What the eye tells the brain: retinal feature extraction

Neuroforum ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Klaudia P. Szatko ◽  
Katrin Franke
Keyword(s):  
Feature Extraction ◽  
Visual System ◽  
Visual Information ◽  
Functional Organization ◽  
Neural Mechanisms ◽  
Visual Features ◽  
Incoming Information ◽  
Motion Contrast ◽  
Parallel Feature ◽  
The Brain

Abstract To provide a compact and efficient input to the brain, sensory systems separate the incoming information into parallel feature channels. In the visual system, parallel processing starts in the retina. Here, the image is decomposed into multiple retinal output channels, each selective for a specific set of visual features like motion, contrast, or edges. In this article, we will summarize recent findings on the functional organization of the retinal output, the neural mechanisms underlying its diversity, and how single visual features, like color, are extracted by the retinal network. Unraveling how the retina – as the first stage of the visual system – filters the visual input is an important step toward understanding how visual information processing guides behavior.

scholarly journals Unique Features of Subcortical Circuits in a Macaque Model of Congenital Blindness

2019 ◽  
Vol 30 (3) ◽  
pp. 1407-1421 ◽  
Author(s):  
Loïc Magrou ◽  
Pascal Barone ◽  
Nikola T Markov ◽  
Gwylan Scheeren ◽  
Herbert P Killackey ◽  
...  
Keyword(s):  
Visual System ◽  
Functional Organization ◽  
Extrastriate Cortex ◽  
Drastic Reduction ◽  
Congenital Blindness ◽  
Macaque Model ◽  
Cortical Projections ◽  
Visual Areas ◽  
Functional Consequences ◽  
The Brain

Abstract There is an extensive modification of the functional organization of the brain in the congenital blind human, although there is little understanding of the structural underpinnings of these changes. The visual system of macaque has been extensively characterized both anatomically and functionally. We have taken advantage of this to examine the influence of congenital blindness in a macaque model of developmental anophthalmia. Developmental anophthalmia in macaque effectively removes the normal influence of the thalamus on cortical development leading to an induced “hybrid cortex (HC)” combining features of primary visual and extrastriate cortex. Here we show that retrograde tracers injected in early visual areas, including HC, reveal a drastic reduction of cortical projections of the reduced lateral geniculate nucleus. In addition, there is an important expansion of projections from the pulvinar complex to the HC, compared to the controls. These findings show that the functional consequences of congenital blindness need to be considered in terms of both modifications of the interareal cortical network and the ascending visual pathways.

scholarly journals Blindsight and Unconscious Vision: What They Teach Us about the Human Visual System

2016 ◽  
Vol 23 (5) ◽  
pp. 529-541 ◽  
Author(s):  
Sara Ajina ◽  
Holly Bridge
Keyword(s):  
Visual Cortex ◽  
Visual System ◽  
Primary Visual Cortex ◽  
Neural Activity ◽  
Human Visual System ◽  
Visual Information ◽  
Visual Loss ◽  
Physiological Conditions ◽  
The World ◽  
The Brain

Damage to the primary visual cortex removes the major input from the eyes to the brain, causing significant visual loss as patients are unable to perceive the side of the world contralateral to the damage. Some patients, however, retain the ability to detect visual information within this blind region; this is known as blindsight. By studying the visual pathways that underlie this residual vision in patients, we can uncover additional aspects of the human visual system that likely contribute to normal visual function but cannot be revealed under physiological conditions. In this review, we discuss the residual abilities and neural activity that have been described in blindsight and the implications of these findings for understanding the intact system.

Mammalian Visual System Organization

2017 ◽  
Author(s):  
Farran Briggs
Keyword(s):  
Visual Cortex ◽  
Visual System ◽  
Visual Information ◽  
Contextual Information ◽  
Sensory Information ◽  
Visual Image ◽  
Brain Structures ◽  
Object Representations ◽  
System A ◽  
The Brain

Many mammals, including humans, rely primarily on vision to sense the environment. While a large proportion of the brain is devoted to vision in highly visual animals, there are not enough neurons in the visual system to support a neuron-per-object look-up table. Instead, visual animals evolved ways to rapidly and dynamically encode an enormous diversity of visual information using minimal numbers of neurons (merely hundreds of millions of neurons and billions of connections!). In the mammalian visual system, a visual image is essentially broken down into simple elements that are reconstructed through a series of processing stages, most of which occur beneath consciousness. Importantly, visual information processing is not simply a serial progression along the hierarchy of visual brain structures (e.g., retina to visual thalamus to primary visual cortex to secondary visual cortex, etc.). Instead, connections within and between visual brain structures exist in all possible directions: feedforward, feedback, and lateral. Additionally, many mammalian visual systems are organized into parallel channels, presumably to enable efficient processing of information about different and important features in the visual environment (e.g., color, motion). The overall operations of the mammalian visual system are to: (1) combine unique groups of feature detectors in order to generate object representations and (2) integrate visual sensory information with cognitive and contextual information from the rest of the brain. Together, these operations enable individuals to perceive, plan, and act within their environment.

CONCEPT OF INFORMATION PROCESSES ORGANIZATION IN HUMAN VISUAL SYSTEM

2020 ◽  
pp. 56-60
Author(s):  
Marina Leonidovna Kochina ◽  
O. V. Yavorsky ◽  
N. M. Maslova
Keyword(s):  
Visual System ◽  
Children And Adolescents ◽  
Visual Information ◽  
Functional Organization ◽  
High Price ◽  
Selective Visual Attention ◽  
Existing Problems ◽  
Information Processes ◽  
Concept Of Information ◽  
Intelligent Data Processing

Recent studies have shown that both traditional and modern (electronic) visual media significantly affect the processes occurring in the visual system of children and adolescents, iin the development of which the concept of controlled and uncontrolled elements is used. When studying the adaptation of the visual system to a visual load, ensuring the uptake, transmission and processing of visual information, its structural and functional organization is taken into account. The proposed summarized scheme of information processes in the visual system takes into account and significantly supplements the main provisions of the object−oriented model of selective visual attention, based on current methods of intelligent data processing. The results of the study indicate the complexity of the visual information transformation path from a visual stimulus to the creation and awareness of the image, occurring in the higher parts of the brain. The whole apparatus of encoding, transmitting, processing and perceiving visual information is useless if the guidance and focusing unit does not provide a clear and undistorted image of the objects of the outside world on the retina. In case of any malfunctions of the first unit or in the presence of defects in the visual system, the processes of finding compensation for this condition and modes of operation are started, which allows to obtain the most complete and high−quality perception of visual objects. These processes can lead to the formation of a visual system with sufficiently high visual functions or monocular one, if the compensation of existing problems will have a high "price". With the help of the proposed concept of organization of information processes in the visual system it is possible to assess the role of each of its considered blocks not only in the perception of visual information, but also the formation of this system in children and adolescents. Key words: visual system, information processes, visual information.

scholarly journals Predictions drive neural representations of visual events ahead of incoming sensory information

2020 ◽  
Vol 117 (13) ◽  
pp. 7510-7515 ◽  
Author(s):  
Tessel Blom ◽  
Daniel Feuerriegel ◽  
Philippa Johnson ◽  
Stefan Bode ◽  
Hinze Hogendoorn
Keyword(s):  
Visual System ◽  
Real Time ◽  
Visual Information ◽  
Sensory Input ◽  
Sensory Information ◽  
Moving Object ◽  
Present Moment ◽  
Neural Representations ◽  
The Brain ◽  
Predictive Mechanisms

The transmission of sensory information through the visual system takes time. As a result of these delays, the visual information available to the brain always lags behind the timing of events in the present moment. Compensating for these delays is crucial for functioning within dynamic environments, since interacting with a moving object (e.g., catching a ball) requires real-time localization of the object. One way the brain might achieve this is via prediction of anticipated events. Using time-resolved decoding of electroencephalographic (EEG) data, we demonstrate that the visual system represents the anticipated future position of a moving object, showing that predictive mechanisms activate the same neural representations as afferent sensory input. Importantly, this activation is evident before sensory input corresponding to the stimulus position is able to arrive. Finally, we demonstrate that, when predicted events do not eventuate, sensory information arrives too late to prevent the visual system from representing what was expected but never presented. Taken together, we demonstrate how the visual system can implement predictive mechanisms to preactivate sensory representations, and argue that this might allow it to compensate for its own temporal constraints, allowing us to interact with dynamic visual environments in real time.

Visual Substitution Systems: Control and Information Processing Considerations

1975 ◽  
Vol 69 (7) ◽  
pp. 300-304
Author(s):  
Raymond M. Fish
Keyword(s):  
Information Processing ◽  
Visual System ◽  
Visual Information ◽  
Control Mechanisms ◽  
Direct Stimulation ◽  
Systems Control ◽  
Display Systems ◽  
The Brain ◽  
Processing Of Visual Information ◽  
Stimulation Of

A detailed discussion of the visual mechanisms found in the higher vertebrates is used as the basis for exploring the problems found in creating visual substitution systems. Specific attention is given to the control mechanisms used in the visual system and to the processing of visual information in the retina and brain. The three types of substitution systems discussed are tactual display systems, audio display systems, and those involving direct stimulation of the brain using electrodes.

The spotlight of attention: shifting, resizing and splitting receptive fields when processing visual motion

e-Neuroforum ◽  
2012 ◽  
Vol 18 (3) ◽  
Author(s):  
S. Treue ◽  
J.C. Martinez-Trujillo
Keyword(s):  
Visual System ◽  
Visual Information ◽  
Visual Motion ◽  
Receptive Fields ◽  
Attentional Focus ◽  
Attention Shifting ◽  
Attentional Modulation ◽  
Spatial Sensitivity ◽  
Visual Inputs ◽  
The Brain

AbstractIn the visual system receptive fields repre­sent the spatial selectivity of neurons for a given set of visual inputs. Their invariance is thought to be caused by a hardwired in­put configuration, which ensures a stable ‘la­beled line’ code for the spatial position of vi­sual stimuli. On the other hand, changeable receptive fields can provide the visual system with flexibility for allocating processing re­sources in space. The allocation of spatial at­tention, often referred to as the spotlight of attention, is a behavioral equivalent of visu­al receptive fields. It dynamically modulates the spatial sensitivity to visual information as a function of the current attentional focus of the organism. Here we focus on the brain sys­tem for encoding visual motion information and review recent findings documenting in­teractions between spatial attention and re­ceptive fields in the visual cortex of primates. Such interactions create a careful balance be­tween the benefits of invariance with those derived from the attentional modulation of information processing according to the cur­rent behavioral goals.

scholarly journals Object-level visual information gets through the bottleneck of crowding

2011 ◽  
Vol 106 (3) ◽  
pp. 1389-1398 ◽  
Author(s):  
Jason Fischer ◽  
David Whitney
Keyword(s):  
Visual Processing ◽  
Visual Information ◽  
Neural Mechanisms ◽  
Visual Features ◽  
Object Representations ◽  
Dense Array ◽  
Processing Stream ◽  
High Level ◽  
Fundamental Limitation ◽  
Object Level

Natural visual scenes are cluttered. In such scenes, many objects in the periphery can be crowded, blocked from identification, simply because of the dense array of clutter. Outside of the fovea, crowding constitutes the fundamental limitation on object recognition and is thought to arise from the limited resolution of the neural mechanisms that select and bind visual features into coherent objects. Thus it is widely believed that in the visual processing stream, a crowded object is reduced to a collection of dismantled features with no surviving holistic properties. Here, we show that this is not so: an entire face can survive crowding and contribute its holistic attributes to the perceived average of the set, despite being blocked from recognition. Our results show that crowding does not dismantle high-level object representations to their component features.

scholarly journals Conscious perception of natural images is constrained by category-related visual features

2019 ◽  
Author(s):  
Daniel Lindh ◽  
Ilja G. Sligte ◽  
Sara Assecondi ◽  
Kimron L. Shapiro ◽  
Ian Charest
Keyword(s):  
Visual System ◽  
Natural Images ◽  
Visual Features ◽  
Adaptive Behaviour ◽  
Conscious Perception ◽  
Activation Patterns ◽  
Visual Objects ◽  
High Level ◽  
The Brain ◽  
Insight Into

AbstractConscious perception is crucial for adaptive behaviour yet access to consciousness varies for different types of objects. The visual system comprises regions with widely distributed category information and exemplar-level representations that cluster according to category. Does this categorical organisation in the brain provide insight into object-specific access to consciousness? We address this question using the Attentional Blink (AB) approach with visual objects as targets. We find large differences across categories in the AB then employ activation patterns extracted from a deep convolutional neural network (DCNN) to reveal that these differences depend on mid- to high-level, rather than low-level, visual features. We further show that these visual features can be used to explain variance in performance across trials. Taken together, our results suggest that the specific organisation of the higher-tier visual system underlies important functions relevant for conscious perception of differing natural images.

scholarly journals Establishing the functional relevancy of white matter connections in the visual system and beyond

2021 ◽  
Author(s):  
Mareike Grotheer ◽  
Emily Kubota ◽  
Kalanit Grill-Spector
Keyword(s):  
White Matter ◽  
Visual System ◽  
Large Scale ◽  
Functional Organization ◽  
Temporal Cortex ◽  
Fine Grained ◽  
Brain Functions ◽  
Functional Relationships ◽  
Functional Regions ◽  
The Brain

AbstractFor over a century, researchers have examined the functional relevancy of white matter bundles. Consequently, many large-scale bundles spanning several centimeters have been associated in their entirety with specific brain functions, such as language or attention. However, these coarse structural–functional relationships are at odds with modern understanding of the fine-grained functional organization of human cortex, such as the mosaic of category-selective regions in ventral temporal cortex. Here, we review a multimodal approach that combines fMRI to define functional regions of interest within individual’s brains with dMRI tractography to identify the white matter bundles of the same individual. Combining these data allows to determine which subsets of streamlines within a white matter bundle connect to specific functional regions in each individual. That is, this approach identifies the functionally defined white matter sub-bundles of the brain. We argue that this approach not only enhances the accuracy of interpreting the functional relevancy of white matter bundles, but also enables segmentation of these large-scale bundles into meaningful functional units, which can then be linked to behavior with enhanced precision. Importantly, this approach has the potential for making new discoveries of the fine-grained functional relevancy of white matter connections in the visual system and the brain more broadly, akin to the flurry of research that has identified functional regions in cortex.

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