refinement remain unclear. Previous pharmacologic studies implicate NMDA receptors (NMDARs) in the establishment of retinotopy. In other brain regions, NMDARs are expressed on both the presynaptic and postsynaptic side of the synapse, and recent work suggests that presynaptic and postsynaptic NMDARs play distinct roles in retinotectal developmental dynamics. To directly test the role of NMDARs expressed by RGCs in retinofugal map formation, we took a conditional genetic knock-out approach to delete the obligate GluN1 subunit of NMDARs in RGCs. Here, we demonstrate reduced GluN1 expression in the retina of Chrnb3-Cre;GluN1flox/flox (pre-cKO) mice without altered expression in the SC. Anatomical tracing experiments revealed no significant changes in termination zone size in the SC and dLGN of pre-cKO mice, suggesting NMDAR function in RGCs is not an absolute requirement for topographic refinement. Further, we observed no change in the eye-specific organization of retinal inputs to the SC nor dLGN. To verify that NMDA induces activity in RGC terminals, we restricted GCaMP5 expression to RGCs and confirmed induction of calcium transients in RGC terminals. Together, these findings demonstrate that NMDARs expressed by RGCs are not required for retinofugal topographic map formation nor eye-specific segregation in the mouse.


Assuntos
Células Ganglionares da Retina , Vias Visuais , Animais , Corpos Geniculados , Camundongos , Receptores de N-Metil-D-Aspartato/genética , Retina , Colículos Superiores
17.
Nat Commun ; 12(1): 4448, 2021 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-34290247

RESUMO

Cortical representations of brief, static stimuli become more invariant to identity-preserving transformations along the ventral stream. Likewise, increased invariance along the visual hierarchy should imply greater temporal persistence of temporally structured dynamic stimuli, possibly complemented by temporal broadening of neuronal receptive fields. However, such stimuli could engage adaptive and predictive processes, whose impact on neural coding dynamics is unknown. By probing the rat analog of the ventral stream with movies, we uncovered a hierarchy of temporal scales, with deeper areas encoding visual information more persistently. Furthermore, the impact of intrinsic dynamics on the stability of stimulus representations grew gradually along the hierarchy. A database of recordings from mouse showed similar trends, additionally revealing dependencies on the behavioral state. Overall, these findings show that visual representations become progressively more stable along rodent visual processing hierarchies, with an important contribution provided by intrinsic processing.


Assuntos
Tempo de Reação/fisiologia , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Animais , Locomoção/fisiologia , Camundongos , Modelos Neurológicos , Neurônios/fisiologia , Estimulação Luminosa , Ratos , Vias Visuais/fisiologia , Vigília/fisiologia
18.
Neuron ; 109(16): 2616-2626.e6, 2021 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-34228960

RESUMO

Vision develops rapidly during infancy, yet how visual cortex is organized during this period is unclear. In particular, it is unknown whether functional maps that organize the mature adult visual cortex are present in the infant striate and extrastriate cortex. Here, we test the functional maturity of infant visual cortex by performing retinotopic mapping with functional magnetic resonance imaging (fMRI). Infants aged 5-23 months had retinotopic maps, with alternating preferences for vertical and horizontal meridians indicating the boundaries of visual areas V1 to V4 and an orthogonal gradient of preferences from high to low spatial frequencies. The presence of multiple visual maps throughout visual cortex in infants indicates a greater maturity of extrastriate cortex than previously appreciated. The areas showed subtle age-related fine-tuning, suggesting that early maturation undergoes continued refinement. This early maturation of area boundaries and tuning may scaffold subsequent developmental changes.


Assuntos
Encéfalo/crescimento & desenvolvimento , Córtex Visual/crescimento & desenvolvimento , Campos Visuais/fisiologia , Vias Visuais/crescimento & desenvolvimento , Mapeamento Encefálico/métodos , Feminino , Humanos , Lactente , Imageamento por Ressonância Magnética/métodos , Masculino , Estimulação Luminosa/métodos
19.
Neuroimage ; 238: 118246, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34111516

RESUMO

The functionality of central vision is different from peripheral vision. Central vision is used for fixation and has higher acuity, making it useful for everyday activities such as reading and object identification. The central and peripheral representations in primary visual cortex (V1) also differ in how higher-order processing areas modulate their responses. For example, attention and expectation are top-down processes (i.e., high-order cognitive functions) that influence visual information processing during behavioral tasks. This top-down control is different for central vs. peripheral vision. Since functional networks can influence visual information processing in different ways, networks (such as the Fronto-Parietal (FPN), Default Mode (DMN), and Cingulo-Opercular (CON)) likely differ in how they connect to representations of the visual field across V1. Prior work indicated the central representing portion of V1 was more functionally connected to regions belonging to the FPN, and the far-peripheral representing portion of V1 was more functionally connected to regions belonging to the DMN. Our goals were (1) Assess the reproducibility and generalizability of retinotopic effects on functional connections between V1 and functional networks. (2) Extend this work to understand structural connections of central vs. peripheral representations in V1. (3) Examine the overlapping eccentricity differences in functional and structural connections of V1. (4) Examine the major white matter tracks connecting central V1 to frontal regions. We used resting-state BOLD fMRI and DWI to examine whether portions of V1 that represent different visual eccentricities differ in their functional and structural connectivity to functional networks. All data were acquired and minimally preprocessed by the Human Connectome Project. We identified central and far-peripheral representing regions from a retinotopic template. Functional connectivity was measured by correlated activity between V1 and functional networks, and structural connectivity was measured by probabilistic tractography and converted to track probability. In both modalities, differences between V1 eccentricity segment connections were compared by paired, two-tailed t-test. A spatial permutation approach was used to determine the statistical significance of the spatial overlap between modalities. The identified spatial overlap was then used in a deterministic tractography approach to identify the white matter pathways connecting the overlap to central V1. We found (1) Centrally representing portions of V1 are more strongly functionally connected to frontal regions than are peripherally representing portions of V1, (2) Structural connections also show stronger connections between central V1 and frontal regions, (3) Patterns of structural and functional connections overlaps in the lateral frontal cortex, (4) This lateral frontal overlap is connected to central V1 via the IFOF. In summary, the work's main contribution is a greater understanding of higher-order functional networks' connectivity to V1. There are stronger structural connections to central representations in V1, particularly for lateral frontal regions, implying that the functional relationship between central V1 and frontal regions is built upon direct, long-distance connections via the IFOF. Overlapping structural and functional connections reflect differences in V1 eccentricities, with central V1 preferentially connected to attention-associated regions. Understanding how V1 is functionally and structurally connected to higher-order brain areas contributes to our understanding of how the human brain processes visual information and forms a baseline for understanding any modifications in processing that might occur with training or experience.


Assuntos
Atenção/fisiologia , Conectoma , Lobo Frontal/diagnóstico por imagem , Córtex Visual/diagnóstico por imagem , Vias Visuais/diagnóstico por imagem , Adulto , Imagem de Difusão por Ressonância Magnética , Feminino , Lobo Frontal/fisiologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Córtex Visual/fisiologia , Vias Visuais/fisiologia , Percepção Visual/fisiologia , Adulto Jovem
20.
PLoS Biol ; 19(6): e3001275, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34077415

RESUMO

Episodic memory depends on interactions between the hippocampus and interconnected neocortical regions. Here, using data-driven analyses of resting-state functional magnetic resonance imaging (fMRI) data, we identified the networks that interact with the hippocampus-the default mode network (DMN) and a "medial temporal network" (MTN) that included regions in the medial temporal lobe (MTL) and precuneus. We observed that the MTN plays a critical role in connecting the visual network to the DMN and hippocampus. The DMN could be further divided into 3 subnetworks: a "posterior medial" (PM) subnetwork comprised of posterior cingulate and lateral parietal cortices; an "anterior temporal" (AT) subnetwork comprised of regions in the temporopolar and dorsomedial prefrontal cortex; and a "medial prefrontal" (MP) subnetwork comprised of regions primarily in the medial prefrontal cortex (mPFC). These networks vary in their functional connectivity (FC) along the hippocampal long axis and represent different kinds of information during memory-guided decision-making. Finally, a Neurosynth meta-analysis of fMRI studies suggests new hypotheses regarding the functions of the MTN and DMN subnetworks, providing a framework to guide future research on the neural architecture of episodic memory.


Assuntos
Hipocampo/fisiologia , Rede Nervosa/fisiologia , Humanos , Memória/fisiologia , Descanso/fisiologia , Análise e Desempenho de Tarefas , Lobo Temporal/fisiologia , Vias Visuais/fisiologia
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