Download or read book Membrane Potential and Input Conductance Mechanisms Underlying Orientation Tuning and Length Tuning in Cat Primary Visual Cortex written by Jeffrey S. Anderson and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Models of the origin of orientation tuning in visual cortex propose fundamentally different computational roles for the cerebral cortex. Feedforward models propose that orientation tuning arises from the specificity of thalamocortical inputs to simple cells. Feedback models propose that orientation tuning is an emergent property of intracortical circuitry. Feedforward models have proven consistent with a number of experimental results, but a few perceived inconsistencies have motivated the development of more complex feedback models. The present report both addresses some of these perceived failures of feedforward models, as well as elaborates on additional synaptic mechanisms for orientation tuning and length tuning in visual cortex. First, experiments have shown large numbers of inhibitory cortical connections, to which feedforward models have ascribed little function beyond simple gain control. Various other models suggest that these inhibitory connections are crucial to sensory processing by sharpening the computations performed by thalamocortical inputs. In this report, data are presented from measurements of synaptic conductances showing that inhibitory inputs to cortical simple cells do not sharpen orientation tuning. Second, one of the most troubling criticisms of feedforward models has been their inability to explain the invariance of orientation tuning with stimulus contrast without elaborate modifications. Data are shown that suggest such contrast invariance of orientation tuning is rather a natural consequence of high levels of synaptic noise in cortical cells. Third, it is proposed that at higher stages in visual cortical processing, such as in most complex cells, that synchronized, two-state, membrane potential fluctuations may encode sensory information at the network level. Finally, membrane potential and conductance measurements are presented that suggest a role for intracortical connections in establishing length tuning in visual cortex. A two-part model is suggested by the data: direct, long-range inhibition is observed in some cells to give rise to end-stopping; in other cells, end-stopping is achieved primarily by decreased input from other cells that are themselves end-stopped.

Download or read book The Neural Basis of Early Vision written by A. Kaneko and published by Springer Science & Business Media. This book was released on 2013-03-13 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Dynamic Clamp written by Alain Destexhe and published by Springer Science & Business Media. This book was released on 2009-03-11 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamic-clamp is a fascinating electrophysiology technique that consists of merging living neurons with computational models. The dynamic-clamp (also called “conductance injection”) allows experimentalists and theoreticians to challenge neurons (or any other type of cell) with complex conductance stimuli generated by a computer. The technique can be implemented from neural simulation environments and a variety of custom-made or commercial systems. The real-time interaction between the computer and cell also enables the design of recording paradigms with unprecedented accuracy via a computational model of the electrode. Dynamic-Clamp: From Principles to Applications contains contributions from leading researchers in the field, who investigate these paradigms at the cellular or network level, in vivo and in vitro, and in different brain regions and cardiac cells. Topics discussed include the addition of artificially-generated synaptic activity to neurons; adding, amplifying or neutralizing voltage-dependent conductances; creating hybrid networks with real and artificial cells; attaching simulated dendritic tree structures to the living cell; and connecting different neurons. This book will be of interest to experimental biophysicists, neurophysiologists, and cardiac physiologists, as well as theoreticians, engineers, and computational neuroscientists. Graduate and undergraduate students will also find up-to-date coverage of physiological problems and how they are investigated.

Download or read book Cross Species Mechanisms of Orientation Tuning in the Primary Visual Cortex written by Luis Jimenez and published by . This book was released on 2021 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: Simple cells in the primary visual cortex of all mammals are renown for having an 'orientation preference', meaning that they respond to a specific orientation of an elongated stimulus that lands on their spatial receptive field. Moreover, these cells respond to increments and decrements in luminance in slightly separate regions of their receptive fields, and the angle formed by the centers of these regions can predict their preferred orientation. Despite decades of research into the topic, the mechanism that gives rise to tuned simple cells and their receptive field structure remains an open question. Many models struggle to explain why the properties of simple cells are similar across mammals despite substantial inter-species differences in how simple cells are spatially organized across the cortex. For instance, in the primary visual cortex of cats and primates, vertical columns of cells have similar orientation preferences, and the preferences of these columns rotates smoothly, in a quasiperiodic fashion, as one moves horizontally across the cortex. In contrast, simple cells in mouse primary visual cortex with different tuning preferences are scattered randomly throughout the cortical tissue. Here I assess a mechanistic model of tuning asserting that a single mechanism can generate tuned cells that are either mapped out in an orderly manner across the cortex or arranged in a salt and pepper fashion. The two projects carried out in this thesis test a specific prediction made by the model and compare it to physiological data in mouse primary visual cortex and the thalamic afferents that innervate the cortex. Overall, the results corroborate the model and lend support to the notion that a universal, cross-species mechanism may be used to encode the orientation of a visual stimulus.

Download or read book A Model of Cat Primary Visual Cortex and Its Thalamic Input written by Anton E. Krukowski and published by . This book was released on 2000 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Circuitry Underlying Response Properties of Neurons in the Primary Visual Cortex Spatiotemporal Receptive Field of Synaptic Inputs written by Chenmei Jennie Chen and published by . This book was released on 2009 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book American Doctoral Dissertations written by and published by . This book was released on 2000 with total page 816 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Cat Primary Visual Cortex written by Bertram Payne and published by Academic Press. This book was released on 2001-11-17 with total page 733 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by experts on the forefront of investigations of brain function, vision, and perception, the material presented is of an unparalleled scientific quality, and shows that analyses of enormous breadth and sophistication are required to probe the structure and function of brain regions. The articles are highly persuasive in showing what can be achieved by carrying out careful and imaginative experiments. The Cat Primary Visual Cortex should emerge as essential reading for all those interested in cerebral cortical processing of visual signals or researching or working in any field of vision. - Comprehensive account of cat primary visual cortex - Generous use of illustrations including color - Covers research from structure to connections to functions - Chapters by leaders in the field - Topics presneted on multiple, compatible levels

Download or read book The Cognitive Neurosciences written by Michael S. Gazzaniga and published by MIT Press. This book was released on 2004 with total page 1480 pages. Available in PDF, EPUB and Kindle. Book excerpt: The third edition of a work that defines the field of cognitive neuroscience, with extensive new material including new chapters and new contributors.

Download or read book Contributions of Inhibition and Physiological Noise in a Model of Cat Primary Visual Cortex written by Thomas Zaccarin Lauritzen and published by . This book was released on 2003 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Linear and Nonlinear Mechanisms of Neuronal Function in the Visual Cortex written by Gregory Clarke DeAngelis and published by . This book was released on 1992 with total page 770 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2001 with total page 698 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Relationship Between Spatial Frequency and Orientation Tuning in Cells of the Cat Striate Cortex written by Michael Anderson Webster and published by . This book was released on 1985 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Inhibitory Synaptic Plasticity written by Melanie A. Woodin and published by Springer Science & Business Media. This book was released on 2010-11-02 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume will explore the most recent findings on cellular mechanisms of inhibitory plasticity and its functional role in shaping neuronal circuits, their rewiring in response to experience, drug addiction and in neuropathology. Inhibitory Synaptic Plasticity will be of particular interest to neuroscientists and neurophysiologists.

Download or read book Modeling of Orientation Mapping Based on Optical Recordings of the Feline Visual Cortex written by Danil M. Gorinevski and published by . This book was released on 1998 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 In Vivo Whole Cell Measurements of Sound evoked Synaptic Excitation and Inhibition in Auditory Cortex Neurons written by Andrew Yong-Yi Tan and published by . This book was released on 2006 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: Intensity-tuned neurons were probed with noise bursts of various intensities. In some intensity neurons, intensity-tuning was created solely through disproportionally large synaptic inhibition at high intensities, without any intensity-tuned synaptic excitation. Since synaptic inhibition is essentially cortical in origin, such neurons provide examples of auditory feature-selectivity arising de novo at the cortex.