Human Motion Perception Research Articles

Suprathreshold asymmetries in human motion perception

Detection of asymmetries has been a mainstay of using vestibular reflexes to assess semicircular canal function. However, there has been relatively little work on how vestibular stimuli are perceived. Suprathreshold vestibular perception was measured in 13 normal healthy controls by having them compare the relative sizes of two yaw (vertical-axis rotation) or sway (right-left translation) stimuli. Both stimuli were 1.5 s in duration with a staircase used to adjust the relative size of the stimuli to find a pair of stimuli perceived as equal. Motion stimuli were delivered in darkness using a hexapod motion platform, and visual stimuli simulating motion were presented on a screen in the absence of platform motion. Both same direction (SD) and opposite direction (OD) stimuli were delivered in separate runs. After a two-interval stimulus, subjects reported which movement they perceived as larger. Cumulative distribution functions were fit to the responses so that the relative magnitudes of the two stimuli perceived as equal could be determined. For OD trial blocks, a directional asymmetry index was calculated to compare the relative size of perceived rightward and leftward motion. For all trial blocks, a temporal asymmetry index (TAI) was used to compare the relative size of the first and second intervals. Motion OD stimuli were perceived as equal in all subjects in yaw and all but one in sway. For visual OD stimuli, two subjects had slightly asymmetric responses for both sway and yaw. The TAI demonstrated asymmetry in 54% in yaw, in which the second interval was perceived to be larger in all but one subject who had an asymmetry. For sway, only two subjects had a significant asymmetry. Visual stimuli produced a similar rate of asymmetry. The direction and magnitude of these asymmetries were not significantly correlated with those seen for motion stimuli. Asymmetries were found in a fraction with the TAI in SD stimuli for motion in yaw (42%) and sway (33%), as well as for vision in yaw (60%) and sway (43%). The precision at discriminating SD motion stimuli decreased significantly with age, but there was no difference in OD motion or visual stimuli.

Segmentation-Based Video Compression Using Texture and Motion Models

In recent years, there has been a growing interest in developing novel techniques for increasing the coding efficiency of video compression methods. One approach is to use texture and motion models of the content in a scene. Based on these models parts of the video frame are not coded or “skipped” by a classical motion compensated coder. The models are then used at the decoder to reconstruct the missing or skipped regions. In this paper, we describe several spatial-texture models for video coding. We investigate several texture features in combination with two segmentation strategies in order to detect texture regions in a video sequence. These detected areas are not encoded using motion compensated coding. The model parameters are sent to the decoder as side information. After the decoding process, frame reconstruction is done by inserting the skipped texture areas into the decoded frames. Using similar approach, we consider motion models based on human visual motion perception. We describe a motion classification model to separate foreground objects containing noticeable motion from the background. This motion model is then used in the encoder to again allow regions to be skipped and not coded using a motion compensated encoder. Our results indicate significant increase in terms of coding efficiency in comparison to the spatial texture-based methods. Finally, we discuss the effects and tradeoffs of these techniques based on perceptual experiments and show that in many cases the coding efficiency can be increased by up to 25% given a fixed perceptual quality.

Biological motion task performance predicts superior temporal sulcus activity

Numerous studies implicate superior temporal sulcus (STS) in the perception of human movement. More recent theories hold that STS is also involved in the understanding of human movement. However, almost no studies to date have associated STS function with observable variability in action understanding. The present study directly associated STS activity with performance on a challenging task requiring the interpretation of human movement. During functional MRI scanning, fourteen adults were asked to identify the direction (left or right) in which either a point-light walking figure or spinning wheel were moving. The task was made challenging by perturbing the dot trajectories to a level (determined via pretesting) where each participant achieved 72% accuracy. The walking figure condition was associated with increased activity in a constellation of social information processing and biological motion areas, including STS, MT+/V5, right pars opercularis (inferior frontal gyrus), fusiform gyrus, and amygdala. Correctly answered walking figure trials were uniquely associated with increased activity in two right hemisphere STS clusters and right amygdala. Present findings provide some of the strongest evidence to date that STS plays a critical role in the successful interpretation of human movement.

A Bistable Counterchange Detector for the Perception of Third-Order Motion

Hock, Krogan, & Espinoza (1997) Dynamic, state-dependent thresholds for the perception of singleelement apparent motion: Bistability from local cooperativity. Perception & Psychophysics, 59, 10771088. Hock, Nichols, & Espinoza (2004) When motion is not perceived: Evidence from adaptation and dynamical stability. Spatial Vision, 17, 235-248. Hock, Schoner, & Gilroy (2009) A counterchange mechanism for the perception of motion. Acta Psychologica, 132, 1-21. Lu & Sperling (1995) The functional architecture of human visual motion perception. Vision Research, 35, 2697-2722 Generalized Apparent Motion

Sensory versus motor loci for integration of multiple motion signals in smooth pursuit eye movements and human motion perception

We have investigated how visual motion signals are integrated for smooth pursuit eye movements by measuring the initiation of pursuit in monkeys for pairs of moving stimuli of the same or differing luminance. The initiation of pursuit for pairs of stimuli of the same luminance could be accounted for as a vector average of the responses to the two stimuli singly. When stimuli comprised two superimposed patches of moving dot textures, the brighter stimulus suppressed the inputs from the dimmer stimulus, so that the initiation of pursuit became winner-take-all when the luminance ratio of the two stimuli was 8 or greater. The dominance of the brighter stimulus could be not attributed to either the latency difference or the ratio of the eye accelerations for the bright and dim stimuli presented singly. When stimuli comprised either spot targets or two patches of dots moving across separate locations in the visual field, the brighter stimulus had a much weaker suppressive influence; the initiation of pursuit could be accounted for by nearly equal vector averaging of the responses to the two stimuli singly. The suppressive effects of the brighter stimulus also appeared in human perceptual judgments, but again only for superimposed stimuli. We conclude that one locus of the interaction of two moving visual stimuli is shared by perception and action and resides in local inhibitory connections in the visual cortex. A second locus resides deeper in sensory-motor processing and may be more closely related to action selection than to stimulus selection.

Brain regions involved in human movement perception: A quantitative voxel‐based meta‐analysis

Face, hands, and body movements are powerful signals essential for social interactions. In the last 2 decades, a large number of brain imaging studies have explored the neural correlates of the perception of these signals. Formal synthesis is crucially needed, however, to extract the key circuits involved in human motion perception across the variety of paradigms and stimuli that have been used. Here, we used the activation likelihood estimation (ALE) meta-analysis approach with random effect analysis. We performed meta-analyses on three classes of biological motion: movement of the whole body, hands, and face. Additional analyses of studies of static faces or body stimuli and sub-analyses grouping experiments as a function of their control stimuli or task employed allowed us to identify main effects of movements and forms perception, as well as effects of task demand. In addition to specific features, all conditions showed convergence in occipito-temporal and fronto-parietal regions, but with different peak location and extent. The conjunction of the three ALE maps revealed convergence in all categories in a region of the right posterior superior temporal sulcus as well as in a bilateral region at the junction between middle temporal and lateral occipital gyri. Activation in these regions was not a function of attentional demand and was significant also when controlling for non-specific motion perception. This quantitative synthesis points towards a special role for posterior superior temporal sulcus for integrating human movement percept, and supports a specific representation for body parts in middle temporal, fusiform, precentral, and parietal areas.

Perception Coherence Zones in Flight Simulation

The development and tuning of flight simulator motion filters relies on understanding human motion perception and its limitations. Of particular interest to flight simulation is the study of visual-inertial coherence zones. Coherence zones refer to combinations of visual and inertial cues that, although not being physically coherent, still provide the pilot with the perception of a congruent motion, indicating a realistic simulation. Coherence zones have been measured before during passive tasks, for predetermined stimuli. During a pilot-in-the-loop simulation, however, the type of inertial and visual cues being provided are considerably influenced by the pilot's control strategy. For this reason, it is important to understand how the amplitude and frequency content of the stimuli affect the perception of a coherent motion. Three experiments were performed to measure the effect of cue amplitude and frequency on yaw perception coherence zones. In accordance with previous research, the measured coherence zones were generally wider for higher amplitudes of the visual motion cue. At higher amplitudes of the visual cue, subjects preferred inertial motion amplitudes that were lower than the visual cue amplitude. The stimulus frequency was shown to have an effect on the coherence zones. For a higher frequency stimulus the preferred inertial motion amplitudes were significantly lower than for a lower frequency stimulus. These results are explained using a model of the semicircular canals dynamics. Copyright © 2010.

Anisotropies in judging the direction of moving natural scenes

Although visual systems are optimized to deal with the natural visual environment, our understanding of human motion perception is in large part based on the use of artificial stimuli. Here, we assessed observers' ability to estimate the direction of translating natural images and fractals by having them adjust the orientation of a subsequently viewed line. A system of interleaved staircases, driven by observers' direction estimates, ensured that stimuli were presented near one of 16 reference directions. The resulting error distributions (i.e., the differences between reported and true directions) reveal several anisotropies in global motion processing. First, observers' estimates are biased away from cardinal directions (reference repulsion). Second, the standard deviations of estimates show an "oblique effect" being ∼45% lower around cardinal directions. Third, errors around cardinal directions are more likely (∼22%) to approach zero than would be consistent with Gaussian-distributed errors, suggesting that motion processing minimizes the number as well as magnitude of errors. Fourth, errors are similar for natural scenes and fractals, indicating that observers do not use top-down information to improve performance. Finally, adaptation to unidirectional motion modifies observers' bias by amplifying existing repulsion (e.g., around cardinal directions). This bias change can improve direction discrimination but is not due to a reduction in variability.

Direction anisotropy of human motion perception depends on stimulus speed

A number of previous studies have extensively investigated directional anisotropy in motion perception. However, consensus has not been reached regarding the nature of motion directional anisotropies in human vision. In this study, we investigated the directional anisotropy of human motion perception by moving random-dot stimuli in the peripheral upper visual field. Our findings show that the degree of directional anisotropy depends on the stimulus speed. Furthermore, the high and low speed conditions have preferred directions that are opposite. This may reflect differences in the directional information among temporal frequencies in natural scenes. These differences are thought to have crucial roles in the detection of motion direction.

People watching: visual, motor, and social processes in the perception of human movement.

Successful social behavior requires the accurate perception and interpretation of other peoples' actions. In the last decade, significant progress has been made in understanding how the human visual system analyzes bodily motion. Neurophysiological studies have identified two neural areas, the superior temporal sulcus (STS) and the premotor cortex, which play key roles in the visual perception of human movement. Patterns of neural activity in these areas are reflective of psychophysical measures of visual sensitivity to human movement. Both vary as a function of stimulus orientation and global stimulus structure. Human observers and STS responsiveness share some developmental similarities as both exhibit sensitivities that become increasingly tuned for upright, human movement. Furthermore, the observer's own visual and motor experience with an action as well as the social and emotional content of that action influence behavioral measures of visual sensitivity and patterns of neural activity in the STS and premotor cortex. Finally, dysfunction of motor processes, such as hemiplegia, and dysfunction of social processes, such as Autism, systematically impact visual sensitivity to human movement. In sum, a convergence of visual, motor, and social processes underlies our ability to perceive and interpret the actions of other people. WIREs Cogn Sci 2011 2 68-78 DOI: 10.1002/wcs.88 For further resources related to this article, please visit the WIREs website.

Serviceability design factors for wind-sensitive structures

Wind-sensitive buildings can experience excessive vibrations that cause discomfort and interruption of the activities of the inhabitants of the buildings. To ensure the desired serviceability, codes, standards, and their commentaries have proposed perception curves that limit the expected (or mean) peak acceleration or standard deviation of the acceleration of the buildings. These perception curves are developed based on perceived vibration alone and do not consider the uncertainty in structural dynamic characteristics (i.e., natural frequency of vibration and ratio of damping) and loads such as the wind loading. Therefore, the annual probability that the perception curve is not exceeded for a building whose design is based on the perception curve is unknown. In this study, serviceability design factors are calibrated for selected targeted annual probability of perception levels by considering the uncertainty in the structural dynamic characteristics, wind characteristics, as well as in the human perception of motion. These serviceability design factors are to be used with the estimated mean peak acceleration caused by along-wind and cross-wind excitations given in the commentaries of the current National building code of Canada. The use of calibrated serviceability design factors for design checking is illustrated with a numerical example.

Meaning influences the perception of apparent human motion

Meaning influences the perception of apparent human motion

Frequency, context, and human motion perception

Frequency, context, and human motion perception

Discrimination of locomotion direction in impoverished displays of walkers by macaque monkeys

A vast literature exists on human biological motion perception in impoverished displays, e.g., point-light walkers. Less is known about the perception of impoverished biological motion displays in macaques. We trained 3 macaques in the discrimination of facing direction (left versus right) and forward versus backward walking using motion-capture-based locomotion displays (treadmill walking) in which the body features were represented by cylinder-like primitives. The displays did not contain translatory motion. Discriminating forward versus backward locomotion requires motion information while the facing-direction/view task can be solved using motion and/or form. All monkeys required lengthy training to learn the forward-backward task, while the view task was learned more quickly. Once acquired, the discriminations were specific to walking and stimulus format but generalized across actors. Although the view task could be solved using form cues, there was a small impact of motion. Performance in the forward-backward task was highly susceptible to degradations of spatiotemporal stimulus coherence and motion information. These results indicate that rhesus monkeys require extensive training in order to use the intrinsic motion cues related to forward versus backward locomotion and imply that extrapolation of observations concerning human perception of impoverished biological motion displays onto monkey perception needs to be made cautiously.

A Cybernetic Approach to Assess Flight Simulator Motion Fidelity

Due to a limited understanding of human multimodal motion perception during aircraft control, the definition of requirements for flight simulator motion fidelity is a problem the flight simulation community has struggled with for years. The development of adequate tuning procedures for motion washout algorithms has remained problematic for the same reason. This paper proposes a method for assessment of simulator motion fidelity that makes use of a cybernetic, model-based approach to measuring multimodal pilot control behavior. As illustrated here with data from a recent human-in-the-loop experiment, this approach allows for objective detection of changes in pilot control that result from degraded simulator motion fidelity.

Cortical dynamics underlying the visual perception of stationary and moving stimuli

Event Abstract Back to Event Cortical dynamics underlying the visual perception of stationary and moving stimuli Wenqi Sun1*, Alexander Moiseev2, Faisal Beg1, Urs Ribary1 and Naznin Virji-Babul2 1 Simon Fraser University, Canada 2 Down Syndrome Research Foundation, Canada In this study, we investigated the neural responses during the perception of stationary dots, randomly moving point light dots and point light dots representing human motion. We recorded cortical responses from ten right handed subjects with a 151 channel whole head MEG system (VSM MedTech, Coquitlam, BC). For each subject a three-dimensional spatial distribution of source activity was computed using differential SAM beamforming method. The data were spatially normalized to a common brain template and group-averaged for each condition. Locations showing statistically significant differences between conditions were chosen for time frequency analysis. We compared the random motion and human motion with the stationary display and then compared the random and human motion. Perception of random motion was associated with enhanced neural activity in alpha and beta bands in bilateral visual, parietal and MT regions, as compared with stationary dots. Perception of human motion led to enhanced neural activity in alpha and beta bands in the visual, parietal and MT areas in the right hemisphere, in comparison with random motion. Late activation in the gamma band activity was observed in both motion conditions in the visual area. In addition, the perception of human motion led to increased activity in the alpha band in the left motor region. These data suggest that (a) motion processing involves the dorsal pathways via bi-directional pathways, and (b)that action cues depicting human motion are sufficient to selectively activate premotor regions. Supported by NSERC (RGPGP/355878-2008) Conference: Biomag 2010 - 17th International Conference on Biomagnetism , Dubrovnik, Croatia, 28 Mar - 1 Apr, 2010. Presentation Type: Poster Presentation Topic: Neurocognition and Functional Connectivity Citation: Sun W, Moiseev A, Beg F, Ribary U and Virji-Babul N (2010). Cortical dynamics underlying the visual perception of stationary and moving stimuli. Front. Neurosci. Conference Abstract: Biomag 2010 - 17th International Conference on Biomagnetism . doi: 10.3389/conf.fnins.2010.06.00247 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 31 Mar 2010; Published Online: 31 Mar 2010. * Correspondence: Wenqi Sun, Simon Fraser University, Burnaby, Canada, wsa1@sfu.ca Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Wenqi Sun Alexander Moiseev Faisal Beg Urs Ribary Naznin Virji-Babul Google Wenqi Sun Alexander Moiseev Faisal Beg Urs Ribary Naznin Virji-Babul Google Scholar Wenqi Sun Alexander Moiseev Faisal Beg Urs Ribary Naznin Virji-Babul PubMed Wenqi Sun Alexander Moiseev Faisal Beg Urs Ribary Naznin Virji-Babul Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Biological motion drives perception and action

Presenting a few dots moving coherently on a screen can yield to the perception of human motion. This perception is based on a specific network that is segregated from the traditional motion perception network and that includes the superior temporal sulcus (STS). In this study, we investigate whether this biological motion perception network could influence the smooth pursuit response evoked by a point-light walker. We found that smooth eye velocity during pursuit initiation was larger in response to the point-light walker than in response to one of its scrambled versions, to an inverted walker or to a single dot stimulus. In addition, we assessed the proximity to the point-light walker (i.e. the amount of information about the direction contained in the scrambled stimulus and extracted from local motion cue of biological motion) of each of our scrambled stimuli in a motion direction discrimination task with manual responses and found that the smooth pursuit response evoked by those stimuli moving across the screen was modulated by their proximity to the walker. Therefore, we conclude that biological motion facilitates smooth pursuit eye movements, hence influences both perception and action.

Aim of the Special Issue: Multiple Understandings of Non-Consciousness in Human Perception, Motor Action, and Behavior

The current special issue consists of three review articles, along with an introductory review. The three review articles examine the issues of non-consciousness in human perceptual-motor control and behavior in different disciplinary areas, such as perceptual-motor control, emotional neuroscience, and socio-psychology. The introductory review article first examines previous fundamental literature on non-consciousness in three different areas specific to perceptual-motor control, emotional autonomic responses and behavior, and cognitive and socio-psychological behavior. Following this, several issues essential to a discussion on non-consciousness in human perceptual-motor control and behavior are examined. One issue concerns temporal characteristics indicating that cortical activity lasting around 0.5 s is necessary to produce perceptual consciousness of a given stimulus. Another issue concerns spatial characteristics indicating that motor responses are unaffected when responding to a visual illusion. Finally, MacLean's (1994) view of the brain -that is, the notion of a hierarchy of three brains in one- and the Koch-Greenfield controversy (2009) concerning the issue of how consciousness is produced are briefly examined in line with the notion of consciousness and non-consciousness in the brain.

Phase-linking and the perceived motion during off-vertical axis rotation

Human off-vertical axis rotation (OVAR) in the dark typically produces perceived motion about a cone, the amplitude of which changes as a function of frequency. This perception is commonly attributed to the fact that both the OVAR and the conical motion have a gravity vector that rotates about the subject. Little-known, however, is that this rotating-gravity explanation for perceived conical motion is inconsistent with basic observations about self-motion perception: (a) that the perceived vertical moves toward alignment with the gravito-inertial acceleration (GIA) and (b) that perceived translation arises from perceived linear acceleration, as derived from the portion of the GIA not associated with gravity. Mathematically proved in this article is the fact that during OVAR these properties imply mismatched phase of perceived tilt and translation, in contrast to the common perception of matched phases which correspond to conical motion with pivot at the bottom. This result demonstrates that an additional perceptual rule is required to explain perception in OVAR. This study investigates, both analytically and computationally, the phase relationship between tilt and translation at different stimulus rates-slow (45 degrees /s) and fast (180 degrees /s), and the three-dimensional shape of predicted perceived motion, under different sets of hypotheses about self-motion perception. We propose that for human motion perception, there is a phase-linking of tilt and translation movements to construct a perception of one's overall motion path. Alternative hypotheses to achieve the phase match were tested with three-dimensional computational models, comparing the output with published experimental reports. The best fit with experimental data was the hypothesis that the phase of perceived translation was linked to perceived tilt, while the perceived tilt was determined by the GIA. This hypothesis successfully predicted the bottom-pivot cone commonly reported and a reduced sense of tilt during fast OVAR. Similar considerations apply to the hilltop illusion often reported during horizontal linear oscillation. Known response properties of central neurons are consistent with this ability to phase-link translation with tilt. In addition, the competing "standard" model was mathematically proved to be unable to predict the bottom-pivot cone regardless of the values used for parameters in the model.

Oxytocin enhances the perception of biological motion in humans

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 among a cloud of noise (mask) dots. Sensitivity (d') for motion detection was determined after the administration of oxytocin and placebo. The results showed that oxytocin (relative to placebo) administration increased sensitivity to biological motion but not to nonbiological motion. These results suggest that oxytocin specifically modulates the perception of socially relevant stimuli.