Visual Cortical Representations Of Bottom Up Salience And Perceptual Continuity
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Visual Cortical Representations Of Bottom Up Salience And Perceptual Continuity
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Author : Brittany Edna Burrows
language : en
Publisher:
Release Date : 2011
Visual Cortical Representations Of Bottom Up Salience And Perceptual Continuity written by Brittany Edna Burrows and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
The amount of information available to the retina far exceeds the processing capacity of the visual system. Visual attention provides a means by which we can make use of the information available with optimal efficiency, allowing us to selectively process objects that are most likely to help us achieve our behavioral goals while filtering out others. Decades of research have revealed that visual representations of objects aligned with the locus of attention are enhanced, resulting in perceptual benefits. The attentional modulation of visual cortical responses, however, has been almost exclusively characterized within the context of volitionally deployed, top-down attention. Although the behavioral correlates of involuntarily deployed, bottom-up attention are well known, the underlying neural mechanism and its relationship to top-down attention are not. In Chapters 2 and 3 of this thesis, I describe experiments that investigate the neural correlates and mechanisms of bottom-up attention. In order to examine the neural correlates of bottom-up attention, we measured responses of single neurons in area V4 to "popout" stimuli, which differ uniformly from surrounding items and draw attention in a bottom-up manner, and compared them to responses to "conjunction" stimuli, which are composed of a combination of surrounding features and require top-down selection. We found that V4 responses are modulated by popout stimuli. This selectivity was more robust when larger numbers of surrounding items and multiple features were included in the display, and it was absent when only a few items were presented immediately outside the receptive field (RF). We next examined the relationship between bottom-up and top-down attention by measuring responses to these same stimuli while top-down attention was directed to locations distant from the RF. We found that popout selectivity was eliminated, indicating that the salience of popout stimuli is not sufficient to drive selection by V4 neurons under these conditions. These results demonstrate that neurons in feature-selective cortex are influenced by bottom-up attention, but that this influence is limited by top-down attention. Whether the source of the signal initiating attentional deployment is top-down or bottom-up, our gaze is typically aligned with the locus of our attention, making use of the high density of photoreceptors at the fovea of the retina. As we move our eyes around a visual scene to briefly fixate objects for further processing, we do not perceive the explosive onset of motion between each fixation that is created by these eye movements, nor do we perceive a series of individual snapshots from each fixation. Instead, we have a seamless visual experience of our surroundings. This perception of continuity across eye movements is crucial to efficient behavior, and yet the neural mechanisms that support a continuous visual experience are not well understood. In Chapter 4 of this thesis, I describe an experiment that investigates the neural representations of perceptual continuity during saccadic eye movements. In order to examine whether V4 neurons are involved in creating a continuous perceptual experience, we measured the responses of V4 neurons to probe stimuli presented during the preparation of saccadic eye movements to targets distant from the RF. We observed that the responses of area V4 neurons to probe stimuli depended on the similarity between the neuronal preference and the target of a saccade. Specifically, the suppression of V4 responses normally present during the preparation of saccades to targets outside of a neuron's RF was absent when the features of the target were congruent with the preference of the recorded neuron. This target-dependent modulation resulted in a substantial effect of the target match/non-match manipulation on neuronal selectivity. The results are consistent with a computational model in which saccade preparation automatically results in a global target-dependent modulation of visual cortical signals. We suggest that this modulation may contribute to the continuity of perception across saccadic eye movements. The results of this thesis demonstrate that V4 neurons are selective for stimuli that draw bottom-up attention. Surprisingly, this selectivity depends on the availability of top-down attentional resources, suggesting that these two distinct varieties of visual attention rely, at least in part, on a common mechanism. Additionally, this thesis provides evidence that V4 neurons contribute to a seamless perceptual experience by maintaining important visual information transaccadically.
Understanding Vision
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Author : Li Zhaoping
language : en
Publisher: OUP Oxford
Release Date : 2014-05-08
Understanding Vision written by Li Zhaoping and has been published by OUP Oxford this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014-05-08 with Medical categories.
While the field of vision science has grown significantly in the past three decades, there have been few comprehensive books that showed readers how to adopt a computional approach to understanding visual perception, along with the underlying mechanisms in the brain. Understanding Vision explains the computational principles and models of biological visual processing, and in particular, of primate vision. The book is written in such a way that vision scientists, unfamiliar with mathematical details, should be able to conceptually follow the theoretical principles and their relationship with physiological, anatomical, and psychological observations, without going through the more mathematical pages. For those with a physical science background, especially those from machine vision, this book serves as an analytical introduction to biological vision. It can be used as a textbook or a reference book in a vision course, or a computational neuroscience course for graduate students or advanced undergraduate students. It is also suitable for self-learning by motivated readers. in addition, for those with a focused interest in just one of the topics in the book, it is feasible to read just the chapter on this topic without having read or fully comprehended the other chapters. In particular, Chapter 2 presents a brief overview of experimental observations on biological vision; Chapter 3 is on encoding of visual inputs, Chapter 5 is on visual attentional selection driven by sensory inputs, and Chapter 6 is on visual perception or decoding. Including many examples that clearly illustrate the application of computational principles to experimental observations, Understanding Vision is valuable for students and researchers in computational neuroscience, vision science, machine and computer vision, as well as physicists interested in visual processes.
Encyclopedia Of The Human Brain
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Author :
language : en
Publisher: Elsevier
Release Date : 2002-07-04
Encyclopedia Of The Human Brain written by and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002-07-04 with Science categories.
In the past decade, enormous strides have been made in understanding the human brain. The advent of sophisticated new imaging techniques (e.g. PET, MRI, MEG, etc.) and new behavioral testing procedures have revolutionized our understanding of the brain, and we now know more about the anatomy, functions, and development of this organ than ever before. However, much of this knowledge is scattered across scientific journals and books in a diverse group of specialties: psychology, neuroscience, medicine, etc. The Encyclopedia of the Human Brain places all information in a single source and contains clearly written summaries on what is known of the human brain. Covering anatomy, physiology, neuropsychology, clinical neurology, neuropharmacology, evolutionary biology, genetics, and behavioral science, this four-volume encyclopedia contains over 200 peer reviewed signed articles from experts around the world. The Encyclopedia articles range in size from 5-30 printed pages each, and contain a definition paragraph, glossary, outline, and suggested readings, in addition to the body of the article. Lavishly illustrated, the Encyclopedia includes over 1000 figures, many in full color. Managing both breadth and depth, the Encyclopedia is a must-have reference work for life science libraries and researchers investigating the human brain.
Integrating Computational And Neural Findings In Visual Object Perception
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Author : Judith C. Peters
language : en
Publisher: Frontiers Media SA
Release Date : 2016-06-29
Integrating Computational And Neural Findings In Visual Object Perception written by Judith C. Peters and has been published by Frontiers Media SA this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016-06-29 with Electronic book categories.
The articles in this Research Topic provide a state-of-the-art overview of the current progress in integrating computational and empirical research on visual object recognition. Developments in this exciting multidisciplinary field have recently gained momentum: High performance computing enabled breakthroughs in computer vision and computational neuroscience. In parallel, innovative machine learning applications have recently become available for datamining the large-scale, high resolution brain data acquired with (ultra-high field) fMRI and dense multi-unit recordings. Finally, new techniques to integrate such rich simulated and empirical datasets for direct model testing could aid the development of a comprehensive brain model. We hope that this Research Topic contributes to these encouraging advances and inspires future research avenues in computational and empirical neuroscience.
Perceptual Organization
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Author : Michael Kubovy
language : en
Publisher: Routledge
Release Date : 2017-03-31
Perceptual Organization written by Michael Kubovy and has been published by Routledge this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-03-31 with Psychology categories.
Originally published in 1981, perceptual organization had been synonymous with Gestalt psychology, and Gestalt psychology had fallen into disrepute. In the heyday of Behaviorism, the few cognitive psychologists of the time pursued Gestalt phenomena. But in 1981, Cognitive Psychology was married to Information Processing. (Some would say that it was a marriage of convenience.) After the wedding, Cognitive Psychology had come to look like a theoretically wrinkled Behaviorism; very few of the mainstream topics of Cognitive Psychology made explicit contact with Gestalt phenomena. In the background, Cognition's first love – Gestalt – was pining to regain favor. The cognitive psychologists' desire for a phenomenological and intellectual interaction with Gestalt psychology did not manifest itself in their publications, but it did surface often enough at the Psychonomic Society meeting in 1976 for them to remark upon it in one of their conversations. This book, then, is the product of the editors’ curiosity about the status of ideas at the time, first proposed by Gestalt psychologists. For two days in November 1977, they held an exhilarating symposium that was attended by some 20 people, not all of whom are represented in this volume. At the end of our symposium it was agreed that they would try, in contributions to this volume, to convey the speculative and metatheoretical ground of their research in addition to the solid data and carefully wrought theories that are the figure of their research.
Understanding Vision
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Author : Li Zhaoping
language : en
Publisher: Oxford University Press, USA
Release Date : 2014
Understanding Vision written by Li Zhaoping and has been published by Oxford University Press, USA this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with Medical categories.
Vision science has grown hugely in the past decades, but there have been few books showing readers how to adopt a computional approach to understanding visual perception, along with the underlying mechanisms in the brain. This book explains the computational principles and models of biological visual processing, and in particular, primate vision.
Spatial Biases In Perception And Cognition
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Author : Timothy L. Hubbard
language : en
Publisher: Cambridge University Press
Release Date : 2018-08-23
Spatial Biases In Perception And Cognition written by Timothy L. Hubbard and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-08-23 with Psychology categories.
Numerous spatial biases influence navigation, interactions, and preferences in our environment. This volume considers their influences on perception and memory.
Brain And Visual Perception
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Author : David H. Hubel M.D.
language : en
Publisher: Oxford University Press
Release Date : 2004-10-14
Brain And Visual Perception written by David H. Hubel M.D. and has been published by Oxford University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004-10-14 with Medical categories.
This is the story of a hugely successful and enjoyable 25-year collaboration between two scientists who set out to learn how the brain deals with the signals it receives from the two eyes. Their work opened up a new area of brain research that led to their receiving the Nobel Prize in 1981. The book contains their major papers from 1959 to 1981, each preceded and followed by comments telling how and why the authors went about the study, how the work was received, and what has happened since. It begins with short autobiographies of both men, and describes the state of the field when they started. It is intended not only for neurobiologists, but for anyone interested in how the brain works-biologists, psychologists, philosophers, physicists, historians of science, and students at all levels from high school to graduate level.
The Oxford Handbook Of Perceptual Organization
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Author : Johan Wagemans
language : en
Publisher: OUP Oxford
Release Date : 2015-08-21
The Oxford Handbook Of Perceptual Organization written by Johan Wagemans and has been published by OUP Oxford this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015-08-21 with Psychology categories.
Perceptual organization comprises a wide range of processes such as perceptual grouping, figure-ground organization, filling-in, completion, perceptual switching, etc. Such processes are most notable in the context of shape perception but they also play a role in texture perception, lightness perception, color perception, motion perception, depth perception, etc. Perceptual organization deals with a variety of perceptual phenomena of central interest, studied from many different perspectives, including psychophysics, experimental psychology, neuropsychology, neuroimaging, neurophysiology, and computational modeling. Given its central importance in phenomenal experience, perceptual organization has also figured prominently in classic Gestalt writings on the topic, touching upon deep philosophical issues regarding mind-brain relationships and consciousness. In addition, it attracts a great deal of interest from people working in applied areas like visual art, design, architecture, music, and so forth. The Oxford Handbook of Perceptual Organization provides a broad and extensive review of the current literature, written in an accessible form for scholars and students. With chapter written by leading researchers in the field, this is the state-of-the-art reference work on this topic, and will be so for many years to come.
The Origin Of Concepts
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Author : Susan Carey
language : en
Publisher: Oxford Series in Cognitive Dev
Release Date : 2011
The Origin Of Concepts written by Susan Carey and has been published by Oxford Series in Cognitive Dev this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with Medical categories.
Carey begins by characterizing the innate starting point for conceptual development, namely systems of core cognition. Representations of core cognition are the output of dedicated input analyzers, as with perceptual representations, but these core representations differ from perceptual representations in having more abstract contents and richer functional roles. Carey argues that the key to understanding cognitive development lies in recognizing conceptual discontinuities in which new representational systems emerge that have more expressive power than core cognition and are also incommensurate with core cognition and other earlier representational systems. Finally, Carey fleshes out Quinian bootstrapping, a learning mechanism that has been repeatedly sketched in the literature on the history and philosophy of science. She demonstrates that Quinian bootstrapping is a major mechanism in the construction of new representational resources over the course of children's cognitive development.