Integration of Disparity Information across Multiple Fixations

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 153-153
Author(s):  
J H Sumnall ◽  
B G Cumming ◽  
A J Parker
Keyword(s):  
Spatial Structure ◽  
Temporal Changes ◽  
Retinal Location ◽  
Sequential Presentation ◽  
Opposite Pattern ◽  
Fixation Cross ◽  
Random Dot Stereograms ◽  
Fixation Marker

We measured stereo thresholds for observers viewing noisy, dynamic random-dot stereograms (DRDS) containing either a spatial or a temporal step in depth. Stereograms were presented either with or without a small fixation cross at zero disparity. When the fixation marker was present observers were instructed to maintain fixation throughout the presentation. For spatial steps in depth, the lowest thresholds were found when there was no fixation marker and observers were free to look around the stimulus. Thresholds were higher with a fixation marker in the stimulus. The opposite pattern of results was found for stimuli that contained a temporal step in depth, ie the lowest thresholds were found with a fixation marker. Furthermore, presentation of a single depth region with a fixation marker gave the lowest thresholds of any configuration tested. The results with temporal changes in depth are reminiscent of the findings of Westheimer (1979 Experimental Brain Research36 585 – 597). Westheimer argued that sequential presentation in the same location might depress sensitivity to changes in depth, but in DRDS no single dot changes in depth without also changing in retinal location, so this explanation is not applicable. We conclude that, with a spatial step in depth, it is advantageous to foveate both sides of the step, so multiple fixations help. With a temporal step in depth, the spatial structure of the stimulus is uniform, so multiple fixations may not necessarily help, especially if they result in uncertainty about vergence position.

scholarly journals Bács-Kiskun megye térszerkezete és a telekárak (Területi különbségek a társadalom értékítéletében)

2021 ◽  
Vol 16 (3) ◽  
pp. 57-146
Author(s):  
László Tánczos-Szabó
Keyword(s):  
Correlation Analysis ◽  
Spatial Structure ◽  
Temporal Changes ◽  
Land Price ◽  
Land Prices ◽  
Price Analysis ◽  
Municipal Level

Expanding the investigations related to land price analysis, this study demonstrates the territorial aspects of the issue through the example of Bács-Kiskun county enriching the methodology of spatial structure researches. The applied correlation analysis confirmed our assumption that scarcely more than a decade after the change of ownership relations, great differences can be detected among land prices, which reflect the main features of the county’s spatial structure. The land price map of Bács-Kiskun County demonstrates the main features of the spatial structrure and the characteristics of the centre-periphery relationships at municipal level. High land prices are typical in the areas which are rich in innovations and can be characterized with denser texture. Getting farther from them, the land prices become lower. Their temporal changes are also consistent with the interactions taking place in the spatial structure.

Binocular-Disparity-Dependent Upper—Lower Hemifield Anisotropy and Left—Right Hemifield Isotropy as Revealed by Dynamic Random-Dot Stereograms

Perception ◽  
1976 ◽  
Vol 5 (2) ◽  
pp. 129-141 ◽  
Author(s):  
Bela Julesz ◽  
Bruno Breitmeyer ◽  
Walter Kropfl
Keyword(s):  
Spatial Resolution ◽  
Binocular Disparity ◽  
Human Cortex ◽  
Tilted Surface ◽  
Random Dot Stereograms ◽  
Fixation Marker ◽  
Left And Right ◽  
Temporal And Spatial ◽  
Monocular Depth ◽  
Visual Hemifields

Dynamic random-dot stereograms devoid of all monocular depth cues were used to measure the limits of temporal and spatial resolution in the center of the visual field. The temporal durations for detecting a small, briefly presented test square of different binocular disparity than the surround varied as a function of its location and binocular disparity. The test squares presented in the upper hemifield were detectable at consistently shorter durations than those presented in the lower hemifield for a surround disparity which was uncrossed relative to the fixation marker. For crossed surround disparity this preference reversed, resulting in a superiority of the lower hemifield. The anisotropy diminished for zero surround disparity. No such anisotropy was found when left and right visual hemifields were compared. It was also shown that this upper—lower temporal anisotropy (and left—right isotropy) is paralleled by a similar disparity-dependent upper—lower anisotropy (and left—right isotropy) in spatial resolution. Introduction of monocular clues into the stereograms tended to eliminate the anisotropics. This implies that the anisotropics reflect the spatiotemporal properties and distribution of binocular disparity detectors in the human cortex and result in a tilted surface that pivots around the horizontal midline in the space of binocular depth perception.

scholarly journals HIERARCHIC SKELETAL ORGANIZATION - A FACTOR REGULATING THE STRUCTURE OF FATIGUE INJURIES. PART II. HYPOTHETICAL MODEL OF FORMATION AND DISTRUPTION OF BONDS BETWEEN CRYSTALLITE ASSOCIATIONS

2010 ◽  
Vol 16 (1) ◽  
pp. 48-57
Author(s):  
A. S. Avrunin ◽  
R. M. Tikhilov ◽  
L. K. Parshin ◽  
B. E. Melnikov
Keyword(s):  
Spatial Structure ◽  
Temporal Changes ◽  
Matrix Transformation ◽  
Spatial Gradient ◽  
Hypothetical Model ◽  
Junction Formation ◽  
Mineral Matrix ◽  
Mineralization Degree ◽  
Skeletal Mineralization

The authors discuss the questions concerning local structural-temporal changes in skeletal mineralization degree, local hyper-mineralization, the role of the spatial gradient of skeletal mineralization in forces distribution during locomotion, microstructural distribution of crystallite associations, ultrastructural mineral matrix transformation in the process of its formation. Hypothetical mechanisms of joining crystallite associations into a unified mineral complex are suggested; a hypothetical spatial structure of junction formation between the nearest crystallite associations is described, as well as a supposed schema of mineral massif destruction and restoration of disrupted connections.

Observations of the spatial structure of interstellar hydrogen

1967 ◽  
Vol 31 ◽  
pp. 45-46
Author(s):  
Carl Heiles
Keyword(s):  
High Resolution ◽  
Spatial Structure ◽  
Velocity Dispersion ◽  
Temperature Variations

High-resolution 21-cm line observations in a region aroundlII= 120°,b11= +15°, have revealed four types of structure in the interstellar hydrogen: a smooth background, large sheets of density 2 atoms cm-3, clouds occurring mostly in groups, and ‘Cloudlets’ of a few solar masses and a few parsecs in size; the velocity dispersion in the Cloudlets is only 1 km/sec. Strong temperature variations in the gas are in evidence.

Bang for Your Buck: A Single-Case Experimental Design Study of Practice Amount and Distribution in Treatment for Childhood Apraxia of Speech

2019 ◽  
Vol 62 (9) ◽  
pp. 3160-3182 ◽  
Author(s):  
Edwin Maas ◽  
Christina Gildersleeve-Neumann ◽  
Kathy Jakielski ◽  
Nicolette Kovacs ◽  
Ruth Stoeckel ◽  
...  
Keyword(s):  
Single Case ◽  
Evidence Base ◽  
Distributed Practice ◽  
Single Subject ◽  
Single Subject Design ◽  
Apraxia Of Speech ◽  
Childhood Apraxia Of Speech ◽  
Opposite Pattern ◽  
Massed Practice ◽  
Treatment Conditions

Purpose The aim of this study was to examine 2 aspects of treatment intensity in treatment for childhood apraxia of speech (CAS): practice amount and practice distribution. Method Using an alternating-treatments single-subject design with multiple baselines, we compared high versus low amount of practice, and massed versus distributed practice, in 6 children with CAS. Conditions were manipulated in the context of integral stimulation treatment. Changes in perceptual accuracy, scored by blinded analysts, were quantified with effect sizes. Results Four children showed an advantage for high amount of practice, 1 showed an opposite effect, and 1 showed no condition difference. For distribution, 4 children showed a clear advantage for massed over distributed practice post treatment; 1 showed an opposite pattern, and 1 showed no clear difference. Follow-up revealed a similar pattern. All children demonstrated treatment effects (larger gains for treated than untreated items). Conclusions High practice amount and massed practice were associated with more robust speech motor learning in most children with CAS, compared to low amount and distributed practice, respectively. Variation in effects across children warrants further research to determine factors that predict optimal treatment conditions. Finally, this study adds to the evidence base supporting the efficacy of integral stimulation treatment for CAS. Supplemental Material https://doi.org/10.23641/asha.9630599

Is the Future the Right Time?

2010 ◽  
Vol 57 (4) ◽  
pp. 308-314 ◽  
Author(s):  
Marc Ouellet ◽  
Julio Santiago ◽  
Ziv Israeli ◽  
Shai Gabay
Keyword(s):  
Auditory Task ◽  
English Speakers ◽  
Visual Modality ◽  
Opposite Pattern ◽  
Time Line ◽  
Temporal Reference ◽  
Left Hand ◽  
Reading Direction ◽  
Mental Time Line ◽  
The Right

Spanish and English speakers tend to conceptualize time as running from left to right along a mental line. Previous research suggests that this representational strategy arises from the participants’ exposure to a left-to-right writing system. However, direct evidence supporting this assertion suffers from several limitations and relies only on the visual modality. This study subjected to a direct test the reading hypothesis using an auditory task. Participants from two groups (Spanish and Hebrew) differing in the directionality of their orthographic system had to discriminate temporal reference (past or future) of verbs and adverbs (referring to either past or future) auditorily presented to either the left or right ear by pressing a left or a right key. Spanish participants were faster responding to past words with the left hand and to future words with the right hand, whereas Hebrew participants showed the opposite pattern. Our results demonstrate that the left-right mapping of time is not restricted to the visual modality and that the direction of reading accounts for the preferred directionality of the mental time line. These results are discussed in the context of a possible mechanism underlying the effects of reading direction on highly abstract conceptual representations.

An opposite pattern of cognitive performance in autistic individuals with and without alexithymia.

2019 ◽  
Vol 128 (7) ◽  
pp. 735-737
Author(s):  
Eya-Mist Rødgaard ◽  
Kristian Jensen ◽  
Laurent Mottron
Keyword(s):  
Cognitive Performance ◽  
Opposite Pattern
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