Aging and the Visual Perception of Motion Direction: Solving the Aperture Problem

An experiment required younger and older adults to estimate coherent visual motion direction from multiple motion signals, where each motion signal was locally ambiguous with respect to the true direction of pattern motion. Thus, accurate performance required the successful integration of motion signals across space (i.e., accurate performance required solution of the aperture problem) . The observers viewed arrays of either 64 or 9 moving line segments; because these lines moved behind apertures, their individual local motions were ambiguous with respect to direction (i.e., were subject to the aperture problem). Following 2.4 seconds of pattern motion on each trial (true motion directions ranged over the entire range of 360° in the fronto-parallel plane), the observers estimated the coherent direction of motion. There was an effect of direction, such that cardinal directions of pattern motion were judged with less error than oblique directions. In addition, a large effect of aging occurred—The average absolute errors of the older observers were 46% and 30.4% higher in magnitude than those exhibited by the younger observers for the 64 and 9 aperture conditions, respectively. Finally, the observers’ precision markedly deteriorated as the number of apertures was reduced from 64 to 9.

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Visual Coherence Affects Smooth Pursuit

Perception ◽

10.1068/v96l0202 ◽

1996 ◽

Vol 25 (1_suppl) ◽

pp. 10-10

Author(s):

B R Beutter ◽

J Lorenceau ◽

L S Stone

Keyword(s):

Object Motion ◽

Image Motion ◽

High Luminance ◽

Perceptual Effect ◽

Low Contrast ◽

Line Segments ◽

Motion Signal ◽

Contrast Condition ◽

Retinal Image Motion ◽

Moving Line

For four subjects (one naive), we measured pursuit of a line-figure diamond moving along an elliptical path behind an invisible X-shaped aperture under two conditions. The diamond's corners were occluded and only four moving line segments were visible over the background (38 cd m−2). At low segment luminance (44 cd m−2), the percept is largely a coherently moving diamond. At high luminance (108 cd m−2), the percept is largely four independently moving segments. Along with this perceptual effect, there were parallel changes in pursuit. In the low-contrast condition, pursuit was more related to object motion. A \chi2 analysis showed ( p>0.05) that for 98% of trials subjects were more likely tracking the object than the segments, for 29% of trials one could not reject the hypothesis that subjects were tracking the object and not the segments, and for 100% of trials one could reject the hypothesis that subjects were tracking the segments and not the object. Conversely, in the high-contrast condition, pursuit appeared more related to segment motion. For 66% of trials subjects were more likely tracking the segments than the object; for 94% of trials one could reject the hypothesis that subjects were tracking the object and not the segments; and for 13% of trials one could not reject the hypothesis that subjects were tracking the segments and not the object. These results suggest that pursuit is driven by the same object-motion signal as perception, rather than by simple retinal image motion.

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The direction after-effect is a global motion phenomenon

Royal Society Open Science ◽

10.1098/rsos.190114 ◽

2019 ◽

Vol 6 (3) ◽

pp. 190114

Author(s):

William Curran ◽

Lee Beattie ◽

Delfina Bilello ◽

Laura A. Coulter ◽

Jade A. Currie ◽

...

Keyword(s):

Neural Mechanisms ◽

Motion Processing ◽

Global Motion ◽

Local Motion ◽

Motion Direction ◽

Processing Level ◽

True Motion ◽

Pattern Motion ◽

Moving Stimulus ◽

After Effect

Prior experience influences visual perception. For example, extended viewing of a moving stimulus results in the misperception of a subsequent stimulus's motion direction—the direction after-effect (DAE). There has been an ongoing debate regarding the locus of the neural mechanisms underlying the DAE. We know the mechanisms are cortical, but there is uncertainty about where in the visual cortex they are located—at relatively early local motion processing stages, or at later global motion stages. We used a unikinetic plaid as an adapting stimulus, then measured the DAE experienced with a drifting random dot test stimulus. A unikinetic plaid comprises a static grating superimposed on a drifting grating of a different orientation. Observers cannot see the true motion direction of the moving component; instead they see pattern motion running parallel to the static component. The pattern motion of unikinetic plaids is encoded at the global processing level—specifically, in cortical areas MT and MST—and the local motion component is encoded earlier. We measured the direction after-effect as a function of the plaid's local and pattern motion directions. The DAE was induced by the plaid's pattern motion, but not by its component motion. This points to the neural mechanisms underlying the DAE being located at the global motion processing level, and no earlier than area MT.

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From Following Edges to Pursuing Objects

Journal of Neurophysiology ◽

10.1152/jn.00987.2001 ◽

2002 ◽

Vol 88 (5) ◽

pp. 2869-2873 ◽

Cited By ~ 43

Author(s):

Guillaume S. Masson ◽

Leland S. Stone

Keyword(s):

Accurate Estimate ◽

Object Motion ◽

Initial Direction ◽

Motion Direction ◽

Multiple Features ◽

Retinal Slip ◽

Motion Signal ◽

Critical Issues ◽

Arbitrary Objects ◽

Moving Line

Primates can generate accurate, smooth eye-movement responses to moving target objects of arbitrary shape and size, even in the presence of complex backgrounds and/or the extraneous motion of non-target objects. Most previous studies of pursuit have simply used a spot moving over a featureless background as the target and have thus neglected critical issues associated with the general problem of recovering object motion. Visual psychophysicists and theoreticians have shown that, for arbitrary objects with multiple features at multiple orientations, object-motion estimation for perception is a complex, multi-staged, time-consuming process. To examine the temporal evolution of the motion signal driving pursuit, we recorded the tracking eye movements of human observers to moving line-figure diamonds. We found that pursuit is initially biased in the direction of the vector average of the motions of the diamond's line segments and gradually converges to the true object-motion direction with a time constant of approximately 90 ms. Furthermore, transient blanking of the target during steady-state pursuit induces a decrease in tracking speed, which, unlike pursuit initiation, is subsequently corrected without an initial direction bias. These results are inconsistent with current models in which pursuit is driven by retinal-slip error correction. They demonstrate that pursuit models must be revised to include a more complete visual afferent pathway, which computes, and to some extent latches on to, an accurate estimate of object direction over the first hundred milliseconds or so of motion.

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Temporal Dynamics of 2D Motion Integration for Ocular Following in Macaque Monkeys

Journal of Neurophysiology ◽

10.1152/jn.01061.2009 ◽

2010 ◽

Vol 103 (3) ◽

pp. 1275-1282 ◽

Cited By ~ 10

Author(s):

Fréderic V. Barthélemy ◽

Jérome Fleuriet ◽

Guillaume S. Masson

Keyword(s):

Temporal Dynamics ◽

Time Lag ◽

Small Time ◽

Open Loop ◽

Dynamical Process ◽

Motion Direction ◽

Aperture Problem ◽

Ocular Following ◽

Pattern Motion ◽

Line Ending

Several recent studies have shown that extracting pattern motion direction is a dynamical process where edge motion is first extracted and pattern-related information is encoded with a small time lag by MT neurons. A similar dynamics was found for human reflexive or voluntary tracking. Here, we bring an essential, but still missing, piece of information by documenting macaque ocular following responses to gratings, unikinetic plaids, and barber-poles. We found that ocular tracking was always initiated first in the grating motion direction with ultra-short latencies (∼55 ms). A second component was driven only 10–15 ms later, rotating tracking toward pattern motion direction. At the end the open-loop period, tracking direction was aligned with pattern motion direction (plaids) or the average of the line-ending motion directions (barber-poles). We characterized the dependency on contrast of each component. Both timing and direction of ocular following were quantitatively very consistent with the dynamics of neuronal responses reported by others. Overall, we found a remarkable consistency between neuronal dynamics and monkey behavior, advocating for a direct link between the neuronal solution of the aperture problem and primate perception and action.

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Pattern and component responses of primate MT neurons recorded with multi-contact electrodes, stimulated with 1D and 2D noise patterns.

10.1101/2021.12.23.474004 ◽

2021 ◽

Author(s):

Christian Quaia ◽

Incheol Kang ◽

Bruce G Cumming

Keyword(s):

Type I ◽

Motion Direction ◽

Middle Temporal ◽

Mt Neurons ◽

Aperture Problem ◽

The Past ◽

Cortex Area ◽

Pattern Motion ◽

Alternative Measures ◽

Contact Electrodes

Direction selective neurons in primary visual cortex (area V1) are affected by the aperture problem, i.e., they are only sensitive to motion orthogonal to their preferred orientation. A solution to this problem first emerges in the middle temporal (MT) area, where a subset of neurons (called pattern cells) combine motion information across multiple orientations and directions, becoming sensitive to pattern motion direction. These cells are expected to play a prominent role in subsequent neural processing, but they are intermixed with cells that behave like V1 cells (component cells), and others that do not clearly fall in either group. The picture is further complicated by the finding that cells that behave like pattern cells with one type of pattern, might behave like component cells for another. We recorded from macaque MT neurons using multi-contact electrodes while presenting both type I and unikinetic plaids, in which the components were 1D noise patterns. We found that the indices that have been used in the past to classify neurons as pattern or component cells work poorly when the properties of the stimulus are not optimized for the cell being recorded, as is always the case with multi-contact arrays. We thus propose alternative measures, which considerably ameliorate the problem, and allow us to gain insights in the signals carried by individual MT neurons. We conclude that arranging cells along a component-to-pattern continuum is an oversimplification, and that the signals carried by individual cells only make sense when embodied in larger populations.

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Visual motion assists in social cognition

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2021325117 ◽

2020 ◽

Vol 117 (50) ◽

pp. 32165-32168

Author(s):

Arvid Guterstam ◽

Michael S. A. Graziano

Keyword(s):

Social Cognition ◽

Visual Motion ◽

Cognitive Model ◽

Object Motion ◽

Motion Processing ◽

Attentional State ◽

Motion Direction ◽

Motion Signal ◽

Visual Motion Processing ◽

The Brain

Recent evidence suggests a link between visual motion processing and social cognition. When person A watches person B, the brain of A apparently generates a fictitious, subthreshold motion signal streaming from B to the object of B’s attention. These previous studies, being correlative, were unable to establish any functional role for the false motion signals. Here, we directly tested whether subthreshold motion processing plays a role in judging the attention of others. We asked, if we contaminate people’s visual input with a subthreshold motion signal streaming from an agent to an object, can we manipulate people’s judgments about that agent’s attention? Participants viewed a display including faces, objects, and a subthreshold motion hidden in the background. Participants’ judgments of the attentional state of the faces was significantly altered by the hidden motion signal. Faces from which subthreshold motion was streaming toward an object were judged as paying more attention to the object. Control experiments showed the effect was specific to the agent-to-object motion direction and to judging attention, not action or spatial orientation. These results suggest that when the brain models other minds, it uses a subthreshold motion signal, streaming from an individual to an object, to help represent attentional state. This type of social-cognitive model, tapping perceptual mechanisms that evolved to process physical events in the real world, may help to explain the extraordinary cultural persistence of beliefs in mind processes having physical manifestation. These findings, therefore, may have larger implications for human psychology and cultural belief.

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The Aperture Problem

10.1093/acprof:oso/9780199794607.003.0076 ◽

2017 ◽

Author(s):

Maggie Shiffrar

Keyword(s):

Visual Perception ◽

Visual System ◽

Simple Form ◽

Moving Objects ◽

Visual Motion ◽

Motion Information ◽

Aperture Problem ◽

Simultaneous Integration ◽

Illusory Perception ◽

True Direction

The accurate visual perception of an object’s motion requires the simultaneous integration of motion information arising from that object along with the segmentation of motion information from other objects. When moving objects are seen through apertures, or viewing windows, the resultant illusions highlight some of the challenges that the visual system faces as it balances motion segmentation with motion integration. One example is the barber pole Illusion, in which lines appear to translate orthogonally to their true direction of emotion. Another is the illusory perception of incoherence when simple rectilinear objects translate or rotate behind disconnected apertures. Studies of these illusions suggest that visual motion processes frequently rely on simple form cues.

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Neural selectivity for visual motion in macaque area V3A

10.1101/2020.09.15.298349 ◽

2020 ◽

Author(s):

Nardin Nakhla ◽

Yavar Korkian ◽

Matthew R. Krause ◽

Christopher C. Pack

Keyword(s):

Visual Cortex ◽

Optic Flow ◽

Functional Role ◽

Visual Motion ◽

Flow Patterns ◽

Brain Regions ◽

Direction Selectivity ◽

Motion Processing ◽

Imaging Studies ◽

Motion Direction

AbstractThe processing of visual motion is carried out by dedicated pathways in the primate brain. These pathways originate with populations of direction-selective neurons in the primary visual cortex, which project to dorsal structures like the middle temporal (MT) and medial superior temporal (MST) areas. Anatomical and imaging studies have suggested that area V3A might also be specialized for motion processing, but there have been very few studies of single-neuron direction selectivity in this area. We have therefore performed electrophysiological recordings from V3A neurons in two macaque monkeys (one male and one female) and measured responses to a large battery of motion stimuli that includes translation motion, as well as more complex optic flow patterns. For comparison, we simultaneously recorded the responses of MT neurons to the same stimuli. Surprisingly, we find that overall levels of direction selectivity are similar in V3A and MT and moreover that the population of V3A neurons exhibits somewhat greater selectivity for optic flow patterns. These results suggest that V3A should be considered as part of the motion processing machinery of the visual cortex, in both human and non-human primates.Significance statementAlthough area V3A is frequently the target of anatomy and imaging studies, little is known about its functional role in processing visual stimuli. Its contribution to motion processing has been particularly unclear, with different studies yielding different conclusions. We report a detailed study of direction selectivity in V3A. Our results show that single V3A neurons are, on average, as capable of representing motion direction as are neurons in well-known structures like MT. Moreover, we identify a possible specialization for V3A neurons in representing complex optic flow, which has previously been thought to emerge in higher-order brain regions. Thus it appears that V3A is well-suited to a functional role in motion processing.

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