Here, we describe a motion stimulus in which the quality of rotation is fractal. This makes its motion unavailable to the translation-based motion analysis known to underlie much of our motion perception. In contrast, normal rotation can be extracted through the aggregation of the outputs of translational mechanisms. Neural adaptation ...

The superior temporal sulcus (STS) and surrounding lateral temporal and inferior parietal cortices are an important part of a network involved in the processing of biological movement. It is unclear whether the STS responds to the movement of different body parts uniformly, or if the response depends on the body ...

Coherent global motion is a compelling illusion of visual motion that is seen as the result of spatially and successively presented stimuli that are, in fact, stationary. In the present study the threshold perception of global coherent motion was measured using random-dot kinematograms in a group of normal observers and ...

In order to study the temporal activation course of visual areas V1 and V5 in response to a motion stimulus, a random dots kinematogram paradigm was applied to eight subjects while magnetic fields were recorded using magnetoencephalography (MEG). Sources generating the registered magnetic fields were localized with Magnetic Field Tomography ...

We report on a computational model of retinal motion sensitivity based on correlation-based motion detectors. We simulate object motion detection in the presence of retinal slip caused by the salamander's head movements during locomotion. Our study offers new insights into object motion sensitive ganglion cells in the salamander retina. A ...

Three studies investigated the importance of movement for the recognition of subtle and intense expressions of emotion. In the first experiment, 36 facial emotion displays were duplicated in three conditions either upright or inverted in orientation. A dynamic condition addressed the perception of motion by using four still frames run ...

Optic flow-large-field rotational and radial motion-is processed as efficiently as translational motion for first-order (luminance-defined) stimuli. However, it has been suggested recently that the same pattern does not hold for second-order (e.g. contrast-defined) stimuli. We used random dot kinematogram (RDK) stimuli to determine whether global processing of optic flow is ...

Our understanding of how the visual system processes motion transparency, the phenomenon by which multiple directions of motion are perceived to coexist in the same spatial region, has grown considerably in the past decade. There is compelling evidence that the process is driven by global-motion mechanisms. Consequently, although transparently moving ...

While several previous psychophysical and neurophysiological studies have demonstrated chromatic (red/green) input to motion processing, the nature of this input is still a matter of debate. In particular, there exists controversy as to whether chromatic motion processing is mediated by low-level motion mechanisms versus higher-level, attention- or salience-based mechanisms. To ...

This study investigates four key issues concerning the binocular properties of the mechanisms that encode global motion in human vision: (1) the extent of any binocular advantage; (2) the possible site of this binocular summation; (3) whether or not purely monocular inputs exist for global motion perception; (4) the extent ...

Previous research has shown that it is easier to recognize familiar faces when shown moving, rather than static, especially when viewing conditions are difficult (Knight & Johnston, 1997; Lander, Christie, & Bruce, 1999). One possible theoretical reason for the moving-face advantage is that we learn "characteristic motion signatures" for familiar ...

Visual motion contains a wealth of information about self-motion as well as the three-dimensional structure of the environment. Therefore, it is of utmost importance for any organism with eyes. However, visual motion information is not explicitly represented at the photoreceptor level, but rather has to be computed by the nervous ...

Despite evidence for the broad direction tuning of global-motion detectors, transparent motion can be detected with comparatively small angular separations. The exact means by which this broad population response is decoded to yield multiple signal directions remains unclear. Consequently, we sought to determine the relationship between angular separation thresholds for ...

The low-level deficits associated with amblyopia have been studied extensively, but very little is known about potential impairments to higher-level visual processing such as object recognition or structure-from-motion. Studies on biological motion, a complex form of structure-from-motion depicting human actions, have demonstrated that normal observers can analyze these patterns more ...

Computationally, audio-visual temporal synchrony detection is analogous to visual motion detection in the sense that both solve the correspondence problem. We examined whether audio-visual synchrony detection is mediated by a mechanism similar to low-level motion sensors, by one similar to a higher-level feature matching process, or by both types of ...

The existence of a specialized human cortical area for the processing of auditory motion is still a matter of debate. Initial functional imaging studies identified the planum temporale as being motion selective. Recent data contrasting spatially varying stationary stimuli with moving stimuli found no difference in the amount of activation ...

We investigated the characteristics of mechanisms mediating motion discrimination of S-cone isolating stimuli and found a double dissociation between the effects of luminance noise, which masks linear but not non-linear motion, and chromatic noise, which masks non-linear but not linear motion. We conclude that S-cones contribute to motion via two ...

Older adults consistently show slower reaction times (RTs) to the onset of motion. Both cognitive slowing and motor slowing have been suggested as causes of this effect. The lateralized readiness potential (LRP) of the electroencephalogram can be used to separate perceptual and decision processes from motor programming and execution as ...

Motion is defined as a sequence of positional changes over time. However, in perception, spatial position and motion dynamically interact with each other. This reciprocal interaction suggests that the perception of a moving object itself may dynamically evolve following the onset of motion. Here, we show evidence that the percept ...

Several different directional anisotropies have been found in global motion perception. The purpose of this study was to examine the role of the motion sensitive cortical area V5/MT+ in directional anisotropies for translational flow fields. Experiments 1 and 2 tested direction discrimination and detection of moving random dot patterns. When ...

Stimulus localization affects visual motion processing. Vertical asymmetries favouring lower visual field have been reported in event-related potentials (ERPs) and behavioural studies under different attention conditions. However, there are no studies examining such asymmetries to non-attended motion changes. The present study investigated whether the asymmetry in processing information from the ...

Visual information is crucial for goal-directed reaching. A number of studies have recently shown that motion in particular is an important source of information for the visuomotor system. For example, when reaching a stationary object, movement of the background can influence the trajectory of the hand, even when the background ...

After prolonged viewing of a slowly drifting or rotating pattern under strict fixation, the pattern appears to slow down and then momentarily stop. The authors show that grouping can slow down the process of "motion fading," suggesting that cortical configural form analysis interacts with the computation of motion signals during ...

A number of studies were conducted to determine whether motion-streaks assist motion extraction, and whether a purely motion-based model could account for any observed facilitation. A 3-frame global-motion stimulus was used. Signal dots were manipulated in order to control the strength of the motion-streak. In the long-streak condition, the same ...

Direction-selective neurons in primary visual cortex have small receptive fields that encode the motions of local features. These motions often differ from the motion of the object to which they belong and must therefore be integrated elsewhere. A candidate site for this integration is visual cortical area MT (V5), in ...

Several functional areas are proposed to reside in human lateral occipitotemporal cortex, including the motion-selective human homolog of macaque area MT (hMT), object-form-selective lateral occipital complex (LO), and body-selective extrastriate body area (EBA). Indeed, several functional magnetic resonance imaging (fMRI) studies have reported significant activation overlap among these regions. The ...

There is a growing body of knowledge about the behavioral and neural correlates of cross-modal interactions in the perception of motion direction, as well as about the computations that underlie unimodal visual speed processing. Yet, the multisensory contributions to the perception of motion speed remain largely uncharted. Here we show ...

Neural systems face the challenge of optimizing their performance with limited resources, just as economic systems do. Here, we use tools of neoclassical economic theory to explore how a frugal visual system should use a limited number of neurons to optimize perception of motion. The theory prescribes that vision should ...

Recent evidence indicates that motion smear can provide useful information for the detection and discrimination of motion. Further, it has been shown that the perception of motion smear depends critically on the density of dots in a random-dot (RD) stimulus. Therefore, in the present experiments, the contribution of perceived motion ...

The quality of the representation of an object's motion is limited by the noise in the sensory input as well as by an intrinsic ambiguity due to the spatial limitation of the visual motion analyzers (aperture problem). Perceptual and oculomotor data demonstrate that motion processing of extended objects is initially ...

One of the most important aspects of visual attention is its flexibility; our attentional "window" can be tuned to different spatial scales, allowing us to perceive large-scale global patterns and local features effortlessly. We investigated whether the perception of global and local motion competes for a common attentional resource. Subjects ...

The machinery behind the visual perception of motion and the subsequent sensori-motor transformation, such as in ocular following response (OFR), is confronted to uncertainties which are efficiently resolved in the primate's visual system. We may understand this response as an ideal observer in a probabilistic framework by using Bayesian theory ...

How do visual form and motion processes cooperate to compute object motion when each process separately is insufficient? Consider, for example, a deer moving behind a bush. Here the partially occluded fragments of motion signals available to an observer must be coherently grouped into the motion of a single object. ...

Early 20th century artists including Duchamp and Balla tried to portray moving objects on a static canvas by superimposing objects in successive portrayals of an action. We investigated whether implied motion in those paintings is associated with activation of motion-sensitive area MT+. In Experiment 1, we found that observers rated ...

There is common consensus now that color-defined motion can be perceived by the human visual system. For global motion integration tasks based on isoluminant random dot kinematograms conflicting evidence exists, whether observers can (Ruppertsberg et al., 2003) or cannot (Bilodeau & Faubert, 1999) extract a common motion direction for stimuli ...

Sudden changes of visual stimulation attract attention. The observer's body motion generates retinal-flow field patterns containing information about his/her own speed and trajectory and relative motion of other objects. We investigated the effectiveness of relative motion as an attentional cue and compared it with conventional cueing by appearance of a ...

In the present technical article, we describe a method for generating a new dichoptic motion stimulus, the monocular components of which are dynamic random noise without constant figural cues for feature-tracking-based motion. Our dichoptic motion stimulus adds a new line of evidence, which supports the original conclusion of M. Shadlen ...

Biological motion perception, having both evolutionary and social importance, is performed by the human visual system with a high degree of sensitivity. It is unclear whether peripheral vision has access to the specialized neural systems underlying biological motion perception; however, given the motion component, one would expect peripheral vision to ...

We introduce a new illusion that contradicts common assumptions in the field of visual motion perception. When an unoccluded bar moves at certain speeds and oscillates at certain frequencies, the perceived direction of the bar is not predicted by its intrinsic terminators but is biased to move in the direction ...

Can we search for items based on their type of motion? We consider here visual search based on three types of motion: (i) ballistic motion, in which objects move in a straight line until they encounter a display boundary; (ii) random-walk motion, in which objects change direction randomly; (iii) composite ...

Often it is claimed that humans are particularly sensitive to biological motion. Here, sensitivity as a detection advantage for biological over nonbiological motion is examined. Previous studies comparing biological motion to nonbiological motion have not used appropriate masks or have not taken into account the underlying form present in biological ...

Two psychophysical experiments were conducted to investigate the mechanism that generates stable depth structure from retinal motion combined with extraretinal signals from pursuit eye movements. Stimuli consisted of random dots that moved horizontally in one direction (ie stimuli had common motion on the retina), but at different speeds between adjacent ...

Periodically flipping the contrast of a moving pattern causes a reversal of the perceived direction of motion. This direction reversal, known as reverse-phi motion, has been generally explained with the notion that flipping contrasts actually shifted the balance of motion energy toward the opposite direction. In this sense, the reversal ...

We explain an approach to motion detection based on the biological vision system of the common house fly, Musca domestica. Basing a machine vision system on the house fly has distinct advantages when compared to the limiting properties of current computer vision systems. The advantages of this approach will also ...

BACKGROUND: Biological motions, that is, the movements of humans and other vertebrates, are characterized by dynamic regularities that reflect the structure and the control schemes of the musculo-skeletal system. Early studies on the development of the visual perception of biological motion showed that infants after three months of age distinguished ...

When motion-onset VEPs are elicited by moving luminance patterns, the motion specific component of the response, N2, is more prominent at electrode sites that overlay the lateral occipito-parietal cortex close to area V5/MT, than over the primary visual cortex. Functional segregation suggests that colour and motion processing should take place ...

Models of visual motion processing that introduce priors for low speed through Bayesian computations are sometimes treated with scepticism by empirical researchers because of the convenient way in which parameters of the Bayesian priors have been chosen. Using the effects of motion adaptation on motion perception to illustrate, we show ...

During binocular rivalry, conflicting monocular images undergo alternating suppression. This study explores rivalry suppression by probing visual sensitivity during rivalry with various probe stimuli. When two faces engage in rivalry, sensitivity to face probes is reduced 4-fold during suppression. Rivaling global motions also rivaled very deeply when probed with a ...

Perceived position depends on many factors, including motion present in a visual scene. Convincing evidence shows that high-level motion perception--which is driven by top-down processes such as attentional tracking or inferred motion--can influence the perceived position of an object. Is high-level motion sufficient to influence perceived position, and is attention ...

Selective attention enhances visual information processing, as measured by behavioral performance and neural activity. However, little is known about its effects on subjective experience. Here, we investigated the effect of transient (exogenous) attention on the appearance of visual motion, using a psychophysical procedure that directly measures appearance and controls for ...