scholarly journals Distinct Contributions of the Magnocellular and Parvocellular Visual Streams to Perceptual Selection

2012 ◽  
Vol 24 (1) ◽  
pp. 246-259 ◽  
Author(s):  
Rachel N. Denison ◽  
Michael A. Silver
Keyword(s):  
Visual System ◽  
Binocular Rivalry ◽  
Visual Processing ◽  
Neural Substrates ◽  
Hierarchical Organization ◽  
Neural Basis ◽  
Multiple Stimulus ◽  
Perceptual Alternation ◽  
New Framework ◽  
Regular Alternation

During binocular rivalry, conflicting images presented to the two eyes compete for perceptual dominance, but the neural basis of this competition is disputed. In interocular switch rivalry, rival images periodically exchanged between the two eyes generate one of two types of perceptual alternation: (1) a fast, regular alternation between the images that is time-locked to the stimulus switches and has been proposed to arise from competition at lower levels of the visual processing hierarchy or (2) a slow, irregular alternation spanning multiple stimulus switches that has been associated with higher levels of the visual system. The existence of these two types of perceptual alternation has been influential in establishing the view that rivalry may be resolved at multiple hierarchical levels of the visual system. We varied the spatial, temporal, and luminance properties of interocular switch rivalry gratings and found, instead, an association between fast, regular perceptual alternations and processing by the magnocellular stream and between slow, irregular alternations and processing by the parvocellular stream. The magnocellular and parvocellular streams are two early visual pathways that are specialized for the processing of motion and form, respectively. These results provide a new framework for understanding the neural substrates of binocular rivalry that emphasizes the importance of parallel visual processing streams, and not only hierarchical organization, in the perceptual resolution of ambiguities in the visual environment.

scholarly journals Perceptual Alternation Induced by Visual Transients

Perception ◽  
10.1068/p5245 ◽  
2005 ◽  
Vol 34 (7) ◽  
pp. 803-822 ◽  
Author(s):  
Ryota Kanai ◽  
Farshad Moradi ◽  
Shinsuke Shimojo ◽  
Frans A J Verstraten
Keyword(s):  
Visual System ◽  
Apparent Motion ◽  
Binocular Rivalry ◽  
Structure From Motion ◽  
Necker Cube ◽  
Neural Mechanisms ◽  
Perceptual Alternation ◽  
Ambiguous Stimuli ◽  
Underlying Mechanisms

When our visual system is confronted with ambiguous stimuli, the perceptual interpretation spontaneously alternates between the competing incompatible interpretations. The timing of such perceptual alternations is highly stochastic and the underlying neural mechanisms are poorly understood. We show that perceptual alternations can be triggered by a transient stimulus presented nearby. The induction was tested for four types of bistable stimuli: structure-from-motion, binocular rivalry, Necker cube, and ambiguous apparent motion. While underlying mechanisms may vary among them, a transient flash induced time-locked perceptual alternations in all cases. The effect showed a dependence on the adaptation to the dominant percept prior to the presentation of a flash. These perceptual alternations show many similarities to perceptual disappearances induced by transient stimuli (Kanai and Kamitani, 2003 Journal of Cognitive Neuroscience15 664–672; Moradi and Shimojo, 2004 Vision Research44 449–460). Mechanisms linking these two transient-induced phenomena are discussed.

Connection between Synchronization of Oscillatory Activities at Early Stages and a Final Stage in the Visual System

1998 ◽  
Vol 86 (3) ◽  
pp. 1107-1116 ◽  
Author(s):  
Seiyu Sohmiya ◽  
Kazuko Sohmiya ◽  
Tamotsu Sohmiya
Keyword(s):  
Visual System ◽  
Binocular Rivalry ◽  
Visual Processing ◽  
Time Scale ◽  
Final Stage ◽  
Neuronal Oscillations ◽  
Early Stages ◽  
Millisecond Time Scale ◽  
Last Stage ◽  
Suppression Effects

Singer's group and we found synchronized oscillatory responses at early stages and at a final stage in visual processing, respectively. However, the former occurs on a millisecond time scale and the latter on a second time scale. We have considered that this results from a difference in scale of something which takes part in the oscillations. From this viewpoint, here we first find suppression effects on both figure and ground of a pattern and on only the ground in a binocular-rivalry situation and then examine, using the effects of two steps, what oscillates and synchronizes at the last stage for form. Finally, we conclude that the synchronous neuronal oscillations depend on firing patterns of neurons at early stages in the visual system and the psychophysical ones on configurations of the spread effect of strength of pattern involved closely in whole processing of the visual system and the latter originates in the former.

scholarly journals Color-Binding Errors During Rivalrous Suppression of Form

2009 ◽  
Vol 20 (9) ◽  
pp. 1084-1091 ◽  
Author(s):  
Sang Wook Hong ◽  
Steven K. Shevell
Keyword(s):  
Binocular Rivalry ◽  
The Other ◽  
Physical Stimulus ◽  
Physical Stimulation ◽  
Eye Color ◽  
Neural Representations ◽  
Perceptual Alternation ◽  
Different Color ◽  
Binding Errors

How does a physical stimulus determine a conscious percept? Binocular rivalry provides useful insights into this question because constant physical stimulation during rivalry causes different visual experiences. For example, presentation of vertical stripes to one eye and horizontal stripes to the other eye results in a percept that alternates between horizontal and vertical stripes. Presentation of a different color to each eye (color rivalry) produces alternating percepts of the two colors or, in some cases, a color mixture. The experiments reported here reveal a novel and instructive resolution of rivalry for stimuli that differ in both form and color: perceptual alternation between the rivalrous forms (e.g., horizontal or vertical stripes), with both eyes' colors seen simultaneously in separate parts of the currently perceived form. Thus, the colors presented to the two eyes (a) maintain their distinct neural representations despite resolution of form rivalry and (b) can bind separately to distinct parts of the perceived form.

scholarly journals Single units and conscious vision

1998 ◽  
Vol 353 (1377) ◽  
pp. 1801-1818 ◽  
Author(s):  
◽  
N. K. Logothetis
Keyword(s):  
Binocular Rivalry ◽  
Neural Activity ◽  
Visual Awareness ◽  
Physiological Data ◽  
Neural Basis ◽  
Binocular Fusion ◽  
Neural Representations ◽  
Multistable Perception ◽  
Visual Areas ◽  
Psychophysical Studies

Figures that can be seen in more than one way are invaluable tools for the study of the neural basis of visual awareness, because such stimuli permit the dissociation of the neural responses that underlie what we perceive at any given time from those forming the sensory representation of a visual pattern. To study the former type of responses, monkeys were subjected to binocular rivalry, and the response of neurons in a number of different visual areas was studied while the animals reported their alternating percepts by pulling levers. Perception–related modulations of neural activity were found to occur to different extents in different cortical visual areas. The cells that were affected by suppression were almost exclusively binocular, and their proportion was found to increase in the higher processing stages of the visual system. The strongest correlations between neural activity and perception were observed in the visual areas of the temporal lobe. A strikingly large number of neurons in the early visual areas remained active during the perceptual suppression of the stimulus, a finding suggesting that conscious visual perception might be mediated by only a subset of the cells exhibiting stimulus selective responses. These physiological findings, together with a number of recent psychophysical studies, offer a new explanation of the phenomenon of binocular rivalry. Indeed, rivalry has long been considered to be closely linked with binocular fusion and stereopsis, and the sequences of dominance and suppression have been viewed as the result of competition between the two monocular channels. The physiological data presented here are incompatible with this interpretation. Rather than reflecting interocular competition, the rivalry is most probably between the two different central neural representations generated by the dichoptically presented stimuli. The mechanisms of rivalry are probably the same as, or very similar to, those underlying multistable perception in general, and further physiological studies might reveal a much about the neural mechanisms of our perceptual organization.

scholarly journals Visual search for object categories is predicted by the representational architecture of high-level visual cortex

2017 ◽  
Vol 117 (1) ◽  
pp. 388-402 ◽  
Author(s):  
Michael A. Cohen ◽  
George A. Alvarez ◽  
Ken Nakayama ◽  
Talia Konkle
Keyword(s):  
Visual Cortex ◽  
Visual Search ◽  
Visual System ◽  
Visual Processing ◽  
Search Task ◽  
Visual Search Task ◽  
Visual Object ◽  
Neural Responses ◽  
Object Categories ◽  
High Level

Visual search is a ubiquitous visual behavior, and efficient search is essential for survival. Different cognitive models have explained the speed and accuracy of search based either on the dynamics of attention or on similarity of item representations. Here, we examined the extent to which performance on a visual search task can be predicted from the stable representational architecture of the visual system, independent of attentional dynamics. Participants performed a visual search task with 28 conditions reflecting different pairs of categories (e.g., searching for a face among cars, body among hammers, etc.). The time it took participants to find the target item varied as a function of category combination. In a separate group of participants, we measured the neural responses to these object categories when items were presented in isolation. Using representational similarity analysis, we then examined whether the similarity of neural responses across different subdivisions of the visual system had the requisite structure needed to predict visual search performance. Overall, we found strong brain/behavior correlations across most of the higher-level visual system, including both the ventral and dorsal pathways when considering both macroscale sectors as well as smaller mesoscale regions. These results suggest that visual search for real-world object categories is well predicted by the stable, task-independent architecture of the visual system. NEW & NOTEWORTHY Here, we ask which neural regions have neural response patterns that correlate with behavioral performance in a visual processing task. We found that the representational structure across all of high-level visual cortex has the requisite structure to predict behavior. Furthermore, when directly comparing different neural regions, we found that they all had highly similar category-level representational structures. These results point to a ubiquitous and uniform representational structure in high-level visual cortex underlying visual object processing.

scholarly journals The neural basis of lightness and color constancy in the visual system

2011 ◽  
Vol 11 (11) ◽  
pp. 351-351
Author(s):  
P. J. Kohler ◽  
S. V. Fogelson ◽  
E. A. Reavis ◽  
P. U. Tse
Keyword(s):  
Visual System ◽  
Color Constancy ◽  
Neural Basis

scholarly journals Action selection based on multiple-stimulus aspects in the wind-elicited escape behavior of crickets

2021 ◽  
Author(s):  
Nodoka Sato ◽  
Hisashi Shidara ◽  
Hiroto Ogawa
Keyword(s):  
Escape Behavior ◽  
Movement Direction ◽  
Neural Basis ◽  
Stimulus Velocity ◽  
Sensory Stimuli ◽  
Defensive Behaviors ◽  
Multiple Stimulus ◽  
Stimulus Parameters ◽  
Direction Control ◽  
Escape Responses

ABSTRACTAnimals detect approaching predators via sensory inputs through various modalities and immediately show an appropriate behavioral response to survive. Escape behavior is essential to avoid the predator’s attack and is more frequently observed than other defensive behaviors. In some species, multiple escape responses are exhibited with different movements. It has been reported that the approaching speed of a predator is important in choosing which escape action to take among the multiple responses. However, it is unknown whether other aspects of sensory stimuli, that indicate the predator’s approach, affect the selection of escape responses. We focused on two distinct escape responses (running and jumping) to a stimulus (short airflow) in crickets and examined the effects of multiple stimulus aspects (including the angle, velocity, and duration) on the choice between these escape responses. We found that the faster and longer the airflow, the more frequently the crickets jumped, meaning that they could choose their escape response depending on both velocity and duration of the stimulus. This result suggests that the neural basis for choosing escape responses includes the integration process of multiple stimulus parameters. It was also found that the moving speed and distance changed depending on the stimulus velocity and duration during running but not during jumping, suggesting higher adaptability of the running escape. In contrast, the movement direction was accurately controlled regardless of the stimulus parameters in both responses. The escape direction depended only on stimulus orientation, but not on velocity and duration.Summary statementWhen air currents triggering escape are faster and longer, crickets more frequently jump than run. Running speed and distance depend on stimulus velocity and duration, but direction control is independent.

Binocular rivalry between identical retinal stimuli with an induced color difference

2008 ◽  
Vol 25 (3) ◽  
pp. 361-364 ◽  
Author(s):  
SANG WOOK HONG ◽  
STEVEN K. SHEVELL
Keyword(s):  
Binocular Rivalry ◽  
Binocular Disparity ◽  
Color Difference ◽  
Color Appearance ◽  
Neural Representation ◽  
Stereoscopic Depth ◽  
Perceptual Alternation ◽  
Physically Identical ◽  
Open Question

An open question in color rivalry is whether alternation between two colors is caused by a difference in receptoral stimulation or a difference in the neural representation of color appearance. This question was examined with binocular rivalry between physically identical lights that differed in appearance due to chromatic induction. Perceptual alternation was measured between gratings of the same chromaticity; each one was presented within a different patterned surround that caused the gratings, one to each eye, to appear unequal in hue because of chromatic induction. The gratings were presented dichoptically with binocular disparity so the rivalrous gratings appeared in front of the surround. Perceptual alternation in hue was found for the two physically identical chromaticities. Stereoscopic depth also was perceived, corroborating binocular neural combination despite color rivalry (Treisman, 1962). The results show that color rivalry is resolved after color-appearance shifts caused by chromatic context, and that color rivalry does not require competing unequal cone excitations from the rivalrous stimuli.

Glutamate in the pathophysiology of schizophrenia

2020 ◽  
pp. 287-296
Author(s):  
Daniel C. Javitt
Keyword(s):  
Visual System ◽  
Visual Processing ◽  
Negative Symptoms ◽  
Glutamate Release ◽  
Critical Role ◽  
Brain Regions ◽  
Long Term Memory ◽  
Subcortical Structures ◽  
Impaired Metabolism

Glutamate theories of schizophrenia were first proposed over 30 years ago and since that time have become increasingly accepted. Theories are supported by the ability of N-methyl-D-aspartate receptor (NMDAR) antagonists such as phencyclidine (PCP) or ketamine to induce symptoms that closely resemble those of schizophrenia. Moreover, NMDAR antagonists uniquely reproduce the level of negative symptoms and cognitive deficits observed in schizophrenia, suggesting that such models may be particularly appropriate to poor outcome forms of the disorder. As opposed to dopamine, which is most prominent within frontostriatal brain regions, glutamate neurons are present throughout cortex and subcortical structures. Thus, NMDAR theories predict widespread disturbances across cortical and thalamic pathways, including sensory brain regions. In auditory cortex, NMDAR play a critical role in the generation of mismatch negativity (MMN), which may therefore serve as a translational marker of NMDAR dysfunction across species. In the visual system, NMDAR play a critical role in function of the magnocellular visual system. Deficits in both auditory and visual processing contribute to social and communication deficits, which, in turn, lead to poor functional outcome. By contrast, NMDAR dysfunction within the frontohippocampal system may contribute to well described deficits in working memory, executive processing and long-term memory formation. Deficits in NMDAR function may be driven by disturbances in presynaptic glutamate release, impaired metabolism of NMDAR modulators such as glycine or D-serine, or intrinsic abnormalities in NMDAR themselves.

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