Aftereffects in Binocular Rivalry

Perception ◽  
1986 ◽  
Vol 15 (4) ◽  
pp. 419-434 ◽  
Author(s):  
Nicholas J Wade ◽  
Charles M M De Weert
Keyword(s):  
Binocular Rivalry ◽  
Vertical Grating ◽  
Circular Pattern ◽  
Binocular Interaction ◽  
Fourth Experiment ◽  
The Right ◽  
Horizontal Grating

Five experiments are reported in which the aftereffect paradigm was applied to binocular rivalry. In the first three experiments rivalry was between a vertical grating presented to the left eye and a horizontal grating presented to the right eye. In the fourth experiment the rivalry stimuli consisted of a rotating sectored disc presented to the left eye and a static concentric circular pattern presented to the right. In experiment 5 rivalry was between static radiating and circular patterns. The predominance durations were systematically influenced by direct (same eye) and indirect (interocular) adaptation in a manner similar to that seen for spatial aftereffects. Binocular adaptation produced an aftereffect that was significantly smaller than the direct aftereffect, but not significantly different from the indirect one. A model is developed to account for the results; it involves two levels of binocular interaction in addition to monocular channels. It is suggested that the site of spatial aftereffects is the same as that for binocular rivalry, rather than sequentially prior.

scholarly journals Endoscopic Observation of the Growth Process of a Right-Side Sessile Serrated Adenoma/Polyp with Cytological Dysplasia to an Invasive Submucosal Adenocarcinoma

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Kaoru Omori ◽  
Kanako Yoshida ◽  
Sadafumi Tamiya ◽  
Tsutomu Daa ◽  
Masahiro Kan
Keyword(s):  
Narrow Band Imaging ◽  
Rapid Progression ◽  
Imaging Features ◽  
Sessile Serrated Adenoma ◽  
Serrated Adenoma ◽  
Small Nodule ◽  
Circular Pattern ◽  
Endoscopic Observation ◽  
Submucosal Adenocarcinoma ◽  
The Right

A sessile serrated adenoma/polyp (SSA/P) with cytological dysplasia in the right colon, which transformed to an invasive submucosal adenocarcinoma finally, was endoscopically observed in a 76-year-old woman. A whitish soft SSA/P (approximately 25 mm in diameter) was detected in the cecum. Biopsy samples were obtained from the small nodule, and the lesion was eventually diagnosed as an SSA/P with cytological dysplasia, considering endoscopic observations, among which the narrow-band imaging features suggested that the lesion was adenomatous, that is, a round-oval pattern, and hyperplastic, that is, comprising a circular pattern with dots and an invisible capillary vessel. After 11 months, an SSA/P had rapidly developed into a submucosal adenocarcinoma with lymphatic infiltrations, and the most aggressive deep invasion was observed in the central depression. This case suggests that right-side SSA/Ps with cytological dysplasia should be removed immediately, considering the potential for rapid progression to a larger size and eventually to deep and extensive cancer.

Horizontal and Vertical Composite Effects in Novel Faces

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 118-118
Author(s):  
N P Costen ◽  
T Kato ◽  
I G Craw ◽  
S Akamatsu
Keyword(s):  
Face Recognition ◽  
Response Accuracy ◽  
Processing Strategy ◽  
Composite Construction ◽  
Composite Effect ◽  
Configural Information ◽  
The Third ◽  
Left And Right ◽  
Fourth Experiment ◽  
The Right

The composite effect, where the recognition of the upper half of a face is disrupted by a discrepant lower half relative to an isolated half-face, without a corresponding effect for vertical half-faces, provides a ready method of investigating configural information in face recognition. In previous studies purely photographic techniques have been used for composite construction. We investigated the effects of more face-like stimuli, constructed by morphing techniques. Subjects were trained to identify frontal Japanese faces, and tested on recognition on marked upper, lower, left, and right halves, both as half-faces and with distractors. While response accuracy for the upper and lower composites was lower than those for the relevant halves, there was no such effect for the right - left composites. A familiarity design was used in the second experiment to replicate this result. In the third experiment quarter-faces (top left - bottom right facial quadrants) were used to control for the information present. We found a strong composite effect for the right - left composites, and weaker ones for the top - bottom and quarter composites. In the fourth experiment we examined whether this effect was dependent on the presence of the quarter-composites by presenting them in a second block but found no effect of this manipulation. It thus appears that although there is a composite effect with faces composed in a shape-free manner, this effect is unstable. Under certain circumstances subjects may convert from a top - bottom relational processing strategy to a right - left strategy. The information used, even with a constant task, is dependent upon the variability of the images involved.

Binocular Rivalry and Immediate Memory

1967 ◽  
Vol 19 (3) ◽  
pp. 224-231 ◽  
Author(s):  
H. Sampson ◽  
J. B. Horrocks
Keyword(s):  
Binocular Rivalry ◽  
Experimental Situation ◽  
Memory Task ◽  
Visual Display ◽  
Cerebral Dominance ◽  
Spatial Cues ◽  
Immediate Memory ◽  
Superior Recall ◽  
The Right

Three experiments examine features of a simple memory task on which right-handed, right eye dominant subjects have been reported to recall digits projected to the right eye more accurately than those projected simultaneously to the left eye. Superior recall by these subjects of information projected to the right eye was observed only when stimuli projected simultaneously to both eyes were seen as overlapped in the binocular percept. Under monocular presentations, accuracy of recall was not related to the eye with which stimuli were viewed. The binocular oveslap condition has a significance other than that of simply increasing the difficulty of identifying the elements in a visual display for there were no differences in accuracy of recall from each eye when overlapped stimuli were viewed monocularly. More accurate recall of right eye information appears to reflect the resolution of a conflict between inputs from each eye. The possible relation of this finding to cerebral dominance is also discussed. Order of recall in these experiments depended mainly on spatial cues provided by the experimental situation.

The Rotating Tilted Lines Illusion

2017 ◽  
Author(s):  
Simone Gori
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Stimulus Pattern ◽  
Motion Processing ◽  
White Background ◽  
Radial Expansion ◽  
Circular Pattern ◽  
Counterclockwise Direction ◽  
The Right ◽  
Rotatory Motion

This chapter describes the Rotating-Tilted-Lines illusion , which is a new motion illusion that arises in a circular pattern composed by black, radial lines tilted to the right and presented on a white background. When one approaches the stimulus pattern, the radial lines appear to rotate in the counterclockwise direction, whereas when one recedes from it, they appear to rotate clockwise. It is the simplest pattern able to elicit illusory rotatory motion in presence of physical radial expansion. This surprising misperception of motion seems to be a result of the competition between two motion processing units in the primary visual cortex (V1, V5)

Proprioceptive coordination of movement sequences: discrimination of joint angle versus angular distance

1994 ◽  
Vol 71 (5) ◽  
pp. 1862-1872 ◽  
Author(s):  
L. Bevan ◽  
P. Cordo ◽  
L. Carlton ◽  
M. Carlton
Keyword(s):  
Visual Information ◽  
Joint Angle ◽  
Human Subjects ◽  
Joint Space ◽  
Angular Distance ◽  
Target Distance ◽  
Central Position ◽  
Starting Position ◽  
Fourth Experiment ◽  
The Right

1. The purpose of these experiments was to determine the accuracy with which human subjects could discriminate proprioceptive (nonretinotopic) targets during movement. The targets were located at either a specified angle in joint space, or a specified angular distance from an initial joint angle. 2. In these experiments the right elbows of normal human subjects were passively extended from either predictable or unpredictable starting angles. The subjects were instructed to open the right hand to indicate that the elbow was passing through a target joint angle or a target angular distance. The subjects were not given visual information about the location of the elbow, so they had to rely on proprioceptive input to perform this task. The target (criterion joint angle or angular distance) was learned by the use of proprioception during 8-15 practice trials. 3. Four experiments were conducted. In three experiments the target was located at a constant joint angle, and in the fourth experiment the target was located at a constant angular distance from the starting angle. The starting angle in all four experiments was pseudorandomly varied from trial to trial. 4. On the basis of an analysis of constant errors, subjects were more accurate at discriminating angular distance than joint angle. The slope of the relationship between the starting position and the constant errors was dictated by the task requirement. 5. In the distance discrimination experiment, when the starting angle was more flexed than the intermediate (i.e., central) position, the subjects slightly overshot the target distance. Conversely, when the starting angle was more extended than the intermediate position, the subjects slightly undershot the target distance. 6. In the joint angle discrimination experiments, the opposite results were obtained. Subjects overshot the target when the starting position of the elbow was more extended than the intermediate starting position, and they undershot the target when the starting position was more flexed than the intermediate starting position. The amplitude of these systematic errors increased when the subjects were unaware that the initial angle of their elbow was variable. 7. It is concluded that, in kinesthetic tasks of this type, the discrimination of angular distance is more accurate than the discrimination of joint angle. We hypothesize that the nervous system extracts kinematic information related to both joint angle and angular distance from proprioceptors, and that the encoding and or decoding of angular distance is more accurate than that of absolute joint angle.(ABSTRACT TRUNCATED AT 400 WORDS)

Binocular Rivalry with Rotary and Radial Motions

Perception ◽  
1986 ◽  
Vol 15 (4) ◽  
pp. 435-442 ◽  
Author(s):  
Nicholas J Wade ◽  
Charles M M De Weert
Keyword(s):  
Spatial Frequency ◽  
Binocular Rivalry ◽  
Linear Velocity ◽  
Stimulus Strength ◽  
Radial Pattern ◽  
Circular Pattern ◽  
The Third ◽  
Angular Velocities ◽  
Outward Motion ◽  
The Mean

Binocular rivalry between a radially sectored and a concentrically circular pattern was investigated in three experiments. Motion of the circular pattern was either cyclical expansion and contraction with corresponding changes in spatial frequency (experiment 1), or outward motion with a constant linear velocity (experiment 2). When both patterns were static the circular pattern was visible for longer than the radial one. Motion of either pattern alone resulted in an increase in the predominance duration and the mean period for which the pattern was visible. This is at variance with Levelt's model of rivalry. In the third experiment, rivalry was between a static circular pattern and a radial pattern that could be rotated at different angular velocities. Again it was found that an increase in stimulus strength, as measured by predominance, led to an increase in the mean periods of visibility of the rotating pattern.

Inhibition of Return without Visual Awareness

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 175-175
Author(s):  
K Watanabe ◽  
S Shimojo
Keyword(s):  
Reaction Time ◽  
Binocular Rivalry ◽  
Inhibition Of Return ◽  
Visual Awareness ◽  
Reaction Times ◽  
Horizontal Line ◽  
Vertical Segment ◽  
Line Segments ◽  
Eye Dominance ◽  
The Right

When a cue and a target are successively presented at the same location, reaction times to discriminate the location of the target are longer than when they are at different locations (inhibition of return: IOR). We found that visual awareness of the cue was not necessary for IOR to occur. Both eyes dichoptically viewed 9 × 9 scattered arrays of vertical or horizontal line segments. To avoid effects of eye dominance and binocular rivalry, cue displays were presented briefly (33, 50, or 200 ms). Three types of cue displays were randomised: (i) no cue: horizontal segments for the left (right) eye and vertical segments for the right (left) eye; subjects perceived scattered binocularly-combined crosses, (ii) binocular (fusible) cue: displays for both eyes had cue elements (a horizontal or vertical segment popping out among orthogonal background segments) and identical interocularly; subjects easily perceived the cue; (iii) dichoptic cue: displays for both eyes had cues at the same location, but all the segments were interocularly orthogonal. Here, because of the brief presentation that horizontal and vertical segments were just combined binocularly, and subjects could see only scattered crosses. Thus, they could not be aware of the cue, which exists at the monocular level. After the cue display disappeared, the target displays [same as the cue display in (ii), but with an independent location of the pop-out target] were presented (ISI=400, 800, or 1200 ms). Reaction time to discriminate location of the target was measured for three subjects who fixated on a fixation point. In our results, IOR took place in conditions (ii) and (iii). This suggests that localisation of the cue occurs without visual awareness, which then leads to IOR.

Multistage Model for Binocular Rivalry

2005 ◽  
Vol 94 (6) ◽  
pp. 4412-4420 ◽  
Author(s):  
Alan W. Freeman
Keyword(s):  
Binocular Rivalry ◽  
Visual Processing ◽  
Nonlinear Differential Equations ◽  
Neural Processing ◽  
Mutual Inhibition ◽  
Multistage Model ◽  
Cortical Areas ◽  
The Mean ◽  
The Right ◽  
Dominance Duration

Binocular rivalry is the alternating perception that occurs when incompatible stimuli are presented to the two eyes: one monocular stimulus dominates vision and then the other stimulus dominates, with a perceptual switch occurring every few seconds. There is a need for a binocular rivalry model that accounts for both well-established results on the timing of dominance intervals and for more recent evidence on the distributed neural processing of rivalry. The model for binocular rivalry developed here consists of four parallel visual channels, two driven by the left eye and two by the right. Each channel consists of several consecutive processing stages representing successively higher cortical levels, with mutual inhibition between the channels at each stage. All stages are architecturally identical. With n the number of stages, the model is implemented as 4 n nonlinear differential equations using a total of eight parameters. Despite the simplicity of its architecture, the model accounts for a variety of experimental observations: 1) the increasing depth of rivalry at higher cortical areas, as shown in electrophysiological, imaging, and psychophysical experiments; 2) the unimodal probability density of dominance durations, where the mode is less than the mean; 3) the lack of correlation between successive dominance durations; 4) the effect of interocular stimulus differences on dominance duration; and 5) eye suppression, as opposed to feature suppression. The model is potentially applicable to issues of visual processing more general than binocular rivalry.

scholarly journals ABIAKĖS KONKURENCIJOS REIŠKINIO LAIKINĖS CHARAKTERISTIKOS

Psichologija ◽  
2008 ◽  
Vol 37 ◽  
pp. 7-19
Author(s):  
Donatas Noreika ◽  
Algimantas Švegžda ◽  
Rytis Stanikūnas ◽  
Vygandas Vanagas ◽  
Henrikas Vaitkevičius
Keyword(s):  
Binocular Rivalry ◽  
Stimulus Presentation ◽  
Theoretical Models ◽  
Normal Vision ◽  
Black Line ◽  
Temporal Features ◽  
The Subject ◽  
The Right ◽  
Male Subjects ◽  
Line Crossing

Abiakė (binokulinė) konkurencija (angl. binocular rivalry) – tai suvokimo reiškinys, kai sąmoningas suvokimas pakaitomis persijunginėja tarp dviejų vaizdų, pateikiamų į vieną ir kitą akį. Tyrimo tikslas – ištirti abiakės konkurencijos reiškinio vidutinio dominavimo laiko priklausomybę nuo pateikiamų stimulų mirksėjimo dažnio. Į abi akis buvo pateikiami milisekundžių dažniu mirksintys stimulai ir tirta, ar nuo stimulo mirksėjimo dažnio priklauso vidutinis dominavimo laikas. Šią sąveiką tyrimo rezultatai patvirtino. Taip pat nustatėme, kad vidutinio dominavimo laiko priklausomybės nuo stimulo mirksėjimo dažnio funkcija nėra monotoninė: jai būdingi ekstremumai, dažniausiai pasitaikantis atstumas tarp artimiausių ekstremumų yra 5–12 ms. Ekstremumų taškų padėtis mirksėjimo dažnio skalėje nėra stabili.Pagrindiniai žodžiai: suvokimas, akių konkurencija, laikinės charakteristikos.Temporal Features of Binocular Rivalry Donatas Noreika, Algimantas Švegžda, Rytis Stanikūnas, Vygandas Vanagas, Henrikas Vaitkevičius SummaryBinocular rivalry is a phenomenon of visual perception in which perception alternates between two different images, presented to each eye’s resopective sites. Binocular rivalry has been investigated for decades, yet its nature has not been understood well. Most investigators agree now that rivalry is not a simple process but is based on complex interaction of hierarchical processes of visual system. Theoretical models are being created to describe binocular rivalry. One of the key things which the models have to explain is the temporal features of binocular rivalry: its dominant time distribution, the influence of the strength of the stimulus upon that etc. There is no agreement whether subtle temporal changes in presentation of stimuli are crucial for rivalry processes. The aim of the study was to investigate whether rivalry dominant time is influenced by flickering rate of stimuli presented to both eyes. 4 male subjects (mean age 31.8 y. with normal or corrected to normal vision) took part in the study. The stimuli were white round circles with a 45° slanting black line crossing it. The lines shown to different eyes were orthogonal to each other. Each line was subtended by 1.7 degrees. A special tachistoscope was constructed for presenting of the stimuli. In experiment 1 the stimuli were flickering in counter phase. The duration of the stimulus presentation was 5, 7, 10, 12, 15, 17, 20, 25, 30 ms. Moreover we also investigated dominant time under continuous stimuli presentation (constant view). In the second experiment the stimulus displayed to the right eye was flickering and the left one was kept steady. The subject had to press the corresponding key when he perceived the line displayed to the left eye. Dominant time was the time during which the corresponding key was pressed by the subject. Each subject took part in some 3 to 28 experiments. The results show that the flickering rate of the stimuli influences the dominant time. The function of mean dominant time versus the rate of the flickering is not a monotonic function – it has extremums with distance between two closest maximum or minimum being equal to about 5–12 ms. But the location of the extremums on the frequencies scale is not stable. We discuss a possible relation of the obtained results with the known neurophysiologic data and the theories of discrete perception.Key words: perception, binocular rivalry, temporal features.

Binocular Rivalry in Half-Occluded Regions of Coloured Stereograms Where the Background is a Drifting Grating

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 2-2
Author(s):  
M Suzuki
Keyword(s):  
Binocular Rivalry ◽  
Vertical Grating ◽  
Uncrossed Disparity ◽  
Disappearance Time ◽  
S Period ◽  
Cumulative Time

Binocular rivalry in half-occluded (HO) regions was studied with coloured stereograms where the background was a drifting grating. The coloured stereograms consisted of a central square-shaped region, a background, and HO regions. The central square-shaped region was coloured green, and was presented in either crossed or uncrossed disparity. The background was a stationary or drifting vertical grating consisting of white and grey bars. The HO regions were coloured blue, and the luminance was fixed or was changed consistently with the drifting grating in the background. Subjects judged the disappearance of the HO regions, and the cumulative time of disappearance was measured during a 30 s period. When the luminance of the HO regions was fixed against the background of a drifting grating, the disappearance time was the same as for the static grating background. However, when the luminance of the HO regions was modulated consistently with the drifting background grating, the cumulative disappearance time was significantly less than when the background was a static grating. These results suggest that the HO regions escape binocular rivalry when they correlate with the background.

Sign in / Sign up

Export Citation Format

Share Document