Movement Aftereffects Contingent on Binocular Disparity

Perception ◽  
1974 ◽  
Vol 3 (2) ◽  
pp. 153-168 ◽  
Author(s):  
S M Anstis ◽  
J P Harris
Keyword(s):  
Binocular Disparity ◽  
Total Duration ◽  
Test Field ◽  
Movement Aftereffect ◽  
Elapsed Time ◽  
Uncrossed Disparity ◽  
Stationary Test ◽  
Time Movement

Five subjects adapted for 30 min to a textured disc lying in front of the fixation point with 0·1 deg(1) crossed disparity, which rotated clockwise at 4 rev/min, alternating with a disc behind the fixation point, with 0·1 deg of arc uncrossed disparity, which rotated anticlockwise. A stationary test field then appeared to rotate anticlockwise when it lay in front of the fixation point, and clockwise when it lay behind. Conversely, a test field in the plane of fixation briefly appeared to lie a few millimetres behind the fixation plane when it rotated clockwise, and in front when it rotated anticlockwise. The movement aftereffect contingent on disparity reappeared each time the test disparity was reversed, but the total duration of each successive aftereffect in the series decreased exponentially with elapsed time. Movement aftereffects contingent on disparity were very much stronger than those contingent on colour and won out over them when disparity was pitted against colour.

scholarly journals Chromatic assimilation unaffected by perceived depth of inducing light

2004 ◽  
Vol 21 (3) ◽  
pp. 373-376 ◽  
Author(s):  
STEVEN K. SHEVELL ◽  
DINGCAI CAO
Keyword(s):  
Depth Perception ◽  
Binocular Disparity ◽  
Neural Mechanism ◽  
Relative Depth ◽  
Test Field ◽  
Neural Process ◽  
Test Light ◽  
Chromatic Assimilation ◽  
Field Organization ◽  
Receptive Field Organization

Chromatic assimilation is a shift toward the color of nearby light. Several studies conclude that a neural process contributes to assimilation but the neural locus remains in question. Some studies posit a peripheral process, such as retinal receptive-field organization, while others claim the neural mechanism follows depth perception, figure/ground segregation, or perceptual grouping. The experiments here tested whether assimilation depends on a neural process that follows stereoscopic depth perception. By introducing binocular disparity, the test field judged in color was made to appear in a different depth plane than the light that induced assimilation. The chromaticity and spatial frequency of the inducing light, and the chromaticity of the test light, were varied. Chromatic assimilation was found with all inducing-light sizes and chromaticities, but the magnitude of assimilation did not depend on the perceived relative depth planes of the test and inducing fields. We found no evidence to support the view that chromatic assimilation depends on a neural process that follows binocular combination of the two eyes' signals.

The Effect of Stationary Patterns on Adaptation for Movement: Evidence for Inhibitory Interaction

Perception ◽  
1975 ◽  
Vol 4 (3) ◽  
pp. 311-329 ◽  
Author(s):  
John E W Mayhew
Keyword(s):  
Test Pattern ◽  
Threshold Elevation ◽  
Inhibitory Interaction ◽  
Movement Aftereffect ◽  
Specific Adaptation ◽  
Neural Processes ◽  
Stationary Test ◽  
Simple Movement ◽  
Moving Patterns ◽  
Moving Pattern

Contingent movement aftereffects (CMAEs) can be demonstrated by adapting to a red pattern rotating clockwise (cw) alternating with a green pattern rotating counterclockwise (ccw). After 5 min subjects typically report stationary test patterns as apparently rotating clockwise when they are green and counterclockwise when they are red. Also, luminance thresholds for motion now depend on both the colour and direction of the moving pattern. The thresholds for red—cw and green—ccw motion will be relatively greater than for the opposite colour motion pairings. This is called contingent threshold elevation. When stationary dots the same colour as the moving patterns are added to the adapting stimuli, subjects report weak CMAEs but no contingent threshold elevation can be demonstrated. When stationary dots opposite in colour to the moving patterns are added to the adapting stimuli, neither CMAEs nor contingent threshold elevation can be demonstrated. And yet colour specific adaptation does occur, and can be demonstrated in the colour specificity of the simple movement aftereffect. When stationary dots are added to the adapting pattern, the simple movement aftereffect though reduced, is greatest on a test pattern of the same colour as the moving dots. These findings suggest that the CMAE, contingent threshold elevation, and the colour specificity of the movement aftereffect involves neural processes differentially sensitive to the presence of stationary patterns.

Influences of Motion and Depth on Brightness Induction: An Illusory Transparency Effect?

Perception ◽  
10.1068/p3439 ◽  
2002 ◽  
Vol 31 (12) ◽  
pp. 1449-1457 ◽  
Author(s):  
Kazunori Morikawa ◽  
Thomas V Papathomas
Keyword(s):  
Binocular Disparity ◽  
Uncrossed Disparity ◽  
The Difference

Two experiments were performed to investigate whether motion and binocular disparity influence brightness induction, and whether the effects of motion and binocular disparity, if any, interact with each other. In order to introduce motion, textured backgrounds were used as the inducing field. The results showed that motion and/or crossed disparity reduce brightness induction, whereas uncrossed disparity increases it. The effect of motion and the effect of disparity are independent of each other and additive, which suggests that, to the extent that brightness induction reflects segmentation of objects, motion and binocular disparity serve independently to segment objects from their background. The difference between the effects of crossed and uncrossed disparity can be explained by what we call ‘illusory transparency’.

A Transparent Motion Aftereffect Contingent on Binocular Disparity

Perception ◽  
1994 ◽  
Vol 23 (10) ◽  
pp. 1181-1188 ◽  
Author(s):  
Frans A J Verstraten ◽  
Reinder Verlinde ◽  
R Eric Fredericksen ◽  
Wim A van de Grind
Keyword(s):  
Binocular Disparity ◽  
Motion Aftereffect ◽  
Stimulus Configuration ◽  
Retinal Disparity ◽  
Transparent Motion ◽  
Stationary Test ◽  
Vector Sum ◽  
Moving Patterns

Under transparent motion conditions overlapping surfaces are perceived simultaneously, each with its own direction. The motion aftereffect (MAE) of transparent motion, however, is unidirectional and its direction is opposite to that of a sensitivity-weighted vector sum of both inducing vectors. Here we report a bidirectional and transparent MAE contingent on binocular disparity. Depth (from retinal disparity) was introduced between two patterns. A fixation dot was presented at zero disparity, that is, located between the two adaptation patterns. After adaptation to such a stimulus configuration testing was carried out with two stationary test patterns at the same depths as the preceding moving patterns. For opposite directions a clear transparent MAE was perceived. However, if the adaptation directions were orthogonal the chance of a transparent MAE being perceived decreased substantially. This was subject dependent. Some subjects perceived an orthogonal transparent MAE whereas others saw the negative vector sum—an integrated MAE. In addition the behaviour of the MAE when the distance in depth between adapting and test patterns was increased was investigated: it was found that the visibility of the MAE then decreased. Visibility is defined in this paper as: (i) the percentage of the trials in which MAEs are perceived and (ii) the average MAE duration. Both measures decreased with increasing distance. The results suggest that segregation and integration may be mediated by direction-tuned channels that interact with disparity-tuned channels.

Strength of Motion Aftereffect Varies with Segregation of Test Field and Surround

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 64-64 ◽  
Author(s):  
J P Harris ◽  
D Sullivan
Keyword(s):  
Visual Motion ◽  
Test Pattern ◽  
Motion Aftereffect ◽  
Auditory Signal ◽  
Test Field ◽  
Rectangular Window ◽  
Stationary Test ◽  
Two Measures ◽  
Motion Detectors ◽  
Good Agreement

It is widely accepted that the motion aftereffect (MAE) results from the adaptation of visual motion detectors. However, recent work suggests that how the effects of that adaptation are expressed (the nature of the perceived MAE) depends on the nature of the inducing and test fields. We investigated how the strength of the MAE varied with the nature of the boundary between the test field and the surround. The surround (18.5 deg wide × 13.5 deg high) to the adapting and test fields was an area of vertical square-wave grating of 0.7 cycle deg−1. During adaptation, vertical stripes of the same spatial frequency as the background moved horizontally at a speed of 2 deg s−1 for 14 s within a central rectangular window of 9.7 deg wide × 7.6 deg high. At the end of adaptation, one of six different test fields was presented in the central window. In three of these, the stationary test stripes were exactly aligned with the surrounding stripes, and in the other three they were offset by half a stripe width. For two of these conditions (one aligned, one offset), a black outline was drawn around the edge of the adapting window (and so was visible only where it crossed white areas), and for two others (one aligned, one offset) the outline was red, and so visible in its entirety. The strength of MAEs in twelve subjects was assessed both by ratings at an auditory signal which occurred 0.5 s after the end of adaptation and also by measurement of their durations. There was good agreement between these two measures. MAEs were significantly stronger on the offset than on the aligned test fields. The presence of an outline increased MAE strength compared with no outline, but these outline effects were much weaker than those of offsetting the test stripes from the surround. We suggest that the MAE depends in part on the presence of a visually separable test pattern to which motion may be allocated.

Decoding conjunctions of direction-of-motion and binocular disparity from human visual cortex

2012 ◽  
Vol 107 (9) ◽  
pp. 2335-2341 ◽  
Author(s):  
Kiley J. Seymour ◽  
Colin W. G. Clifford
Keyword(s):  
Visual Processing ◽  
Binocular Disparity ◽  
Dorsal Stream ◽  
Visual Stream ◽  
Activation Patterns ◽  
Independent Information ◽  
Uncrossed Disparity ◽  
Multivariate Pattern ◽  
Joint Encoding ◽  
Dorsal Visual Stream

Motion and binocular disparity are two features in our environment that share a common correspondence problem. Decades of psychophysical research dedicated to understanding stereopsis suggest that these features interact early in human visual processing to disambiguate depth. Single-unit recordings in the monkey also provide evidence for the joint encoding of motion and disparity across much of the dorsal visual stream. Here, we used functional MRI and multivariate pattern analysis to examine where in the human brain conjunctions of motion and disparity are encoded. Subjects sequentially viewed two stimuli that could be distinguished only by their conjunctions of motion and disparity. Specifically, each stimulus contained the same feature information (leftward and rightward motion and crossed and uncrossed disparity) but differed exclusively in the way these features were paired. Our results revealed that a linear classifier could accurately decode which stimulus a subject was viewing based on voxel activation patterns throughout the dorsal visual areas and as early as V2. This decoding success was conditional on some voxels being individually sensitive to the unique conjunctions comprising each stimulus, thus a classifier could not rely on independent information about motion and binocular disparity to distinguish these conjunctions. This study expands on evidence that disparity and motion interact at many levels of human visual processing, particularly within the dorsal stream. It also lends support to the idea that stereopsis is subserved by early mechanisms also tuned to direction of motion.

Fuzzy multi-objective decision making approach for nuclear power plant installation

2020 ◽  
Vol 39 (5) ◽  
pp. 6339-6350
Author(s):  
Esra Çakır ◽  
Ziya Ulukan
Keyword(s):  
Linear Programming ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Energy Supply ◽  
Energy Demand ◽  
Nuclear Power ◽  
Power Plants ◽  
Total Duration ◽  
Objective Functions ◽  
Multi Objective

Due to the increase in energy demand, many countries suffer from energy poverty because of insufficient and expensive energy supply. Plans to use alternative power like nuclear power for electricity generation are being revived among developing countries. Decisions for installation of power plants need to be based on careful assessment of future energy supply and demand, economic and financial implications and requirements for technology transfer. Since the problem involves many vague parameters, a fuzzy model should be an appropriate approach for dealing with this problem. This study develops a Fuzzy Multi-Objective Linear Programming (FMOLP) model for solving the nuclear power plant installation problem in fuzzy environment. FMOLP approach is recommended for cases where the objective functions are imprecise and can only be stated within a certain threshold level. The proposed model attempts to minimize total duration time, total cost and maximize the total crash time of the installation project. By using FMOLP, the weighted additive technique can also be applied in order to transform the model into Fuzzy Multiple Weighted-Objective Linear Programming (FMWOLP) to control the objective values such that all decision makers target on each criterion can be met. The optimum solution with the achievement level for both of the models (FMOLP and FMWOLP) are compared with each other. FMWOLP results in better performance as the overall degree of satisfaction depends on the weight given to the objective functions. A numerical example demonstrates the feasibility of applying the proposed models to nuclear power plant installation problem.

Experimentally increased costs of parental care are shunted to offspring in species with extended care

2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser
Keyword(s):  
Life History ◽  
Parental Care ◽  
Total Duration ◽  
Bird Species ◽  
Life History Strategy ◽  
Experimental Treatment ◽  
Cost Of Care ◽  
Adult Survival ◽  
Supporting Evidence ◽  
Trade Offs

Biparental care systems are a valuable model to examine conflict, cooperation, and coordination between unrelated individuals, as the product of the interactions between the parents influences the fitness of both individuals. A common experimental technique for testing coordinated responses to changes in the costs of parental care is to temporarily handicap one parent, inducing a higher cost of providing care. However, dissimilarity in experimental designs of these studies has hindered interspecific comparisons of the patterns of cost distribution between parents and offspring. Here we apply a comparative experimental approach by handicapping a parent at nests of five bird species using the same experimental treatment. In some species, a decrease in care by a handicapped parent was compensated by its partner, while in others the increased costs of care were shunted to the offspring. Parental responses to an increased cost of care primarily depended on the total duration of care that offspring require. However, life history pace (i.e., adult survival and fecundity) did not influence parental decisions when faced with a higher cost of caring. Our study highlights that a greater attention to intergenerational trade-offs is warranted, particularly in species with a large burden of parental care. Moreover, we demonstrate that parental care decisions may be weighed more against physiological workload constraints than against future prospects of reproduction, supporting evidence that avian species may devote comparable amounts of energy into survival, regardless of life history strategy.

Pre-emptive Analgesia for Postoperative Pain Relief in Children – Role of Paracetamol

2009 ◽  
pp. 9-16
Author(s):  
Rubina Yasmin ◽  
AKM Akhtaruzzaman ◽  
Paresh Chandra Sarker ◽  
Neaz Ahmed ◽  
Ranadhir Kumar Kundu ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Postoperative Pain ◽  
Diclofenac Sodium ◽  
Total Duration ◽  
Pain Scale ◽  
Prospective Clinical Study ◽  
High Dose ◽  
Induction Of Anaesthesia

This prospective clinical study was carried out in the Dept. of Anaesthesia, Analgesia and Intensive Care Medicine, BSMMU, Dhaka, during the period of May 2003 to July 2003. The study was done to emphasize the importance of giving analgesics preemptively instead of waiting for the child to complain of pain and to produce smooth recovery after surgery by decreasing immediate postoperative pain in children by a simple, safe acceptable drug. The children scheduled for tonsillectomy under general anaesthesia were recruited in this study. The analgesic efficiency of rectal paracetamol in two doses, 25 mg/kg bodywt.(Gr-P25) and 50 mg/kg. bodywt. (Gr-P50) were compared with Diclofenac Sodium suppository 1mg/ kg body weight (Gr-D) given half an hour before induction of anaesthesia. Pain scoring was done by TPPPS (Toddler Pre-schooler postoperative pain scale). Heart rate and blood pressure were stable in Gr-P50 and Gr-D. Time of first demand of analgesic was delayed in Gr-P50 and Gr-D. Total paracetamol consumption in 24 hours was less in Gr-P50(181±14.25) and Gr-D (212±25) than Gr-P25(318± 26.39). Total duration of analgesia in Gr- P50 (657±9.94) mins. and in Gr- D(502±10.63) mins. and in Gr-P25(288±23.17) mins. Pre-emptive high dose rectal paracetamol appears to be more effective than diclofenac sodium suppository for postoperative analgesia in children undergoing tonsillectomy. Journal of BSA, Vol. 18, No. 1 & 2, 2005 p.9-16

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