Monocular and Dichoptic Interactions between Moving and Stationary Stimuli

Perception ◽  
1993 ◽  
Vol 22 (9) ◽  
pp. 1111-1119 ◽  
Author(s):  
Nicholas J Wade ◽  
Michael T Swanston
Keyword(s):  
Visual Motion ◽  
The Other ◽  
Fixation Stimulus ◽  
Motion In Depth ◽  
Moving Stimuli ◽  
Stationary Stimulus ◽  
Binocular Interaction ◽  
Induced Motion ◽  
Moving Stimulus ◽  
Display Configuration

Visual motion of a physically stationary stimulus can be induced by the movement of adjacent stimuli. The frequencies of motion reports and the angular separations required to induce motion were determined for a number of stimulus configurations. A stationary stimulus was fixated in the centre of the display and the point at which induced motion was initially reported was measured. In the first experiment either one or two stationary stimuli were presented in the centre of a display and either one or two similar stimuli moved horizontally towards them. The percentage of trials on which motion was induced varied with the display configuration, being greatest with two moving and one stationary stimuli. The angular separations at which motion was reported were about 2 deg for all conditions. In the second experiment the binocular interaction of such induced motion was examined. A single static fixation stimulus was presented binocularly and a range of monocular or dichoptic conditions was examined: a single moving stimulus to one eye, two moving stimuli to one eye, or two moving stimuli dichoptically. Induced motion was reported on about 90% of the trials for the monocular and dichoptic conditions with two moving stimuli. Motion was first induced at similar angular separations by two moving stimuli, whether presented monocularly or dichoptically. Binocular interaction was further examined with a display that induced motion in the stimulus presented to one eye but not in that presented to the other: this resulted in the apparent motion in depth of the binocularly fixated stimulus.

scholarly journals Screw dislocations in the X-cube fracton model

2021 ◽  
Vol 10 (4) ◽  
Author(s):  
Nandagopal Manoj ◽  
Kevin Slagle ◽  
Wilbur Shirley ◽  
Xie Chen
Keyword(s):  
Screw Dislocation ◽  
Layered Structure ◽  
Ground State ◽  
The Other ◽  
Screw Dislocations ◽  
Topological States ◽  
Ground State Degeneracy ◽  
Induced Motion ◽  
D Model

The X-cube model, a prototypical gapped fracton model, was shown in Ref. [1] to have a foliation structure. That is, inside the 3+1 D model, there are hidden layers of 2+1 D gapped topological states. A screw dislocation in a 3+1 D lattice can often reveal nontrivial features associated with a layered structure. In this paper, we study the X-cube model on lattices with screw dislocations. In particular, we find that a screw dislocation results in a finite change in the logarithm of the ground state degeneracy of the model. Part of the change can be traced back to the effect of screw dislocations in a simple stack of 2+1 D topological states, hence corroborating the foliation structure in the model. The other part of the change comes from the induced motion of fractons or sub-dimensional excitations along the dislocation, a feature absent in the stack of 2+1D layers.

Suprathreshold Motion Sensitivity and Ocular Dominance

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 72-72
Author(s):  
B E Arnold-Schultz-Gahmen ◽  
W H Ehrenstein ◽  
L Schlykowa
Keyword(s):  
Binocular Vision ◽  
Visual Motion ◽  
Ocular Dominance ◽  
Motion Sensitivity ◽  
Eye Dominance ◽  
Direction Of Movement ◽  
Moving Stimulus ◽  
And Gender ◽  
Time Required ◽  
Condition B

Sensitivity to visual motion was investigated by measuring the time required to deflect a joystick in the direction of movement. The stimulus was a small light spot that moved at 2 deg s−1 for 1 s to the left or right; observation was binocular. Two conditions were tested: (A) a single moving stimulus suddenly appeared 5 deg left or right of fixation; (B) two stimuli were constantly visible at 5 deg left and 5 deg right of fixation before one of them began to move. Walls' (1951 A.M.A. Archives of Ophthalmology45 387 – 412) pointing test and a subset of Coren's (1993 Bulletin of the Psychonomic Society31 1 – 3) laterality questionnaire were used to identify two groups of eight subjects (matched for age, handedness, and gender) with pronounced dominance of their left or right eyes, respectively. The data suggest a higher suprathreshold motion sensitivity (better visuomotor performance) for right-eyed persons who were, on average, faster by 11 ms (A) and by 32 ms (B) than left-eyed persons. Although a similar effect of ocular dominance on suprathreshold motion sensitivity had been shown before [Schlykowa and Ehrenstein, 1993, in Gene - Brain - Behaviour Eds N Elsner, M Heisenberg (Stuttgart: Thieme) page 439], this was for monocular comparison of the dominant versus nondominant eye. Here, however, eye-dominance effects still occur with binocular vision, especially in condition B where motion has to be detected from two mirror-symmetric stimulus locations.

Experimental Study of the Effect of the Pontoon Presence on the Flow-Induced Motion of a Semi-Submersible Platform With Four Square Columns

2019 ◽  
Author(s):  
Rodolfo T. Gonçalves ◽  
Hideyuki Suzuki ◽  
Fredi Cenci ◽  
André L. C. Fujarra ◽  
Shinichiro Hirabayashi
Keyword(s):  
Experimental Study ◽  
Fatigue Life ◽  
Transverse Direction ◽  
The Other ◽  
Mooring Line ◽  
Towing Tank ◽  
Spacing Ratio ◽  
Floating System ◽  
Induced Motion ◽  
Four Square

Abstract The Flow-Induced Motions (FIM) is an essential topic on multi-column platforms due to the effect on the mooring line fatigue life. Vortex-Induced Motions (VIM) or galloping behavior can be observed for an array of four columns with square sections. The presence of pontoons showed to be important for changing the flow around the array and promote different amplitude behavior of the motions in the transverse direction mainly. This article aims to understand the effect of the presence of two pontoons on the FIM of a semi-submersible platform (SS) with four columns and square sections. Model tests of a floating system supported elastically utilizing four springs were performed in a towing tank. Five different pontoon ratios were tested, namely P/L = 0, 0.25, 0.50, 0.75 and 1.00; where P is the pontoon height, and L is the length of the square column face. The draft condition was kept constant as H/L = 1.5; where H is the draft of the platform. The spacing ratio of the columns was S/L = 4; where S is the distance between column centers. Three incidence angles of the current were carried out, i.e., 0-deg incidence represents the condition in which the two pontoons are aligned to the current, 45-deg incidence represents the non-symmetric condition in which the pontoons are 45 degrees positioned to the current, and 90-deg incidence represents the condition in which the two pontoons are perpendicular to the current. The transverse amplitudes decreased with increasing the pontoon ratio for 0 and 45-deg incidences. On the other hand, the transverse amplitudes increased with increasing the pontoon ratio for 90-deg incidence. The pontoon presence needs to be well investigated to choose the best condition to avoid raising the FIM.

The Effects of Visual Depth and Eccentricity on Manual Bias, Induced Motion, and Vection

Perception ◽  
1993 ◽  
Vol 22 (8) ◽  
pp. 929-945 ◽  
Author(s):  
Fred H Previc ◽  
Michael Donnelly
Keyword(s):  
The Other ◽  
Manual Control ◽  
Roll Motion ◽  
Entire Body ◽  
Manual Tracking ◽  
Visual Depth ◽  
Visual Inputs ◽  
Central Display ◽  
Induced Motion ◽  
The Relationship

The relationship between the effects of visual-surround roll motion on compensatory manual tracking of a central display and the perceptual phenomena of induced motion and vection were investigated. To determine if manual-control biases generated in the direction of surround rotation compensate primarily for the perceived counterrotation of the central display (‘induced motion’) or the perceived counterrotation of the entire body (‘vection’), the depth and eccentricity of the visual surround were varied. In the first experiment, twelve subjects attempted to keep an unstable central display level while viewing rotating visual surrounds in three depth planes: near (∼20 cm in front of the central display), coplanar, and far (∼21 cm behind the central display). In the second experiment, twelve additional subjects viewed a rotating surround that was presented either in the full visual field (0–110 deg) or in central and peripheral regions of similar width. Manual-control biases and induced motion were shown to be closely related to one another and strongly influenced both by central and by peripheral surround motion at or beyond the plane of fixation. Vection, on the other hand, was shown to be much more dependent on peripheral visual inputs.

Induced Motion and the Visual Vertical: Effects of Frame Size

1994 ◽  
Vol 79 (3_suppl) ◽  
pp. 1443-1450 ◽  
Author(s):  
Janice N. Brooks ◽  
Michael F. Sherrick
Keyword(s):  
Spatial Orientation ◽  
Present Experiment ◽  
Visual Motion ◽  
Frame Size ◽  
Frame Effect ◽  
Visual Vertical ◽  
Induced Motion ◽  
Perceived Motion ◽  
Extensive Involvement ◽  
Rod And Frame

Induced visual motion and the rod-and-frame effect have both been explained in terms of changes in the observer's spatial orientation. Accordingly, we examined the effects of large and small visual frames on the two phenomena in the present experiment, testing 8 male and 8 female undergraduates. During induced motion, subjects noted the perceived motion of a stationary central point of light and then moved this light back to its apparent original location. For the visual vertical, subjects aligned two points of light to indicate the perceived vertical in the presence of straight and tilted frames. As predicted, the larger frames generated more induced motion and greater displacement of the visual vertical. These results may have occurred because the larger frame had a greater effect on the subjects' spatial orientation, perhaps due to the more extensive involvement of the peripheral, or ambient, visual system.

Binocular interaction in the optokinetic system of the crab Carcinus maenas (L.): Optokinetic gain modified by bilateral image flow

1993 ◽  
Vol 10 (5) ◽  
pp. 873-885 ◽  
Author(s):  
Hans-Ortwin Nalbach ◽  
Peter Thier ◽  
Dezsö Varjú
Keyword(s):  
Eye Movements ◽  
Phase Shift ◽  
Carcinus Maenas ◽  
The Other ◽  
Rotational Component ◽  
Control Loop ◽  
Optokinetic System ◽  
Image Flow ◽  
Binocular Interaction ◽  
Better Than

AbstractWe recorded optokinetic eye movements of the crab, Carcinus maenas, in split-drum experiments. The patterns were either oscillated in antiphase on both sides mimicking translational image flow or they were oscillated in phase producing rotational image flow. Eye movements elicited by the rotational stimulus were larger than those produced by the pseudotranslational pattern movements. The smaller response to the latter is mainly a consequence of binocular interaction, the strength of which depends on both the phase-shift and amplitude of pattern oscillation. We develop two hypotheses to explain our results: either (1) signals from each eye modify the gain of the linkage signals coming from the other eye, or (2) the signals coming from the other eye modify the gain of the control loop itself. Quantitative evaluation of the data favors the second of these two hypotheses, which comprises the models of Barnes and Horridge (1969) and Nalbach et al. (1985). In addition, we found that it is the signals from the two slow channels of the crab's movement-detecting system that are transferred from one eye to the other, while signals of the fastest channel act almost exclusively ipsilaterally. We discuss our results as an adaptation by which an animal with panoramic vision compensates exclusively the rotational component of image flow during locomotion. The fact that freely walking crabs distinguish the two components of image flow better than restrained crabs indicates that further visual and nonvisual signals help to disentangle image flow.

Hearing visual motion in depth

Nature ◽  
2002 ◽  
Vol 416 (6877) ◽  
pp. 172-174 ◽  
Author(s):  
Norimichi Kitagawa ◽  
Shigeru Ichihara
Keyword(s):  
Visual Motion ◽  
Motion In Depth

Induced Motion Considered as a Visually Induced Oculogyral Illusion

Perception ◽  
1986 ◽  
Vol 15 (2) ◽  
pp. 131-138 ◽  
Author(s):  
Robert B Post
Keyword(s):  
Optokinetic Nystagmus ◽  
Optokinetic Stimulation ◽  
Fixation Target ◽  
Illusory Motion ◽  
Reverse Phase ◽  
Ocular Pursuit ◽  
Stationary Stimulus ◽  
Oculogyral Illusion ◽  
Induced Motion ◽  
Perceived Motion

The possibility that nystagmus suppression contributes to illusory motion was investigated by measuring perceived motion of a stationary stimulus following the removal of an optokinetic stimulus. This was done because optokinetic nystagmus typically outlasts cessation of an optokinetic stimulus. Therefore, it would be expected that a stationary fixated stimulus should appear to move after removal of an optokinetic stimulus if illusory motion results from nystagmus suppression. Illusory motion was reported for a stationary fixation target following optokinetic stimulation. This motion was reported first in the same direction as the preceding induced motion, then in the opposite direction. The two directions of illusory motion following optokinetic stimulation are interpreted as resulting from the use of smooth ocular pursuit to suppress first one phase of optokinetic afternystagmus and then the reverse phase. Implications for the origins of induced motion are discussed.

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