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Author: Hulusi Kafaligonul
Publisher: Frontiers Media SA
ISBN: 2889195945
Category : Feedback
Languages : en
Pages : 153
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Book Description
The visual system consists of hierarchically organized distinct anatomical areas functionally specialized for processing different aspects of a visual object (Felleman & Van Essen, 1991). These visual areas are interconnected through ascending feedforward projections, descending feedback projections, and projections from neural structures at the same hierarchical level (Lamme et al., 1998). Accumulating evidence from anatomical, functional and theoretical studies suggests that these three projections play fundamentally different roles in perception. However, their distinct functional roles in visual processing are still subject to debate (Lamme & Roelfsema, 2000). The focus of this Research Topic is the roles of feedforward and feedback projections in vision. Even though the notions of feedforward, feedback, and reentrant processing are widely accepted, it has been found difficult to distinguish their individual roles on the basis of a single criterion. We welcome empirical contributions, theoretical contributions and reviews that fit into any one (or a combination) of the following domains: 1) their functional roles for perception of specific features of a visual object 2) their contributions to the distinct modes of visual processing (e.g., pre-attentive vs. attentive, conscious vs. unconscious) 3) recent techniques/methodologies to identify distinct functional roles of feedforward and feedback projections and corresponding neural signatures. We believe that the current Research Topic will not only provide recent information about feedforward/feedback processes in vision but also contribute to the understanding fundamental principles of cortical processing in general.
Author: Hulusi Kafaligonul
Publisher: Frontiers Media SA
ISBN: 2889195945
Category : Feedback
Languages : en
Pages : 153
Get Book Here
Book Description
The visual system consists of hierarchically organized distinct anatomical areas functionally specialized for processing different aspects of a visual object (Felleman & Van Essen, 1991). These visual areas are interconnected through ascending feedforward projections, descending feedback projections, and projections from neural structures at the same hierarchical level (Lamme et al., 1998). Accumulating evidence from anatomical, functional and theoretical studies suggests that these three projections play fundamentally different roles in perception. However, their distinct functional roles in visual processing are still subject to debate (Lamme & Roelfsema, 2000). The focus of this Research Topic is the roles of feedforward and feedback projections in vision. Even though the notions of feedforward, feedback, and reentrant processing are widely accepted, it has been found difficult to distinguish their individual roles on the basis of a single criterion. We welcome empirical contributions, theoretical contributions and reviews that fit into any one (or a combination) of the following domains: 1) their functional roles for perception of specific features of a visual object 2) their contributions to the distinct modes of visual processing (e.g., pre-attentive vs. attentive, conscious vs. unconscious) 3) recent techniques/methodologies to identify distinct functional roles of feedforward and feedback projections and corresponding neural signatures. We believe that the current Research Topic will not only provide recent information about feedforward/feedback processes in vision but also contribute to the understanding fundamental principles of cortical processing in general.
Author: Ivaylo P. Riskov
Publisher:
ISBN:
Category :
Languages : en
Pages : 174
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Book Description
The goal of this work is to explore a potential improvement on a visual recognition system. The system is a biologically-plausible computational model of the feedforward part of the ventral stream in the visual cortex and successfully models human performance on visual recognition tasks for the first 50-100 milliseconds since the presentation of the visual stimulus. We make the first steps to a possible augmentation of the system that will account for both feedforward and feedback processes in the ventral stream. We explore the plausibility of Bayesian network models for feedback. Our results show that although the resulting system under performs the original, it has a better rate of improvement as more and more training examples are added to it.
Author: Bartlett Doe Moore
Publisher:
ISBN: 9781124025605
Category :
Languages : en
Pages :
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Book Description
The unique ecological utility provided by the complex sensory processing that occurs in the brains of visual animals cannot be over appreciated. Psychologists, physiologists, mathematicians, and philosophers, among others, have subjected vision in humans and non-human animals to intense scrutiny. Perhaps the most studied regions of the mammalian visual system are the early visual pathways: the retina, the dorsal lateral geniculate nucleus of the thalamus (LGN), and area 17 of the primary visual cortex (V1). This dissertation was conceived and conducted to elucidate some of the contributions of feedforward processes to sensory responses in the early visual system. Extracellular recordings were collected from individual neurons in the retina, visual thalamus, and primary visual cortex of cats, and the primary visual cortex of ferrets while controlling the sensory input to the system. These methods were used to characterize five distinct features of information processing: 1) the influence of stimulus temporal frequency on orientation tuning in V1 neurons, 2) the influence of stimulus temporal frequency on direction selectivity in V1 neurons, 3) the response properties of LGN neurons in the absence of On-center retinal input, 4) the orientation tuning in V1 neurons in the absence of On-center LGN input, and 5) the direction selectivity of V1 neurons in the absence of On-center LGN input. The results presented in the following chapters show that the paradigmatic feedforward model of processing in the early visual system and its contribution to neuronal response properties requires further refinement. The work presented in chapter 2 show that the direction selectivity--but not orientation tuning--of ferret V1 neurons is dependant on the temporal frequency of stimuli, suggesting that stability of orientation tuning is an important aspect of early visual processing. The work presented in chapter 3 suggest there is more frequent divergence of connections in the retinogeniculate pathway of the cat than previously recognized and that functionally silent, non-specific retinal inputs can undergo rapid plasticity when the On pathway is disrupted. The work presented in chapter 4 investigates the response properties of V1 neurons in the absence of On-center LGN activity. The results show that while orientation tuning is resilient to the reduction in feedforward input, direction selectivity behaves more erratically. The early visual system is the computational foundation upon which more complex features are detected in the visual environment. In order to understand how visual processing in later visual pathways is accomplished, it is critical that the feedforward contributions to response properties in the early visual pathways be understood.
Author: Dieter Jaeger
Publisher:
ISBN: 9781461473206
Category : Computational neuroscience
Languages : en
Pages :
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Book Description
Author: Helga Kolb
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Author: Li Zhaoping
Publisher: Oxford University Press, USA
ISBN: 0199564663
Category : Medical
Languages : en
Pages : 397
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Book Description
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.
Author: Peter H. Schiller
Publisher: Oxford University Press, USA
ISBN: 0199936536
Category : Medical
Languages : en
Pages : 441
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Book Description
'Vision and the Visual System' offers students, teachers and researchers a rigorous, yet accessible account of how the brain analyses the visual scene. Schiller and Tehovnik describe key aspects of visual perception such as colour, motion, pattern and depth while explaining the relationship between eye movements and neural structures in the brain.
Author: Bruno Breitmeyer
Publisher: Oxford University Press, USA
ISBN: 0198530676
Category : Medical
Languages : en
Pages : 383
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Book Description
Where most current approaches to the study of visual consciousness adopt a 'steady-state' view, the approach presented in this book explores its dynamic properties down to a resolution in the millisecond range."--BOOK JACKET.
Author: Susana Martinez-Conde
Publisher: Elsevier
ISBN: 0080466087
Category : Psychology
Languages : en
Pages : 341
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Book Description
This book presents a collection of articles reflecting state-of-the-art research in visual perception, specifically concentrating on neural correlates of perception. Each section addresses one of the main topics in vision research today. Volume 1 Fundamentals of Vision: Low and Mid-Level Processes in Perception covers topics from receptive field analyses to shape perception and eye movements. A variety of methodological approaches are represented, including single-neuron recordings, fMRI and optical imaging, psychophysics, eye movement characterization and computational modelling. The contributions will provide the reader with a valuable perspective on the current status of vision research, and more importantly, with critical insight into future research directions and the discoveries yet to come. · Provides a detailed breakdown of the neural and psychophysical bases of Perception · Presents never-before-published original discoveries · Includes multiple full-color illustrations
Author: Galina V. Paramei
Publisher: Frontiers Media SA
ISBN: 288919857X
Category : Psychology
Languages : en
Pages : 136
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Book Description
Starting from psychophysics, over the last 50 years, most progress in unravelling the mechanisms of color vision has been made through the study of single cell responses, mainly in LGN and striate cortex. A similar development in the study of form perception may seem to be underway, centred on the study of temporal cortex. However, because of the combinatorial characteristics of form perception, we are also observing the opposite tendency: from single-cell activity to population coding, and from static receptive field structures to system dynamics and integration and, ultimately, a synthetic form of psychophysics of color and form perception. From single cells to system integration: it is this development the present Research Topic wishes to highlight and promote. How does this development affect our views on the various attributes of perception? In particular, we are interested in to what extent evolving knowledge in the field of color perception is relevant within a developing integrative framework of form perception. The goal of this Research Topic is to bring together experimental research encompassing both color and form perception. For this volume, we planned a broad scope of topics – on color in complex scenes, color and form, as well as dynamic aspects of form perception. We expect that the Research Topic will be attractive to the community of researchers whose work straddles the boundary between the two visual perception fields, as well as to the wider community interested in integrative/systems neuroscience.
