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Functional Organisation and Plasticity of the Auditory Cortex

Author: Robert V. Harrison

Publisher: S Karger Ag

Published: 1998-01-01

Total Pages: 162

ISBN-13: 9783805566834

One of the most important neuroscientific findings during the last decade has been that the central nervous system (CNS) is capable of reacting with plastic reorganization to altered conditions. The ability of the CNS to exhibit such plasticity had now been demonstrated in the auditory, visual and somatosensory systems. Owing to the development of noninvasive functional imaging techniques, such as magnetoencephalography and functional magnetic resonance imaging, these alterations can now be traced not only in animals, but also in humans. This publication presents noninvasive studies of the functional organization and reorganization of the human auditory cortex compared with invasive animal investigations. Among the topics covered are the relationship between function and structure of the auditory cortex, representation of speech sounds at different levels of the auditory system, hemispheric differences, plastic reorganization of tonotopic maps after cochlear damage, and learning-induced receptive field plasticity. Neuroscientists, neurologists and neurophysiologists will find the sections on cortical plasticity of particular interest, while audiologists will appreciate the valuable data on the functional organization of the auditory system.

The Functional Organization of the Auditory System

Author: Monica Muñoz-Lopez

Publisher: Frontiers Media SA

Published: 2017-02-07

Total Pages: 332

ISBN-13: 2889450619

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This eBook comprises s series of original research and review articles dealing with the anatomical, genetic, and physiological organization of the auditory system from humans to monkeys and mice.

Plasticity of the Auditory System

Author: Thomas N. Parks

Publisher: Springer Science & Business Media

Published: 2013-03-09

Total Pages: 336

ISBN-13: 1475742193

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The auditory system has a remarkable ability to adjust to an ever-changing environment. The six review chapters that comprise Plasticity of the Central Auditory System cover a spectrum of issues concerning this ability to adapt, defined by the widely applicable term "plasticity". With chapters focusing on the development of the cochlear nucleus, the mammalian superior olivary complex, plasticity in binaural hearing, plasticity in the auditory cortex, neural plasticity in bird songs, and plasticity in the insect auditory system, this volume represents much of the most current research in this field. The volume is thorough enough to stand alone, but is closely related a previous SHAR volume, Development of the Auditory System (Volume 9) by Rubel, Popper, and Fay. The book fully addresses the difficulties, challenges, and complexities of this topic as it applies to the auditory development of a wide variety of species.

The Auditory Cortex

Author: Jeffery A. Winer

Publisher: Springer Science & Business Media

Published: 2010-12-02

Total Pages: 711

ISBN-13: 1441900748

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There has been substantial progress in understanding the contributions of the auditory forebrain to hearing, sound localization, communication, emotive behavior, and cognition. The Auditory Cortex covers the latest knowledge about the auditory forebrain, including the auditory cortex as well as the medial geniculate body in the thalamus. This book will cover all important aspects of the auditory forebrain organization and function, integrating the auditory thalamus and cortex into a smooth, coherent whole. Volume One covers basic auditory neuroscience. It complements The Auditory Cortex, Volume 2: Integrative Neuroscience, which takes a more applied/clinical perspective.

Exploring the Structural and Functional Organization of the Dorsal Zone of Auditory Cortex in Hearing and Deafness

Author: Melanie A. Kok

Publisher:

Published: 2015

Total Pages:

ISBN-13:

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Recent neuroscientific research has focused on cortical plasticity, which refers to the ability of the cerebral cortex to adapt as a consequence of experience. Over the past decade, an increasing number of studies have convincingly shown that the brain can adapt to the loss or impairment of a sensory system, resulting in the expansion or heightened ability of the remaining senses. A particular region in cat auditory cortex, the dorsal zone (DZ), has been shown to mediate enhanced visual motion detection in deaf animals. The purpose of this thesis is to further our understanding of the structure and function of DZ in both hearing and deaf animals, in order to better understand how the brain compensates following insult or injury to a sensory system, with the ultimate goal of improving the utility of sensory prostheses. First, I demonstrate that the brain connectivity profile of animals with early- and late-onset deafness is similar to that of hearing animals, but the projection strength to visual brain regions involved in motion processing increases as a consequence of deafness. Second, I specifically evaluate the functional impact of the strongest auditory connections to area DZ using reversible deactivation and electrophysiological recordings. I show that projections that ultimately originate in primary auditory cortex (A1) form much of the basis of the response of DZ neurons to auditory stimulation. Third, I show that almost half of the neurons in DZ are influenced by visual or somatosensory information. I further demonstrate that this modulation by other sensory systems can have effects that are opposite in direction during different portions of the auditory response. I also show that techniques that incorporate the responses of multiple neurons, such as multi-unit and local field potential recordings, may vastly overestimate the degree to which multisensory processing occurs in a given brain region. Finally, I confirm that individual neurons in DZ become responsive mainly to visual stimulation following deafness. Together, these results shed light on the function and structural organization of area DZ in both hearing and deaf animals, and will contribute to the development of a comprehensive model of cross-modal plasticity.

Developmental Plasticity in the Auditory Cortex of the Cat

Author: Susan Gay Stanton

Publisher:

Published: 1997

Total Pages: 0

ISBN-13:

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The consequences of an abnormal pattern of sensory input during development on the organization of the auditory cortex and the thalamocortical pathway were examined. Two different experimental paradigms were used to change the peripheral pattern of neural input to the system: (1) auditory deprivation: partial cochlear lesions were induced by treating newborn kittens with the ototoxic aminoglycoside drug amikacin and (2) auditory augmentation: newborn kittens were reared in an altered acoustic environment, consisting predominantly of a continuous 8 kHz FM tone. Standard microelectrode recording techniques were used to examine the functional organization of primary auditory cortex and revealed an altered cortical frequency map as a consequence of these experimental manipulations. Scanning electron microscopy (SEM) was used to examine the cochlea, and auditory brainstem responses (ABR audiogram) were used to measure frequency-specific threshold changes in ascending neural activity. Retrograde tracers were introduced in AI, and were used to examine the organization of the thalamocortical projection. As a result of neonatal partial cochlear lesions the cochleotopic organization of primary auditory cortex was altered, with the deprived high frequency region of AI devoted instead to the representation of low frequencies. Furthermore, the deafferented region of the cortical map displayed an abnormally large cortical area (expansion) with neurons having common characteristic frequencies. The range of characteristic frequencies within this monotonic cortical region corresponded to both the high frequency border of the hearing loss and the edge of the cochlear lesion. However, retrograde tracer injections into different regions in AI produced a normal pattern of labelling in the medial geniculate body of the thalamus. These results suggest that the cochleotopic organization of the thalamocortical projection is not disrupted in deafened cats, despite the extensive physiological reorganization of the cortical frequency map observed in these animals. As a consequence of rearing newborn kittens in an altered acoustic environment, the cochleotapic representation in AI also develops abnormally. Exposure to a continuous 8 kHz FM signal during a period from birth to three months of age produced a significant expansion of the 6-12 kHz frequency region of the cortical map in mature cats. These studies have shown that manipulating the pattern of cochlear activity during the neonatal period induces changes in the functional organization of the cochleotopic map in primary auditory cortex of the cat. In conclusion, the cochleotopic map within auditory cortex is altered in a manner which reflects the pattern of sensory input from the periphery during development.

Plasticity and Signal Representation in the Auditory System

Author: Josef Syka

Publisher: Springer Science & Business Media

Published: 2006-11-22

Total Pages: 404

ISBN-13: 0387231811

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The symposium that has provided the basis for this book, "Plasticity of the Central Auditory System and Processing of Complex Acoustic Signals" was held in Prague on July 7-10, 2003. This is the fourth in a series of seminal meetings summarizing the state of development of auditory system neuroscience that has been organized in that great world city. Books that have resulted from these meetings represent important benchmarks for auditory neuroscience over the past 25 years. A 1980 meeting, "Neuronal Mechanisms of Hearing" hosted the most distinguished hearing researchers focusing on underlying brain processes from this era. It resulted in a highly influential and widely subscribed and cited proceedings co-edited by professor Lindsay Aitkin. The subject of the 1987 meeting was the "Auditory Pathway - Structure and Function". It again resulted in another important update of hearing science research in a widely referenced book - edited by the late Bruce Masterton. While the original plan was to hold a meeting summarizing the state of auditory system neuroscience every 7 years, historical events connected with the disintegration of the Soviet Empire and return of freedom to Czechoslovakia resulted in an unavoidable delay of what was planned to be a 1994 meeting. It wasn't until 1996 that we were able to meet for the third time in Prague, at that time to review "Acoustical Signal Processing in the Central Auditory System".

The Auditory Cortex

Author: Peter Heil

Publisher: Psychology Press

Published: 2005-05-06

Total Pages: 929

ISBN-13: 1135613354

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Understanding human hearing is not only a scientific challenge but also a problem of growing social and political importance, given the steadily increasing numbers of people with hearing deficits or even deafness. This book is about the highest level of hearing in humans and other mammals. It brings together studies of both humans and animals thereby giving a more profound understanding of the concepts, approaches, techniques, and knowledge of the auditory cortex. All of the most up-to-date procedures of non-invasive imaging are employed in the research that is described.

The Human Auditory Cortex

Author: David Poeppel

Publisher: Springer Science & Business Media

Published: 2012-04-12

Total Pages: 404

ISBN-13: 1461423139

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We live in a complex and dynamically changing acoustic environment. To this end, the auditory cortex of humans has developed the ability to process a remarkable amount of diverse acoustic information with apparent ease. In fact, a phylogenetic comparison of auditory systems reveals that human auditory association cortex in particular has undergone extensive changes relative to that of other species, although our knowledge of this remains incomplete. In contrast to other senses, human auditory cortex receives input that is highly pre-processed in a number of sub-cortical structures; this suggests that even primary auditory cortex already performs quite complex analyses. At the same time, much of the functional role of the various sub-areas in human auditory cortex is still relatively unknown, and a more sophisticated understanding is only now emerging through the use of contemporary electrophysiological and neuroimaging techniques. The integration of results across the various techniques signify a new era in our knowledge of how human auditory cortex forms basis for auditory experience. This volume on human auditory cortex will have two major parts. In Part A, the principal methodologies currently used to investigate human auditory cortex will be discussed. Each chapter will first outline how the methodology is used in auditory neuroscience, highlighting the challenges of obtaining data from human auditory cortex; second, each methods chapter will provide two or (at most) three brief examples of how it has been used to generate a major result about auditory processing. In Part B, the central questions for auditory processing in human auditory cortex are covered. Each chapter can draw on all the methods introduced in Part A but will focus on a major computational challenge the system has to solve. This volume will constitute an important contemporary reference work on human auditory cortex. Arguably, this will be the first and most focused book on this critical neurological structure. The combination of different methodological and experimental approaches as well as a diverse range of aspects of human auditory perception ensures that this volume will inspire novel insights and spurn future research.

Reprogramming the Cerebral Cortex

Author: Stephen Lomber

Publisher: OUP Oxford

Published: 2006-10-12

Total Pages: 456

ISBN-13: 019158343X

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The brain has a remarkable ability to adapt in the event of damage - in many cases shifting responsibility for specific cognitive functions to other non-damaged brain regions. This 'plasticity' can be crucial in aiding recovery from stroke, trauma, and peripheral damage such as eye or ear damage. Over the past thirty years our view of cortical plasticity has evolved greatly. Early studies suggested that changes to cortical function due to peripheral lesions could only occur during development and that these plastic changes were specific to a particular temporal window or "critical period". Over time, it has been demonstrated that cortical modifications as a consequence of either peripheral or central lesions can induce adaptive, or beneficial, changes in cortical function in an effort to preserve or enhance function. More recently, studies have identified that many of these adaptive changes, once thought only possible in the developing brain, are also possible in the mature or developed brain. At present, many laboratories are defining the beneficial capabilities of cerebral cortex plasticity, upon which many proactive and therapeutic strategies may be developed in order to maximiSe the "reprogramming" capabilities of the cerebrum. 'Reprogramming the Cerebral Cortex' describes these exciting studies and examines adaptive cortical plasticity in a variety of systems (visual, auditory, somatomotor, cross-modal, language and cognition). The book leads the reader through the complexities and promise of neuroplasticity, and presents insights into current and future research and clinical practice. It is unique in looking at the beneficial capabilities of cerebral cortex plasticity, upon which many proactive and therapeutic strategies may be developed. The book will be a valuable resource for behavioural, systems, computational and cognitive neuroscientists, as well as clinicians and neuropsychologists.