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1.
Atten Percept Psychophys ; 83(4): 1508-1517, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33751451

RESUMO

According to the behavioral urgency hypothesis, organisms have evolved various mechanisms that facilitate their survival by focusing attention and resources on approaching danger. One example of such mechanisms is the looming bias-the tendency for an individual to judge an approaching object's distance as being closer or time-to-collision as being sooner than receding or stationary objects. To date, most research on the looming bias has explored the ways in which human factors and object characteristics influence the strength and direction of the bias. The current study expanded on this field of research in two novels ways by exploring (a) whether cognitive vulnerabilities may influence the strength of the looming bias in the visual domain, and (b) whether the combination of human factors (i.e., cognitive load) and object characteristics (i.e., object threat) interact to create an additive effect on looming bias strength. Findings appear to only partially support the hypotheses that cognitive vulnerabilities can influence looming bias strength in the visual domain, and that factors related to both the individual and the looming object may interact to create a stronger looming bias. These findings help to highlight possible evolutionary advantages of the looming bias and its presence across modalities, as well as add some strength to the claims that the margin of safety theory can be generalized to include psychological factors.


Assuntos
Percepção Auditiva , Percepção de Movimento , Cognição , Humanos
2.
J Physiol ; 599(8): 2239-2254, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33599981

RESUMO

KEY POINTS: Sensory systems are adapted to the statistical structure of natural stimuli, thereby optimizing neural coding. Head motion during natural activities is first sensed and then processed by central vestibulo-motor pathways to influence subsequent behaviour, thereby establishing a feedback loop. To investigate the role of this vestibular feedback on the statistical structure of the head movements, we compared head movements in patients with unilateral vestibular loss and healthy controls. We show that the loss of vestibular feedback substantially alters the statistical structure of head motion for activities that require rapid online feedback control and predict this change by modelling the effects of increased movement variability. Our findings suggest that, following peripheral vestibular loss, changes in the reliability of the sensory input to central pathways impact the statistical structure of head motion during voluntary behaviours. ABSTRACT: It is widely believed that sensory systems are adapted to optimize neural coding of their natural stimuli. Recent evidence suggests that this is the case for the vestibular system, which senses head movement and contributes to essential functions ranging from the most automatic reflexes to voluntary motor control. During everyday behaviours, head motion is sensed by the vestibular system. In turn, this sensory feedback influences subsequent behaviour, raising the questions of whether and how real-time feedback provided by the vestibular system alters the statistical structure of head movements. We predicted that a reduction in vestibular feedback would alter head movement statistics, particularly for tasks reliant on rapid vestibular feedback. To test this proposal, we recorded six-dimensional head motion in patients with variable degrees of unilateral vestibular loss during standard balance and gait tasks, as well as dynamic self-paced activities. While distributions of linear accelerations and rotational velocities were comparable for patients and age-matched healthy controls, comparison of power spectra revealed significant differences during more dynamic and challenging activities. Specifically, consistent with our prediction, head movement power spectra were significantly altered in patients during two tasks that required rapid online vestibular feedback: active repetitive jumping and walking on foam. Using computational methods, we analysed concurrently measured torso motion and identified increases in head-torso movement variability. Taken together, our results demonstrate that vestibular loss significantly alters head movement statistics and further suggest that increased variability and impaired feedback to internal models required for accurate motor control contribute to the observed changes.


Assuntos
Percepção de Movimento , Vestíbulo do Labirinto , Movimentos da Cabeça , Humanos , Movimento (Física) , Movimento , Reprodutibilidade dos Testes
3.
Atten Percept Psychophys ; 83(4): 1752-1765, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33629261

RESUMO

Flow parsing is a way to estimate the direction of scene-relative motion of independently moving objects during self-motion of the observer. So far, this has been tested for simple geometric shapes such as dots or bars. Whether further cues such as prior knowledge about typical directions of an object's movement, e.g., typical human motion, are considered in the estimations is currently unclear. Here, we adjudicated between the theory that the direction of scene-relative motion of humans is estimated exclusively by flow parsing, just like for simple geometric objects, and the theory that prior knowledge about biological motion affects estimation of perceived direction of scene-relative motion of humans. We placed a human point-light walker in optic flow fields that simulated forward motion of the observer. We introduced conflicts between biological features of the walker (i.e., facing and articulation) and the direction of scene-relative motion. We investigated whether perceived direction of scene-relative motion was biased towards biological features and compared the results to perceived direction of scene-relative motion of scrambled walkers and dot clouds. We found that for humans the perceived direction of scene-relative motion was biased towards biological features. Additionally, we found larger flow parsing gain for humans compared to the other walker types. This indicates that flow parsing is not the only visual mechanism relevant for estimating the direction of scene-relative motion of independently moving objects during self-motion: observers also rely on prior knowledge about typical object motion, such as typical facing and articulation of humans.


Assuntos
Percepção de Movimento , Fluxo Óptico , Humanos , Movimento (Física) , Movimento , Estimulação Luminosa
4.
Acta Psychol (Amst) ; 215: 103277, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33640594

RESUMO

When observing point light walkers orthographically projected onto a frontoparallel plane, the direction in which they are walking is ambiguous. Nevertheless, observers more often perceive them as facing towards than as facing away from them. This phenomenon is known as the "facing-the-viewer bias" (FTV). Two interpretations of the facing-the-viewer bias exist in the literature: a top-down and a bottom-up interpretation. Support for the top-down interpretation comes from evidence that social anxiety correlates with the FTV bias. However, the direction of the relationship between the FTV bias and social anxiety is inconsistent across studies and evidence for a correlation has mostly been obtained with relatively small samples. Therefore, the first aim of the current study was to provide a strong test of the hypothesized relationship between social anxiety and the facing-the-viewer bias in a large sample of 200 participants recruited online. In addition, a second aim was to further extend top-down accounts by investigating if the FTV bias is also related to autistic traits. Our results replicate the FTV bias, showing that people indeed tend to perceive orthographically projected point light walkers as facing towards them. However, no correlation between the FTV bias and social interaction anxiety (tau = -0.01, p = .86, BF = 0.18) or autistic traits (tau = -0.0039, p = .45, BF = 0.18) was found. As such, our data cannot confirm the top-down interpretation of the facing-the-viewer bias.


Assuntos
Percepção de Movimento , Ansiedade , Transtornos de Ansiedade , Humanos , Percepção Social , Caminhada
5.
Nat Commun ; 12(1): 360, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33452252

RESUMO

Endogenous attention is the cognitive function that selects the relevant pieces of sensory information to achieve goals and it is known to be controlled by dorsal fronto-parietal brain areas. Here we expand this notion by identifying a control attention area located in the temporal lobe. By combining a demanding behavioral paradigm with functional neuroimaging and diffusion tractography, we show that like fronto-parietal attentional areas, the human posterior inferotemporal cortex exhibits significant attentional modulatory activity. This area is functionally distinct from surrounding cortical areas, and is directly connected to parietal and frontal attentional regions. These results show that attentional control spans three cortical lobes and overarches large distances through fiber pathways that run orthogonally to the dominant anterior-posterior axes of sensory processing, thus suggesting a different organizing principle for cognitive control.


Assuntos
Atenção/fisiologia , Lobo Frontal/fisiologia , Lobo Parietal/fisiologia , Lobo Temporal/fisiologia , Adulto , Mapeamento Encefálico , Imagem de Tensor de Difusão , Feminino , Lobo Frontal/diagnóstico por imagem , Voluntários Saudáveis , Humanos , Masculino , Percepção de Movimento/fisiologia , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiologia , Lobo Parietal/diagnóstico por imagem , Estimulação Luminosa/métodos , Lobo Temporal/diagnóstico por imagem , Adulto Jovem
6.
Phys Rev Lett ; 126(1): 018101, 2021 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-33480762

RESUMO

Many organisms use visual signals to estimate motion, and these estimates typically are biased. Here, we ask whether these biases may reflect physical rather than biological limitations. Using a camera-gyroscope system, we sample the joint distribution of images and rotational motions in a natural environment, and from this distribution we construct the optimal estimator of velocity based on local image intensities. Over most of the natural dynamic range, this estimator exhibits the biases observed in neural and behavioral responses. Thus, imputed errors in sensory processing may represent an optimal response to the physical signals sampled from the environment.


Assuntos
Modelos Biológicos , Percepção de Movimento/fisiologia , Animais , Meio Ambiente , Fotografação
7.
Atten Percept Psychophys ; 83(3): 1263-1274, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33409901

RESUMO

Multiple-object tracking studies consistently reveal attentive tracking limits of approximately three to five items. How do factors such as visual grouping and ensemble perception impact these capacity limits? Which heuristics lead to the perception of multiple objects as a group? This work investigates the role of grouping on multiple-object tracking ability, and more specifically, in identifying the heuristics that lead to the formation and perception of ensembles within dynamic contexts. First, we show that group tracking limits are approximately four groups of objects and are independent of the number of items that compose the groups. Further, we show that group tracking performance declines as inter-object spacing increases. We also demonstrate the role of group rigidity in tracking performance in that disruptions to common fate negatively impact ensemble tracking ability. The findings from this work contribute to our overall understanding of the perception of dynamic groups of objects. They characterize the properties that determine the formation and perception of dynamic object ensembles. In addition, they inform development and design decisions considering cognitive limitations involving tracking groups of objects.


Assuntos
Atenção , Percepção de Movimento , Humanos , Percepção , Percepção Espacial , Percepção Visual
8.
PLoS One ; 16(1): e0243381, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33406125

RESUMO

Human perception is based on expectations. We expect visual upright and gravity upright, sensed through vision, vestibular and other sensory systems, to agree. Equally, we expect that visual and vestibular information about self-motion will correspond. What happens when these assumptions are violated? Tilting a person from upright so that gravity is not where it should be impacts both visually induced self-motion (vection) and the perception of upright. How might the two be connected? Using virtual reality, we varied the strength of visual orientation cues, and hence the probability of participants experiencing a visual reorientation illusion (VRI) in which visual cues to orientation dominate gravity, using an oriented corridor and a starfield while also varying head-on-trunk orientation and body posture. The effectiveness of the optic flow in simulating self-motion was assessed by how much visual motion was required to evoke the perception that the participant had reached the position of a previously presented target. VRI was assessed by questionnaire When participants reported higher levels of VRI they also required less visual motion to evoke the sense of traveling through a given distance, regardless of head or body posture, or the type of visual environment. We conclude that experiencing a VRI, in which visual-vestibular conflict is resolved and the direction of upright is reinterpreted, affects the effectiveness of optic flow at simulating motion through the environment. Therefore, any apparent effect of head or body posture or type of environment are largely indirect effects related instead, to the level of VRI experienced by the observer. We discuss potential mechanisms for this such as reinterpreting gravity information or altering the weighting of orientation cues.


Assuntos
Ego , Gravitação , Percepção de Movimento/fisiologia , Orientação Espacial , Percepção Visual/fisiologia , Adulto , Feminino , Mãos/fisiologia , Humanos , Masculino , Postura/fisiologia
9.
Percept Mot Skills ; 128(2): 585-604, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33423612

RESUMO

The perception of time is not veridical, but, rather, it is susceptible to environmental context, like the intrinsic dynamics of moving stimuli. The direction of motion has been reported to affect time perception such that movement of objects toward an observer (i.e., looming stimuli) is perceived as longer in duration than movement of objects away from the observer (i.e., receding stimuli). In the current study we investigated whether this looming/receding temporal asymmetry can be modulated by the direction of movement implied by static cues of images. Participants were presented with images of a running person, rendered from either the front or the back (i.e., representing movement toward or away from the observer). In Experiment 1, the size of the images was constant. In Experiment 2, the image sizes varied (i.e., increasing: looming; or decreasing: receding). In both experiments, participants performed a temporal bisection task by judging the duration of the image presentation as "short" or "long". In Experiment 1, we found no influence of implied-motion direction in the participants' duration perceptions. In Experiment 2, however, participants overestimated the duration of the looming, as compared to the receding image in relation to real motion. This finding replicated previous findings of the looming/receding asymmetry using naturalistic human-character stimuli. Further, in Experiment 2 we observed a directional congruency effect between real and implied motion; stimuli were perceived as lasting longer when the directions of real and implied motion were congruent versus when these directions were incongruent. Thus, looming (versus receding) movement, a perceptually salient stimulus, elicits differential temporal processing, and higher-order motion processing integrates signals of real and implied motion in time perception.


Assuntos
Percepção de Movimento , Percepção do Tempo , Percepção Auditiva , Sinais (Psicologia) , Humanos , Movimento (Física) , Estimulação Luminosa
10.
Proc Biol Sci ; 288(1942): 20202823, 2021 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-33434457

RESUMO

The motion dazzle hypothesis posits that high contrast geometric patterns can cause difficulties in tracking a moving target and has been argued to explain the patterning of animals such as zebras. Research to date has only tested a small number of patterns, offering equivocal support for the hypothesis. Here, we take a genetic programming approach to allow patterns to evolve based on their fitness (time taken to capture) and thus find the optimal strategy for providing protection when moving. Our 'Dazzle Bug' citizen science game tested over 1.5 million targets in a touch screen game at a popular visitor attraction. Surprisingly, we found that targets lost pattern elements during evolution and became closely background matching. Modelling results suggested that targets with lower motion energy were harder to catch. Our results indicate that low contrast, featureless targets offer the greatest protection against capture when in motion, challenging the motion dazzle hypothesis.


Assuntos
Ciência do Cidadão , Percepção de Movimento , Animais , Movimento (Física) , Movimento
11.
Neuroimage ; 228: 117688, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33385563

RESUMO

There is growing research interest in the neural mechanisms underlying the recognition of material categories and properties. This research field, however, is relatively more recent and limited compared to investigations of the neural mechanisms underlying object and scene category recognition. Motion is particularly important for the perception of non-rigid materials, but the neural basis of non-rigid material motion remains unexplored. Using fMRI, we investigated which brain regions respond preferentially to material motion versus other types of motion. We introduce a new database of stimuli - dynamic dot materials - that are animations of moving dots that induce vivid percepts of various materials in motion, e.g. flapping cloth, liquid waves, wobbling jelly. Control stimuli were scrambled versions of these same animations and rigid three-dimensional rotating dots. Results showed that isolating material motion properties with dynamic dots (in contrast with other kinds of motion) activates a network of cortical regions in both ventral and dorsal visual pathways, including areas normally associated with the processing of surface properties and shape, and extending to somatosensory and premotor cortices. We suggest that such a widespread preference for material motion is due to strong associations between stimulus properties. For example viewing dots moving in a specific pattern not only elicits percepts of material motion; one perceives a flexible, non-rigid shape, identifies the object as a cloth flapping in the wind, infers the object's weight under gravity, and anticipates how it would feel to reach out and touch the material. These results are a first important step in mapping out the cortical architecture and dynamics in material-related motion processing.


Assuntos
Encéfalo/fisiologia , Percepção de Movimento/fisiologia , Adulto , Mapeamento Encefálico/métodos , Feminino , Percepção de Forma/fisiologia , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Estimulação Luminosa , Adulto Jovem
12.
Neural Netw ; 136: 180-193, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33494035

RESUMO

Efficient and robust motion perception systems are important pre-requisites for achieving visually guided flights in future micro air vehicles. As a source of inspiration, the visual neural networks of flying insects such as honeybee and Drosophila provide ideal examples on which to base artificial motion perception models. In this paper, we have used this approach to develop a novel method that solves the fundamental problem of estimating angular velocity for visually guided flights. Compared with previous models, our elementary motion detector (EMD) based model uses a separate texture estimation pathway to effectively decode angular velocity, and demonstrates considerable independence from the spatial frequency and contrast of the gratings. Using the Unity development platform the model is further tested for tunnel centering and terrain following paradigms in order to reproduce the visually guided flight behaviors of honeybees. In a series of controlled trials, the virtual bee utilizes the proposed angular velocity control schemes to accurately navigate through a patterned tunnel, maintaining a suitable distance from the undulating textured terrain. The results are consistent with both neuron spike recordings and behavioral path recordings of real honeybees, thereby demonstrating the model's potential for implementation in micro air vehicles which have only visual sensors.


Assuntos
Voo Animal/fisiologia , Percepção de Movimento/fisiologia , Redes Neurais de Computação , Realidade Virtual , Vias Visuais/fisiologia , Animais , Abelhas , Insetos , Neurônios/fisiologia
13.
Atten Percept Psychophys ; 83(4): 1479-1490, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33398657

RESUMO

We used a form of ambiguous apparent motion known as Ternus motion to isolate the effects of object-based and space-based attention, and to explore functional differences between them. Two frames of horizontally aligned disks that were shifted by one position between frames were temporally separated by either a short or a long inter-stimulus interval (ISI). Short ISI displays were perceived as element motion where one disk appeared to jump across the other two. Long ISI displays were perceived as group motion where all three disks appeared to move together. Because element and group motion imply mutually exclusive object structures, adding stimuli (e.g., a small gap) to one disk in each frame created conditions of orthogonal object and location status (same or different), depending on ISI. We used two tasks with different functional demands, an identification task (Experiments 1 and 3a) in which observers responded to a single attribute of the final stimulus, and a comparison task (Experiments 2 and 3b) in which observers compared two attributes across two stimuli. Reliable object-specific effects occurred only with the comparison task, whereas location-specific effects occurred with both tasks. These results confirm that attention can be directed to objects separately from spatial locations and vice versa, and, moreover, that object-based and space-based attention are engaged differently depending on the processing demands of the task.


Assuntos
Percepção de Movimento , Atenção , Humanos , Movimento (Física) , Percepção Espacial
14.
Atten Percept Psychophys ; 83(4): 1455-1462, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33400220

RESUMO

Illusions can induce striking differences between perception and retinal input. For instance, a static Gabor with a moving internal texture appears to be shifted in the direction of its internal motion, a shift that increases dramatically when the Gabor itself is also in motion. Here, we ask whether attention operates on the perceptual or physical location of this stimulus. To do so, we generated an attentional tracking task where participants (N = 15) had to keep track of a single target among three Gabors that rotated around a common center in the periphery. During tracking, the illusion was used to make three Gabors appear either shifted away from or toward one another while maintaining the same physical separation. Because tracking performance depends in part on target to distractor spacing, if attention selects targets from perceived positions, performance should be better when the Gabors appear further apart and worse when they appear closer together. We find that tracking performance is superior with greater perceived separation, implying that attentional tracking operates over perceived rather than physical positions.


Assuntos
Ilusões , Percepção de Movimento , Atenção , Humanos , Estimulação Luminosa
15.
Atten Percept Psychophys ; 83(4): 1804-1817, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33409903

RESUMO

Vection is a perceptual phenomenon that describes the visually induced subjective sensation of self-motion in the absence of physical motion. Previous research has discussed the potential involvement of top-down cognitive mechanisms on vection. Here, we quantified how cognitive manipulations such as contextual information (i.e., expectation) and plausibility (i.e., chair configuration) alter vection. We also explored how individual traits such as field dependence, depersonalization, anxiety, and social desirability might be related to vection. Fifty-one healthy adults were exposed to an optic flow stimulus that consisted of horizontally moving black-and-white bars presented on three adjacent monitors to generate circular vection. Participants were divided into three groups and given experimental instructions designed to induce either strong, weak, or no expectation with regard to the intensity of vection. In addition, the configuration of the chair (rotatable or fixed) was modified during the experiment. Vection onset time, duration, and intensity were recorded. Results showed that expectation altered vection intensity, but only when the chair was in the rotatable configuration. Positive correlations for vection measures with field dependence and depersonalization, but no sex-related effects were found. Our results show that vection can be altered by cognitive factors and that individual traits can affect the perception of vection, suggesting that vection is not a purely perceptual phenomenon, but can also be affected by top-down mechanisms.


Assuntos
Ilusões , Percepção de Movimento , Adulto , Cognição , Humanos , Movimento (Física) , Personalidade
16.
Neural Netw ; 135: 13-28, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33338802

RESUMO

The biological visual system includes multiple types of motion sensitive neurons which preferentially respond to specific perceptual regions. However, it still keeps open how to borrow such neurons to construct bio-inspired computational models for multiple-regional collision detection. To fill this gap, this work proposes a visual joint perception neural network with two subnetworks - presynaptic and postsynaptic neural networks, inspired by the preferentialperception characteristics of three horizontal and vertical motion sensitive neurons. Related to the neural network and three hazard detection mechanisms, an artificial fly visual synthesized collision detection model for multiple-regional collision detection is originally developed to monitor possible danger occurrence in the case where one or more moving objects appear in the whole field of view. The experiments can clearly draw two conclusions: (i) the acquired neural network can effectively display the characteristics of visual movement, and (ii) the collision detection model, which outperforms the compared models, can effectively perform multiple-regional collision detection at a high success rate, and only takes about 0.24s to complete the process of collision detection for each virtual or actual image frame with resolution 110×60.


Assuntos
Inteligência Artificial , Percepção de Movimento/fisiologia , Movimento/fisiologia , Redes Neurais de Computação , Estimulação Luminosa/métodos , Vias Visuais/fisiologia , Animais , Inteligência Artificial/tendências , Dípteros , Humanos , Neurônios/fisiologia , Percepção Visual/fisiologia
17.
Rev. int. med. cienc. act. fis. deporte ; 20(80): 577-594, dic. 2020. tab
Artigo em Espanhol | IBECS | ID: ibc-198574

RESUMO

El objetivo del presente estudio fue analizar las diferencias en el número y tipo de acciones técnico-tácticas de los porteros en competición en función de la división y de si juegan como local o visitante. Para ello, se han analizado 80 partidos con un total de 160 porteros de 1ª, 2ª, 2ªB y 3ª división española. Los resultados mostraron que no existen diferencias significativas entre el número de acciones medias realizadas por partido en cada división, pero sí se encontraron diferencias significativas en 9 de los 48 gestos técnico-tácticos específicos estudiados. Además, se encontraron pequeñas diferencias en cuanto al número de acciones en función de si los porteros juegan como local o visitante. Por tanto, la principal conclusión de este estudio es la importancia de analizar los tipos de acciones técnico-tácticas de los porteros ya que nos pueden ofrecer información relevante para el entrenamiento y la competición


The present study tries to respond about three different objectives: a) to quantify the number of technical-tactical actions carried out by goalkeepers during matches and to analyze if there are differences between divisions, b) to examine the possible differences in the number and type of technical-tactical actions between divisions under investigation, and c) to analyze the differences between this number and the type of technical-tactical actions when goalkeepers play at home team or away teams . To this end, a viewing was made of the 80 matches of the four most important divisions of Spanish football and a total of 160 goalkeepers were analyzed using the observational methodology. After the application of the tests the H-test of Krustal-Wallis and U of Mann-Whitney, showed no significant differences between the number of average actions performed per game in each division. Only significant differences were found in 9 of the 48 specific technical-tactical gestures studied. So, the first conclusion in this study is the importance of analyzing the types of technical-tactical actions of goalkeepers, due to they can offer relevant information for training and competition


Assuntos
Humanos , Masculino , Adulto , Futebol/fisiologia , Futebol/psicologia , Percepção de Movimento/fisiologia , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Percepção Visual , Esportes/psicologia
18.
PLoS One ; 15(12): e0243430, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33315877

RESUMO

A large number of psychophysical and neurophysiological studies have demonstrated that smooth pursuit eye movements are tightly related to visual motion perception. This could be due to the fact that visual motion sensitive cortical areas such as meddle temporal (MT), medial superior temporal (MST) areas are involved in motion perception as well as pursuit initiation. Although the directional-discrimination and perceived target velocity tasks are used to evaluate visual motion perception, it is still uncertain whether the speed of visual motion perception, which is determined by visuomotor reaction time (RT) to a small target, is related to pursuit initiation. Therefore, we attempted to determine the relationship between pursuit latency/acceleration and the visual motion RT which was measured to the visual motion stimuli that moved leftward or rightward. The participants were instructed to fixate on a stationary target and press one of the buttons corresponding to the direction of target motion as soon as possible once the target starts to move. We applied five different visual motion stimuli including first- and second-order motion for smooth pursuit and visual motion RT tasks. It is well known that second-order motion induces lower retinal image motion, which elicits weaker responses in MT and MST compared to first-order motion stimuli. Our results showed that pursuit initiation including latency and initial eye acceleration were suppressed by second-order motion. In addition, second-order motion caused a delay in visual motion RT. The better performances in both pursuit initiation and visual motion RT were observed for first-order motion, whereas second-order (theta motion) induced remarkable deficits in both variables. Furthermore, significant Pearson's correlation and within-subjects correlation coefficients were obtained between visual motion RT and pursuit latency/acceleration. Our findings support the suggestion that there is a common neuronal pathway involved in both pursuit initiation and the speed of visual motion perception.


Assuntos
Movimentos Oculares/fisiologia , Neurônios/fisiologia , Acompanhamento Ocular Uniforme/fisiologia , Córtex Visual/fisiologia , Adulto , Animais , Feminino , Humanos , Macaca mulatta/fisiologia , Masculino , Percepção de Movimento/fisiologia , Estimulação Luminosa , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Lobo Temporal/fisiologia , Percepção Visual/fisiologia , Adulto Jovem
19.
PLoS One ; 15(12): e0244110, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33332442

RESUMO

Recently, Flavell et al. (2019) demonstrated that an object's motion fluency (how smoothly and predictably it moves) influences liking of the object itself. Though the authors demonstrated learning of object-motion associations, participants only preferred fluently associated objects over disfluently associated objects when ratings followed a moving presentation but not a stationary presentation. In the presented experiment, we tested the possibility that this apparent failure of associative learning / evaluative conditioning was due to stimulus choice. To do so we replicate part of the original work but change the 'naturally stationary' household object stimuli with winged insects which move in a similar way to the original motions. Though these more ecologically valid stimuli should have facilitated object to motion associations, we again found that preference effects were only apparent following moving presentations. These results confirm the potential of motion fluency for 'in the moment' preference change, and they demonstrate a critical boundary condition that should be considered when attempting to generalise fluency effects across contexts such as in advertising or behavioural interventions.


Assuntos
Atenção/fisiologia , Comportamento de Escolha/fisiologia , Aprendizagem/fisiologia , Percepção de Movimento/fisiologia , Feminino , Humanos , Masculino
20.
Proc Natl Acad Sci U S A ; 117(52): 33161-33169, 2020 12 29.
Artigo em Inglês | MEDLINE | ID: mdl-33328275

RESUMO

There is considerable support for the hypothesis that perception of heading in the presence of rotation is mediated by instantaneous optic flow. This hypothesis, however, has never been tested. We introduce a method, termed "nonvarying phase motion," for generating a stimulus that conveys a single instantaneous optic flow field, even though the stimulus is presented for an extended period of time. In this experiment, observers viewed stimulus videos and performed a forced-choice heading discrimination task. For nonvarying phase motion, observers made large errors in heading judgments. This suggests that instantaneous optic flow is insufficient for heading perception in the presence of rotation. These errors were mostly eliminated when the velocity of phase motion was varied over time to convey the evolving sequence of optic flow fields corresponding to a particular heading. This demonstrates that heading perception in the presence of rotation relies on the time-varying evolution of optic flow. We hypothesize that the visual system accurately computes heading, despite rotation, based on optic acceleration, the temporal derivative of optic flow.


Assuntos
Percepção de Movimento , Fluxo Óptico , Aceleração , Adulto , Discriminação Psicológica , Feminino , Humanos , Masculino , Rotação , Tempo
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