scholarly journals A touchy subject: advancing the modulated visual pathways account of altered vision near the hand

2015 ◽  
Vol 6 (1) ◽  
pp. 1-7 ◽  
Author(s):  
J. Eric T. Taylor ◽  
Davood G. Gozli ◽  
David Chan ◽  
Greg Huffman ◽  
Jay Pratt
Keyword(s):  
Visual Pathway ◽  
Visual Pathways ◽  
Human Vision ◽  
Hand Position ◽  
Alternative Account ◽  
Trade Off ◽  
Parvocellular Pathway ◽  
Growing Body ◽  
New Research ◽  
Magnocellular Visual Pathway

AbstractA growing body of evidence demonstrates that human vision operates differently in the space near and on the hands; for example, early findings in this literature reported that rapid onsets are detected faster near the hands, and that objects are searched more thoroughly. These and many other effects were attributed to enhanced attention via the recruitment of bimodal visual-tactile neurons representing the hand and near-hand space. However, recent research supports an alternative account: stimuli near the hands are preferentially processed by the action-oriented magnocellular visual pathway at the expense of processing in the parvocellular pathway. This Modulated Visual Pathways (MVP) account of altered vision near the hands describes a hand position-dependent trade-off between the two main retinal-cortical visual pathways between the eye and brain. The MVP account explains past findings and makes new predictions regarding near-hand vision supported by new research.

scholarly journals Attention and the motion after effect: New measurements with visual search reveal important individual differences in adaptability

2018 ◽  
Author(s):  
Michael J. Morgan ◽  
Joshua A. Solomon
Keyword(s):  
Reaction Times ◽  
Visual Pathway ◽  
Human Vision ◽  
The Other ◽  
Test Array ◽  
Mouse Click ◽  
Search Speed ◽  
After Effect ◽  
The One ◽  
Do So

AbstractIt is usually assumed that sensory adaptation is a universal property of human vision. However, in two experiments designed to measure adaptation without bias, we have discovered a minority of participants who were unusual in the extent of their adaptation to motion. One experiment was designed so that targets would be invisible without adaptation; the other, so that adaptation would interfere with target detection. In the first, participants adapted to a spatial array of moving Gabor patches. On each trial the adapting array was followed by a test array in which but all of the test patches except one were identical to their spatially corresponding adaptors; the target moved in the opposite direction to its adaptor. Participants were required to identify the location of the changed target with a mouse click. The ability to do so increased with the number of adapting trials. Neither search speed nor accuracy was affected by an attentionally-demanding conjunction task at the fixation point during adaptation, suggesting low-level (pre-attentive) sites in the visual pathway for the adaptation. However, a minority of participants found the task virtually impossible. In the second experiment the same participants were required to identify the one element in the test array that was slowly moving: reaction times in this case were elevated following adaptation. The putatively weak adapters from the first experiment found this task easier than the strong adapters.

Zooming Diamonds: A New Illusion, and a Warning on the Biological Relevance of Parallel Projection

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 119-119
Author(s):  
R Cowie
Keyword(s):  
Vision Research ◽  
Biological Systems ◽  
Human Vision ◽  
Motion Path ◽  
Parallel Projection ◽  
Shape Discrimination ◽  
Elevation Change ◽  
Size Change ◽  
Trade Off ◽  
Fixed Distance

A new illusion is described. Observers watch parallel projections of ‘diamonds’ (rhombi) tumbling in 3-D. The displays are generated by moving a viewpoint round a fixed rhombus on a trajectory with two components—a circle parallel to the plane of the diamond, and a superimposed change in elevation which varies sinusoidally. To a greater or lesser extent, depending on the phase of the sinusoid, elevation change is misinterpreted as ‘zooming’ in and out—though in fact the projection always corresponds to an object at a fixed distance. The illusion was devised to underline the questions surrounding the treatment of parallel projection in biological systems. The standard formulations considered in computational vision preclude the kind of size - distance trade-off that the illusion demonstrates, but they do imply that observers should be able to register the shape of an object from this kind of display. A less familiar formulation, ‘paraperspective projection’, allows size - distance trade-off as in perspective projection, but it suggests the shape of a lamina should be impossible to recover from motion. Stimuli which promote ‘zooming’ do weaken shape discrimination, but the trade-off is incomplete. A possible solution is that human vision picks out size change in a way that is appropriate when either object or motion path is ‘friendly’, but that misleads when awkward combinations occur. Certainly vision research should avoid assuming that the attractively simple consequences associated with standard parallel projection govern the way biological systems operate.

The role of discounting in global social issues

1995 ◽  
Vol 18 (1) ◽  
pp. 144-144
Author(s):  
Craig Summers
Keyword(s):  
Environmental Sustainability ◽  
Social Issues ◽  
Self Control ◽  
Experimental Literature ◽  
Behavioral Models ◽  
Trade Off ◽  
Research Questions ◽  
New Research ◽  
Future Consequences

AbstractThe willingness to trade off large but ill-defined future consequences for immediate work characterizes social problems such as environmental sustainability. This commentary argues that important applications of behavioral models of self-control are being overlooked in the experimental literature. Tying the experimental literature to longterm health, environmental, and other risks makes the experimental work more germane, and raises new research questions for experimental modeling.

scholarly journals Dynamics of Visual Adaptation With Simultaneous Stimulation of Two Visual Pathways

2021 ◽  
Vol 15 ◽  
Author(s):  
Clemente Paz-Filgueira ◽  
Michael Tan ◽  
Sarah Elliott ◽  
Dingcai Cao
Keyword(s):  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Visual Pathway ◽  
Visual Pathways ◽  
Visual Adaptation ◽  
Time Varying ◽  
Retinal Ganglion ◽  
Simultaneous Stimulation ◽  
Adaptation Model ◽  
Stimulation Of

Primates’ retinal ganglion cells in different visual pathways have been shown to adapt independently (Current Biology 22 (2012) 220–224). However, the manner in which adaptation occurs under simultaneous stimulation of two visual pathways has not yet been explored. In this study, the dynamics of color afterimages were measured while stimulating one or two visual pathway using a time-varying afterimage paradigm. The dynamics of adaptation was approximately equivalent among the three primary visual pathways, but adaptation was slower for simultaneous stimulation of two visual pathways compared to the stimulation of one visual pathway. In addition, we found that the speed of adaptation also depends upon which two pathways are combined. We developed a two-stage adaptation model, both with the same dynamics, to account for the results with simultaneous stimulation of two pathways.

Sounds can affect visual perception mediated primarily by the parvocellular pathway

2009 ◽  
Vol 26 (5-6) ◽  
pp. 477-486 ◽  
Author(s):  
PHILIP M. JAEKL ◽  
LAURENCE R. HARRIS
Keyword(s):  
Sensory Integration ◽  
Visual Target ◽  
High Spatial Frequency ◽  
Visual Pathway ◽  
Orientation Discrimination ◽  
Target Onset ◽  
Parvocellular Pathway ◽  
Gabor Patch ◽  
Visual Tasks ◽  
Sound Target

AbstractWe investigated the effect of auditory–visual sensory integration on visual tasks that were predominantly dependent on parvocellular processing. These tasks were (i) detecting metacontrast-masked targets and (ii) discriminating orientation differences between high spatial frequency Gabor patch stimuli. Sounds that contained no information relevant to either task were presented before, synchronized with, or after the visual targets, and the results were compared to conditions with no sound. Both tasks used a two-alternative forced choice technique. For detecting metacontrast-masked targets, one interval contained the visual target and both (or neither) intervals contained a sound. Sound–target synchrony within 50 ms lowered luminance thresholds for detecting the presence of a target compared to when no sound occurred or when sound onset preceded target onset. Threshold angles for discriminating the orientation of a Gabor patch consistently increased in the presence of a sound. These results are compatible with sound-induced activity in the parvocellular visual pathway increasing the visibility of flashed targets and hindering orientation discrimination.

scholarly journals Relation of Structural and Functional Changes in Auditory and Visual Pathways after Temporal Lobe Epilepsy Surgery

2018 ◽  
Vol 8 (10) ◽  
pp. 92
Author(s):  
Margarita Báez-Martín ◽  
Lilia Morales-Chacón ◽  
Iván García-Maeso ◽  
Bárbara Estupiñán-Díaz ◽  
María García-Navarro ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Epilepsy Surgery ◽  
Visual Pathway ◽  
Visual Pathways ◽  
Temporal Lobectomy ◽  
Epileptogenic Zone ◽  
Drug Resistant ◽  
Anatomical Connectivity ◽  
Anatomical Connection

Auditory and visual pathways may be affected as a consequence of temporal lobe epilepsy surgery because of their anatomical relationships with this structure. The purpose of this paper is to correlate the results of the auditory and visual evoked responses with the parameters of tractography of the visual pathway, and with the state of connectivity between respective thalamic nuclei and primary cortices in both systems after the surgical resection of the epileptogenic zone in drug-resistant epileptic patients. Tractography of visual pathway and anatomical connectivity of auditory and visual thalamus-cortical radiations were evaluated in a sample of eight patients. In general, there was a positive relationship of middle latency response (MLR) latency and length of resection, while a negative correlation was found between MLR latency and the anatomical connection strength and anatomical connection probability of the auditory radiations. In the visual pathway, significant differences between sides were found with respect to the number and length of tracts, which was lower in the operated one. Anatomical connectivity variables and perimetry (visual field defect index) were particularly correlated with the latency of P100 wave which was obtained by quadrant stimulation. These results demonstrate an indirect functional modification of the auditory pathway and a direct traumatic lesion of the visual pathway after anterior temporal lobectomy in patients with drug resistant epilepsy.

Selective suppression of the magnocellular visual pathway during saccadic eye movements

Nature ◽  
1994 ◽  
Vol 371 (6497) ◽  
pp. 511-513 ◽  
Author(s):  
David C. Burr ◽  
M. Concetta Morrone ◽  
John Ross
Keyword(s):  
Eye Movements ◽  
Saccadic Eye Movements ◽  
Visual Pathway ◽  
Selective Suppression ◽  
Magnocellular Visual Pathway

scholarly journals Harmonics added to a flickering light can upset the balance between ON and OFF pathways to produce illusory colors

2018 ◽  
Vol 115 (17) ◽  
pp. E4081-E4090 ◽  
Author(s):  
Andrew T. Rider ◽  
G. Bruce Henning ◽  
Rhea T. Eskew ◽  
Andrew Stockman
Keyword(s):  
Visual Pathways ◽  
Human Vision ◽  
Perceptual Quality ◽  
Time Varying ◽  
Neural Signals ◽  
Color Processing ◽  
Retinal Photoreceptor ◽  
Half Wave ◽  
On And Off Pathways ◽  
The Brain

The neural signals generated by the light-sensitive photoreceptors in the human eye are substantially processed and recoded in the retina before being transmitted to the brain via the optic nerve. A key aspect of this recoding is the splitting of the signals within the two major cone-driven visual pathways into distinct ON and OFF branches that transmit information about increases and decreases in the neural signal around its mean level. While this separation is clearly important physiologically, its effect on perception is unclear. We have developed a model of the ON and OFF pathways in early color processing. Using this model as a guide, we can produce imbalances in the ON and OFF pathways by changing the shapes of time-varying stimulus waveforms and thus make reliable and predictable alterations to the perceived average color of the stimulus—although the physical mean of the waveforms does not change. The key components in the model are the early half-wave rectifying synapses that split retinal photoreceptor outputs into the ON and OFF pathways and later sigmoidal nonlinearities in each pathway. The ability to systematically vary the waveforms to change a perceptual quality by changing the balance of signals between the ON and OFF visual pathways provides a powerful psychophysical tool for disentangling and investigating the neural workings of human vision.

Sign in / Sign up

Export Citation Format

Share Document