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1.
Nat Commun ; 11(1): 4602, 2020 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-32929071

RESUMO

Human behaviors are extremely sophisticated, relying on the adaptive, plastic and event-driven network of sensory neurons. Such neuronal system analyzes multiple sensory cues efficiently to establish accurate depiction of the environment. Here, we develop a bimodal artificial sensory neuron to implement the sensory fusion processes. Such a bimodal artificial sensory neuron collects optic and pressure information from the photodetector and pressure sensors respectively, transmits the bimodal information through an ionic cable, and integrates them into post-synaptic currents by a synaptic transistor. The sensory neuron can be excited in multiple levels by synchronizing the two sensory cues, which enables the manipulating of skeletal myotubes and a robotic hand. Furthermore, enhanced recognition capability achieved on fused visual/haptic cues is confirmed by simulation of a multi-transparency pattern recognition task. Our biomimetic design has the potential to advance technologies in cyborg and neuromorphic systems by endowing them with supramodal perceptual capabilities.


Assuntos
Células Receptoras Sensoriais/fisiologia , Tato/fisiologia , Visão Ocular/fisiologia , Animais , Linhagem Celular , Eletrodos , Humanos , Camundongos , Movimento (Física) , Nanotubos de Carbono/química , Reconhecimento Automatizado de Padrão
2.
Proc Natl Acad Sci U S A ; 117(37): 23085-23095, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32873637

RESUMO

Animals use active sensing to respond to sensory inputs and guide future motor decisions. In flight, flies generate a pattern of head and body movements to stabilize gaze. How the brain relays visual information to control head and body movements and how active head movements influence downstream motor control remains elusive. Using a control theoretic framework, we studied the optomotor gaze stabilization reflex in tethered flight and quantified how head movements stabilize visual motion and shape wing steering efforts in fruit flies (Drosophila). By shaping visual inputs, head movements increased the gain of wing steering responses and coordination between stimulus and wings, pointing to a tight coupling between head and wing movements. Head movements followed the visual stimulus in as little as 10 ms-a delay similar to the human vestibulo-ocular reflex-whereas wing steering responses lagged by more than 40 ms. This timing difference suggests a temporal order in the flow of visual information such that the head filters visual information eliciting downstream wing steering responses. Head fixation significantly decreased the mechanical power generated by the flight motor by reducing wingbeat frequency and overall thrust. By simulating an elementary motion detector array, we show that head movements shift the effective visual input dynamic range onto the sensitivity optimum of the motion vision pathway. Taken together, our results reveal a transformative influence of active vision on flight motor responses in flies. Our work provides a framework for understanding how to coordinate moving sensors on a moving body.


Assuntos
Drosophila/fisiologia , Voo Animal/fisiologia , Visão Ocular/fisiologia , Vias Visuais/fisiologia , Animais , Fenômenos Biomecânicos/fisiologia , Movimentos da Cabeça/fisiologia , Mecanorreceptores/fisiologia , Movimento (Física) , Asas de Animais/fisiologia
3.
Nat Commun ; 11(1): 3983, 2020 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-32770078

RESUMO

Frontal top-down cortical neurons projecting to sensory cortical regions are well-positioned to integrate long-range inputs with local circuitry in frontal cortex to implement top-down attentional control of sensory regions. How adolescence contributes to the maturation of top-down neurons and associated local/long-range input balance, and the establishment of attentional control is poorly understood. Here we combine projection-specific electrophysiological and rabies-mediated input mapping in mice to uncover adolescence as a developmental stage when frontal top-down neurons projecting from the anterior cingulate to visual cortex are highly functionally integrated into local excitatory circuitry and have heightened activity compared to adulthood. Chemogenetic suppression of top-down neuron activity selectively during adolescence, but not later periods, produces long-lasting visual attentional behavior deficits, and results in excessive loss of local excitatory inputs in adulthood. Our study reveals an adolescent sensitive period when top-down neurons integrate local circuits with long-range connectivity to produce attentional behavior.


Assuntos
Envelhecimento/fisiologia , Atenção/fisiologia , Comportamento Animal/fisiologia , Neurônios/fisiologia , Potenciais de Ação/fisiologia , Animais , Channelrhodopsins/metabolismo , Giro do Cíngulo/fisiologia , Masculino , Camundongos Endogâmicos C57BL , Modelos Neurológicos , Inibição Neural/fisiologia , Terminações Pré-Sinápticas/fisiologia , Raiva/fisiopatologia , Sinapses/fisiologia , Visão Ocular/fisiologia
4.
PLoS One ; 15(8): e0226122, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32853238

RESUMO

Essential for successful interaction with the environment is the human capacity to resolve events in time. Typical event timing paradigms are judgements of simultaneity (SJ) and of temporal order (TOJ). It remains unclear whether SJ and TOJ are based on the same underlying mechanism and whether there are fixed thresholds for resolution. The current study employed four visual event timing task versions: horizontal and vertical SJ and TOJ. Binary responses were analysed using multilevel binary regression modelling. Modulatory effects of potential explanatory variables on event timing perception were investigated: (1) Individual factors (sex and age), (2) temporal factors (SOA, trial number, order of experiment, order of stimuli orientation, time of day) and (3) spatial factors (left or right stimulus first, top or bottom stimulus first, horizontal vs. vertical orientation). The current study directly compares for the first time, performance on SJ and TOJ tasks using the same paradigm and presents evidence that a variety of factors and their interactions selectively modulate event timing functions in humans, explaining the variance found in previous studies. We conclude that SJ and TOJ are partially independent functions, because they are modulated differently by individual and contextual variables.


Assuntos
Percepção do Tempo/fisiologia , Visão Ocular/fisiologia , Percepção Visual/fisiologia , Adulto , Percepção Auditiva/fisiologia , Feminino , Humanos , Julgamento/fisiologia , Masculino , Orientação , Tempo de Reação/fisiologia
5.
PLoS One ; 15(8): e0236497, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32785230

RESUMO

When human movement is assisted or controlled with a muscle actuator, such as electrical muscle stimulation, a critical issue is the integration of such induced movement with the person's motion intention and how this movement then affects their motor control. Towards achieving optimal integration and reducing feelings of artificiality and enforcement, we explored perceptual simultaneity through electrical muscle stimulation, which involved changing the interval between intentional and induced movements. We report on two experiments in which we evaluated the ranges between detection and stimulus for perceptual simultaneity achievable with an electromyography-triggered electrical muscle stimulation system. We found that the peak range was approximately 80-160 ms, with the timing of perceptual simultaneity shifting according to different adaptation states. Our results indicate that perceptual simultaneity is controllable using this adaptation strategy.


Assuntos
Eletromiografia , Córtex Motor/fisiologia , Movimento/fisiologia , Músculo Esquelético/fisiologia , Adulto , Estimulação Elétrica , Mãos/fisiologia , Humanos , Masculino , Córtex Motor/diagnóstico por imagem , Músculo Esquelético/diagnóstico por imagem , Visão Ocular/fisiologia , Adulto Jovem
6.
Proc Natl Acad Sci U S A ; 117(37): 23044-23053, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32839324

RESUMO

Visual motion detection is one of the most important computations performed by visual circuits. Yet, we perceive vivid illusory motion in stationary, periodic luminance gradients that contain no true motion. This illusion is shared by diverse vertebrate species, but theories proposed to explain this illusion have remained difficult to test. Here, we demonstrate that in the fruit fly Drosophila, the illusory motion percept is generated by unbalanced contributions of direction-selective neurons' responses to stationary edges. First, we found that flies, like humans, perceive sustained motion in the stationary gradients. The percept was abolished when the elementary motion detector neurons T4 and T5 were silenced. In vivo calcium imaging revealed that T4 and T5 neurons encode the location and polarity of stationary edges. Furthermore, our proposed mechanistic model allowed us to predictably manipulate both the magnitude and direction of the fly's illusory percept by selectively silencing either T4 or T5 neurons. Interestingly, human brains possess the same mechanistic ingredients that drive our model in flies. When we adapted human observers to moving light edges or dark edges, we could manipulate the magnitude and direction of their percepts as well, suggesting that mechanisms similar to the fly's may also underlie this illusion in humans. By taking a comparative approach that exploits Drosophila neurogenetics, our results provide a causal, mechanistic account for a long-known visual illusion. These results argue that this illusion arises from architectures for motion detection that are shared across phyla.


Assuntos
Drosophila/fisiologia , Ilusões/fisiologia , Percepção de Movimento/fisiologia , Animais , Humanos , Movimento (Física) , Neurônios/fisiologia , Visão Ocular/fisiologia , Vias Visuais/fisiologia
7.
Proc Natl Acad Sci U S A ; 117(27): 15684-15693, 2020 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-32571921

RESUMO

Mitochondria are known to play an essential role in photoreceptor function and survival that enables normal vision. Within photoreceptors, mitochondria are elongated and extend most of the inner-segment length, where they supply energy for protein synthesis and the phototransduction machinery in the outer segment, as well as acting as a calcium store. Here, we examined the arrangement of the mitochondria within the inner segment in detail using three-dimensional (3D) electron microscopy techniques and show they are tethered to the plasma membrane in a highly specialized arrangement. Remarkably, mitochondria and their cristae openings align with those of neighboring inner segments. The pathway by which photoreceptors meet their high energy demands is not fully understood. We propose this to be a mechanism to share metabolites and assist in maintaining homeostasis across the photoreceptor cell layer. In the extracellular space between photoreceptors, Müller glial processes were identified. Due to the often close proximity to the inner-segment mitochondria, they may, too, play a role in the inner-segment mitochondrial arrangement as well as metabolite shuttling. OPA1 is an important factor in mitochondrial homeostasis, including cristae remodeling; therefore, we examined the photoreceptors of a heterozygous Opa1 knockout mouse model. The cristae structure in the Opa1 +/- photoreceptors was not greatly affected, but the mitochondria were enlarged and had reduced alignment to neighboring inner-segment mitochondria. This indicates the importance of key regulators in maintaining this specialized photoreceptor mitochondrial arrangement.


Assuntos
GTP Fosfo-Hidrolases/genética , Mitocôndrias/genética , Membranas Mitocondriais/ultraestrutura , Visão Ocular/genética , Animais , Membrana Celular/genética , Membrana Celular/ultraestrutura , Células Ependimogliais/metabolismo , Células Ependimogliais/ultraestrutura , Humanos , Camundongos , Microscopia Eletrônica , Mitocôndrias/ultraestrutura , Membranas Mitocondriais/metabolismo , Células Fotorreceptoras/ultraestrutura , Visão Ocular/fisiologia
8.
Science ; 368(6495): 1108-1113, 2020 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-32499439

RESUMO

Enabling near-infrared light sensitivity in a blind human retina may supplement or restore visual function in patients with regional retinal degeneration. We induced near-infrared light sensitivity using gold nanorods bound to temperature-sensitive engineered transient receptor potential (TRP) channels. We expressed mammalian or snake TRP channels in light-insensitive retinal cones in a mouse model of retinal degeneration. Near-infrared stimulation increased activity in cones, ganglion cell layer neurons, and cortical neurons, and enabled mice to perform a learned light-driven behavior. We tuned responses to different wavelengths, by using nanorods of different lengths, and to different radiant powers, by using engineered channels with different temperature thresholds. We targeted TRP channels to human retinas, which allowed the postmortem activation of different cell types by near-infrared light.


Assuntos
Cegueira/terapia , Ouro , Raios Infravermelhos , Nanotubos , Degeneração Retiniana/terapia , Limiar Sensorial/efeitos da radiação , Canais de Cátion TRPC/fisiologia , Visão Ocular/efeitos da radiação , Animais , Cegueira/fisiopatologia , Modelos Animais de Doenças , Potenciais Evocados Visuais/fisiologia , Potenciais Evocados Visuais/efeitos da radiação , Engenharia Genética , Células HEK293 , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Estimulação Luminosa , Ratos , Células Fotorreceptoras Retinianas Cones/fisiologia , Células Fotorreceptoras Retinianas Cones/efeitos da radiação , Degeneração Retiniana/fisiopatologia , Células Ganglionares da Retina/fisiologia , Células Ganglionares da Retina/efeitos da radiação , Limiar Sensorial/fisiologia , Serpentes , Canais de Cátion TRPC/genética , Canais de Cátion TRPV/genética , Canais de Cátion TRPV/fisiologia , Visão Ocular/fisiologia , Córtex Visual/fisiopatologia , Córtex Visual/efeitos da radiação
9.
PLoS One ; 15(6): e0234380, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32542032

RESUMO

It is well-known that correction of blur can improve visual perception. However, it is unclear how the beneficial effect of correction is affected by the regions of correction and the spatial uncertainty introduced by the retinal stimulation. The purpose of this study was two-fold: first, to compare the impacts of blur correction between isoeccentric locations of the visual field; and second, to evaluate the effect of spatial cueing in each corrected location on performing a simple task. Five subjects were asked to complete a simple detection task of a small dark spot stimulus presented randomly at four cardinal retinal locations (eccentricity: 5°) under manipulation of attention via an exogenous cue. Both clear and blurred targets were randomly displayed across the visual field and viewed monocularly through a vision simulator, used to minimize peripheral ocular aberrations. Results confirmed the advantage of clear vs/ blurred images under spatial uncertainty. It was also found that the visual benefit from blur correction is unequal at isoeccentric locations, even for a simple detection task. While manipulation of attention in the presence of spatial uncertainty significantly modulated response time (RT) performance, no differential effect was observed for clear and blurred stimuli, suggesting that attention has only a small effect on the optical benefit for a simple detection task when the display is depleted (no distractor). Those observations highlight the importance of field performance asymmetries in optical interventions and may offer useful implications for the design of extrafoveal refractive correction. Further studies are needed to elucidate how the focus of attention interacts with the perceived gain of vision correction.


Assuntos
Visão Ocular/fisiologia , Percepção Visual/fisiologia , Adulto , Atenção/fisiologia , Simulação por Computador , Sinais (Psicologia) , Olho Artificial , Óculos , Humanos , Orientação Espacial , Estimulação Luminosa , Tempo de Reação/fisiologia , Erros de Refração/fisiopatologia , Erros de Refração/psicologia , Testes Visuais , Acuidade Visual , Campos Visuais , Adulto Jovem
10.
Nat Commun ; 11(1): 3057, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32546681

RESUMO

It is uncontroversial that land animals have more elaborated cognitive abilities than their aquatic counterparts such as fish. Yet there is no apparent a-priori reason for this. A key cognitive faculty is planning. We show that in visually guided predator-prey interactions, planning provides a significant advantage, but only on land. During animal evolution, the water-to-land transition resulted in a massive increase in visual range. Simulations of behavior identify a specific type of terrestrial habitat, clustered open and closed areas (savanna-like), where the advantage of planning peaks. Our computational experiments demonstrate how this patchy terrestrial structure, in combination with enhanced visual range, can reveal and hide agents as a function of their movement and create a selective benefit for imagining, evaluating, and selecting among possible future scenarios-in short, for planning. The vertebrate invasion of land may have been an important step in their cognitive evolution.


Assuntos
Comportamento Predatório , Visão Ocular , Algoritmos , Animais , Organismos Aquáticos , Aprendizagem da Esquiva , Evolução Biológica , Aves , Cognição , Simulação por Computador , Ecossistema , Mamíferos , Navegação Espacial , Visão Ocular/fisiologia
11.
PLoS One ; 15(6): e0232796, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32479506

RESUMO

AIMS: To determine the cost and quality of life impact imposed by glaucoma in Tanzania, East Africa. METHODS: An expert panel of eye health professionals was convened to agree current glaucoma practice in Tanzania. In addition a structured patient survey was developed and administered. Supplemental cost and quality of life information was collected using cost questionnaires and validated quality of life measures, including the EQ5D and VFQ-25. RESULTS: Key findings include following. Non-adherence is a major issue, especially in rural settings where over 50% of the patients may fail to return for review. Whilst medical therapy is overwhelmingly the first line treatment, the cost of maintaining this represents up to 25% of a patient's income. There is an impact of glaucoma on patients general well-being as determined by the EQ-5D and more tellingly on visual function with particular impact on role limitations as determined by the VF25. Despite our sample being taken in a private clinic and thus containing a much larger proportion of professionals than the general population, one third of the population earned Tanzanian Shillings (TZS) 170,000 per month which is below the minimum wage. CONCLUSION: These findings are of great importance for health care planners seeking to determine cost-effective, acceptable methods of both identifying and treating this major cause of preventable blindness.


Assuntos
Glaucoma/economia , Glaucoma/epidemiologia , Glaucoma/fisiopatologia , Adolescente , Adulto , Idoso , Análise Custo-Benefício/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Qualidade de Vida/psicologia , Inquéritos e Questionários , Tanzânia/epidemiologia , Visão Ocular/fisiologia , Acuidade Visual/fisiologia , Campos Visuais/fisiologia
12.
Nature ; 581(7806): 83-88, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32376950

RESUMO

Photoreceptor loss is the final common endpoint in most retinopathies that lead to irreversible blindness, and there are no effective treatments to restore vision1,2. Chemical reprogramming of fibroblasts offers an opportunity to reverse vision loss; however, the generation of sensory neuronal subtypes such as photoreceptors remains a challenge. Here we report that the administration of a set of five small molecules can chemically induce the transformation of fibroblasts into rod photoreceptor-like cells. The transplantation of these chemically induced photoreceptor-like cells (CiPCs) into the subretinal space of rod degeneration mice (homozygous for rd1, also known as Pde6b) leads to partial restoration of the pupil reflex and visual function. We show that mitonuclear communication is a key determining factor for the reprogramming of fibroblasts into CiPCs. Specifically, treatment with these five compounds leads to the translocation of AXIN2 to the mitochondria, which results in the production of reactive oxygen species, the activation of NF-κB and the upregulation of Ascl1. We anticipate that CiPCs could have therapeutic potential for restoring vision.


Assuntos
Reprogramação Celular/efeitos dos fármacos , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Degeneração Retiniana/terapia , Células Fotorreceptoras Retinianas Bastonetes/citologia , Células Fotorreceptoras Retinianas Bastonetes/transplante , Visão Ocular/efeitos dos fármacos , Animais , Proteína Axina/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Modelos Animais de Doenças , Citometria de Fluxo , Camundongos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , NF-kappa B/metabolismo , Transporte Proteico/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Degeneração Retiniana/patologia , Células Fotorreceptoras Retinianas Bastonetes/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Visão Ocular/fisiologia
13.
PLoS One ; 15(5): e0228365, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32421714

RESUMO

We investigated the global structure of intrinsic cross-frequency dynamics by systematically examining power-based temporal associations among a broad range of oscillation frequencies both within and across EEG-based current sources (sites). We focused on power-based associations that could reveal unique timescale dependence independently of interacting frequencies. Large spectral-power fluctuations across all sites occurred at two characteristic timescales, sub-second and seconds, yielding distinct patterns of cross-frequency associations. On the fast sub-second timescale, within-site (local) associations were consistently between pairs of ß-γ frequencies differing by a constant Δf (particularly Δf ~ 10 Hz at posterior sites and Δf ~ 16 Hz at lateral sites) suggesting that higher-frequency oscillations are organized into Δf amplitude-modulated packets, whereas cross-site (long-distance) associations were all within-frequency (particularly in the >30 Hz and 6-12 Hz ranges, suggestive of feedforward and feedback interactions). On the slower seconds timescale, within-site (local) associations were characterized by a broad range of frequencies selectively associated with ~10 Hz at posterior sites and associations among higher (>20 Hz) frequencies at lateral sites, whereas cross-site (long-distance) associations were characterized by a broad range of frequencies at posterior sites selectively associated with ~10 Hz at other sites, associations among higher (>20 Hz) frequencies among lateral and anterior sites, and prevalent associations at ~10 Hz. Regardless of timescale, within-site (local) cross-frequency associations were weak at anterior sites indicative of frequency-specific operations. Overall, these results suggest that the fast sub-second-timescale coordination of spectral power is limited to local amplitude modulation and insulated within-frequency long-distance interactions (likely feedforward and feedback interactions), while characteristic patterns of cross-frequency interactions emerge on the slower seconds timescale. The results also suggest that the occipital α oscillations play a role in organizing higher-frequency oscillations into ~10 Hz amplitude-modulated packets to communicate with other regions. Functional implications of these timescale-dependent cross-frequency associations await future investigations.


Assuntos
Comportamento/fisiologia , Córtex Cerebral/fisiologia , Eletroencefalografia , Fenômenos Fisiológicos Oculares , Adolescente , Adulto , Córtex Cerebral/diagnóstico por imagem , Feminino , Humanos , Masculino , Percepção , Visão Ocular/fisiologia , Adulto Jovem
14.
Invest Ophthalmol Vis Sci ; 61(5): 37, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-32437548

RESUMO

Purpose: To determine the influence of RIBEYE deletion and the resulting absence of synaptic ribbons on retinal light signaling by electroretinography. Methods: Full-field flash electroretinograms (ERGs) were recorded in RIBEYE knock-out (KO) and wild-type (WT) littermate mice under photopic and scotopic conditions, with oscillatory potentials (OPs) extracted by digital filtering. Flicker ERGs and ERGs following intravitreal injection of pharmacological agents were also obtained under scotopic conditions. Results: The a-wave amplitudes were unchanged between RIBEYE KO and WT mice; however, the b-wave amplitudes were reduced in KOs under scotopic, but not photopic, conditions. Increasing stimulation frequency led to a greater reduction in RIBEYE KO b-wave amplitudes compared with WTs. Furthermore, we observed prominent, supernormal OPs in RIBEYE KO mice in comparison with WT mice. Following intravitreal injections with l-2 amino-4-phosphonobutyric acid and cis-2,3 piperidine dicarboxylic acid to block ON and OFF responses at photoreceptor synapses, OPs were completely abolished in both mice types, indicating a synaptic origin of the prominent OPs in the KOs. Conversely, tetrodotoxin treatment to block voltage-gated Na+ channels/spiking neurons did not differentially affect OPs in WT and KO mice. Conclusions: The decreased scotopic b-wave and decreased responses to increased stimulation frequencies are consistent with signaling malfunctions at photoreceptor and inner retinal ribbon synapses. Because phototransduction in the photoreceptor outer segments is unaffected in the KOs, their supernormal OPs presumably result from a dysfunction in retinal synapses. The relatively mild ERG phenotype in KO mice, particularly in the photopic range, is probably caused by compensatory mechanisms in retinal signaling pathways.


Assuntos
Oxirredutases do Álcool/fisiologia , Proteínas Correpressoras/fisiologia , Eletrorretinografia , Células Fotorreceptoras Retinianas Cones/fisiologia , Sinapses/fisiologia , Transmissão Sináptica , Visão Ocular/fisiologia , Aminobutiratos/farmacologia , Animais , Potenciais Evocados Visuais/fisiologia , Agonistas de Aminoácidos Excitatórios/farmacologia , Feminino , Deleção de Genes , Injeções Intravítreas , Masculino , Camundongos , Camundongos Knockout , Microscopia Eletrônica de Transmissão , Visão Noturna/fisiologia , Estimulação Luminosa , Piperidinas/farmacologia , Células Fotorreceptoras Retinianas Cones/ultraestrutura , Bloqueadores dos Canais de Sódio/farmacologia , Sinapses/efeitos dos fármacos , Sinapses/ultraestrutura , Tetrodotoxina/farmacologia
15.
Invest Ophthalmol Vis Sci ; 61(5): 63, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-32462198

RESUMO

Purpose: To longitudinally evaluate vision-related quality of life (VRQoL) in geographic atrophy (GA) secondary to age-related macular degeneration (AMD) and define its relation to visual function and structural biomarkers. Methods: Patients with GA secondary to AMD were recruited in the context of the prospective, non-interventional, natural-history Directional Spread in Geographic-Atrophy study (NCT02051998). Fundus autofluorescence and infrared reflectance images were semi-automatically annotated for GA. Linear mixed-effects models were applied to investigate the association of putative determinants with the National Eye Institute Visual Function Questionnaire 25 (NEI VFQ-25) VRQoL. Results: A total of 87 patients with a mean age ± SD of 77.07 ± 7.49 years were included in the analysis. At baseline, median (IQR) best-corrected visual acuity (BCVA) was 0.3 (0.51) for the better eye and 0.89 (0.76) for the worse eye; 46% of the patients showed binocular and 25.3% monocular non-central GA. The VRQoL composite score was impaired: 69.96 (24.03). Sixty-six patients with a median of 2 (2) follow-up visits after 1.08 (0.78) years were examined longitudinally. Conclusions: Vision-related quality of life is significantly impaired in patients with GA secondary to AMD. The cross-sectional and longitudinal association of VRQoL with visual functional and structural biomarkers supports the validity of the NEI VFQ-25 VRQoL.


Assuntos
Atrofia Geográfica/etiologia , Atrofia Geográfica/fisiopatologia , Degeneração Macular/complicações , Degeneração Macular/fisiopatologia , Qualidade de Vida , Visão Ocular/fisiologia , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Feminino , Humanos , Estudos Longitudinais , Masculino , Estudos Prospectivos
16.
J Neurosci ; 40(23): 4565-4575, 2020 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-32371603

RESUMO

Pupil diameter determines how much light hits the retina and, thus, how much information is available for visual processing. This is regulated by a brainstem reflex pathway. Here, we investigate whether this pathway is under the control of internal models about the environment. This would allow adjusting pupil dynamics to environmental statistics to augment information transmission. We present image sequences containing internal temporal structure to humans of either sex and male macaque monkeys. We then measure whether the pupil tracks this temporal structure not only at the rate of luminance variations, but also at the rate of statistics not available from luminance information alone. We find entrainment to environmental statistics in both species. This entrainment directly affects visual processing by increasing sensitivity at the environmentally relevant temporal frequency. Thus, pupil dynamics are matched to the temporal structure of the environment to optimize perception, in line with an active sensing account.SIGNIFICANCE STATEMENT When light hits the retina, the pupil reflexively constricts. This determines how much light and thus how much information is available for visual processing. We show that the rate at which the pupil constricts and dilates is matched to the temporal structure of our visual environment, although this information is not directly contained in the light variations that usually trigger reflexive pupil constrictions. Adjusting pupil diameter in accordance with environmental regularities optimizes information transmission at ecologically relevant temporal frequencies. We show that this is the case in humans and macaque monkeys, suggesting that the reflex pathways that regulate pupil diameter are under some degree of cognitive control across primate species.


Assuntos
Meio Ambiente , Estimulação Luminosa/métodos , Reflexo Pupilar/fisiologia , Visão Ocular/fisiologia , Adulto , Animais , Feminino , Humanos , Macaca mulatta , Masculino
17.
Proc Natl Acad Sci U S A ; 117(20): 11178-11183, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32358186

RESUMO

It is known that attention shifts prior to a saccade to start processing the saccade target before it lands in the foveola, the high-resolution region of the retina. Yet, once the target is foveated, microsaccades, tiny saccades maintaining the fixated object within the fovea, continue to occur. What is the link between these eye movements and attention? There is growing evidence that these eye movements are associated with covert shifts of attention in the visual periphery, when the attended stimuli are presented far from the center of gaze. Yet, microsaccades are primarily used to explore complex foveal stimuli and to optimize fine spatial vision in the foveola, suggesting that the influences of microsaccades on attention may predominantly impact vision at this scale. To address this question we tracked gaze position with high precision and briefly presented high-acuity stimuli at predefined foveal locations right before microsaccade execution. Our results show that visual discrimination changes prior to microsaccade onset. An enhancement occurs at the microsaccade target location. This modulation is highly selective and it is coupled with a drastic impairment at the opposite foveal location, just a few arcminutes away. This effect is strongest when stimuli are presented closer to the eye movement onset time. These findings reveal that the link between attention and microsaccades is deeper than previously thought, exerting its strongest effects within the foveola. As a result, during fixation, foveal vision is constantly being reshaped both in space and in time with the occurrence of microsaccades.


Assuntos
Atenção/fisiologia , Movimentos Oculares/fisiologia , Fóvea Central/fisiologia , Movimentos Sacádicos/fisiologia , Visão Ocular/fisiologia , Adolescente , Adulto , Feminino , Humanos , Masculino , Estimulação Luminosa , Percepção Visual , Adulto Jovem
18.
PLoS Comput Biol ; 16(4): e1007698, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32271746

RESUMO

Humans are able to track multiple objects at any given time in their daily activities-for example, we can drive a car while monitoring obstacles, pedestrians, and other vehicles. Several past studies have examined how humans track targets simultaneously and what underlying behavioral and neural mechanisms they use. At the same time, computer-vision researchers have proposed different algorithms to track multiple targets automatically. These algorithms are useful for video surveillance, team-sport analysis, video analysis, video summarization, and human-computer interaction. Although there are several efficient biologically inspired algorithms in artificial intelligence, the human multiple-target tracking (MTT) ability is rarely imitated in computer-vision algorithms. In this paper, we review MTT studies in neuroscience and biologically inspired MTT methods in computer vision and discuss the ways in which they can be seen as complementary.


Assuntos
Inteligência Artificial , Memória/fisiologia , Visão Ocular/fisiologia , Algoritmos , Animais , Encéfalo/fisiologia , Cognição , Humanos , Processamento de Imagem Assistida por Computador/métodos , Movimento (Física) , Neurociências , Gravação em Vídeo/métodos
19.
PLoS Comput Biol ; 16(4): e1007699, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32275711

RESUMO

The human visual system is foveated: we can see fine spatial details in central vision, whereas resolution is poor in our peripheral visual field, and this loss of resolution follows an approximately logarithmic decrease. Additionally, our brain organizes visual input in polar coordinates. Therefore, the image projection occurring between retina and primary visual cortex can be mathematically described by the log-polar transform. Here, we test and model how this space-variant visual processing affects how we process binocular disparity, a key component of human depth perception. We observe that the fovea preferentially processes disparities at fine spatial scales, whereas the visual periphery is tuned for coarse spatial scales, in line with the naturally occurring distributions of depths and disparities in the real-world. We further show that the visual system integrates disparity information across the visual field, in a near-optimal fashion. We develop a foveated, log-polar model that mimics the processing of depth information in primary visual cortex and that can process disparity directly in the cortical domain representation. This model takes real images as input and recreates the observed topography of human disparity sensitivity. Our findings support the notion that our foveated, binocular visual system has been moulded by the statistics of our visual environment.


Assuntos
Visão Binocular/fisiologia , Acuidade Visual/fisiologia , Adulto , Percepção de Profundidade , Feminino , Humanos , Masculino , Modelos Neurológicos , Neurônios , Estimulação Luminosa , Disparidade Visual , Visão Ocular/fisiologia , Córtex Visual , Campos Visuais/fisiologia
20.
J Neurosci ; 40(20): 4059-4072, 2020 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-32265257

RESUMO

Photoreceptor neurons are surrounded by an extracellular matrix, called the interphotoreceptor matrix (IPM). Activities crucial to vision occur within the IPM, including trafficking of nutrients and metabolites, retinal attachment, and interactions needed for normal outer segment phagocytosis. The IPM includes the following two unique proteoglycans: IPM proteoglycan 1 (IMPG1) and IMPG2. Patients with mutations in IMPG1/IMPG2 develop visual deficits with subretinal material accumulation, highlighting the critical role of the IPM in vision. To determine the role of these proteoglycans in retinal physiology and the pathologic mechanisms that lead to vision loss, we generated mouse models lacking IMPG1/IMPG2. In normal retina, IMPG1 and IMPG2 occupy distinct IPM compartments, represent the main source of chondroitin sulfate and are fundamental for the constitution of the cone-specific glycocalyx stained by the PNA (peanut agglutinin) lectin marker. No evident morphologic or functional deficits were found in mice lacking IMPG1. In the absence of IMPG2, IMPG1 abnormally accumulated at the subretinal space need, likely leading to the formation of subretinal lesions and reduced visual function. Interestingly, mice lacking both IMPG1 and IMPG2, regardless of sex, showed normal retinal structure and function, demonstrating that the aberrant IMPG1 distribution is the main cause of the visual alterations observed in the absence of IMPG2. In conclusion, our results show the dependence of secreted proteoglycans such as IMPG1 on the extracellular environment to properly integrate into the matrix, demonstrate the role of IMPG2 in shaping the IPM, and shed light on the potential mechanisms leading to the development of subretinal lesions and vision loss.SIGNIFICANCE STATEMENT The photoreceptors are specialized neurons that drive phototransduction in the mammalian retina. These cells are organized and surrounded by an extracellular matrix, the interphotoreceptor matrix (IPM). Mutations in IPM proteoglycans are associated with blindness in humans. Our studies show that two specific proteoglycans of the IPM, IPM proteoglycan 1 (IMPG1) and IMPG2, form a dynamic structure with distinct localization and dependency. When IMPG2 is absent, IMPG1 cannot integrate into the IPM, leading to abnormal proteoglycan accumulation and visual deficits. This work adds a new layer of understanding to IPM physiology and describes the pathologic events following deficits in proteoglycans, providing novel possibilities for visual restoration in patients with IMPG-related pathologies.


Assuntos
Células Fotorreceptoras de Vertebrados/fisiologia , Proteoglicanas/genética , Visão Ocular/fisiologia , Animais , Sulfatos de Condroitina/metabolismo , Eletrorretinografia , Proteínas da Matriz Extracelular/genética , Espaço Extracelular , Proteínas do Olho/genética , Feminino , Humanos , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Knockout , Mutação , Retina/fisiopatologia , Células Fotorreceptoras Retinianas Cones/metabolismo , Transtornos da Visão/genética
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