Single Circuit in V1 Capable of Switching Contexts during Movement Using an Inhibitory Population as a Switch

2022 ◽  
pp. 1-54
Author(s):  
Doris Voina ◽  
Stefano Recanatesi ◽  
Brian Hu ◽  
Eric Shea-Brown ◽  
Stefan Mihalas
Keyword(s):  
Visual Processing ◽  
Visual Space ◽  
Cell Types ◽  
Biologically Inspired ◽  
Inhibitory Cell ◽  
Flexible Architecture ◽  
Inhibitory Population ◽  
Context Integration ◽  
Complex Architecture ◽  
Shed Light

Abstract As animals adapt to their environments, their brains are tasked with processing stimuli in different sensory contexts. Whether these computations are context dependent or independent, they are all implemented in the same neural tissue. A crucial question is what neural architectures can respond flexibly to a range of stimulus conditions and switch between them. This is a particular case of flexible architecture that permits multiple related computations within a single circuit. Here, we address this question in the specific case of the visual system circuitry, focusing on context integration, defined as the integration of feedforward and surround information across visual space. We show that a biologically inspired microcircuit with multiple inhibitory cell types can switch between visual processing of the static context and the moving context. In our model, the VIP population acts as the switch and modulates the visual circuit through a disinhibitory motif. Moreover, the VIP population is efficient, requiring only a relatively small number of neurons to switch contexts. This circuit eliminates noise in videos by using appropriate lateral connections for contextual spatiotemporal surround modulation, having superior denoising performance compared to circuits where only one context is learned. Our findings shed light on a minimally complex architecture that is capable of switching between two naturalistic contexts using few switching units.

scholarly journals Single circuit in V1 capable of switching contexts during movement using VIP population as a switch

2020 ◽  
Author(s):  
Doris Voina ◽  
Stefano Recanatesi ◽  
Brian Hu ◽  
Eric Shea-Brown ◽  
Stefan Mihalas
Keyword(s):  
Visual System ◽  
Visual Processing ◽  
Visual Space ◽  
Cell Types ◽  
Flexible Architecture ◽  
Multiple Cell ◽  
Context Dependent ◽  
Spatio Temporal ◽  
Context Integration ◽  
The Brain

AbstractAs animals adapt to their environments, their brains are tasked with processing stimuli in different sensory contexts. Whether these computations are context dependent or independent, they are all implemented in the same neural tissue. A crucial question is what neural architectures can respond flexibly to a range of stimulus conditions and switch between them. This is a particular case of flexible architecture that permits multiple related computations within a single circuit.Here, we address this question in the specific case of the visual system circuitry, focusing on context integration, defined as the integration of feedforward and surround information across visual space. We show that a biologically inspired microcircuit with multiple inhibitory cell types can switch between visual processing of the static context and the moving context. In our model, the VIP population acts as the switch and modulates the visual circuit through a disinhibitory motif. Moreover, the VIP population is efficient, requiring only a relatively small number of neurons to switch contexts. This circuit eliminates noise in videos by using appropriate lateral connections for contextual spatio-temporal surround modulation, having superior denoising performance compared to circuits where only one context is learned. Our findings shed light on a minimally complex architecture that is capable of switching between two naturalistic contexts using few switching units.Author SummaryThe brain processes information at all times and much of that information is context-dependent. The visual system presents an important example: processing is ongoing, but the context changes dramatically when an animal is still vs. running. How is context-dependent information processing achieved? We take inspiration from recent neurophysiology studies on the role of distinct cell types in primary visual cortex (V1).We find that relatively few “switching units” — akin to the VIP neuron type in V1 in that they turn on and off in the running vs. still context and have connections to and from the main population — is sufficient to drive context dependent image processing. We demonstrate this in a model of feature integration, and in a test of image denoising. The underlying circuit architecture illustrates a concrete computational role for the multiple cell types under increasing study across the brain, and may inspire more flexible neurally inspired computing architectures.

scholarly journals Visual numerosity estimation is based on anisotropic representations of visual space

2021 ◽  
Author(s):  
Miao Li ◽  
Bert Reynvoet ◽  
Bilge Sayim
Keyword(s):  
Visual Field ◽  
Convex Hull ◽  
Visual Fields ◽  
Spatial Vision ◽  
Visual Space ◽  
Stimulus Features ◽  
Numerosity Estimation ◽  
Numerosity Perception ◽  
Average Eccentricity ◽  
Shed Light

Humans can estimate the number of visually displayed items without counting. This capacity of numerosity perception has often been attributed to a dedicated system to estimate numerosity, or alternatively to the exploitation of various stimulus features, such as density, convex hull, the size of items and occupancy area. The distribution of the presented items is usually not varied with eccentricity in the visual field. However, our visual fields are highly asymmetric, and to date, it is unclear how inhomogeneities of the visual field impact numerosity perception. Besides eccentricity, a pronounced asymmetry is the radial-tangential anisotropy. For example, in crowding, radially placed flankers interfere more strongly with target perception than tangentially placed flankers. Similarly, in redundancy masking, the number of perceived items in repeating patterns is reduced when the items are arranged radially but not when they are arranged tangentially. Here, we investigated whether numerosity perception is subject to the radial-tangential anisotropy of spatial vision to shed light on the underlying topology of numerosity perception. Observers were presented with varying numbers of discs and asked to report the perceived number. There were two conditions. Discs were predominantly arranged radially in the “radial” condition and tangentially in the “tangential” condition. Additionally, the spacing between discs was scaled with eccentricity. Physical properties, such as average eccentricity, average spacing, convex hull, and density were kept as similar as possible in the two conditions. Radial arrangements were expected to yield underestimation compared to tangential arrangements. Consistent with the hypothesis, numerosity estimates in the radial condition were lower compared to the tangential condition. Magnitudes of radial alignment (as well as predicted crowding strength) correlated with the observed numerosity estimates. Our results demonstrate a robust radial-tangential anisotropy, suggesting that the topology of spatial vision determines numerosity estimation. We suggest that asymmetries of spatial vision should be taken into account when investigating numerosity estimation.

scholarly journals Idiosyncratic Perception: A Link Between Acuity, Perceived Position, and Apparent Size

2020 ◽  
Author(s):  
Zixuan Wang ◽  
Yuki Murai ◽  
David Whitney
Keyword(s):  
Visual Field ◽  
Visual Processing ◽  
Human Perception ◽  
Visual Space ◽  
Apparent Size ◽  
Matching Task ◽  
Object Size ◽  
Vernier Acuity ◽  
Visual Hierarchy ◽  
Different Levels

AbstractPerceiving the positions of objects is a prerequisite for most other visual and visuomotor functions, but human perception of object position varies from one individual to the next. The source of these individual differences in perceived position and their perceptual consequences are unknown. Here, we tested whether idiosyncratic biases in the underlying representation of visual space propagate across different levels of visual processing. In Experiment 1, using a position matching task, we found stable, observer-specific compressions and expansions within local regions throughout the visual field. We then measured Vernier acuity (Experiment 2) and perceived size of objects (Experiment 3) across the visual field and found that individualized spatial distortions were closely associated with variations in both visual acuity and apparent object size. Our results reveal idiosyncratic biases in perceived position and size, originating from a heterogeneous spatial resolution that carries across the visual hierarchy.

Contour Interaction in Visual Space

1978 ◽  
Vol 22 (1) ◽  
pp. 74-77
Author(s):  
Robert Fox
Keyword(s):  
Visual Processing ◽  
Visual Masking ◽  
Random Element ◽  
Visual Space ◽  
Depth Information ◽  
Implicit Assumption ◽  
Depth Position ◽  
Series Of Experiments ◽  
Contour Interaction ◽  
Inhibitory Interactions

Virtually all the extensive research on inhibitory interactions among adjacent visual stimuli seen in such phenomena as simultaneous contrast and visual masking have employed situations in which the interacting stimulus elements occupy the same depth plane, i.e., the z-axis values are the same, in deference to the implicit assumption that processing of depth information occurs only after the visual processing of contour information is completed. But there are theoretical reasons and some data suggesting that the interactions among contours depend critically upon their relative positions in depth—interactions may not occur if the stimulus elements occupy different depth positions. The extent to which the metacontrast form of visual masking is dependent upon depth position was investigated in a series of experiments that used stereoscopic contours formed from random-element stereograms as test and mask stimuli. The random-element stereogram generation system permitted large variations in depth to be made without introducing confounding changes in proximal stimulation. The main results are 1) separation of test and mask stimuli in depth substantially reduces masking, and 2) when more than one stimulus is in visual space the stimulus that either appears first or appears closer to the observer receives preferential processing by the visual system.

Visual Perception of Apparent Motion Abides by Minimization Principles of Geometry

2021 ◽  
Author(s):  
Yaxin Liu ◽  
Stella F. Lourenco
Keyword(s):  
Visual Perception ◽  
Target Detection ◽  
Apparent Motion ◽  
Visual Space ◽  
Detection Task ◽  
Newtonian Physics ◽  
Kinematic Geometry ◽  
Shed Light ◽  
Target Detection Task ◽  
Perceptual Phenomenon

Apparent motion is a robust perceptual phenomenon in which observers perceive a stimulus traversing the vacant visual space between two flashed stimuli. Although it is known that the “filling-in” of apparent motion favors the simplest and most economical path, the interpolative computations remain poorly understood. Here, we tested whether the perception of apparent motion is best characterized by Newtonian physics or kinematic geometry. Participants completed a target detection task while Pacmen- shaped objects were presented in succession to create the perception of apparent motion. We found that target detection was impaired when apparent motion, as predicted by kinematic geometry, not Newtonian physics, obstructed the target’s location. Our findings shed light on the computations employed by the visual system, suggesting specifically that the “filling-in” perception of apparent motion may be dominated by kinematic geometry, not Newtonian physics.

scholarly journals The final steps of [FeFe]-hydrogenase maturation

2019 ◽  
Vol 116 (32) ◽  
pp. 15802-15810 ◽  
Author(s):  
Oliver Lampret ◽  
Julian Esselborn ◽  
Rieke Haas ◽  
Andreas Rutz ◽  
Rosalind L. Booth ◽  
...  
Keyword(s):  
Functional Integration ◽  
Structural Features ◽  
Site Directed Mutagenesis ◽  
Structural Reorganization ◽  
Biologically Inspired ◽  
Hydrogenase Maturation ◽  
Flexible Loop ◽  
Loop Region ◽  
Shed Light ◽  
Secondary Ligand

The active site (H-cluster) of [FeFe]-hydrogenases is a blueprint for the design of a biologically inspired H2-producing catalyst. The maturation process describes the preassembly and uptake of the unique [2FeH] cluster into apo-hydrogenase, which is to date not fully understood. In this study, we targeted individual amino acids by site-directed mutagenesis in the [FeFe]-hydrogenase CpI of Clostridium pasteurianum to reveal the final steps of H-cluster maturation occurring within apo-hydrogenase. We identified putative key positions for cofactor uptake and the subsequent structural reorganization that stabilizes the [2FeH] cofactor in its functional coordination sphere. Our results suggest that functional integration of the negatively charged [2FeH] precursor requires the positive charges and individual structural features of the 2 basic residues of arginine 449 and lysine 358, which mark the entrance and terminus of the maturation channel, respectively. The results obtained for 5 glycine-to-histidine exchange variants within a flexible loop region provide compelling evidence that the glycine residues function as hinge positions in the refolding process, which closes the secondary ligand sphere of the [2FeH] cofactor and the maturation channel. The conserved structural motifs investigated here shed light on the interplay between the secondary ligand sphere and catalytic cofactor.

Crustacean Visual Circuits Underlying Behavior

2019 ◽  
Author(s):  
Daniel Tomsic ◽  
Julieta Sztarker
Keyword(s):  
Visual Processing ◽  
Visual Information ◽  
General Structure ◽  
Visual Space ◽  
Experimental Manipulation ◽  
Visually Guided ◽  
Decapod Crustaceans ◽  
Behavioral Experiments ◽  
Electrophysiological Recordings ◽  
Visual Behaviors

Decapod crustaceans, in particular semiterrestrial crabs, are highly visual animals that greatly rely on visual information. Their responsiveness to visual moving stimuli, with behavioral displays that can be easily and reliably elicited in the laboratory, together with their sturdiness for experimental manipulation and the accessibility of their nervous system for intracellular electrophysiological recordings in the intact animal, make decapod crustaceans excellent experimental subjects for investigating the neurobiology of visually guided behaviors. Investigations of crustaceans have elucidated the general structure of their eyes and some of their specializations, the anatomical organization of the main brain areas involved in visual processing and their retinotopic mapping of visual space, and the morphology, physiology, and stimulus feature preferences of a number of well-identified classes of neurons, with emphasis on motion-sensitive elements. This anatomical and physiological knowledge, in connection with results of behavioral experiments in the laboratory and the field, are revealing the neural circuits and computations involved in important visual behaviors, as well as the substrate and mechanisms underlying visual memories in decapod crustaceans.

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