On Information Processing in the Visual System of Vertebrates. I. PDF Download

Author: Werner VON Seelen
Publisher:
ISBN:
Category :
Languages : en
Pages : 50

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Book Description
In the domain of form recognition the human visual system surpasses by far the capacity of actually existing technical devices designed to serve the same purpose. Therefore it appears advantageous to undertake a communication-theoretic function-description and structure-description of the biological system in order to gain suggestions for the solution of technical problems and in order to make possible the adaptation of technical apparatus to human beings. Over and above this an understanding of visual information processing will probably permit inferences to be drawn regarding the functioning of fairly large parts of the brain since the information picked up by the peripheral sense organs is processed in similarly structured networks in the cerebrum. The following investigation is based essentially on the electrophysiological studies of Hubel and Wiesel on the visual cortex of cats and monkeys. (Author).

Author: Ron Douglas
Publisher: Springer Science & Business Media
ISBN: 9400904118
Category : Science
Languages : en
Pages : 531

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A question often asked of those of us who work in the seemingly esoteric field of fish vision is, why? To some of us the answer seems obvious - how many other visual scientists get to dive in a tropical lagoon in the name of science and then are able to eat their subjects for dinner? However, there are better, or at least scientifically more acceptable, reasons for working on the visual system of fish. First, in terms of numbers, fish are by far the most important of all vertebrate classes, probably accounting for over half (c. 22 000 species) of all recognized vertebrate species (Nelson, 1984). Furthermore, many of these are of commercial importance. Secondly, if one of the research aims is to understand the human visual system, animals such as fish can tell us a great deal, since in many ways their visual systems, and specifically their eyes, are similar to our own. This is fortunate, since there are several techniques, such as intracellular retinal recording, which are vital to our understanding of the visual process, that cannot be performed routinely on primates. The cold blooded fish, on the other hand, is an ideal subject for such studies and much of what we know about, for example, the fundamentals of information processing in the retina is based on work carried out on fish (e. g. Svaetichin, 1953).

Author: F. Crescitelli
Publisher: Springer Science & Business Media
ISBN: 3642664687
Category : Medical
Languages : en
Pages : 816

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Book Description
The vertebrate eye has been, and continues to be, an object of interest and of inquiry for biologists, physicists, chemists, psychologists, and others. Quite apart from its important role in the development of ophthalmology and related medical disciplines, the vertebrate eye is an exemplar of the ingenuity of living systems in adapting to the diverse and changing environments in which vertebrates have evolved. The wonder is not so much that the visual system, like other body systems, has been able to adapt in this way, but rather that these adaptations have taken such a variety of forms. In a previous volume in this series (VII/I) Eakin expressed admiration for the diversity of invertebrate photoreceptors. A comparable situation exists for the vertebrate eye as a whole and one object of this volume is to present to the reader the nature of this diversity. One result of this diversification of ocular structures and properties is that the experimental biologist has available a number of systems for study that are unique or especially favorable for the investigation of particular questions in visual science or neurobiology. This volume includes some examples of progress made by the use of such specially selected vertebrate systems. It is our hope that this comparative approach will continue to reveal new and useful preparations for the examination of important questions.

Author: Martin J. Tovée
Publisher: Cambridge University Press
ISBN: 1139472674
Category : Medical
Languages : en
Pages : 229

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Book Description
Building on the successful formula of the first edition, Martin Tovée offers a concise but detailed account of how the visual system is organised and functions to produce visual perception. He takes his readers from first principles; the structure and function of the eye and what happens when light enters, to how we see and process images, recognise patterns and faces, and through to the most recent discoveries in molecular genetics and brain imaging, and how they have uncovered a host of new advances in our understanding of how visual information is processed within the brain. Incorporating new material throughout, including almost 50 new images, every chapter has been updated to include the latest research, and culminates in helpful key points, which summarise the lessons learnt. This book is an invaluable course text for students within the fields of psychology, neuroscience, biology and physiology.

Author: Rüdiger Wehner
Publisher: Springer Science & Business Media
ISBN: 3642654770
Category : Science
Languages : en
Pages : 325

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It is now generally accepted for a variety of reasons - morphological as well as physiologica- that the visual systems of arthropods provide a suitable model for the study of information proces sing in neuronal networks. Unlike the neurophysiology of the visual pathway in the frog and the cat which is more than adequately documented, recent work on the compound eye and optical ganglia of spiders, crustaceans, and insects has scarcely been summarized. In order to fill this void so that others, especially vertebrate neurophysiologists may become familiar with the advan tages of these systems, our group at Zurich University organized here in March 1972, a European meeting to discuss the anatomical. ! neurophysiological and behavioral knowledge on the compound eye and the visual. pathway of arthropods. Systems analysis was regarded as the main theme of the conference, but systems analysis of a network of neurons cannot be done as a mere "black-box" maneuver. The conference therefore tried to reconcile neurophysiology and behavioral analysis in order to make predictions about a necessary and sufficient neural structure. The "wiring dia grams" of such a structure might then be confirmed histologically. Hence the aim of the conferen ce was not to deal only with the structure and function of the compound eye - i. e.

Author: H. Autrum
Publisher: Springer
ISBN: 9783540057697
Category : Medical
Languages : en
Pages : 0

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The present volume covers the physiology of the visual system beyond the optic nerve. It is a continuation of the two preceding parts on the photochemistry and the physiology of the eye, and forms a bridge from them to the fourth part on visual psychophysics. These fields have all developed as independent speciali ties and need integrating with each other. The processing of visual information in the brain cannot be understood without some knowledge of the preceding mechanisms in the photoreceptor organs. There are two fundamental reasons, ontogenetic and functional, why this is so: 1) the retina of the vertebrate eye has developed from a specialized part of the brain; 2) in processing their data the eyes follow physiological principles similar to the visual brain centres. Peripheral and central functions should also be discussed in context with their final synthesis in subjective experience, i. e. visual perception. Microphysiology and ultramicroscopy have brought new insights into the neuronal basis of vision. These investigations began in the periphery: HARTLINE'S pioneering experiments on single visual elements of Limulus in 1932 started a successful period of neuronal recordings which ascended from the retina to the highest centres in the visual brain. In the last two decades modern electron microscopic techniques and photochemical investigations of single photoreceptors further contributed to vision research.

Author: Adam Reichenthal
Publisher:
ISBN:
Category :
Languages : en
Pages :

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"Numerous studies have generated valuable data on the early visual system, but this information may be biased or at least incomplete since most studies have focused on terrestrial mammals. To better account for visual systems in different living environments and animal classes, we studied the function and structure of the early visual processing system of the archerfish, a species that is far removed evolutionarily from terrestrial mammals. To do so, we first studied what visual features guide attention in its early visual system. This was done by conducting search experiments on archerfish visual search in which its reaction time to detect a target against a backdrop of distractors that differed in their visual features from the target, was measured. If the archerfish detected the target quickly, independently of the number of distractors, this suggested that the visual feature was fundamental to its early visual system. We also compared the results to human performance in these experiments. We found that both species exhibit similar search behavior in terms of color, size, orientation and motion as well as in conjunction search tasks involving color and size. In contrast, performance differed between the two species on visual search tasks defined by shape. Next, to study how visual information is represented in the archerfish visual system we characterized the neural properties of the optic tectum, the main visual processing region in the fish brain. Receptive field structures were measured and linear non-linear cascades were used to analyze their properties. The findings indicated that the spatial receptive field structures lie on a continuum between circular and elliptical shapes. In addition, the cells' functional properties displayed a richness of response characteristics, since many cells could be captured by more than a single linear filter. Finally, the non-linear response functions that link linear filters and neuronal responses were found to be similar to the non-linear functions of models that describe terrestrial mammalian single cell activity. Overall, our findings illustrate the many functional and neuronal mechanism similarities between the archerfish and mammalian vertebrates and therefore suggest the existence of a universality in the visual system's processing algorithm across vertebrates."-- abstract.

Author: Jonathan Stone
Publisher: Springer
ISBN:
Category : Computers
Languages : en
Pages : 466

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In the mid-sixties, John Robson and Christina Enroth-Cugell, without realizing what they were doing, set off a virtual revolution in the study of the visual system. They were trying to apply the methods of linear systems analysis (which were already being used to describe the optics of the eye and the psychophysical performance of the human visual system) to the properties of retinal ganglion cells in the cat. Their idea was to stimulate the retina with patterns of stripes and to look at the way that the signals from the center and the antagonistic surround of the respective field of each ganglion cell (first described by Stephen Kuffier) interact to generate the cell's responses. Many of the ganglion cells behaved themselves very nicely and John and Christina got into the habit (they now say) of calling them I (interesting) cells. However. to their annoyance, the majority of neurons they recorded had nasty, nonlinear properties that couldn't be predicted on the basis of simple summ4tion of light within the center and the surround. These uncoop erative ganglion cells, which Enroth-Cugell and Robson at first called D (dull) cells, produced transient bursts of impulses every time the distribution of light falling on the receptive field was changed, even if the total light flux was unaltered.

Author: A. Kaneko
Publisher: Springer
ISBN:
Category : Juvenile Nonfiction
Languages : en
Pages : 280

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Book Description
Researchers in recent decades have elucidated signal transduction in the retina and the function of the visual cortex. The highly flexible nature of neural circuits in the visual cortex especially during the critical period has been an interesting subject for studying neural plasticity and development. Recent advances in the visual neurosciences of the vertebrate retina and the visual cortex were discussed during the 12th Keio International Symposium for Life Science and Medicine, meeting jointly with Vision Forum 2002. Contributions to the symposium collected in this volume reflect the convergence of physiological, cell biological, molecular, mathematical, and clinical approaches. The book covers topics ranging from phototransduction to visual information processing in the primary visual cortex, and includes clinical studies on hereditary night blindness, creating a valuable source of information for researchers and clinicians in the visual neurosciences.

Author: Helga Kolb
Publisher:
ISBN:
Category :
Languages : en
Pages :

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