Download or read book The Encoding of Natural Images in Human Visual Cortex written by Kendrick Norris Kay and published by . This book was released on 2009 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Encoding and Decoding of Natural Images by the Mid level Visual System written by Ryan James Prenger and published by . This book was released on 2008 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Encoding of Natural Scene Statistics in the Visual Cortex of the Mouse written by and published by . This book was released on 2014 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Attention in Cognitive Systems Theories and Systems from an Interdisciplinary Viewpoint written by Lucas Paletta and published by Springer. This book was released on 2007-12-03 with total page 507 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides a much-needed interdisciplinary angle on the subject of attention in cognitive systems. It constitutes the thoroughly refereed post-workshop proceedings of the 5th International Workshop on Attention in Cognitive Systems, held in Hyderabad, India, in January 2007. The 31 papers are organized in topical sections that cover every aspect of the subject, from the embodiment of attention and its cognitive control, to the applications of attentive vision.
Download or read book Energy Minimization Methods in Computer Vision and Pattern Recognition written by Alan L. Yuille and published by Springer. This book was released on 2007-08-14 with total page 505 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the refereed proceedings of the 6th International Conference on Energy Minimization Methods in Computer Vision and Pattern Recognition held in Ezhou, China, in August 2007. Twenty-two full papers are presented along with fifteen poster papers. The papers are organized into topical sections on algorithms, applications, image parsing, image processing, motion, shape, and three-dimensional processing.
Download or read book The New Visual Neurosciences written by John S. Werner and published by MIT Press. This book was released on 2013-10-25 with total page 1693 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive review of contemporary research in the vision sciences, reflecting the rapid advances of recent years. Visual science is the model system for neuroscience, its findings relevant to all other areas. This essential reference to contemporary visual neuroscience covers the extraordinary range of the field today, from molecules and cell assemblies to systems and therapies. It provides a state-of-the art companion to the earlier book The Visual Neurosciences (MIT Press, 2003). This volume covers the dramatic advances made in the last decade, offering new topics, new authors, and new chapters. The New Visual Neurosciences assembles groundbreaking research, written by international authorities. Many of the 112 chapters treat seminal topics not included in the earlier book. These new topics include retinal feature detection; cortical connectomics; new approaches to mid-level vision and spatiotemporal perception; the latest understanding of how multimodal integration contributes to visual perception; new theoretical work on the role of neural oscillations in information processing; and new molecular and genetic techniques for understanding visual system development. An entirely new section covers invertebrate vision, reflecting the importance of this research in understanding fundamental principles of visual processing. Another new section treats translational visual neuroscience, covering recent progress in novel treatment modalities for optic nerve disorders, macular degeneration, and retinal cell replacement. The New Visual Neurosciences is an indispensable reference for students, teachers, researchers, clinicians, and anyone interested in contemporary neuroscience. Associate Editors Marie Burns, Joy Geng, Mark Goldman, James Handa, Andrew Ishida, George R. Mangun, Kimberley McAllister, Bruno Olshausen, Gregg Recanzone, Mandyam Srinivasan, W.Martin Usrey, Michael Webster, David Whitney Sections Retinal Mechanisms and Processes Organization of Visual Pathways Subcortical Processing Processing in Primary Visual Cortex Brightness and Color Pattern, Surface, and Shape Objects and Scenes Time, Motion, and Depth Eye Movements Cortical Mechanisms of Attention, Cognition, and Multimodal Integration Invertebrate Vision Theoretical Perspectives Molecular and Developmental Processes Translational Visual Neuroscience
Download or read book Spatiotemporal Responses to Natural Images and Their Phase shuffled Version in the Primary Visual Cortex written by Sepide Movaghati and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "According to classical models of visual information processing, the visual cortex acts as a hierarchical structure in which information flow is unidirectional and transmitted from the primary visual cortex (V1) to higher visual areas. This model considers V1 as an inflexible processing unit, which filters local basic features of visual input, such as the spatial frequency and orientation of the changes in luminance. Contrary to this classical model, recent studies have reported variant activity in V1 based on the presence of higher-order features within visual inputs. In other words, specific characteristics, such as phase content or spatial coherence, potentially modulate the activity of V1. However, the explicit characteristics and the precise timing of their modulatory effect remain unclear. In this study, MagnetoEncephaloGraphy (MEG) was used to test whether the spatiotemporal response to natural images of animals is different from the response to their phase-shuffled counterparts. The frequency content and the total contrast of the images were maintained throughout the phase-scrambling approach. Meanwhile, higher-order image statistics, such as Kurtosis, were manipulated. We investigated the effect of this manipulation on the evoked response of V1 by taking advantage of (1) the high temporal resolution of the MEG technique and (2) the Minimum norm source localization method. The results of this thesis show that the modulation of activity associated with the presentation of natural images appears as early as 50ms post-stimulation. This effect can be observed in the power of the signals recorded by MEG sensors as well as in sources localized in the primary visual cortex. The phase scrambling of visual input increased the amplitude of the early response (30-70ms post-stimulation) and the M170 component (140-200ms post-stimulation). The weaker population response to natural images during the early response is consistent with a model proposing sparse neuronal coding for natural images. The increased M170 activation of V1 to non-natural phase-scrambled images is consistent with the predictive coding model. According to this model, the prediction error in lower order sensory areas increases with decreasing predictability of the sensory input. An increase in the power of gamma frequency (60-80Hz) was observed in response to phase-scrambled images. These findings are in accordance with a previous study that found prediction errors in auditory cortex to be predominantly conveyed via the high (gamma) frequency range. In addition, spatially coherent features in visual input induce a stronger surround suppression effect and reduce the population activity in V1. Therefore, the mechanisms underlying the late modulatory effect on the M170 component may also involve surround suppression in the visual cortex. Our findings suggest that feedback modulates the neuronal response of the primary visual cortex. Further, they identify V1 as a dynamic filter that can be modulated by the higher-order characteristics of visual input, as opposed to previous models that deem V1 to be an inflexible low-level processing unit." --
Download or read book Visual Population Codes written by Nikolaus Kriegeskorte and published by MIT Press. This book was released on 2012 with total page 659 pages. Available in PDF, EPUB and Kindle. Book excerpt: How visual content is represented in neuronal population codes and how to analyze such codes with multivariate techniques. Vision is a massively parallel computational process, in which the retinal image is transformed over a sequence of stages so as to emphasize behaviorally relevant information (such as object category and identity) and deemphasize other information (such as viewpoint and lighting). The processes behind vision operate by concurrent computation and message passing among neurons within a visual area and between different areas. The theoretical concept of "population code" encapsulates the idea that visual content is represented at each stage by the pattern of activity across the local population of neurons. Understanding visual population codes ultimately requires multichannel measurement and multivariate analysis of activity patterns. Over the past decade, the multivariate approach has gained significant momentum in vision research. Functional imaging and cell recording measure brain activity in fundamentally different ways, but they now use similar theoretical concepts and mathematical tools in their modeling and analyses. With a focus on the ventral processing stream thought to underlie object recognition, this book presents recent advances in our understanding of visual population codes, novel multivariate pattern-information analysis techniques, and the beginnings of a unified perspective for cell recording and functional imaging. It serves as an introduction, overview, and reference for scientists and students across disciplines who are interested in human and primate vision and, more generally, in understanding how the brain represents and processes information.
Download or read book The Case for Mental Imagery written by Stephen M. Kosslyn and published by Oxford University Press. This book was released on 2006-03-09 with total page 257 pages. Available in PDF, EPUB and Kindle. Book excerpt: When we try to remember whether we left a window open or closed, do we actually see the window in our mind? If we do, does this mental image play a role in how we think? For almost a century, scientists have debated whether mental images play a functional role in cognition. In The Case for Mental Imagery, Stephen Kosslyn, William Thompson, and Giorgio Ganis present a complete and unified argument that mental images do depict information, and that these depictions do play a functional role in human cognition. They outline a specific theory of how depictive representations are used in information processing, and show how these representations arise from neural processes. To support this theory, they seamlessly weave together conceptual analyses and the many varied empirical findings from cognitive psychology and neuroscience. In doing so, they present the conceptual grounds for positing this type of internal representation and summarize and refute arguments to the contrary. Their argument also serves as a historical review of the imagery debate from its earliest inception to its most recent phases, and provides ample evidence that significant progress has been made in our understanding of mental imagery. In illustrating how scientists think about one of the most difficult problems in psychology and neuroscience, this book goes beyond the debate to explore the nature of cognition and to draw out implications for the study of consciousness. Student and professional researchers in vision science, cognitive psychology, philosophy, and neuroscience will find The Case for Mental Imagery to be an invaluable resource for understanding not only the imagery debate, but also and more broadly, the nature of thought, and how theory and research shape the evolution of scientific debates.
Download or read book From Scenes to Spikes written by Joel Leon Zylberberg and published by . This book was released on 2012 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: The human genome (containing around 1E10 bits of information) is unlikely to fully specify the connectivity between neurons in our brains, such a "wiring diagram" requires around 1E14 bits. Physiological evidence suggests that the genome instead specifies plasticity rules through which the brain self organizes in response to experience. As systems neuroscientists, we seek to understand those rules and, by extension, our brains. In this thesis, I will use this approach to study the primary visual cortex (V1), the brain region that receives visual inputs from the eyes, via a relay station called the lateral geniculate nucleus. I first study the statistical structure of natural images, which provide the visual experience that shapes V1. Then, I introduce a biophysically motivated model for visual cortex, which adapts to natural image statistics in order to efficiently encode them, in this case, the neural plasticity rules can be shown to optimize this efficient representation. I then demonstrate that this model can account for several features of V1 physiology, including the features to which V1 neurons respond (receptive fields), and the developmental trends in the sparseness of V1 activity. I will conclude that efficient coding models can be implemented within the constraints imposed by the neural substrate, and that efficient coding principles may yield a parsimonious systems level understanding of visual cortex.
Download or read book Principles of Frontal Lobe Function written by Donald T. Stuss and published by Oxford University Press. This book was released on 2002-06-27 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides a comprehensive review of historical and current research on the function of the frontal lobes and frontal systems of the brain. The content spans frontal lobe functions from birth to old age, from biochemistry and anatomy to rehabilitation, and from normal to disrupted function. The book is intended to be a standard reference work on the frontal lobes for researchers, clinicians, and students in the field of neurology, neuroscience, psychiatry, psychology, and health care.
Download or read book Academic Press Library in Signal Processing written by and published by Academic Press. This book was released on 2013-09-14 with total page 1131 pages. Available in PDF, EPUB and Kindle. Book excerpt: This fourth volume, edited and authored by world leading experts, gives a review of the principles, methods and techniques of important and emerging research topics and technologies in Image, Video Processing and Analysis, Hardware, Audio, Acoustic and Speech Processing. With this reference source you will: - Quickly grasp a new area of research - Understand the underlying principles of a topic and its application - Ascertain how a topic relates to other areas and learn of the research issues yet to be resolved - Quick tutorial reviews of important and emerging topics of research in Image, Video Processing and Analysis, Hardware, Audio, Acoustic and Speech Processing - Presents core principles and shows their application - Reference content on core principles, technologies, algorithms and applications - Comprehensive references to journal articles and other literature on which to build further, more specific and detailed knowledge - Edited by leading people in the field who, through their reputation, have been able to commission experts to write on a particular topic
Download or read book Cortical Processing of Natural Visual Stimuli written by Gidon Shachar Felsen and published by . This book was released on 2004 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computational Models of Primary Visual Cortex and the Structure of Natural Images written by Hauke Bartsch and published by . This book was released on 2004 with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Processing of Natural Images by the Human Visual System written by Yoav Tadmor and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Mechanisms of Reliable Coding in Mouse Visual Cortex written by Rajeev Vijay Rikhye and published by . This book was released on 2016 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: As we interact with the environment, our senses are constantly bombarded with information. Neurons in the visual cortex have to transform these complex inputs into robust and parsimonious neural codes that effectively guide behavior. The ability of neurons to efficiently convey information is, however, limited by intrinsic and shared variability. Despite this limitation, neurons in primary visual cortex (V1) are able to respond with high fidelity to relevant stimuli. My thesis proposes that high fidelity encoding can be achieved by dynamically increasing trial-to-trial response reliability. In particular, in this thesis, I use the mouse primary visual cortex (V1) as a model to understand how reliable coding arises, and why it is important for visual perception. Using a combination of novel experimental and computational techniques, my thesis identifies three main factors that can modulate intrinsic variability. My first goal was to understand the extrinsic, stimulus-dependent, factors responsible for reliably coding (Chapter 3). Natural scenes contain unique statistical properties that could be leveraged by the visual cortex for efficient coding. Thus, the first aim is to elucidate how image statistics modulate reliable coding in V1. To this end, I developed a novel noise masking procedure that allowed us to specifically perturb the spectral content of natural movies without altering the edges. Using high-speed twophoton calcium imaging in mice, I discovered that movies with stronger spatial correlations are more reliably processed by V1 neurons than movies lacking these correlations. In particular, perturbing spatial correlations in the movie dynamically altered the structure of interneuronal correlations. Movies with more naturalistic correlations typically recruited large neuronal ensembles that were weakly noise correlated. Using computational modeling, I discovered that these ensembles were able reduce shared noise through divisive normalization. Together, these findings demonstrate that natural scene statistics dynamically recruit neuronal ensembles to ensure reliable coding. Microcircuits of inhibitory interneurons lie at the heart of all cortical computations. It has been proposed that these interneurons are responsible for reliable spiking by controlling the temporal window over which synaptic inputs are integrated. However, no study has yet conclusively investigated the role of different interneuron subtypes. Thus, my second goal was to establish how natural scenes are reliably encoded by dissecting the inhibitory mechanisms underlying reliable coding (Chapter 4). Specifically, I investigated the role of somatostatin-expressing dendrite targeting interneurons (SST) and parvalbumin-expressing soma targeting interneurons (PV), which are known to provide distinct forms of inhibition onto pyramidal neurons. Using a novel combination of dual-color calcium imaging and optogenetic manipulation, I have discovered that the SST->PV inhibitory circuit plays a crucial role in modulating pyramidal cell reliability. In particular, by transiently suppressing PV neurons, SST neurons are able to route inhibition rapidly from the soma to the dendrites. Strong dendritic inhibition allows noisy inputs to be filtered out by the dendrites, while weaker somatic inhibition allows these inputs to be integrated to produce reliable spikes. In agreement with these results, I found that selectively deleting MeCP2 from these interneurons resulted in unreliable visual processing and other circuit-specific deficits, which are commonly observed in Rett Syndrome (Chapter 5). These results underscore the importance of intact inhibitory microcircuits in reliable processing. Finally, my goal was to determine why reliable coding is necessary for visual processing (Chapter 6). To this end, I trained head-fixed mice to perform a natural movie discrimination task. Mice were able to learn how to discriminate between two movies after a short training period. By perturbing the amplitude spectrum of these movies, I discovered that mice used structural information in the phase spectrum to discriminate between the different movies. This suggests that mice also use similar strategies as higher mammals for scene recognition. Inspired by this result, we trained mice on a harder target categorization task, where mice had to identify the movies from an ensemble that were more similar to the target movie to gain a water reward. We developed this movie ensemble by blending together the phase spectrum of a target and non-target movie at different fractions. Optically activating SST neurons in V1 improved the ability of mice to correctly identify "target-like" movies. This increase in behavioral performance correlated well with an increase in V1 coding reliability. Thus, reliable codes are a prerequisite for accurate visual perception. Taken together, this work bridges the gap between cells, circuits and behavior, and provides mechanistic insight into how complex visual stimuli are encoded with high fidelity in the visual cortex.
Download or read book Foundations of Vision written by Brian A. Wandell and published by Sinauer Associates, Incorporated. This book was released on 1995 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: Designed for students, scientists and engineers interested in learning about the core ideas of vision science, this volume brings together the broad range of data and theory accumulated in this field.
