Inhibitory Mechanisms in Visual Motion Perception PDF Download

Author: Sandra Arranz Paraíso
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
The world around us is constantly changing, with multiple objects in the environment changing position, luminance, and color. These objects can also move on static or in motion backgrounds, with the same or different speed, in opposite direction, etc. Our Visual System can segregate figures from the background and thus extract information about objects in complex environments. Understanding how humans process motion is one of the most relevant and sophisticated problems in visual perception (see review of Nishida, 2011). The functional characteristics of the underlying mechanisms are not completely known, in particular, the role of the inhibitory mechanisms in motion perception. Therefore, the main goal of this Thesis is the psychophysical characterization of the functional properties of two inhibitory mechanisms involved in visual motion perception. It has traditionally been proposed that the antagonistic center-surround mechanisms are implicated in the segregation of the figure from the background (Lappin & Tadin, 2004;Tadin et al., 2019). The normal functioning of these mechanisms causes difficulties in perceiving large moving objects at high contrast (Derrington & Goddard, 1989). However, at low contrast, the larger the size of the object, the easier it is to detect its motion (Tadin etal., 2003). To explain these results, it is assumed that in these mechanisms, when the stimulus is large and has high contrast, the peripheral region suppresses or inhibits the activation of the center, and for low contrast, it facilitates the activation of the center. The same results have been found by analyzing the response of neurons with antagonistic center-surround receptive fields present in the medial temporal (MT) area of the visual cortex (Pack, Hunter & Born, 2005) and in the medial superior temporal (MST) area (Eifuku & Wurtz, 1998). The shape of these receptive fields is not fully characterized, although recent studies suggest an elongated spatial configuration in the direction of movement (Serrano-Pedraza, Hogg & Read, 2011), in agreement with physiological evidence (Xiao et al., 1997)...

Author: Guillaume S. Masson
Publisher: Springer Science & Business Media
ISBN: 1441907815
Category : Medical
Languages : en
Pages : 362

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Book Description
Motion processing is an essential piece of the complex brain machinery that allows us to reconstruct the 3D layout of objects in the environment, to break camouflage, to perform scene segmentation, to estimate the ego movement, and to control our action. Although motion perception and its neural basis have been a topic of intensive research and modeling the last two decades, recent experimental evidences have stressed the dynamical aspects of motion integration and segmentation. This book presents the most recent approaches that have changed our view of biological motion processing. These new experimental evidences call for new models emphasizing the collective dynamics of large population of neurons rather than the properties of separate individual filters. Chapters will stress how the dynamics of motion processing can be used as a general approach to understand the brain dynamics itself.

Author: D.J. Ingle
Publisher: Springer Science & Business Media
ISBN: 9400950713
Category : Psychology
Languages : en
Pages : 486

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Book Description
This volume contains chapters derived from a N. A. T. O. Advanced Study Institute held in June 1983. As the director of this A. S. I. it was my hope that some of the e1ectrophysiologists could express the potentialities of their work for perceptual theory, and that some perceptionists could speculate on the underlying "units" of perception in a way that would engage the imagination of physio logists. The reader will have to be the judge of whether this was achieved, or whether such a psychophysiological inter1ingua is still overly idealistic. It is clear that after the revolution prec~pitated by Hube1 and Weisel in understanding of visual cortical neurons we still have only a foggy idea of the behavioral output of any particular species of cortical detector. It was therefore particularly unfortunate that two persons who have made great strides in correlating interesting facets of cat cortical physio logy with human psychophysics (Max Cynader and Martin Regan of Dalhousie University) were unable to attend this meeting. Never theless, a number of new and challenging ideas regarding both spatial perception and cortical mechanisms are represented in this volume, and it is hoped that the reader will remember not only the individual demonstrations but the critical questions posed by the apposition of the two different collections of experimental facts. David Ingle April 1984 VII TABLE OF CONTENTS PREFACE V D. N. Lee and D. S. Young Visual Timing of Interceptive Action 1 J. J.

Author: Liu Liu
Publisher:
ISBN:
Category :
Languages : en
Pages :

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"The visual nervous system transforms the input from the visual scene into electrical signals. The electrical signals are in turn read out by other areas of the brain to form perceptual decisions. The relationship between neuronal responses evoked by sensory stimuli and their perceptual correlates is an important research question in modern computational and systems neuroscience. Previous studies of this relationship focused on correlating the response of single neurons to stimuli in their receptive field (RF), defined as a region of the visual space where selective stimuli can evoke a response. However, single neurons are part of a local circuitry that controls their selectivity and modulates their response. The local circuitry is composed of many neurons that encode surrounding regions of the visual space. The neurons in the circuit can interact via excitatory or inhibitory connections. The interactions are crucial for contextual modulation of single neuron response, since any stimulus on the RF of a neuron is part of a larger visual context. Aside from the contextual modulation of neuronal responses, another part of the sensory-to-decision transformation is how the responses of neurons are read out from a population. Correlations in the responses of neurons can have a large impact in the amount of information in a population, and this correlation should be quantified when considering a population readout.Another level of complexity is that downstream areas must use this sensory code flexibly in perceptual decision making. Many neurons and areas can contain the information about the sensory stimulus, and the readout should correspond to the experience of the animal. This thesis investigates these issues in order. In chapter 2, I determine the neural basis for a type of contextual modulation in our motion perception, the worsening of motion perception at large stimulus size. Large stimuli suppress the firing rate of neurons in a form of contextual modulation known as surround suppression. I simultaneously record from multiple neurons in the middle temporal visual area (MT), and I perform a simulation of the recorded responses and the correlation structure. I find surround suppression improves the population sensitivity for small stimuli at the expense of weaker sensitivity for large stimuli. In chapter 3, I examine the underlying circuitry mechanisms for surround suppression. Recent work suggests that the cortex operates in a theoretical network where excitation alone is strong enough to induce instability but inhibition maintains the stability. I pharmacologically manipulate the efficacy of inhibitory processes and find that the neuronal dynamics are consistent with the predictions. I then perform additional experiments to confirm that this network mechanism can be generalized to different stimulus dimensions in MT. In chapter 4, I examine the flexibility of the readout of sensory information. The readout of sensory evidence for visual perception is plastic and depends on recent training experience. I use reversible inactivation and microstimulation to probe the causal relationship between MT neuronal response and perception. I find the causal contribution of MT to visual motion perception depends on training the animals on a specific task of motion integration. This thesis has implications in the broader context of neural coding in health and diseases. Previous work shows that natural aging or disease processes can lead to deficits in our sensory perception, and the reduction of inhibition efficacy has been implicated. Therefore, an understanding of the inhibitory interactions in local cortical circuitry may lead to future treatments and interventions." --

Author: R. Held
Publisher: Springer Science & Business Media
ISBN: 3642463541
Category : Psychology
Languages : en
Pages : 986

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Book Description
This volume was designed to focus on the problems of perception and originally was to have been solely edited by Professor Hans-Lukas Teuber who was a member of the editorial board which initiated production of the Handbook. Accordingly, he issued invitations to a number of researchers III perception asking them to contribute chapters written in a style described III his words: " . . . Ire hope that no author lI'ill feel COl/strained to undertake a major search of the literature: he could In'ite, instead. on an area in which he has been quite actire himse?t~ and II'here most of the issues are immediately obt"ious to him. In this Iray, the IITiting of the chapter should be cnjoyable rather than a chore . . it should result in a personal account of the state of a given area rather than in an encyclopedic treatise . . . the field deserves this sort of summary ret'iell", particularly (f it is pointed toward the future and speeds the convergence of det'elopments in sensory physiology and psychological studies of perception, " With the growing burden of national and international commitments includ ing departmental headship, Professor Teuber felt that it would be wise to share the editorial responsibilities for this volume and accordingly, asked Professors Richard Held and Herschel Leibowitz to co-edit the volume with him in the same spirit as outlined in his invitation to authors. They agreed to help in this task.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 318

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Author: Frederick Albert Miles
Publisher: Elsevier Science & Technology
ISBN:
Category : Medical
Languages : en
Pages : 452

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Book Description
Hardbound. This fifth volume of Reviews of Oculomotor Research is mainly concerned with the visual stabilization mechanisms but, unlike the previous volumes in the series, the coverage goes beyond the mammalian literature. The emphasis is on the visual processing problems that must be solved if the motor responses are to be appropriate. Chapters are included dealing specifically with the psychophysics and physiology of visual motion, areas of intense research activity in recent years.The first section deals with the fundamental problem of how motion is first decoded by the visual system. The second section deals with more global aspects of the visual motion experienced by the moving observer. The third and last section deals with specific stabilizing behaviors and their underlying physiology.An excellent book, at the cutting edge of research developments in visual stabilization mechanisms.

Author:
Publisher: Academic Press
ISBN: 0128054093
Category : Medical
Languages : en
Pages : 5215

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Book Description
The Senses: A Comprehensive Reference, Second Edition, Seven Volume Set is a comprehensive reference work covering the range of topics that constitute current knowledge of the neural mechanisms underlying the different senses. This important work provides the most up-to-date, cutting-edge, comprehensive reference combining volumes on all major sensory modalities in one set. Offering 264 chapters from a distinguished team of international experts, The Senses lays out current knowledge on the anatomy, physiology, and molecular biology of sensory organs, in a collection of comprehensive chapters spanning 4 volumes. Topics covered include the perception, psychophysics, and higher order processing of sensory information, as well as disorders and new diagnostic and treatment methods. Written for a wide audience, this reference work provides students, scholars, medical doctors, as well as anyone interested in neuroscience, a comprehensive overview of the knowledge accumulated on the function of sense organs, sensory systems, and how the brain processes sensory input. As with the first edition, contributions from leading scholars from around the world will ensure The Senses offers a truly international portrait of sensory physiology. The set is the definitive reference on sensory neuroscience and provides the ultimate entry point into the review and original literature in Sensory Neuroscience enabling students and scientists to delve into the subject and deepen their knowledge. All-inclusive coverage of topics: updated edition offers readers the only current reference available covering neurobiology, physiology, anatomy, and molecular biology of sense organs and the processing of sensory information in the brain Authoritative content: world-leading contributors provide readers with a reputable, dynamic and authoritative account of the topics under discussion Comprehensive-style content: in-depth, complex coverage of topics offers students at upper undergraduate level and above full insight into topics under discussion

Author: William Epstein
Publisher: John Wiley & Sons
ISBN:
Category : Psychology
Languages : en
Pages : 492

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Book Description
Historical introduction to the constancies; Visuomotor coordination in visual direction and position constancies; The constancies in object orientation: an algorithm processing approach; Stereoscopic depth constancy; The metric of visual space; Analysis of causal relations in the perceptual constancies; Instruction and perceptual constancy judgments; Illusion and constancies; Constancies in the perceptual world of the infant; In defense of unconscious inference; Spatial constancy and motion in visual perception; Lessons in constancy from neurophysiology; Observations concerning the contemporary analysis of constancies.

Author: Johannes M. Zanker
Publisher: Springer Science & Business Media
ISBN: 3642565506
Category : Science
Languages : en
Pages : 424

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Book Description
In six parts, this book considers the extent to which computational, neural, and ecological constraints have shaped the mechanisms underlying motion vision: - Early Motion Vision - Motion Signals for Local and Global Analysis - Optical Flow Patterns - Motion Vision in Action - Neural Coding of Motion - Motion in Natural Environments Each topic is introduced by a keynote chapter which is accompanied by several companion articles. Written by an international group of experts in neurobiology, psychophysics, animal behaviour, machine vision, and robotics, the book is designed to explore as comprehensively as possible the present state of knowledge concerning the principal factors that have guided the evolution of motion vision.