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1.
Exp Psychol ; 67(3): 161-168, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32900298

RESUMO

Dynamic visual noise (DVN) selectively impairs memory for some types of stimuli (e.g., colors, textures, concrete words), but not for others (e.g., matrices, Chinese characters, simple shapes). According to the image definition hypothesis, the key difference is whether the stimulus leads to images that are ill-defined or well-defined. The former will be affected because the addition of noise quickly reduces the usefulness of the image in supplying information about the item's identity. The image definition hypothesis predicts that fonts should lead to ill-defined images and therefore should be affected by DVN, and although three previous studies appear to show this result, they lack a key control condition and report only proportion correct. Two experiments reassessed whether DVN affects memory for fonts, but, unlike the previous studies, both included a static visual noise condition and both were analyzed using signal detection measures. There was no evidence that DVN affected memory for font information, thus disconfirming a prediction of the original version of image definition hypothesis. We suggest a revised version that focuses on redintegration can explain the results.


Assuntos
Memória de Curto Prazo/fisiologia , Ruído , Percepção Visual/fisiologia , Adulto , Feminino , Humanos , Masculino , Adulto Jovem
2.
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
3.
PLoS One ; 15(8): e0237344, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32818953

RESUMO

PURPOSE: In this study, we investigate to what degree augmented reality technology can be used to create and evaluate a visual-to-auditory sensory substitution device to improve the performance of blind persons in navigation and recognition tasks. METHODS: A sensory substitution algorithm that translates 3D visual information into audio feedback was designed. This algorithm was integrated in an augmented reality based mobile phone application. Using the mobile device as sensory substitution device, a study with blind participants (n = 7) was performed. The participants navigated through pseudo-randomized obstacle courses using either the sensory substitution device, a white cane or a combination of both. In a second task, virtual 3D objects and structures had to be identified by the participants using the same sensory substitution device. RESULTS: The realized application for mobile devices enabled participants to complete the navigation and object recognition tasks in an experimental environment already within the first trials without previous training. This demonstrates the general feasibility and low entry barrier of the designed sensory substitution algorithm. In direct comparison to the white cane, within the study duration of ten hours the sensory substitution device did not offer a statistically significant improvement in navigation.


Assuntos
Realidade Aumentada , Cegueira/reabilitação , Equipamentos de Autoajuda , Navegação Espacial/fisiologia , Pessoas com Deficiência Visual/reabilitação , Adulto , Idoso , Percepção Auditiva/fisiologia , Cegueira/fisiopatologia , Bengala , Estudos de Viabilidade , Retroalimentação Sensorial/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Aplicativos Móveis , Projetos Piloto , Percepção Visual/fisiologia , Adulto Jovem
4.
PLoS One ; 15(8): e0237339, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32833969

RESUMO

BACKGROUND: Cognitive ability refers to the ability to receive, process, store, and extract information. It is the most important psychological condition for people to successfully complete activities. Previous studies have shown that the design of the human-computer interface of the command and control system cannot exceed the cognitive ability of the operator of the command and control system, and it must match the cognitive ability of the operator in order to reduce the mental load intensity, and improve the accuracy, timeliness and work efficiency. However, previous researchers in the field of cognitive science have not put forward a core index system that can represent the cognitive ability of ship command and control system operators and the importance of each index, and there are few achievements that can be used for reference. OBJECTIVE: To explore the core index system of cognitive ability that affecting the cognitive process of command and control system operators, and to verify the index system. METHODS: Based on the classic O*NET questionnaire, two indexes of O*NET were revised, three indexes of response ability were added, and then a questionnaire on the importance evaluation of cognitive abilities index was formed. The questionnaire includes 24 indexes in six aspects: verbal abilities, idea generation and reasoning abilities, quantitative abilities, visual perception abilities, mnemonic and attentive abilities, and response abilities. The cognitive ability importance evaluation data of 202 people from different positions in the ship command and control system were collected. These data reflect the overall level of cognitive ability of operators in the whole ship command and control field. RESULTS: The data analysis results show that: firstly, the most important cognitive abilities affecting command and control system operators were visual perception abilities, mnemonic and attentive abilities, and response abilities. Secondly, the results of confirmatory factor analysis show that CMIN/DF, GFI, CFI, TLI, RMSEA, RMR and other indicators used in the model test all meet the requirements. The model has a good fitting degree, and the overall index extraction method is feasible. Thirdly, the independence T test results show that for beginners and experienced experts, there is a significant difference in the important evaluation of mnemonic and attentive abilities, while there is no significant difference in the important evaluation of response and visual perception abilities. Fourthly, the results of Bi-group confirmatory factor analysis experiment show that the structural model has good stability and factor invariance. CONCLUSIONS: Through the research of this paper, the index system which can express the core cognitive ability of the commander of command and control system is successfully constructed, and the index system has been fully verified by mathematics. The 3 abilities and 10 indexes in the index system are closely related to the work tasks of operators, which also reflects the correctness of our construction results to a certain extent. According to the results of data analysis, there are differences between assistant commanders and professional commanders in the evaluation of the importance of some indexes, which reflects the importance of working age and experience to the promotion of position skills. The results of this research are of great significance for the subsequent acquisition of cognitive ability data and assessment of post cognitive ability of command and control system operators.


Assuntos
Cognição/fisiologia , Militares/psicologia , Navios/instrumentação , Interface Usuário-Computador , Adulto , Atenção/fisiologia , Análise Fatorial , Estudos de Viabilidade , Humanos , Masculino , Memória/fisiologia , Militares/estatística & dados numéricos , Modelos Psicológicos , Inquéritos e Questionários/estatística & dados numéricos , Estados Unidos , Percepção Visual/fisiologia
5.
PLoS Biol ; 18(8): e3000548, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32745077

RESUMO

Sleep is vital for survival. Yet under environmentally challenging conditions, such as starvation, animals suppress their need for sleep. Interestingly, starvation-induced sleep loss does not evoke a subsequent sleep rebound. Little is known about how starvation-induced sleep deprivation differs from other types of sleep loss, or why some sleep functions become dispensable during starvation. Here, we demonstrate that down-regulation of the secreted cytokine unpaired 2 (upd2) in Drosophila flies may mimic a starved-like state. We used a genetic knockdown strategy to investigate the consequences of upd2 on visual attention and sleep in otherwise well-fed flies, thereby sidestepping the negative side effects of undernourishment. We find that knockdown of upd2 in the fat body (FB) is sufficient to suppress sleep and promote feeding-related behaviors while also improving selective visual attention. Furthermore, we show that this peripheral signal is integrated in the fly brain via insulin-expressing cells. Together, these findings identify a role for peripheral tissue-to-brain interactions in the simultaneous regulation of sleep quality and attention, to potentially promote adaptive behaviors necessary for survival in hungry animals.


Assuntos
Atenção/fisiologia , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Comportamento Alimentar/fisiologia , Inanição/genética , Percepção Visual/fisiologia , Animais , Encéfalo/citologia , Encéfalo/metabolismo , Proteínas de Drosophila/deficiência , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Corpo Adiposo/metabolismo , Feminino , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Insulina/genética , Insulina/metabolismo , Neurônios/citologia , Neurônios/metabolismo , Neuropeptídeos/genética , Neuropeptídeos/metabolismo , Transdução de Sinais , Sono/fisiologia , Privação do Sono/genética , Privação do Sono/metabolismo , Inanição/metabolismo
6.
Nat Commun ; 11(1): 3925, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32764538

RESUMO

Adaptation is a ubiquitous property of sensory systems. It is typically considered that neurons adapt to dominant energy in the ambient environment to function optimally. However, perceptual representation of the stimulus, often modulated by feedback signals, sometimes do not correspond to the input state of the stimulus, which tends to be more linked with feedforward signals. Here we investigated the relative contributions to cortical adaptation from feedforward and feedback signals, taking advantage of a visual illusion, the Flash-Grab Effect, to disassociate the feedforward and feedback representation of an adaptor. Results reveal that orientation adaptation is exclusively dependent on the perceived rather than the retinal orientation of the adaptor. Combined fMRI and EEG measurements demonstrate that the perceived orientation of the Flash-Grab Effect is indeed supported by feedback signals in the cortex. These findings highlight the important contribution of feedback signals for cortical neurons to recalibrate their sensitivity.


Assuntos
Adaptação Fisiológica , Ilusões/fisiologia , Orientação Espacial/fisiologia , Adulto , Eletroencefalografia , Potenciais Evocados Visuais , Retroalimentação Fisiológica , Feminino , Neuroimagem Funcional , Humanos , Imagem por Ressonância Magnética , Masculino , Ilusões Ópticas/fisiologia , Estimulação Luminosa , Psicofísica , Retina/fisiologia , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Adulto Jovem
7.
PLoS One ; 15(7): e0236702, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32735602

RESUMO

When humans are administered continuous and predictable perturbations of stance, an adaptation period precedes the steady state of balancing behaviour. Little information is available on the modulation of adaptation by vision and perturbation frequency. Moreover, performance of supra-postural tasks may modulate adaptation in as yet unidentified ways. Our purpose was to identify differences in adaptation associated to distinct visual tasks and perturbation frequencies. Twenty non-disabled adult volunteers stood on a platform translating 10 cm in antero-posterior (AP) direction at low (LF, 0.18 Hz) and high frequency (HF, 0.56 Hz) with eyes open (EO) and closed (EC). Additional conditions were reading a text fixed to platform (EO-TP) and reading a text stationary on ground (EO-TG). Peak-to-peak (PP) displacement amplitude and AP position of head and pelvis markers were computed for each of 27 continuous perturbation cycles. The time constant and extent of head and pelvis adaptation and the cross-correlation coefficients between head and pelvis were compared across visual conditions and frequencies. Head and pelvis mean positions in space varied little across conditions and perturbation cycles but the mean head PP displacements changed over time. On average, at LF, the PP displacement of the head and pelvis increased progressively. Adaptation was rapid or ineffective with EO, but slower with EO-TG, EO-TP, EC. At HF, the head PP displacement amplitude decreased progressively with fast adaptation rates, while the pelvis adaptation was not apparent. The results show that visual tasks can modulate the adaptation rate, highlight the effect of the perturbation frequency on adaptation and provide evidence of priority assigned to pelvis stabilization over visual tasks at HF. The effects of perturbation frequency and optic flow and their interaction with other sensory inputs and cognitive tasks on the adaptation strategies should be investigated in impaired individuals and considered in the design of rehabilitation protocols.


Assuntos
Adaptação Fisiológica/fisiologia , Equilíbrio Postural/fisiologia , Percepção Visual/fisiologia , Adulto , Feminino , Humanos , Masculino , Pelve/fisiologia
8.
PLoS One ; 15(8): e0236467, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32785238

RESUMO

Can people categorize complex visual scenes unconsciously? The possibility of unconscious perception remains controversial. Here, we addressed this question using psychophysical methods applied to unmasked visual stimuli presented for extremely short durations (in the µsec range) by means of a custom-built modern tachistoscope. Our experiment was composed of two phases. In the first phase, natural or urban scenes were either absent or present (for varying durations) on the tachistoscope screen, and participants were simply asked to evaluate their subjective perception using a 3-points scale (absence of stimulus, stimulus detection or stimulus identification). Participants' responses were tracked by means of two staircases. The first psychometric function aimed at defining participants' proportion of subjective detection responses (i.e., not having seen anything vs. having seen something without being able to identify it), while the second staircase tracked the proportion of subjective identification rates (i.e., being unaware of the stimulus' category vs. being aware of it). In the second phase, the same participants performed an objective categorization task in which they had to decide, on each trial, whether the image was a natural vs. an urban scene. A third staircase was used in this phase so as to build a psychometric curve reflecting the objective categorization performance of each participant. In this second phase, participants also rated their subjective perception of each stimulus on every trial, exactly as in the first phase of the experiment. Our main result is that objective categorization performance, here assumed to reflect the contribution of both conscious and unconscious trials, cannot be explained based exclusively on conscious trials. This clearly suggests that the categorization of complex visual scenes is possible even when participants report being unable to consciously perceive the contents of the stimulus.


Assuntos
Estado de Consciência/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Inconsciente Psicológico , Percepção Visual/fisiologia , Adulto , Conscientização , Feminino , Humanos , Masculino , Estimulação Luminosa , Psicometria/métodos , Adulto Jovem
9.
Plast Reconstr Surg ; 146(3): 614-619, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32842112

RESUMO

Unilateral coronal nonsyndromic craniosynostosis is associated with asymmetric skull growth, which may influence cerebral long-term function. Twenty affected adolescents who underwent cranial vault remodeling at a mean age of 8.2 months (12 from the Yale Craniofacial Clinic and eight from the Children's Hospital of Philadelphia) all completed a double-blinded neurodevelopmental assessment at an average age of 12.1 years. The study cohort included 55 percent female and 50 percent right-sided craniosynostosis. Mean verbal intelligence quotient was highest at 117.3, and mean performance intelligence quotient was 106.4, for a mean full-scale intelligence quotient of 112.5. Patients performed above the national average on all academic achievements except for numerical operations, which was significantly lower than word reading (p = 0.022). Patients performed below average on all Beery-Buktenica visual motor tests; motor-coordination was poorer than both visual motor integration and visual perception (p = 0.027 and p = 0.005). Significant positive correlations existed between paternal education/visual perception (r = 0.450; p = 0.046) and household income/verbal intelligence quotient (r = 0.628; p = 0.004). Patients with right unilateral coronal nonsyndromic craniosynostosis had improved spelling compared with left-sided patients on multivariate regression (p = 0.033). Female patients had higher motor coordination (p = 0.024). Breast-fed patients had better performance intelligence quotient (p = 0.024), visual motor integration (p = 0.014), and visual perception (p = 0.031). Adolescents who underwent cranial vault remodeling at two institutions had above average intelligence quotient scores, but worse mathematical and visual motor achievement compared with control subjects. Left-side craniosynostosis patients performed worse in spelling than right-side patients. Breast-feeding was an independent predictor for improved performance intelligence quotient, visual motor achievement, and visual perception performance. Study findings are limited by the cohort size. A larger population study is required, which could validate or modify the study conclusions.


Assuntos
Sucesso Acadêmico , Craniossinostoses/cirurgia , Leitura , Procedimentos Cirúrgicos Reconstrutivos/métodos , Percepção Visual/fisiologia , Adolescente , Criança , Craniossinostoses/fisiopatologia , Método Duplo-Cego , Feminino , Seguimentos , Humanos , Masculino , Testes Neuropsicológicos , Período Pós-Operatório , Estudos Prospectivos
10.
PLoS One ; 15(8): e0224471, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32797090

RESUMO

We present normative data for an expanded set of stimuli designed to investigate past experience effects on object detection. The stimuli are vertically-elongated "bipartite" displays comprising two equal-area regions meeting at an articulated central border. When the central border is assigned to one side, a shaped figure (i.e., an object) is detected on that side. Participants viewing brief masked exposures typically detect figures more often on the critical side of Intact displays where a common ("familiar") object is depicted than on a matched critical side of Part-Rearranged (PR) displays comprising the same parts arranged in novel configurations. This pattern of results showed that past experience in the form of familiar configuration rather than familiar parts is a prior for figure assignment. Spurred by research implicating a network involving the perirhinal cortex of the medial temporal lobe in these familiar configuration effects, we enlarged the stimulus set from 24 to 48 base stimuli to increase its usefulness for behavioral, neuropsychological, and neuroimaging experiments. We measured the percentage of participants who agreed on a single interpretation for each side of Intact, Upright PR, and Inverted PR displays (144 displays; 288 sides) under long exposure conditions. High inter-subject agreement is taken to operationally define a familiar configuration. This new stimulus set is well-suited to investigate questions concerning how parts and wholes are integrated and how high- and low-level brain areas interact in object detection. This set also allows tests of predictions regarding cross-border competition in figure assignment and assessments of individual differences. The displays, their image statistics, and normative data are available online (https://osf.io/j9kz2/).


Assuntos
Percepção de Forma/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Percepção Visual/fisiologia , Adulto , Encéfalo , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Estimulação Luminosa/métodos , Reconhecimento Psicológico , Lobo Temporal
11.
Nat Commun ; 11(1): 4014, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32782303

RESUMO

Perception reflects not only sensory inputs, but also the endogenous state when these inputs enter the brain. Prior studies show that endogenous neural states influence stimulus processing through non-specific, global mechanisms, such as spontaneous fluctuations of arousal. It is unclear if endogenous activity influences circuit and stimulus-specific processing and behavior as well. Here we use intracranial recordings from 30 pre-surgical epilepsy patients to show that patterns of endogenous activity are related to the strength of trial-by-trial neural tuning in different visual category-selective neural circuits. The same aspects of the endogenous activity that relate to tuning in a particular neural circuit also correlate to behavioral reaction times only for stimuli from the category that circuit is selective for. These results suggest that endogenous activity can modulate neural tuning and influence behavior in a circuit- and stimulus-specific manner, reflecting a potential mechanism by which endogenous neural states facilitate and bias perception.


Assuntos
Rede Nervosa/fisiologia , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Adulto , Eletrocorticografia , Epilepsia/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Neurológicos , Reconhecimento Visual de Modelos/fisiologia , Estimulação Luminosa , Tempo de Reação/fisiologia
12.
PLoS One ; 15(7): e0236416, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32735572

RESUMO

Proprioception acquires a crucial role in estimating the configuration of our body segments in space when visual information is not available. Proprioceptive accuracy is assessed by asking participants to match the perceived position of an unseen body landmark through reaching movements. This task was also adopted to study the perceived hand structure by computing the relative distances between averaged proprioceptive judgments (hand Localization Task). However, the pattern of proprioceptive errors leading to the misperceived hand structure is unexplored. Here, we aimed to characterize this pattern across different hand landmarks, having different anatomo-physiological properties and cortical representations. Furthermore, we sought to describe the error consistency and its stability over time. To this purpose, we analyzed the proprioceptive errors of 43 healthy participants during the hand Localization Task. We found larger but more consistent errors for the fingertips compared to the knuckles, possibly due to poorer proprioceptive signal, compensated by other sources of spatial information. Furthermore, we found a shift (overlap effect) and a temporal drift of the hand perceived position towards the shoulder of origin, which was consistent within and between subjects. The overlap effect had a greater influence on lateral compared to medial landmarks, leading to the hand width overestimation. Our results are compatible with domain-general and body-specific spatial biases affecting the proprioceptive localization of the hand landmarks, thus the apparent hand structure misperception.


Assuntos
Mãos/fisiologia , Movimento/fisiologia , Propriocepção/fisiologia , Desempenho Psicomotor/fisiologia , Adulto , Feminino , Dedos/fisiologia , Corpo Humano , Humanos , Julgamento , Aprendizagem/fisiologia , Masculino , Polegar/fisiologia , Percepção Visual/fisiologia , Adulto Jovem
13.
PLoS Comput Biol ; 16(8): e1008018, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32813688

RESUMO

Visually inferring material properties is crucial for many tasks, yet poses significant computational challenges for biological vision. Liquids and gels are particularly challenging due to their extreme variability and complex behaviour. We reasoned that measuring and modelling viscosity perception is a useful case study for identifying general principles of complex visual inferences. In recent years, artificial Deep Neural Networks (DNNs) have yielded breakthroughs in challenging real-world vision tasks. However, to model human vision, the emphasis lies not on best possible performance, but on mimicking the specific pattern of successes and errors humans make. We trained a DNN to estimate the viscosity of liquids using 100.000 simulations depicting liquids with sixteen different viscosities interacting in ten different scenes (stirring, pouring, splashing, etc). We find that a shallow feedforward network trained for only 30 epochs predicts mean observer performance better than most individual observers. This is the first successful image-computable model of human viscosity perception. Further training improved accuracy, but predicted human perception less well. We analysed the network's features using representational similarity analysis (RSA) and a range of image descriptors (e.g. optic flow, colour saturation, GIST). This revealed clusters of units sensitive to specific classes of feature. We also find a distinct population of units that are poorly explained by hand-engineered features, but which are particularly important both for physical viscosity estimation, and for the specific pattern of human responses. The final layers represent many distinct stimulus characteristics-not just viscosity, which the network was trained on. Retraining the fully-connected layer with a reduced number of units achieves practically identical performance, but results in representations focused on viscosity, suggesting that network capacity is a crucial parameter determining whether artificial or biological neural networks use distributed vs. localized representations.


Assuntos
Modelos Neurológicos , Redes Neurais de Computação , Viscosidade , Percepção Visual/fisiologia , Adulto , Biologia Computacional , Feminino , Humanos , Masculino , Adulto Jovem
14.
Nat Commun ; 11(1): 3341, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32620746

RESUMO

The oculomotor system keeps the eyes steady in expectation of visual events. Here, recording microsaccades while people performed a tactile, frequency discrimination task enabled us to test whether the oculomotor system shows an analogous preparatory response for unrelated tactile events. We manipulated the temporal predictability of tactile targets using tactile cues, which preceded the target by either constant (high predictability) or variable (low predictability) time intervals. We find that microsaccades are inhibited prior to tactile targets and more so for constant than variable intervals, revealing a tight crossmodal link between tactile temporal expectation and oculomotor action. These findings portray oculomotor freezing as a marker of crossmodal temporal expectation. Moreover, microsaccades occurring around the tactile target presentation are associated with reduced task performance, suggesting that oculomotor freezing mitigates potential detrimental, concomitant effects of microsaccades and revealing a crossmodal coupling between tactile perception and oculomotor action.


Assuntos
Movimentos Oculares/fisiologia , Desempenho Psicomotor/fisiologia , Percepção do Tempo/fisiologia , Percepção do Tato/fisiologia , Tato/fisiologia , Percepção Visual/fisiologia , Adulto , Sinais (Psicologia) , Feminino , Humanos , Masculino , Músculos Oculomotores/inervação , Músculos Oculomotores/fisiologia , Estimulação Luminosa , Tempo de Reação/fisiologia , Movimentos Sacádicos/fisiologia , Adulto Jovem
15.
Nat Commun ; 11(1): 3524, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32665559

RESUMO

Eye movements are inhibited prior to the onset of temporally-predictable visual targets. This oculomotor inhibition effect could be considered a marker for the formation of temporal expectations and the allocation of temporal attention in the visual domain. Here we show that eye movements are also inhibited before predictable auditory targets. In two experiments, we manipulate the period between a cue and an auditory target to be either predictable or unpredictable. The findings show that although there is no perceptual gain from avoiding gaze-shifts in this procedure, saccades and blinks are inhibited prior to predictable relative to unpredictable auditory targets. These findings show that oculomotor inhibition occurs prior to auditory targets. This link between auditory expectation and oculomotor behavior reveals a multimodal perception action coupling, which has a central role in temporal expectations.


Assuntos
Atenção/fisiologia , Movimentos Oculares/fisiologia , Músculos Oculomotores/fisiologia , Adulto , Análise de Variância , Feminino , Humanos , Tempo de Reação/fisiologia , Percepção Visual/fisiologia , Adulto Jovem
16.
PLoS One ; 15(7): e0235352, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32649694

RESUMO

Generative adversarial networks (GANs) have been used to obtain super-resolution (SR) videos that have improved visual perception quality and more coherent details. However, the latest methods perform poorly in areas with dense textures. To better recover the areas with dense textures in video frames and improve the visual perception quality and coherence in videos, this paper proposes a multiresolution mixture generative adversarial network for video super-resolution (MRMVSR). We propose a multiresolution mixture network (MRMNet) as the generative network that can simultaneously generate multiresolution feature maps. In MRMNet, the high-resolution (HR) feature maps can continuously extract information from low-resolution (LR) feature maps to supplement information. In addition, we propose a residual fluctuation loss function for video super-resolution. The residual fluctuation loss function is used to reduce the overall residual fluctuation on SR and HR video frames to avoid a scenario where local differences are too large. Experimental results on the public benchmark dataset show that our method outperforms the state-of-the-art methods for the majority of the test sets.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Gravação em Vídeo/métodos , Percepção Visual/fisiologia , Humanos , Redes Neurais de Computação , Gravação em Vídeo/tendências
17.
Proc Natl Acad Sci U S A ; 117(26): 15262-15269, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32541022

RESUMO

Thyroid hormone (TH) signaling plays an important role in the regulation of long-wavelength vision in vertebrates. In the retina, thyroid hormone receptor ß (thrb) is required for expression of long-wavelength-sensitive opsin (lws) in red cone photoreceptors, while in retinal pigment epithelium (RPE), TH regulates expression of a cytochrome P450 enzyme, cyp27c1, that converts vitamin A1 into vitamin A2 to produce a red-shifted chromophore. To better understand how TH controls these processes, we analyzed the phenotype of zebrafish with mutations in the three known TH nuclear receptor transcription factors (thraa, thrab, and thrb). We found that no single TH nuclear receptor is required for TH-mediated induction of cyp27c1 but that deletion of all three (thraa -/- ;thrab -/- ;thrb -/- ) completely abrogates its induction and the resulting conversion of A1- to A2-based retinoids. In the retina, loss of thrb resulted in an absence of red cones at both larval and adult stages without disruption of the underlying cone mosaic. RNA-sequencing analysis revealed significant down-regulation of only five genes in adult thrb -/- retina, of which three (lws1, lws2, and miR-726) occur in a single syntenic cluster. In the thrb -/- retina, retinal progenitors destined to become red cones were transfated into ultraviolet (UV) cones and horizontal cells. Taken together, our findings demonstrate cooperative regulation of cyp27c1 by TH receptors and a requirement for thrb in red cone fate determination. Thus, TH signaling coordinately regulates both spectral sensitivity and sensory plasticity.


Assuntos
Visão de Cores/fisiologia , Sistema Enzimático do Citocromo P-450/metabolismo , Opsinas/metabolismo , Receptores dos Hormônios Tireóideos/fisiologia , Percepção Visual/fisiologia , Proteínas de Peixe-Zebra/metabolismo , Animais , Visão de Cores/genética , Sistema Enzimático do Citocromo P-450/genética , Deleção de Genes , Regulação da Expressão Gênica , Opsinas/genética , Células Fotorreceptoras Retinianas Cones , Raios Ultravioleta , Peixe-Zebra , Proteínas de Peixe-Zebra/genética
18.
Proc Natl Acad Sci U S A ; 117(26): 14682-14687, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32546523

RESUMO

We predict and experimentally verify an entoptic phenomenon through which humans are able to perceive and discriminate optical spin-orbit states. Direct perception and discrimination of these particular states of light with polarization-coupled spatial modes is possible through the observation of distinct profiles induced by the interaction between polarization topologies and the radially symmetric dichroic elements that are centered on the foveola in the macula of the human eye. A psychophysical study was conducted where optical states with a superposition of right and left circular polarization coupled to two different orbital angular momentum (OAM) values ([Formula: see text] and [Formula: see text]) were directed onto the retina of participants. The number of azimuthal fringes that a human sees when viewing the spin-orbit states is shown to be equal to the number (N) of radial lines in the corresponding polarization profile of the beam, where [Formula: see text] The participants were able to correctly discriminate between two states carrying OAM [Formula: see text] and differentiated by [Formula: see text] and [Formula: see text], with an average success probability of 77.6% (average sensitivity [Formula: see text], [Formula: see text], [Formula: see text]). These results enable methods of robustly characterizing the structure of the macula, probing retina signaling pathways, and conducting experiments with human detectors and optical states with nonseparable modes.


Assuntos
Fenômenos Fisiológicos Oculares , Retina/fisiologia , Percepção Visual/fisiologia , Humanos , Luz , Estimulação Luminosa , Teoria Quântica
19.
Nat Commun ; 11(1): 3247, 2020 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-32591544

RESUMO

The brain derives cognitive maps from sensory experience that guide memory formation and behavior. Despite extensive efforts, it still remains unclear how the underlying population activity unfolds during spatial navigation and how it relates to memory performance. To examine these processes, we combined 7T-fMRI with a kernel-based encoding model of virtual navigation to map world-centered directional tuning across the human cortex. First, we present an in-depth analysis of directional tuning in visual, retrosplenial, parahippocampal and medial temporal cortices. Second, we show that tuning strength, width and topology of this directional code during memory-guided navigation depend on successful encoding of the environment. Finally, we show that participants' locomotory state influences this tuning in sensory and mnemonic regions such as the hippocampus. We demonstrate a direct link between neural population tuning and human cognition, where high-level memory processing interacts with network-wide visuospatial coding in the service of behavior.


Assuntos
Comportamento/fisiologia , Navegação Espacial/fisiologia , Percepção Visual/fisiologia , Adulto , Feminino , Humanos , Lógica , Masculino , Memória Espacial/fisiologia , Análise e Desempenho de Tarefas , Realidade Virtual , Adulto Jovem
20.
PLoS Comput Biol ; 16(6): e1007973, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32542056

RESUMO

A longstanding question in sensory neuroscience is what types of stimuli drive neurons to fire. The characterization of effective stimuli has traditionally been based on a combination of intuition, insights from previous studies, and luck. A new method termed XDream (EXtending DeepDream with real-time evolution for activation maximization) combined a generative neural network and a genetic algorithm in a closed loop to create strong stimuli for neurons in the macaque visual cortex. Here we extensively and systematically evaluate the performance of XDream. We use ConvNet units as in silico models of neurons, enabling experiments that would be prohibitive with biological neurons. We evaluated how the method compares to brute-force search, and how well the method generalizes to different neurons and processing stages. We also explored design and parameter choices. XDream can efficiently find preferred features for visual units without any prior knowledge about them. XDream extrapolates to different layers, architectures, and developmental regimes, performing better than brute-force search, and often better than exhaustive sampling of >1 million images. Furthermore, XDream is robust to choices of multiple image generators, optimization algorithms, and hyperparameters, suggesting that its performance is locally near-optimal. Lastly, we found no significant advantage to problem-specific parameter tuning. These results establish expectations and provide practical recommendations for using XDream to investigate neural coding in biological preparations. Overall, XDream is an efficient, general, and robust algorithm for uncovering neuronal tuning preferences using a vast and diverse stimulus space. XDream is implemented in Python, released under the MIT License, and works on Linux, Windows, and MacOS.


Assuntos
Neurônios/fisiologia , Estimulação Luminosa , Córtex Visual/fisiologia , Algoritmos , Animais , Redes Neurais de Computação , Percepção Visual/fisiologia
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