scholarly journals Effect of Vertical Disparities on Depth Representation in Macaque Monkeys: MT Physiology and Behavior

2008 ◽  
Vol 99 (2) ◽  
pp. 876-887 ◽  
Author(s):  
Syed A. Chowdhury ◽  
Daniel L. Christiansen ◽  
Michael L. Morgan ◽  
Gregory C. DeAngelis
Keyword(s):  
Viewing Distance ◽  
Horizontal Disparity ◽  
Egocentric Distance ◽  
Physiological Mechanisms ◽  
Distance Information ◽  
Vertical Disparity ◽  
Mt Neurons ◽  
Behavioral Studies ◽  
Early Visual Cortex ◽  
And Behavior

Horizontal binocular disparities provide information about the distance of objects relative to the point of ocular fixation and must be combined with an estimate of viewing distance to recover the egocentric distance of an object. Vergence angle and the gradient of vertical disparities across the visual field are thought to provide independent sources of viewing distance information based on human behavioral studies. Although the effect of vergence angle on horizontal disparity selectivity in early visual cortex has been examined (with mixed results), the effect of the vertical disparity field has not been explored. We manipulated the vertical disparities in a large random-dot stimulus to simulate different viewing distances, and we examined the effect of this manipulation on both the responses of neurons in the middle temporal (MT) area and on the psychophysical performance of the animal in a curvature discrimination task. We report here that alterations to the vertical disparity field have no effect on the horizontal disparity tuning of MT neurons. However, the same manipulation strongly and systematically biases the monkey's judgments of curvature, consistent with previous human studies. We conclude that monkeys, like humans, make use of the vertical disparity field to estimate viewing distance, but that the physiological mechanisms for this effect occur either downstream of MT or in a different pathway.

The Interpretation of Stereo-Disparity Information: The Computation of Surface Orientation and Depth

Perception ◽  
1982 ◽  
Vol 11 (4) ◽  
pp. 387-407 ◽  
Author(s):  
John Mayhew
Keyword(s):  
Surface Orientation ◽  
The Other ◽  
Surface Patch ◽  
Viewing Distance ◽  
Horizontal Disparity ◽  
Planar Surface ◽  
Local Surface ◽  
Stereo Disparity ◽  
The Gaze ◽  
Perceptual Phenomenon

Two methods for interpreting disparity information are described. Neither requires extraretinal information to scale for distance: one method uses horizontal disparities to solve for the viewing distance, the other uses the vertical disparities. Method 1 requires the assumption that the disparities derive from a locally planar surface. Then from the horizontal disparities measured at four retinal locations the viewing distance and the equation of local surface ‘patch’ can be obtained. Method 2 does not need this assumption. The vertical disparities are first used to obtain the values of the gaze and viewing distance. These are then used to interpret the horizontal disparity information. An algorithm implementing the methods has been tested and is found to be subject to a perceptual phenomenon known as the ‘induced effect’.

scholarly journals Social Exclusion Down-Regulates Pain Empathy at the Late Stage of Empathic Responses: Electrophysiological Evidence

2021 ◽  
Vol 15 ◽  
Author(s):  
Min Fan ◽  
Jing Jie ◽  
Pinchao Luo ◽  
Yu Pang ◽  
Danna Xu ◽  
...  
Keyword(s):  
Social Exclusion ◽  
Social Inclusion ◽  
Event Related Potentials ◽  
Body Parts ◽  
Controlled Processing ◽  
Behavioral Studies ◽  
The Social ◽  
Central Regions ◽  
Related Potentials ◽  
And Behavior

Social exclusion has a significant impact on cognition, emotion, and behavior. Some behavioral studies investigated how social exclusion affects pain empathy. Conclusions were inconsistent, and there is a lack of clarity in identifying which component of pain empathy is more likely to be affected. To investigate these issues, we used a Cyberball task to manipulate feelings of social exclusion. Two groups (social exclusion and social inclusion) participated in the same pain empathy task while we recorded event-related potentials (ERP) when participants viewed static images of body parts in painful and neutral situations. The results showed early N2 differentiation between painful and neutral pictures in the central regions in both groups. The pattern at the late controlled processing stage was different. Parietal P3 amplitudes for painful pictures were significantly smaller than those for neutral pictures in the social exclusion group; they did not differ in the social inclusion group. We observed a parietal late positive potential (LPP) differentiation between painful and neutral pictures in both groups. LPP amplitudes were significantly smaller in the social exclusion group than those in the social inclusion group for painful stimuli. Our results indicate that social exclusion does not affect empathic responses during the early emotional sharing stage. However, it down-regulates empathic responses at the late cognitive controlled stage, and this modulation is attenuated gradually. The current study provides neuroscientific evidence of how social exclusion dynamically influences pain empathy.

Administrative, Constitutional, and International Law

2018 ◽  
Author(s):  
Eyal Zamir ◽  
Doron Teichman
Keyword(s):  
International Law ◽  
Choice Theory ◽  
Freedom Of Speech ◽  
Administrative Law ◽  
Public Law ◽  
Public Officials ◽  
Behavioral Studies ◽  
Governmental Institutions ◽  
And Behavior ◽  
Rule Making

Public choice theory—the application of standard economics to the behavior of public officials and citizens—has long been criticized as mischaracterizing people’s motivations and behavior. The chapter analyzes how behavioral studies might contribute to a better understanding and developing of public law, including constitutional and administrative law. It critically discusses the behavioral analysis of governmental institutions and rule-making, citizens’ judgments and choices, and human rights (including issues in freedom of speech, the fight against terrorism, and affirmative action). Finally, the chapter critically examines recent behavioral analyses of public international law, the challenges they face, and the contributions they make.

Monocular Egocentric Distance Information Generated by Head Movement

1994 ◽  
Vol 6 (3) ◽  
pp. 219-238 ◽  
Author(s):  
Geoffrey P. Bingham ◽  
Michael G. Stassen
Keyword(s):  
Head Movement ◽  
Egocentric Distance ◽  
Distance Information

Normalization Principles in Computational Neuroscience

2019 ◽  
Author(s):  
Kenway Louie ◽  
Paul W. Glimcher
Keyword(s):  
Information Processing ◽  
Computational Neuroscience ◽  
Linear Models ◽  
Brain Regions ◽  
Information Coding ◽  
Brain Organization ◽  
Contextual Modulation ◽  
Early Visual Cortex ◽  
And Function ◽  
And Behavior

A core question in systems and computational neuroscience is how the brain represents information. Identifying principles of information coding in neural circuits is critical to understanding brain organization and function in sensory, motor, and cognitive neuroscience. This provides a conceptual bridge between the underlying biophysical mechanisms and the ultimate behavioral goals of the organism. Central to this framework is the question of computation: what are the relevant representations of input and output, and what algorithms govern the input-output transformation? Remarkably, evidence suggests that certain canonical computations exist across different circuits, brain regions, and species. Such computations are implemented by different biophysical and network mechanisms, indicating that the unifying target of conservation is the algorithmic form of information processing rather than the specific biological implementation. A prime candidate to serve as a canonical computation is divisive normalization, which scales the activity of a given neuron by the activity of a larger neuronal pool. This nonlinear transformation introduces an intrinsic contextual modulation into information coding, such that the selective response of a neuron to features of the input is scaled by other input characteristics. This contextual modulation allows the normalization model to capture a wide array of neural and behavioral phenomena not captured by simpler linear models of information processing. The generality and flexibility of the normalization model arises from the normalization pool, which allows different inputs to directly drive and suppress a given neuron, effectively separating information that drives excitation and contextual modulation. Originally proposed to describe responses in early visual cortex, normalization has been widely documented in different brain regions, hierarchical levels, and modalities of sensory processing; furthermore, recent work shows that the normalization extends to cognitive processes such as attention, multisensory integration, and decision making. This ubiquity reinforces the canonical nature of the normalization computation and highlights the importance of an algorithmic framework in linking biological mechanism and behavior.

Changes in activity rates in the cherry shrimp Neocaridina davidi Bouvier, 1904 (Decapoda: Caridea: Atyidae) in response to concentrations of neuropeptides and glucose

2019 ◽  
Vol 39 (6) ◽  
pp. 689-694
Author(s):  
Joseph S Stout ◽  
Carla L Granda ◽  
Molly L Mancuso
Keyword(s):  
Food Pellet ◽  
Inhibitory Effect ◽  
Dopaminergic Drugs ◽  
Behavioral Studies ◽  
Seeking Behavior ◽  
Food Seeking ◽  
And Behavior ◽  
Rats And Mice ◽  
Reduced Activity ◽  
Over Time

Abstract Although behavioral studies of whole animals are usually undertaken on rats and mice, studies in crustaceans offer an alternative group that provides new evolutionary insights into the relationship between physiology and behavior. In the cherry shrimp Neocaridina davidi (Bouvier, 1904), food-seeking movement increases in response to glutamate (MSG), decreases when exposed to dopamine, and increases when exposed to glucose. Activity of shrimp individuals was observed in 4l tanks over twenty minutes after individuals were exposed to treatments applied directly into the water. Glutamate-stimulated seeking behavior was statistically similar to seeking behavior after exposure to food pellet filtrate. Glucose also stimulated seeking behavior, but with a reduction over time, whereas MSG-stimulated seeking behavior increased over time. Insulin reduced activity but showed no effect when paired with glucose, whereas dopamine increased activity when paired with glucose. This was contrary to the reduced activity observed when dopamine was paired with MSG. The decrease in activity after exposure to dopamine also contrasts with vertebrate (rat) models where dopaminergic drugs such as caffeine and cocaine are stimulants. The stimulatory effect of dopamine paired with glucose was unexpected given its inhibitory effect on its own or when paired with MSG. This crustacean-based model aims to give new insights regarding the role of inhibitory and stimulatory neurotransmitters on the behavior of whole crustacean individuals. These mechanisms show different results than predicted by vertebrate models, implying either differences in underlying physiology, problems with the vertebrate models, or both.

The Perception of Distance in Simulated Visual Displays:A Comparison of the Effectiveness and Accuracy of Multiple Depth Cues Across Viewing Distances

1997 ◽  
Vol 6 (5) ◽  
pp. 513-531 ◽  
Author(s):  
R. Troy Surdick ◽  
Elizabeth T. Davis ◽  
Robert A. King ◽  
Larry F. Hodges
Keyword(s):  
Relative Size ◽  
Linear Perspective ◽  
Depth Information ◽  
Texture Gradient ◽  
Viewing Distance ◽  
Relative Height ◽  
Distance Information ◽  
Depth Cues ◽  
Relative Brightness ◽  
Depth Cue

The ability effectively and accurately to simulate distance in virtual and augmented reality systems is a challenge currently facing R&D. To examine this issue, we separately tested each of seven visual depth cues (relative brightness, relative size, relative height, linear perspective, foreshortening, texture gradient, and stereopsis) as well as the condition in which all seven of these cues were present and simultaneously providing distance information in a simulated display. The viewing distances were 1 and 2 m. In developing simulated displays to convey distance and depth there are three questions that arise. First, which cues provide effective depth information (so that only a small change in the depth cue results in a perceived change in depth)? Second, which cues provide accurate depth information (so that the perceived distance of two equidistant objects perceptually matches)? Finally, how does the effectiveness and accuracy of these depth cues change as a function of the viewing distance? Ten college-aged subjects were tested with each depth-cue condition at both viewing distances. They were tested using a method of constant stimuli procedure and a modified Wheat-stone stereoscopic display. The perspective cues (linear perspective, foreshortening, and texture gradient) were found to be more effective than other depth cues, while effectiveness of relative brightness was vastly inferior. Moreover, relative brightness, relative height, and relative size all significantly decreased in effectiveness with an increase in viewing distance. The depth cues did not differ in terms of accuracy at either viewing distance. Finally, some subjects experienced difficulty in rapidly perceiving distance information provided by stereopsis, but no subjects had difficulty in effectively and accurately perceiving distance with the perspective information used in our experiment. A second experiment demonstrated that a previously stereo-anomalous subject could be trained to perceive stereoscopic depth in a binocular display. We conclude that the use of perspective cues in simulated displays may be more important than the other depth cues tested because these cues are the most effective and accurate cues at both viewing distances, can be easily perceived by all subjects, and can be readily incorporated into simpler, less complex displays (e.g., biocular HMDs) or more complex ones (e.g., binocular or see-through HMDs).

scholarly journals Understanding the Cortical Specialization for Horizontal Disparity

2004 ◽  
Vol 16 (10) ◽  
pp. 1983-2020 ◽  
Author(s):  
Jenny C.A. Read ◽  
Bruce G. Cumming
Keyword(s):  
Orientation Tuning ◽  
Horizontal Disparity ◽  
Vertical Disparity ◽  
V1 Neurons ◽  
Relative Response ◽  
Response Range ◽  
Divisive Normalization ◽  
Identical Position ◽  
Recent Experimental Work ◽  
To Receive

Because the eyes are displaced horizontally, binocular vision is inherently anisotropic. Recent experimental work has uncovered evidence of this anisotropy in primary visual cortex (V1): neurons respond over a wider range of horizontal than vertical disparity, regardless of their orientation tuning. This probably reflects the horizontally elongated distribution of two-dimensional disparity experienced by the visual system, but it conflicts with all existing models of disparity selectivity, in which the relative response range to vertical and horizontal disparities is determined by the preferred orientation. Potentially, this discrepancy could require us to abandon the widely held view that processing in V1 neurons is initially linear. Here, we show that these new experimental data can be reconciled with an initial linear stage; we present two physiologically plausible ways of extending existing models to achieve this. First, we allow neurons to receive input from multiple binocular subunits with different position disparities (previous models have assumed all subunits have identical position and phase disparity). Then we incorporate a form of divisive normalization, which has successfully explained many response properties of V1 neurons but has not previously been incorporated into a model of disparity selectivity. We show that either of these mechanisms decouples disparity tuning from orientation tuning and discuss how the models could be tested experimentally. This represents the first explanation of how the cortical specialization for horizontal disparity may be achieved.

Accommodation and Apparent Distance

Perception ◽  
1988 ◽  
Vol 17 (5) ◽  
pp. 609-621 ◽  
Author(s):  
S Kay Fisher ◽  
Kenneth J Ciuffreda
Keyword(s):  
Linear Function ◽  
Apparent Distance ◽  
Optical Range ◽  
Egocentric Distance ◽  
Distance Information ◽  
Accommodative Response ◽  
The Poor ◽  
Tonic Level ◽  
Limiting Case ◽  
Source Of Information

The ability to judge egocentric distance was assessed in sixteen normal observers under conditions where monocular blur-driven accommodation provided the only source of information regarding changes in target dioptric distance. Accommodation and apparent distance were measured over an optical range of 2 to 6 D for each of three targets which differed in their effectiveness as accommodative stimuli (excellent, moderate, and poor). For the excellent and moderate accommodative targets, apparent distance decreased as accommodation increased, with both targets sharing a common linear function. Apparent distance, however, tended to exceed accommodative distance and was relatively compressed in scale. As expected, accommodative response and apparent distance diminished in range as target effectiveness was reduced. The poor accommodative target represented the limiting case wherein accommodation failed to deviate from the tonic level, and apparent distance remained constant. There were considerable intersubject differences in the ability to judge distances on the basis of accommodation. The results indicate that accommodation can indeed serve as a source of distance information, particularly for some individuals.

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