Central perimetric sensitivity estimates are directly influenced by the fixation target

This study assessed visual-otolith interaction in healthy older humans and compared responses from older subjects to those of younger subjects. Using off-vertical axis rotation (OVAR) to stimulate the otolith organs, eye movement responses, measured using electro-oculography, were recorded during rotation in the dark, rotation with an earth-fixed lighted visual surround, and rotation with a subject-fixed fixation target. Results indicated that older subjects, like young subjects, exhibit a modulation component that was as large during rotation with a lighted earth-fixed visual surround as that seen in the dark and a modulation component during rotation with a subject-fixed visual target that was incompletely suppressed. The modulation component was, in general, larger in the older subjects. This study confirms findings from a previous study of visual-otolith interaction in young subjects and suggests that older subjects, like young subjects, have difficulty visually suppressing the modulation component induced by off-vertical axis rotation.

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The fixation target influences the near deviation and AC/A ratio in intermittent exotropia

Journal of American Association for Pediatric Ophthalmology and Strabismus ◽

10.1016/j.jaapos.2009.11.014 ◽

2010 ◽

Vol 14 (1) ◽

pp. 25-30 ◽

Cited By ~ 7

Author(s):

Thong Le ◽

Konstandina Koklanis ◽

Zoran Georgievski

Keyword(s):

Fixation Target ◽

Intermittent Exotropia

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Saccade Mechanism Based on Processes for Depth Estimation and Incongruity Detection between Binocular Retinal Images – Analysis of Gazing Positions and Inter-saccade Intervals –

Journal of Robotics and Mechatronics ◽

10.20965/jrm.1997.p0111 ◽

1997 ◽

Vol 9 (2) ◽

pp. 111-120

Author(s):

Hiroaki Kudo ◽

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Kenya Uomori ◽

Mitsuho Yamada ◽

Noboru Ohnishi ◽

...

Keyword(s):

Visual Processing ◽

Early Stage ◽

Depth Estimation ◽

Retinal Images ◽

Fixation Target ◽

Occlusion Detection ◽

Detection Mechanism ◽

Left And Right

We analyzed binocular gazing positions in the existence of a rim occlusion. When a human gazes at the rim of a textured cylinder, the gazing position shifts from the fixation target, When a human gazes at the rim of a cylinder whose upper-surface is visible, the gazing points are located at the estimated surface's depth. In this paper, to investigate the mechanism changing the gazing point, we analyzed inter-saccade intervals. The result shows that an occlusion detection mechanism exists at an early stage of human visual processing, and the mechanism causes a shorter-interval saccade when incongruity regions between left and right retinal images are detected. We propose a saccade mechanism which includes processes for depth estimation and incongruity detection between binocular retinal images based on relationships between the gazing positions and the results of inter-saccade intervals.

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Cue-dependent deficits in grating orientation discrimination after V4 lesions in macaques

Visual Neuroscience ◽

10.1017/s0952523800008208 ◽

1996 ◽

Vol 13 (3) ◽

pp. 529-538 ◽

Cited By ~ 53

Author(s):

Peter De Weerd ◽

Robert Desimone ◽

Leslie G. Ungerleider

Keyword(s):

Visual Field ◽

Normal Control ◽

Illusory Contour ◽

Visual Area ◽

Orientation Discrimination ◽

Fixation Target ◽

Illusory Contours ◽

Pattern Vision ◽

Area V4

AbstractTo examine the role of visual area V4 in pattern vision, we tested two monkeys with lesions of V4 on tasks that required them to discriminate the orientation of contours defined by several different cues. The cues used to separate the contours from their background included luminance, color, motion, and texture, as well as phase-shifted abutting gratings that created an “illusory” contour. The monkeys were trained to maintain fixation on a fixation target while discriminating extrafoveal stimuli, which were located in either a normal control quadrant of the visual field or in a quadrant affected by a lesion of area V4 in one hemisphere. Comparing performance in the two quadrants, we found significant deficits for contours defined by texture and for the illusory contour, but smaller or no deficits for motion-, color-, and luminance-defined contours. The data suggest a specific role of V4 in the perception of illusory contours and contours defined by texture.

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Smaller Fixation Target Size Is Associated with More Stable Fixation and Less Variance in Threshold Sensitivity

PLoS ONE ◽

10.1371/journal.pone.0165046 ◽

2016 ◽

Vol 11 (11) ◽

pp. e0165046 ◽

Cited By ~ 3

Author(s):

Kazunori Hirasawa ◽

Kana Okano ◽

Risako Koshiji ◽

Wakana Funaki ◽

Nobuyuki Shoji

Keyword(s):

Threshold Sensitivity ◽

Target Size ◽

Fixation Target ◽

Stable Fixation

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Visual encoding and fixation target selection in free viewing: presaccadic brain potentials

Frontiers in Systems Neuroscience ◽

10.3389/fnsys.2013.00026 ◽

2013 ◽

Vol 7 ◽

Cited By ~ 15

Author(s):

Andrey R. Nikolaev ◽

Peter Jurica ◽

Chie Nakatani ◽

Gijs Plomp ◽

Cees van Leeuwen

Keyword(s):

Target Selection ◽

Fixation Target ◽

Brain Potentials ◽

Free Viewing ◽

Visual Encoding

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Induced Motion Considered as a Visually Induced Oculogyral Illusion

Perception ◽

10.1068/p150131 ◽

1986 ◽

Vol 15 (2) ◽

pp. 131-138 ◽

Cited By ~ 31

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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