Effect of disparity in the peripheral field on short-latency ocular following responses

1994 ◽  
Vol 11 (4) ◽  
pp. 833-837 ◽  
Author(s):  
K. Kawano ◽  
Y. Inoue ◽  
A. Takemura ◽  
F. A. Miles
Keyword(s):  
Central Region ◽  
Short Latency ◽  
The Other ◽  
Visual Scene ◽  
Visual Images ◽  
Viewing Distance ◽  
Other Hand ◽  
Uncrossed Disparity ◽  
Ocular Following ◽  
Random Dot Pattern

AbstractOcular following responses induced by brief movements of the visual scene were examined in monkeys for their dependence on disparity in the peripheral field. A random dot pattern was projected onto a tangent screen and partitioned into central and peripheral regions. Test stimuli were velocity steps applied in the central region, while stimuli in the periphery were stationary. The visual images in the central region were seen always in the plane of the screen, while stimuli in the periphery could be seen in front, behind, or in the plane of the screen (achieved by a system of polarizing filters). Initial ocular following responses were larger when the peripheral stimuli were presented with an uncrossed disparity than without disparity. On the other hand, responses were smaller when the peripheral stimuli were presented with crossed disparity (<5.0 deg) than without disparity. The result is consistent with the idea that ocular following responses are dependent on the perceived viewing distance.

Producing a Mental Representation of a Cup of Sake

2019 ◽  
pp. 430-448
Author(s):  
Hiroki Fukushima
Keyword(s):  
Experimental Method ◽  
Mental Representation ◽  
Mental Representations ◽  
Visual Image ◽  
The Other ◽  
Experimental Methodology ◽  
Visual Images ◽  
Other Hand ◽  
Average Person ◽  
Supporting Tool

In this chapter, methodologies for producing a mental representation of a cup of sake are introduced. Mental representations of taste are often vague and fuzzy in comparison to audio or visual images. On the other hand, some individuals, such as sommeliers or tasters of sake, are able to readily formulate a representation of the taste they experience. How can the average person produce words or other types of mental representations in such a situation? In this chapter, the author presents three methodologies for eliciting mental representations of taste: a new supporting tool for verbalizing an image of taste, an experimental method for testing a verbal and visual image for taste, and an experimental methodology for producing a free drawing representation of a cup of sake.

The effect of frontal eye field and superior colliculus lesions on saccadic latencies in the rhesus monkey

1987 ◽  
Vol 57 (4) ◽  
pp. 1033-1049 ◽  
Author(s):  
P. H. Schiller ◽  
J. H. Sandell ◽  
J. H. Maunsell
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Short Latency ◽  
The Other ◽  
Frontal Eye Field ◽  
Express Saccades ◽  
Unimodal Distribution ◽  
Other Hand ◽  
Eye Field ◽  
The Mean

Rhesus monkeys were trained to make saccadic eye movements to visual targets using detection and discrimination paradigms in which they were required to make a saccade either to a solitary stimulus (detection) or to that same stimulus when it appeared simultaneously with several other stimuli (discrimination). The detection paradigm yielded a bimodal distribution of saccadic latencies with the faster mode peaking around 100 ms (express saccades); the introduction of a pause between the termination of the fixation spot and the onset of the target (gap) increased the frequency of express saccades. The discrimination paradigm, on the other hand, yielded only a unimodal distribution of latencies even when a gap was introduced, and there was no evidence for short-latency "express" saccades. In three monkeys either the frontal eye field or the superior colliculus was ablated unilaterally. Frontal eye field ablation had no discernible long-term effects on the distribution of saccadic latencies in either the detection or discrimination tasks. After unilateral collicular ablation, on the other hand, express saccades obtained in the detection paradigm were eliminated for eye movements contralateral to the lesion, leaving only a unimodal distribution of latencies. This deficit persisted throughout testing, which in one monkey continued for 9 mo. Express saccades were not observed again for saccades contralateral to the lesion, and the mean latency of the contralateral saccades was longer than the mean latency of the second peak for the ipsiversive saccades. The latency distribution of saccades ipsiversive to the collicular lesion was unaffected except for a few days after surgery, during which time an increase in the proportion of express saccades was evident. Saccades obtained with the discrimination paradigm yielded a small but reliable increase in saccadic latencies following collicular lesions, without altering the shape of the distribution. Unilateral muscimol injections into the superior colliculus produced results similar to those obtained immediately after collicular lesions: saccades contralateral to the injection site were strongly inhibited and showed increased saccadic latencies. This was accompanied by a decrease of ipsilateral saccadic latencies and an increase in the number of saccades falling into the express range. The results suggest that the superior colliculus is essential for the generation of short-latency (express) saccades and that the frontal eye fields do not play a significant role in shaping the distribution of saccadic latencies in the paradigms used in this study.(ABSTRACT TRUNCATED AT 400 WORDS)

Binocular Rivalry in Half-Occluded Regions of Coloured Random-Dot Stereograms

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 154-154
Author(s):  
M Suzuki
Keyword(s):  
Binocular Rivalry ◽  
Ecological Validity ◽  
The Other ◽  
Other Hand ◽  
Uncrossed Disparity ◽  
Random Dot Stereograms ◽  
Normal Perception

In normal perception, binocular rivalry does not arise in half-occluded regions. However, when coloured random-dot stereograms (RDSs) were observed, binocular rivalry arose in half-occluded regions. In this study, binocular rivalry in half-occluded regions was studied with coloured RDSs. Coloured RDSs consisted of a central square-shaped region, a background, half-occluded regions, and a probe. The central square-shaped region was coloured white, and was presented in either crossed or uncrossed disparity. The background was coloured yellow. The half-occluded regions were coloured either white, yellow, or blue. The probe was coloured red, and was presented in either of the half-occluded regions. Subjects judged the disappearance of the probe and stereopsis. When the half-occluded regions were coloured the same as the front plane, the probe and stereopsis both disappeared. On the other hand, when the half-occluded regions were coloured the same as the back plane or differently from both planes only the probe disappeared while stereopsis did not disappear. Also, disappearance of the probe decreased more when the half-occluded regions were coloured the same as the back plane, than when the half-occluded regions were coloured differently from both planes. These results suggest that half-occluded regions escape binocular rivalry for several reasons, including ecological validity in 3-D representation, and that half-occluded regions are suppressed interocularly when a static stereogram is observed statically.

Short-latency ocular following responses of monkey. II. Dependence on a prior saccadic eye movement

1986 ◽  
Vol 56 (5) ◽  
pp. 1355-1380 ◽  
Author(s):  
K. Kawano ◽  
F. A. Miles
Keyword(s):  
Time Course ◽  
Visual Stimulation ◽  
Interocular Transfer ◽  
Sine Wave ◽  
Stimulus Onset ◽  
Short Latency ◽  
Visual Scene ◽  
Retinal Stimulation ◽  
Ocular Following ◽  
Eye Velocity

The ocular following responses elicited by brief unexpected movements of the visual scene were studied in eight rhesus monkeys. Test patterns were random dots except in one experiment when sine-wave gratings were used. Test stimuli were velocity steps of 100-ms duration applied after spontaneous saccades. Two response measures were used: the initial peak in the eye velocity profile (ei), and the average final eye velocity over the period of 110-140 ms measured from stimulus onset (ef). Responses were best when the test ramps began soon after saccades and attenuated progressively as the postsaccadic delay interval was increased: postsaccadic enhancement of ocular following. The decline in ei was roughly exponential: average time constant, 60 ms; average asymptote, 22%. Later measures (ef) were generally less affected. We suggest that this transient enhancement aids the visual suppression of postsaccadic ocular drifts (glissades) and the tracking of moving images newly acquired with a saccade. The magnitude of the postsaccadic enhancement was dependent on the amount of retinal stimulation during the antecedent saccade; when this stimulation was compromised, as when a vertical saccade was made while viewing a grating pattern with vertically oriented stripes, subsequent enhancement of ocular following was much reduced. Further, saccade-like conditioning movements of the visual scene resulted in an enhancement of the ocular following, elicited by subsequent test ramps, that was similar in magnitude and time course to that in the wake of real saccades. We conclude that the postsaccadic enhancement of ocular following is largely due to the visual stimulation produced by the saccade sweeping the scene across the retina. Data obtained with the visual field partitioned into central and peripheral regions (center 20-60 degrees diam) and with gaze centered suggested that the short-latency ocular following system and the enhancement mechanism that modulates it both receive their major inputs from the central 40 degrees of the retina. Further, when this central region was partitioned, enhancement was obtained only when the conditioning and test stimuli were presented to the same region of retina. Visual enhancement showed only weak interocular transfer: the conditioning and test stimuli had to be seen by the same eye to produce appreciable enhancement. These data suggest that the enhancement involves local spatial interactions at an "early" point in the visual pathway before the inputs from the two eyes have converged. When the conditioning and test stimuli impinged on different regions of the retina, brief powerful suppression of ocular following was obtained.(ABSTRACT TRUNCATED AT 400 WORDS)

Asymmetrical Effect of Crossed and Uncrossed Disparity on Stereoscopic Capture

Perception ◽  
1993 ◽  
Vol 22 (12) ◽  
pp. 1403-1413 ◽  
Author(s):  
Akira Ishigushi ◽  
Jeremy M Wolfe
Keyword(s):  
Subjective Contour ◽  
The Other ◽  
Apparent Depth ◽  
Transparent Surface ◽  
Other Hand ◽  
Uncrossed Disparity ◽  
Asymmetrical Effect ◽  
The Asymmetry ◽  
Surface Construction

When a real or subjective contour is superimposed on a repetitive texture or ‘wallpaper pattern’, the apparent depth of the elements of the wallpaper pattern may be influenced by the contour. When the contour has crossed disparity, the elements inside the contour are seen floating in the plane of the contour. This is called ‘stereoscopic capture’. On the other hand, when the contour has uncrossed disparity a different, somewhat unstable, percept is seen. The wallpaper elements are either seen to form a transparent surface floating in front of the contour, or all of the elements inside and outside of the contour are seen to lie in the uncrossed plane of the inducing contour. We suggest that the asymmetry between crossed and uncrossed stereo capture is a by-product of the different roles played by crossed and uncrossed disparity in stereoscopic surface construction: specifically, crossed and, perhaps, zero disparity spreads one-directionally into a figure from a contour whereas uncrossed disparity spreads out from a figure in all directions. These points are illustrated with a series of demonstrations.

scholarly journals Landscapes of memory: the first visual images of the Bororo of Central Brazil

2019 ◽  
Vol 16 ◽  
Author(s):  
Edgar Teodoro da Cunha ◽  
Sylvia Caiuby Novaes
Keyword(s):  
The Other ◽  
Visual Images ◽  
Central Brazil ◽  
The Past ◽  
Other Hand ◽  
History Of ◽  
Made In

Abstract The opportunity of exhibiting in a Bororo village in Central Brazil the film Matto Grosso, the Great Brazilian Wilderness (1931), and translating into Portuguese this typical travelogue and widely considered to be the first documentary with synchronized sound, led the authors to analyze visual images on the Bororo society made in the first decades of the XX century. The article focuses on how visual images - films and photographs - frequently show the intentions of the author and on the other hand may enhance memories and create a particular relationship with the past and history of a people.

The Western Balkans in translated children’s literature

2021 ◽  
Author(s):  
Marija Todorova
Keyword(s):  
Children's Literature ◽  
Production Process ◽  
Children’S Literature ◽  
The Other ◽  
Visual Images ◽  
Western Balkans ◽  
Other Hand ◽  
Target Culture

Abstract This study approaches translations as framing and representation sites that can serve to either contest or promote stereotypes. Critically looking at textual and visual images of the source culture, the discussion considers how the particular location of different participants in the translation production process contributes to the presentation of violence as a predominant image of Western Balkan nations. The analysis uncovers networks of source-based production participants focusing on images of ‘nesting’ Balkanisms and self-representations centring on love and humaneness. On the other hand, networks led by editors located in the target culture often emphasise the preconceived stereotypes of dominant violence in the Western Balkans or turn towards globalising the images of violence.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

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