scholarly journals A neural mechanism for detecting object motion during self-motion

2021 ◽  
Author(s):  
HyungGoo Kim ◽  
Dora Angelaki ◽  
Gregory DeAngelis
Keyword(s):  
Visual System ◽  
Moving Objects ◽  
Binocular Disparity ◽  
Motion Parallax ◽  
Neural Mechanism ◽  
Object Motion ◽  
Depth Cues ◽  
Behavioral Studies ◽  
Observer Motion ◽  
Self Motion

Detecting objects that move in a scene is a fundamental computation performed by the visual system. This computation is greatly complicated by observer motion, which causes most objects to move across the retinal image. How the visual system detects scene-relative object motion during self-motion is poorly understood. Human behavioral studies suggest that the visual system may identify local conflicts between motion parallax and binocular disparity cues to depth, and may use these signals to detect moving objects. We describe a novel mechanism for performing this computation based on neurons in macaque area MT with incongruent depth tuning for binocular disparity and motion parallax cues. Neurons with incongruent tuning respond selectively to scene-relative object motion and their responses are predictive of perceptual decisions when animals are trained to detect a moving object during selfmotion. This finding establishes a novel functional role for neurons with incongruent tuning for multiple depth cues.

scholarly journals Psychophysical evidence for auditory motion parallax

2018 ◽  
Vol 115 (16) ◽  
pp. 4264-4269 ◽  
Author(s):  
Daria Genzel ◽  
Michael Schutte ◽  
W. Owen Brimijoin ◽  
Paul R. MacNeilage ◽  
Lutz Wiegrebe
Keyword(s):  
Motion Parallax ◽  
Relative Depth ◽  
Auditory Motion ◽  
Motion Platform ◽  
Sound Sources ◽  
Binaural Cues ◽  
Binaural Processing ◽  
Perceptual Strategy ◽  
Observer Motion ◽  
Self Motion

Distance is important: From an ecological perspective, knowledge about the distance to either prey or predator is vital. However, the distance of an unknown sound source is particularly difficult to assess, especially in anechoic environments. In vision, changes in perspective resulting from observer motion produce a reliable, consistent, and unambiguous impression of depth known as motion parallax. Here we demonstrate with formal psychophysics that humans can exploit auditory motion parallax, i.e., the change in the dynamic binaural cues elicited by self-motion, to assess the relative depths of two sound sources. Our data show that sensitivity to relative depth is best when subjects move actively; performance deteriorates when subjects are moved by a motion platform or when the sound sources themselves move. This is true even though the dynamic binaural cues elicited by these three types of motion are identical. Our data demonstrate a perceptual strategy to segregate intermittent sound sources in depth and highlight the tight interaction between self-motion and binaural processing that allows assessment of the spatial layout of complex acoustic scenes.

scholarly journals Causal inference accounts for heading perception in the presence of object motion

2019 ◽  
Vol 116 (18) ◽  
pp. 9060-9065 ◽  
Author(s):  
Kalpana Dokka ◽  
Hyeshin Park ◽  
Michael Jansen ◽  
Gregory C. DeAngelis ◽  
Dora E. Angelaki
Keyword(s):  
Causal Inference ◽  
Virtual World ◽  
Moving Objects ◽  
Object Motion ◽  
Image Motion ◽  
Inference Problem ◽  
Accuracy And Precision ◽  
The World ◽  
Self Motion ◽  
The Brain

The brain infers our spatial orientation and properties of the world from ambiguous and noisy sensory cues. Judging self-motion (heading) in the presence of independently moving objects poses a challenging inference problem because the image motion of an object could be attributed to movement of the object, self-motion, or some combination of the two. We test whether perception of heading and object motion follows predictions of a normative causal inference framework. In a dual-report task, subjects indicated whether an object appeared stationary or moving in the virtual world, while simultaneously judging their heading. Consistent with causal inference predictions, the proportion of object stationarity reports, as well as the accuracy and precision of heading judgments, depended on the speed of object motion. Critically, biases in perceived heading declined when the object was perceived to be moving in the world. Our findings suggest that the brain interprets object motion and self-motion using a causal inference framework.

scholarly journals Border-ownership-dependent tilt aftereffect for shape defined by binocular disparity and motion parallax

2018 ◽  
Author(s):  
Reuben Rideaux ◽  
William J Harrison
Keyword(s):  
Binocular Disparity ◽  
Motion Parallax ◽  
Neural Systems ◽  
Visual Object ◽  
Access To Information ◽  
Tilt Aftereffect ◽  
Critical Function ◽  
Depth Order ◽  
Depth Cues ◽  
Ground Segmentation

ABSTRACTDiscerning objects from their surrounds (i.e., figure-ground segmentation) in a way that guides adaptive behaviours is a fundamental task of the brain. Neurophysiological work has revealed a class of cells in the macaque visual cortex that may be ideally suited to support this neural computation: border-ownership cells (Zhou, Friedman, & von der Heydt, 2000). These orientation-tuned cells appear to respond conditionally to the borders of objects. A behavioural correlate supporting the existence of these cells in humans was demonstrated using two-dimensional luminance defined objects (von der Heydt, Macuda, & Qiu, 2005). However, objects in our natural visual environments are often signalled by complex cues, such as motion and depth order. Thus, for border-ownership systems to effectively support figure-ground segmentation and object depth ordering, they must have access to information from multiple depth cues with strict depth order selectivity. Here we measure in humans (of both sexes) border-ownership-dependent tilt aftereffects after adapting to figures defined by either motion parallax or binocular disparity. We find that both depth cues produce a tilt aftereffect that is selective for figure-ground depth order. Further, we find the effects of adaptation are transferable between cues, suggesting that these systems may combine depth cues to reduce uncertainty (Bülthoff & Mallot, 1988). These results suggest that border-ownership mechanisms have strict depth order selectivity and access to multiple depth cues that are jointly encoded, providing compelling psychophysical support for their role in figure-ground segmentation in natural visual environments.SIGNIFICANCE STATEMENTSegmenting a visual object from its surrounds is a critical function that may be supported by “border-ownership” neural systems that conditionally respond to object borders. Psychophysical work indicates these systems are sensitive to objects defined by luminance contrast. To effectively support figure-ground segmentation, however, neural systems supporting border-ownership must have access to information from multiple depth cues and depth order selectivity. We measured border-ownership-dependent tilt aftereffects to figures defined by either motion parallax or binocular disparity and found aftereffects for both depth cues. These effects were transferable between cues, but selective for figure-ground depth order. Our results suggest that the neural systems supporting figure-ground segmentation have strict depth order selectivity and access to multiple depth cues that are jointly encoded.

scholarly journals Flow parsing and biological motion

2021 ◽  
Author(s):  
Katja M. Mayer ◽  
Hugh Riddell ◽  
Markus Lappe
Keyword(s):  
Prior Knowledge ◽  
Relative Motion ◽  
Biological Motion ◽  
Moving Objects ◽  
Human Motion ◽  
Object Motion ◽  
Biological Features ◽  
Typical Object ◽  
Point Light ◽  
Self Motion

AbstractFlow 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.

scholarly journals Processing of object motion and self-motion in the lateral subdivision of the medial superior temporal area in macaques

2019 ◽  
Vol 121 (4) ◽  
pp. 1207-1221 ◽  
Author(s):  
Ryo Sasaki ◽  
Dora E. Angelaki ◽  
Gregory C. DeAngelis
Keyword(s):  
Visual Cues ◽  
Moving Objects ◽  
Visual Motion ◽  
Object Motion ◽  
Image Motion ◽  
Motion Processing ◽  
Temporal Area ◽  
Medial Superior Temporal ◽  
Visual Motion Processing ◽  
Self Motion

Multiple areas of macaque cortex are involved in visual motion processing, but their relative functional roles remain unclear. The medial superior temporal (MST) area is typically divided into lateral (MSTl) and dorsal (MSTd) subdivisions that are thought to be involved in processing object motion and self-motion, respectively. Whereas MSTd has been studied extensively with regard to processing visual and nonvisual self-motion cues, little is known about self-motion signals in MSTl, especially nonvisual signals. Moreover, little is known about how self-motion and object motion signals interact in MSTl and how this differs from interactions in MSTd. We compared the visual and vestibular heading tuning of neurons in MSTl and MSTd using identical stimuli. Our findings reveal that both visual and vestibular heading signals are weaker in MSTl than in MSTd, suggesting that MSTl is less well suited to participate in self-motion perception than MSTd. We also tested neurons in both areas with a variety of combinations of object motion and self-motion. Our findings reveal that vestibular signals improve the separability of coding of heading and object direction in both areas, albeit more strongly in MSTd due to the greater strength of vestibular signals. Based on a marginalization technique, population decoding reveals that heading and object direction can be more effectively dissociated from MSTd responses than MSTl responses. Our findings help to clarify the respective contributions that MSTl and MSTd make to processing of object motion and self-motion, although our conclusions may be somewhat specific to the multipart moving objects that we employed. NEW & NOTEWORTHY Retinal image motion reflects contributions from both the observer’s self-motion and the movement of objects in the environment. The neural mechanisms by which the brain dissociates self-motion and object motion remain unclear. This study provides the first systematic examination of how the lateral subdivision of area MST (MSTl) contributes to dissociating object motion and self-motion. We also examine, for the first time, how MSTl neurons represent translational self-motion based on both vestibular and visual cues.

Human temporal coordination of visual and auditory events in virtual reality

2012 ◽  
Vol 25 (0) ◽  
pp. 31
Author(s):  
Michiteru Kitazaki
Keyword(s):  
Virtual Reality ◽  
Temporal Order ◽  
Binocular Disparity ◽  
Color Change ◽  
Motion Parallax ◽  
Near Field ◽  
Auditory Stimuli ◽  
Visual Depth ◽  
Virtual Reality Environment ◽  
Depth Cues

Since the speed of sound is much slower than light, we sometimes hear a sound later than an accompanying light event (e.g., thunder and lightning at a far distance). However, Sugita and Suzuki (2003) reported that our brain coordinates a sound and its accompanying light to be perceived simultaneously within 20 m distance. Thus, the light accompanied with physically delayed sound is perceived simultaneously with the sound in near field. We aimed to test if this sound–light coordination occurs in a virtual-reality environment and investigate effects of binocular disparity and motion parallax. Six naive participants observed visual stimuli on a 120-inch screen in a darkroom and heard auditory stimuli from a headphone. A ball was presented in a textured corridor and its distance from the participant was varied from 3–20 m. The ball changed to be in red before or after a short (10 ms) white noise (time difference: −120, −60, −30, 0, +30, +60, +120 ms), and participants judged temporal order of the color-change and the sound. We varied visual depth cues (binocular disparity and motion parallax) in the virtual-reality environment, and measured the physical delay at which visual and auditory events were perceived simultaneously. In terms of the results, we did not find sound–light coordination without binocular disparity or motion parallax, but found it with both cues. These results suggest that binocular disparity and motion parallax are effective for sound–light coordination in virtual-reality environment, and richness of depth cues are important for the coordination.

Binocular Disparity and Head-Up Displays

1980 ◽  
Vol 22 (4) ◽  
pp. 435-444 ◽  
Author(s):  
Christopher P. Gibson
Keyword(s):  
Visual System ◽  
Binocular Disparity ◽  
Spatial Location ◽  
Retinal Disparity ◽  
Visual Discomfort ◽  
Perceptual Effect ◽  
Depth Cues

Collimation errors present in displays such as the head-up display (HUD) will produce retinal disparity on the retinae of the observer and will have the effect of altering the spatial location of the display. It is apparent that this can, in some instances, give rise to visual discomfort. Psychophysical methods were used to examine the sensitivity and the tolerances of the visual system to binocular disparity in HUDs. It was shown that, when left to their own devices, subjects preferred a small positive disparity to exist between the HUD and the outside world and that even small amounts of negative disparity can have a disturbing perceptual effect. The effect is discussed in relation to the contradictory depth cues which can exist in this kind of electro-optical display.

The Appearance of Surfaces Specified by Motion Parallax and Binocular Disparity

1989 ◽  
Vol 41 (4) ◽  
pp. 697-717 ◽  
Author(s):  
Brian J. Rogers ◽  
Thomas S. Collett
Keyword(s):  
Visual System ◽  
Binocular Disparity ◽  
Motion Parallax ◽  
Vertical Axis ◽  
Line Of Sight ◽  
Depth Information ◽  
Real Surface ◽  
Corrugated Surface ◽  
Corrugated Surfaces ◽  
Matching Technique

The experiments reported in this paper were designed to investigate how depth information from binocular disparity and motion parallax cues is integrated in the human visual system. Observers viewed simulated 3-D corrugated surfaces that translated to and fro across their line of sight. The depth of the corrugations was specified by either motion parallax, or binocular disparities, or some combination of the two. The amount of perceived depth in the corrugations was measured using a matching technique. A monocularly viewed surface specified by parallax alone was seen as a rigid, corrugated surface translating along a fronto-parallel path. The perceived depth of the corrugations increased monotonically with the amount of parallax motion, just as if observers were viewing an equivalent real surface that produced the same parallax transformation. With binocular viewing and zero disparities between the images seen by the two eyes, the perceived depth was only about half of that predicted by the monocular cue. In addition, this binocularly viewed surface appeared to rotate about a vertical axis as it translated to and fro. With other combinations of motion parallax and binocular disparity, parallax only affected the perceived depth when the disparity gradients of the corrugations were shallow. The discrepancy between the parallax and disparity signals was typically resolved by an apparent rotation of the surface as it translated to and fro. The results are consistent with the idea that the visual system attempts to minimize the discrepancies between (1) the depth signalled by disparity and that required by a particular interpretation of the parallax transformation and (2) the amount of rotation required by that interpretation and the amount of rotation signalled by other cues in the display.

scholarly journals Acoustic facilitation of object movement detection during self-motion

2011 ◽  
Vol 278 (1719) ◽  
pp. 2840-2847 ◽  
Author(s):  
F. J. Calabro ◽  
S. Soto-Faraco ◽  
L. M. Vaina
Keyword(s):  
Optic Flow ◽  
Animal Species ◽  
Moving Objects ◽  
Object Motion ◽  
Auditory Stimuli ◽  
Object Representations ◽  
Detection Rates ◽  
Object Movement ◽  
Psychophysical Studies ◽  
Self Motion

In humans, as well as most animal species, perception of object motion is critical to successful interaction with the surrounding environment. Yet, as the observer also moves, the retinal projections of the various motion components add to each other and extracting accurate object motion becomes computationally challenging. Recent psychophysical studies have demonstrated that observers use a flow-parsing mechanism to estimate and subtract self-motion from the optic flow field. We investigated whether concurrent acoustic cues for motion can facilitate visual flow parsing, thereby enhancing the detection of moving objects during simulated self-motion. Participants identified an object (the target) that moved either forward or backward within a visual scene containing nine identical textured objects simulating forward observer translation. We found that spatially co-localized, directionally congruent, moving auditory stimuli enhanced object motion detection. Interestingly, subjects who performed poorly on the visual-only task benefited more from the addition of moving auditory stimuli. When auditory stimuli were not co-localized to the visual target, improvements in detection rates were weak. Taken together, these results suggest that parsing object motion from self-motion-induced optic flow can operate on multisensory object representations.

scholarly journals Object representation and distance encoding in three-dimensional environments by a neural circuit in the visual system of the blowfly

2012 ◽  
Vol 107 (12) ◽  
pp. 3446-3457 ◽  
Author(s):  
Pei Liang ◽  
Jochen Heitwerth ◽  
Roland Kern ◽  
Rafael Kurtz ◽  
Martin Egelhaaf
Keyword(s):  
Visual System ◽  
Optic Flow ◽  
Moving Objects ◽  
Neural Circuit ◽  
Strong Dependence ◽  
Three Dimensional ◽  
Object Motion ◽  
Induced Response ◽  
Wide Field ◽  
Distance Information

Three motion-sensitive key elements of a neural circuit, presumably involved in processing object and distance information, were analyzed with optic flow sequences as experienced by blowflies in a three-dimensional environment. This optic flow is largely shaped by the blowfly's saccadic flight and gaze strategy, which separates translational flight segments from fast saccadic rotations. By modifying this naturalistic optic flow, all three analyzed neurons could be shown to respond during the intersaccadic intervals not only to nearby objects but also to changes in the distance to background structures. In the presence of strong background motion, the three types of neuron differ in their sensitivity for object motion. Object-induced response increments are largest in FD1, a neuron long known to respond better to moving objects than to spatially extended motion patterns, but weakest in VCH, a neuron that integrates wide-field motion from both eyes and, by inhibiting the FD1 cell, is responsible for its object preference. Small but significant object-induced response increments are present in HS cells, which serve both as a major input neuron of VCH and as output neurons of the visual system. In both HS and FD1, intersaccadic background responses decrease with increasing distance to the animal, although much more prominently in FD1. This strong dependence of FD1 on background distance is concluded to be the consequence of the activity of VCH that dramatically increases its activity and, thus, its inhibitory strength with increasing distance.

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