Neural Encoding of Interaural Time Differences in the Midbrain of the Unanesthetized Rabbit PDF Download

Author: William Robert D'Angelo
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Author: William Robert D'Angelo
Publisher:
ISBN:
Category :
Languages : en
Pages : 268

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Author: Nathaniel J. Zuk
Publisher:
ISBN:
Category :
Languages : en
Pages : 130

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In natural environments, sounds are often not static. Usually, moving objects require the most attention, e.g. for identifying the presence and direction of a moving vehicle, or detecting and tracking the trajectory of a predator or prey. Faster time-varying location cues can occur in acoustic environments containing many spatially distributed sound sources, like at a cocktail party. In this case, we can identify the locations of the sources by "glimpsing" at short-duration localization cues when the sound energy from one source dominates the mixture. Even faster time-varying spatial cues result from reverberation in an echoic environment and we perceive them as spatially diffuse. We qualitatively perceive motion, a cocktail party, and reverberation differently, and these three percepts are determined by how quickly the spatial cues are moving. How these percepts come about in the auditory system is unknown. Here, we studied how neurons encode time-varying location cues and how the neural code relates to perception. Our focus was on time-varying interaural time differences (ITD), one of the main cues for localizing sounds in the horizontal plane. We recorded from single neurons in the inferior colliculus (IC) in the auditory midbrain of unanesthetized rabbits. The IC is the site of an obligatory synapse in the auditory pathway and one of the first stages of processing following the initial extraction of spatial cues in the brainstem. We hypothesized that the IC exhibits limitations in its ability to encode time-varying ITD that give rise to these different percepts. First, we show that IC neurons are more "sluggish" on average at synchronizing to the time-varying ITD than to amplitude modulations presented at a static ITD. Binaural sluggishness has been proposed based on human psychophysics but never validated neuro physiologically in the IC. Second, we show that most neurons are unable to synchronize to the time-varying ITD at speeds where humans no longer perceive fluctuations. Instead, neurons exhibit a change in average firing rate that corresponds to binaural decorrelation of the noise for very fast time-varying ITD, and this may explain the percept of a spatially diffuse sound at these speeds. We further recorded neural responses to slow-moving ITDs in opposite directions within the range of perceived motion. Using a generalized linear model to parse the neuron's response into ITD-following and direction selectivity components, we show that the responses of IC neurons are dominated by their ability to follow the ITD more than direction selectivity. In parallel experiments, we asked human participants to either identify the motion direction or detect the slow-moving ITD in the same stimuli and determined the threshold durations for direction identification and for detection for each participant. Direction identification threshold durations were larger than detection threshold durations. We then implemented neural classifiers that either identified the motion direction or detected the slow-moving ITD based on single-neuron responses to the stimuli, and we found that the classifier exhibited duration thresholds that matched human thresholds on both tasks. Together, these results suggest that temporal limitations of neural responses in the IC may give rise to the limiting speeds of time-varying localization cues where we perceive motion, "glimpse" the position of a source amidst a mixture, and perceive a spatially diffuse background in a reverberant environment.

Author: Jeffery A. Winer
Publisher: Springer Science & Business Media
ISBN: 0387270833
Category : Science
Languages : en
Pages : 720

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Connecting the auditory brain stem to sensory, motor, and limbic systems, the inferior colliculus is a critical midbrain station for auditory processing. Winer and Schreiner's The Inferior Colliculus, a critical, comprehensive reference, presents the current knowledge of the inferior colliculus from a variety of perspectives, including anatomical, physiological, developmental, neurochemical, biophysical, neuroethological and clinical vantage points. Written by leading researchers in the field, the book is an ideal introduction to the inferior colliculus and central auditory processing for clinicians, otolaryngologists, graduate and postgraduate research workers in the auditory and other sensory-motor systems.

Author: David R. Moore
Publisher: Oxford University Press, USA
ISBN: 0199233284
Category : Medical
Languages : en
Pages : 592

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Book Description
Volume 1: The Ear (edited by Paul Fuchs) Volume 2: The Auditory Brain (edited by Alan Palmer and Adrian Rees) Volume 3: Hearing (edited by Chris Plack) Auditory science is one of the fastest growing areas of biomedical research. There are now around 10,000 researchers in auditory science, and ten times that number working in allied professions. This growth is attributable to several major developments: Research on the inner ear has shown that elaborate systems of mechanical, transduction and neural processes serve to improve sensitivity, sharpen frequency tuning, and modulate response of the ear to sound. Most recently, the molecular machinery underlying these phenomena has been explored and described in detail. The development, maintenance, and repair of the ear are also subjects of contemporary interest at the molecular level, as is the genetics of hearing disorders due to cochlear malfunctions.

Author: Aage Moller
Publisher: Elsevier
ISBN: 0323141935
Category : Science
Languages : en
Pages : 956

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Book Description
Basic Mechanisms in Hearing is a collection of papers that discusses the function of the auditory system covering its ultrastructure, physiology, and the mechanism's connection with experimental psychology. Papers review the mechanics, morphology, and physiology of the cochlear, including the physiology of individual hair cells and their synapses. One paper examines the combined physiological and anatomical studies of stimulus coding in the mammalian auditory nervous system. The results of these studies pertain to the latency, frequency selectivity, and time pattern of responses to short tone bursts. Other research compare the cochlear nerve, behavioral, and psychophysical frequency selectivity which show that frequency selectivity of the auditory system occurs at the level of the cochlear nerve, becoming downgraded in end-organ deafness. Other papers discuss neural coding at higher levels such as the feature extraction in the auditory system of bats. Some papers also analyze the specialized hearing mechanisms in animals, for example, the echolocation of bats and in some insects, the function of the swimbladder in fish hearing, as well as the "invertebrate frequency analyzer" in the locust ear. Physiologists, neurophysiologists, neurobiologists, general medical practioners, and EENT specialists will find this collection valuable.

Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 806

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Author: Enrique Lopez-Poveda
Publisher: Springer Science & Business Media
ISBN: 1441956867
Category : Science
Languages : en
Pages : 635

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Book Description
This volume contains the papers presented at the 15th International Symposium on Hearing (ISH), which was held at the Hotel Regio, Santa Marta de Tormes, Salamanca, Spain, between 1st and 5th June 2009. Since its inception in 1969, this Symposium has been a forum of excellence for debating the neurophysiological basis of auditory perception, with computational models as tools to test and unify physiological and perceptual theories. Every paper in this symposium includes two of the following: auditory physiology, psychoph- ics or modeling. The topics range from cochlear physiology to auditory attention and learning. While the symposium is always hosted by European countries, p- ticipants come from all over the world and are among the leaders in their fields. The result is an outstanding symposium, which has been described by some as a “world summit of auditory research. ” The current volume has a bottom-up structure from “simpler” physiological to more “complex” perceptual phenomena and follows the order of presentations at the meeting. Parts I to III are dedicated to information processing in the peripheral au- tory system and its implications for auditory masking, spectral processing, and c- ing. Part IV focuses on the physiological bases of pitch and timbre perception. Part V is dedicated to binaural hearing. Parts VI and VII cover recent advances in und- standing speech processing and perception and auditory scene analysis. Part VIII focuses on the neurophysiological bases of novelty detection, attention, and learning.

Author: Nina Kraus
Publisher: Springer
ISBN: 331947944X
Category : Medical
Languages : en
Pages : 306

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Book Description
This volume will cover a variety of topics, including child language development; hearing loss; listening in noise; statistical learning; poverty; auditory processing disorder; cochlear neuropathy; attention; and aging. It will appeal broadly to auditory scientists—and in fact, any scientist interested in the biology of human communication and learning. The range of the book highlights the interdisciplinary series of questions that are pursued using the auditory frequency-following response and will accordingly attract a wide and diverse readership, while remaining a lasting resource for the field.

Author: Ruth Y. Litovsky
Publisher: Springer Nature
ISBN: 3030571009
Category : Medical
Languages : en
Pages : 425

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Book Description
The field of Binaural Hearing involves studies of auditory perception, physiology, and modeling, including normal and abnormal aspects of the system. Binaural processes involved in both sound localization and speech unmasking have gained a broader interest and have received growing attention in the published literature. The field has undergone some significant changes. There is now a much richer understanding of the many aspects that comprising binaural processing, its role in development, and in success and limitations of hearing-aid and cochlear-implant users. The goal of this volume is to provide an up-to-date reference on the developments and novel ideas in the field of binaural hearing. The primary readership for the volume is expected to be academic specialists in the diverse fields that connect with psychoacoustics, neuroscience, engineering, psychology, audiology, and cochlear implants. This volume will serve as an important resource by way of introduction to the field, in particular for graduate students, postdoctoral scholars, the faculty who train them and clinicians.