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Shapiro Arthur - - 2010
The human visual system does not treat all parts of an image equally: the central segments of an image, which fall on the fovea, are processed with a higher resolution than the segments that fall in the visual periphery. Even though the differences between foveal and peripheral resolution are large, ...
Thirkettle M - - 2010
The point light walker (PLW) has been taken to demonstrate the existence of mechanisms specialised in the processing of biological motion, but the roles of form and motion information in such processing remain unclear. While processing is robust to distortion and exclusion of the local motion signals of the individual ...
Saygin Ayse Pinar - - 2010
Perception of biological motion is linked to the action perception system in the human brain, abnormalities within which have been suggested to underlie impairments in social domains observed in autism spectrum conditions (ASC). However, the literature on biological motion perception in ASC is heterogeneous and it is unclear whether deficits ...
de Winkel Ksander N - - 2010
In the present study, we investigated whether the perception of heading of linear self-motion can be explained by Maximum Likelihood Integration (MLI) of visual and non-visual sensory cues. MLI predicts smaller variance for multisensory judgments compared to unisensory judgments. Nine participants were exposed to visual, inertial, or visual-inertial motion conditions ...
Edwards Mark - - 2010
The interaction of first- and second-order motion signals at the local-motion-pooling level were investigated using locally-paired dots that moved orthogonally to each other. Dots were either luminance-defined, which could, potentially drive both first- and second-order local-motion units, or contrast-defined, which only drive second-order local-motion units. The response measure used was ...
Rodr??guez-Sanchez Antonio J - - 2009
As we move, the projection of moving objects on our retinas generates an array of velocity vectors known as optic flow. One class of optic flow is spiral motion, defined by the angle between a local vector direction and the direction of the steepest increase in local speed. By discriminating ...
Fermüller Cornelia - - 2010
A new class of patterns, composed of repeating patches of asymmetric intensity profile, elicit strong perception of illusory motion. We propose that the main cause of this illusion is erroneous estimation of image motion induced by fixational eye movements. Image motion is estimated with spatial and temporal energy filters, which ...
H??ndel Barbara - - 2009
Recent anatomical studies have revealed strong cerebellar projections into parietal and prefrontal cortex. These findings suggest that the cerebellum might not only play a functional role in motor control but also cognitive domains, an idea also supported by neuropsychological testing of patients with cerebellar lesions that has revealed specific deficits. ...
Lappe Markus M Psychological Institute II and Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, Westf. Wilhelms-University, 48149 Münster, Germany. - - 2009
The optic flow generated in the eyes during self-motion provides an important control signal for direction and speed of self-motion, and can be used to track the distance that has been traveled. The use of vision for these behavioral tasks can be studied in isolation in virtual reality setups, in ...
Stevens Laura K - - 2009
The ability to detect the motion of objects is critical to survival, and understanding the cortical mechanisms involved in this process remains a key challenge in sensory neuroscience. A relatively new approach to this problem is to temporarily disrupt processing at specific cortical sites and measure the behavioural consequences. Several ...
Jin Seung-A Annie - - 2009
The "self" concept has grown increasingly important in interactive media environments. This study investigated self-related processes in an avatar-based game console, Wii. A key feature of the Wii is its motion-sensing capability that empowers players to manipulate and interact with items on-screen via movement. The present study examined the effects ...
Raemaekers Mathijs - - 2009
Recently, evidence has emerged for a radial orientation bias in early visual cortex. These results predict that in early visual cortex a tangential bias should be present for motion direction. We tested this prediction in a human imaging study, using a translating random dot pattern that slowly rotated its motion ...
Stoner Gene R - - 2010
Valdes-Sosa, et al. (2000) introduced a transparent-motion design that provides evidence of surface-based processing of visual motion. We show that this design suffers from a motion-duration confound that admits an alternative explanation based on neuronal adaptation and competition. We tested this explanation by reversing the relationship between motion duration and ...
Pilz Karin S - - 2010
Previous studies have shown that older subjects have difficulties discriminating the walking direction of point-light walkers. In two experiments, we investigated the underlying cause in further detail. In Experiment 1, subjects had to discriminate the walking direction of upright and inverted point-light walkers in a cloud of randomly moving dots. ...
Wang Jun - - 2010
The results of multiple investigations indicate visual motion-processing abnormalities in schizophrenia. There is little information, however, about the time course and neural correlates of motion-processing abnormalities among these subjects. For the present study, 13 schizophrenia and 13 healthy subjects performed a simple motion direction discrimination task with peripherally presented moving ...
Pallus Adam C - - 2010
Motion in the visual periphery of lizards, and other animals, often causes a shift of visual attention toward the moving object. This behavioral response must be more responsive to relevant motion (predators, prey, conspecifics) than to irrelevant motion (windblown vegetation). Early stages of visual motion detection rely on simple local ...
Hayashi Ryusuke - - 2010
Visual motion signals, which are initially extracted in parallel at multiple spatial frequencies, are subsequently integrated into a unified motion percept. Cross-frequency integration plays a crucial role when directional information conflicts across frequencies due to such factors as occlusion. We investigated the human observers' open-loop oculomotor tracking responses (ocular following ...
Raudies Florian - - 2010
Transparent motion is perceived when multiple motions are presented in the same part of visual space that move in different directions or with different speeds. Several psychophysical as well as physiological experiments have studied the conditions under which motion transparency occurs. Few computational mechanisms have been proposed that allow to ...
Beck Cornelia - - 2010
In this work, we present a neural model simulating parts of the motion and the form pathway of the visual cortex. It is shown how the visual features motion, disparity, and form that are represented in a distributed way in areas V1, V2, and MT mutually interact at several levels. ...
Yamawaki Yoshifumi - - 2009
Extracellular recordings were made from a directionally selective neuron in the ventral nerve cord of mantises. The neuron's preferred direction of motion was forward and upward over the compound eye contralateral to its axon at the cervical connective. The neuron was sensitive to wide-field motion stimuli, resistant to habituation, and ...
Koldewyn Kami K McGovern Institute for Brain Research, Cambridge, MA 02139, USA. - - 2010
Several groups have recently reported that people with autism may suffer from a deficit in visual motion processing and proposed that these deficits may be related to a general dorsal stream dysfunction. In order to test the dorsal stream deficit hypothesis, we investigated coherent and biological motion perception as well ...
Baglietto Gabriel - - 2009
One of the most popular approaches to the study of the collective behavior of self-driven individuals is the well-known Vicsek model (VM) [T. Vicsek, A. Czirók, E. Ben-Jacob, I. Cohen, and O. Shochet, Phys. Rev. Lett. 75, 1226 (1995)]. In the VM one has that each individual tends to adopt ...
Raudies Florian - - 2010
How does the visual system manage to segment a visual scene into surfaces and objects and manage to attend to a target object? Based on psychological and physiological investigations, it has been proposed that the perceptual organization and segmentation of a scene is achieved by the processing at different levels ...
Williams Adrian L - - 2009
Studies have shown that cortical area MT/V5 is activated by visual motion as well as illusory motion, implied motion in static images, or motion imagery. Cells within these areas are additionally tuned for speed and exhibit different responses depending on the actual speed of an object. In this study, we ...
Bach Michael - - 2010
PURPOSE: A variety of approaches to developing visual prostheses are being pursued: subretinal, epiretinal, via the optic nerve, or via the visual cortex. This report presents a method of comparing their efficacy at genuinely improving visual function, starting at no light perception (NLP). METHODS: A test battery (a computer program, ...
Winawer Jonathan - - 2010
Mental imagery is thought to share properties with perception. To what extent does the process of imagining a scene share neural circuits and computational mechanisms with actually perceiving the same scene? Here, we investigated whether mental imagery of motion in a particular direction recruits neural circuits tuned to the same ...
Wertz Adrian - - 2009
For a moving animal, optic flow is an important source of information about its ego-motion. In flies, the processing of optic flow is performed by motion sensitive tangential cells in the lobula plate. Amongst them, cells of the vertical system (VS cells) have receptive fields with similarities to optic flows ...
Lee Laura C - - 2010
A widely adopted neural model of face perception (Haxby, Hoffman, & Gobbini, 2000) proposes that the posterior superior temporal sulcus (STS) represents the changeable features of a face, while the face-responsive fusiform gyrus (FFA) encodes invariant aspects of facial structure. 'Changeable features' of a face can include rigid and non-rigid ...
Baccus Wendy - - 2009
Although configuration is important for the perception of biological motion, it is not known whether the processing of configuration occurs early or subsequent to local motion processing. Here we report significantly greater adaptation of the N1 event-related potential elicited by a point-light walker (PLW) following an intact PLW relative to ...
Longden Kit D - - 2009
Active locomotive states are metabolically expensive and require efficient sensory processing both to avoid wasteful movements and to cope with an extended bandwidth of sensory stimuli. This is particularly true for flying animals because flight, as opposed to walking or resting, imposes a steplike increase in metabolism for the precise ...
Kaiser Martha D - - 2009
Traditionally, psychological research on autism spectrum disorder (ASD) has focused on social and cognitive abilities. Vision provides an important input channel to both of these processes, and, increasingly, researchers are investigating whether observers with ASD differ from typical observers in their visual percepts. Recently, significant controversies have arisen over whether ...
Thompson Benjamin - - 2009
The neural mechanisms underlying the integration and segregation of motion signals are often studied using plaid stimuli. These stimuli consist of two spatially coincident dynamic gratings of differing orientations, which are either perceived to move in two unique directions or are integrated by the visual system to elicit the percept ...
Gilroy Lee A - - 2009
Motion perception usually is accompanied by the phenomenological impression of sequence as objects move through successions of locations. Nonetheless, there is accumulating evidence that sequential information is neither necessary nor sufficient for perceiving motion. It is shown here that apparent motion is specified by counterchange rather than sequence-that is, by ...
K?ri Szabolcs - - 2010
Previous studies reported impaired visual information processing in patients with fragile X syndrome and in premutation carriers. In this study, we assessed the perception of biological motion (a walking point-light character) and mechanical motion (a rotating shape) in 25 female fragile X premutation carriers and in 20 healthy non-carrier controls. ...
Hisakata Rumi - - 2009
In the motion-induced position shift (MIPS), the position of a moving pattern tapered by a stationary envelope is perceived to shift in the direction of the motion. It was found that plaid motion also elicited a MIPS in the direction of global motion and this global MIPS could not be ...
Clifford Colin W G - - 2009
Luminance gratings reportedly produce a stronger functional magnetic resonance imaging (fMRI) blood oxygen level-dependent (BOLD) signal in those parts of the retinotopic cortical maps where they are oriented radially to the point of fixation. We sought to extend this finding by examining anisotropies in the response of cortical areas V1-V3 ...
Mather George - - 2009
Low-level motion processing in the primate visual system involves two stages. The first stage (in V1) contains specialised motion sensors which respond to local retinal motion, and the second stage (in MT) pools local signals to encode rigid surface motion. Recent psychophysical research shows that motion signals influence the perceived ...
Donner Tobias H - - 2009
Simple perceptual decisions are ideally suited for studying the sensorimotor transformations underlying flexible behavior. During perceptual detection, a noisy sensory signal is converted into a behavioral report of the presence or absence of a perceptual experience. Here, we used magnetoencephalography (MEG) to link the dynamics of neural population activity in ...
Amano Kaoru - - 2009
Cortical neurons that initially extract motion signals have small receptive-fields, and narrow orientation- and bandpass-spatial-frequency tuning. Accurate extraction of the veridical motion of objects typically requires the global pooling of the output of multiple local-motion units across orientation and space. We examined whether the narrow spatial-frequency tuning present at the ...
Kéri Szabolcs - - 2009
Evidence suggests that intranasally administered oxytocin modulates several social cognitive and emotional processes in humans. In this study, we investigated the effect of oxytocin on the perception of biological motion (a walking character) and nonbiological motion (a rotating shape). The participants were 20 healthy volunteers who observed moving dots embedded ...
Tong Jianliang J College of Optometry, 505 J. Davis Armistead Building, University of Houston, Houston, TX 77204-2020, - - 2009
Recent studies indicate that the extent of perceived motion smear is attenuated asymmetrically during smooth pursuit eye movements, based on the relative directions of the target and eye motion. We conducted two experiments to determine if the reduction of perceived smear during pursuit might be associated with an acceleration of ...
Armstrong Vickie - - 2009
We compared the sensitivity of adults and children aged 3-10 years to first- and second-order motion and form. For first-order stimuli, at all ages sensitivity was better for motion than form, and motion thresholds were better at 6 Hz than at 1.5 Hz. For second-order stimuli, at all ages sensitivity ...
Hou C C Smith-Kettlewell Eye Research Institute, San Francisco, CA 94115, United States of America. - - 2009
Motion cues provide a rich source of information about translations of the observer through the environment as well as the movements of objects and surfaces. While the direction of motion can be extracted locally these local measurements are, in general, insufficient for determining object and surface motions. To study the ...
Murphy Patrick - - 2009
A central feature of autistic spectrum disorders (ASDs) is a difficulty in identifying and reading human expressions, including those present in the moving human form. One previous study, by Blake et al. (2003), reports decreased sensitivity for perceiving biological motion in children with autism, suggesting that perceptual anomalies underlie problems ...
Nava Saúl S - - 2009
In animal communication, complex displays usually have multiple functions and, male and female receivers often differ in their utilization and response to different aspects of these displays. The perceptual variability hypothesis suggests that different aspects of complex signals differ in their ability to be detected and processed by different receivers. ...
Sinico Michele - - 2009
We show that human observers strongly underestimate a linear or circular trajectory that a luminous spot follows in the dark. At slow speeds, observers are relatively accurate, but, as the speed increases, the size of the path is progressively underestimated, by up to 35%. The underestimation imposes little memory load ...
Beer Anton L AL Department of Psychology, Boston University, Boston, MA, USA. - - 2009
Previous research has suggested that three-dimensional (3D) structure-from-motion (SFM) perception in humans involves several motion-sensitive occipital and parietal brain areas. By contrast, SFM perception in nonhuman primates seems to involve the temporal lobe including areas MT, MST and FST. The present functional magnetic resonance imaging study compared several motion-sensitive regions ...
Hock Howard S - - 2009
A computational model for the perception of counterchange-specified motion is examined in detail and compared with various versions of the Reichardt motion detection model [Reichardt, W. (1961). Autocorrelation, a principle for the evaluation of sensory information by the central nervous system. In W. A. Rosenblith (Ed.), Sensory communication (pp. 303-317). ...
Hong Bo - - 2009
OBJECTIVE: This study presents a brain-computer interface (BCI) named N200-speller. A matrix of motion stimuli are displayed for inducing the motion-onset visual response that allows the subject to spell out a message by scalp EEG. METHODS: The brief motion of chromatic visual objects embedded in a 36 virtual button onscreen ...
Ho Cindy S - - 2009
Maximum motion displacement (Dmax) is the largest dot displacement in a random-dot kinematogram (RDK) at which direction of motion can be correctly discriminated [Braddick, O. (1974). A short-range process in apparent motion. Vision Research, 14, 519-527]. For first-order RDKs, Dmax gets larger as dot size increases and/or dot density decreases. ...
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