Author: Kaspar Ueli MeyerPublisher:
ISBN:
Category :
Languages : en
Pages : 270
Book Description
Neural Adaptation in the Auditory and the Anteroventral Cochlear Nucleus of the Rat in Response to Repetitive Acoustic Stimuli
Author: Kaspar Ueli MeyerNeural Adaptation in the Auditory Nerve and the Anteroventral Cochlear Nucleus of the Rat in Response to Repetitive Acoustic Stimuli
Author: Kaspar Ueli MeyerNeural Information Processing in the Peripheral Auditory System of the Guinea Pig
Author: George R. HannaPublisher:
ISBN:
Category : Ear
Languages : en
Pages : 36
Book Description
A number of first and second order neurons of the guinea pig auditory system were studied extensively in an attempt to determine the method by which information is conveyed. Single neuron electrophysiological techniques with anatomical controls were used in the study and in response to several different stimuli, various response patterns were observed. Statistical methods of analysis, using a digital computer, were employed. Each fiber in the auditory nerve appears to convey only fragmentary information; therefore, the information carried by a number of fibers is required to extract all the information about a single signal. The data suggest that a pulse density modulation system of encoding is used, in which the 'carrier' appears to be the irregular spontaneous background activity, the pulse density of which is actively increased and decreased to convey information about both pitch and loudness. The system appears to be much more sensitive to sound changes than to absolute values. For example, pulse density correlated far better with rate-of-change of stimulus intensity than with absolute levels of intensity. In addition to frequency and amplitude, the interval between successive stimuli may be an important parameter of stimulation.
Dorsal Cochlear Nucleus Output Neurons in Young and Aged Rats
Author: Tracy A. SchattemanPublisher:
ISBN:
Category : Cochlear nucleus
Languages : en
Pages : 432
Book Description
Age-related hearing loss, presbycusis, is a complex disorder involving the interaction of both peripheral and central neurological deficits. Central auditory dysfunction may contribute to poor temporal discrimination of complex sounds such as speech. This research is timely since our population over 60 years old is increasing rapidly due to advances in medicine and nutrition as well as the advancing age of baby boomers. This study was designed to provide a better understanding of age-related changes in dorsal cochlear nucleus (DCN) physiology. DCN was chosen because it receives direct input from the auditory nerve and much is known about its neuronal morphology, physiology and circuitry. In young animals, DCN output neurons, fusiform cells, receive excitatory inputs from the acoustic nerve, which is modulated and shaped by inhibitory glycinergic inputs from nearby vertical cells. A number of studies in rodents suggested an age-related impairment of glycinergic neurotransmission. To access the functional impact of reduced putative glycinergic input in the central auditory system, this study compared the physiological responses of DCN neurons from young adult and aged rats in response set of simple and more complex acoustic stimuli. Single-unit extracellular recordings were made from two groups of DCN neurons: fusiform cells and cartwheel cells. Fusiform cells reflect the culmination of DCN processing, therefore were good candidates for studying the effect of aging on one ascending auditory stream. Two specific aims were directed at fusiform cell: SA1) Examine the effects of aging on fusiform cell response properties to simple tone burst stimuli; SA2) Examine the effect of aging on DCN output neuron response to complex temporal stimuli. A third aim, SA3) Examine the impact of aging on the response properties of cartwheel cells, a DCN inhibitory interneuron. Fusiform cells recorded from aged rats displayed significantly higher maximum discharge rates to characteristic frequency (CF) tones, fewer nonmonotonic CF rate-level functions and more wide-chopper type post-stimulus time histograms (PSTHs) when compared to neurons from young adult rats. These findings were consistent with an age-related loss of inhibitory glycinergic input. To elucidate how loss of inhibition could lead to functional deficits in temporal processing, fusiform cells were challenged to encode sinusoidally amplitude modulated (SAM) tones. DCN output neurons were presented with SAM tones at three modulation depths at 30 dB above hearing level/response threshold with the carrier frequency set to each unit’s CF. Temporal synchronicity to the SAM envelope was measured using vector strength from temporal modulation transfer functions (tMTFs). Firing rate to SAM tones was also assessed in rate modulation transfer functions (rMTFs). DCN output neurons from aged rats showed no loss of rate response (rMTF) but displayed a selective loss of temporal precision to SAM tones with significant age-related changes in peak vector strength (best modulation frequency), and the shape and category of tMTF. Wide-chopper PSTH types had significantly lower vector strength values than buildup and pauser PSTHs in both young and aged fusiform cells. Since a significantly greater proportion of aged neurons exhibited wide-chopper responses, this could explain, in part, the loss of temporal processing. The age-related response changes in the present study mimicked results from earlier studies were glycine inhibition onto young adult fusiform cells was pharmacologically blocked. Cartwheel cells receive excitatory inputs from granule cell parallel fibers as well as somatosensory dorsal column nucleus and project glycinergic inputs onto DCN output neurons. They appear to play a role in the integration of auditory and somatosensory inputs such as sensing head position. Aged cartwheel neurons exhibited signs of disinhibition showing increased spontaneous activity, increased maximum discharge rates and altered rate-level functions. The observed age-related changes in cartwheel cells are consistent with deafferentation studies using acoustic trauma. Collectively, the changes in DCN output neurons and cartwheel cells reflect a potentially maladaptive age-related neuroplasticity in response to a loss of excitatory acoustic nerve input. These in vivo extracellular findings were consistent with a global downregulation of glycinergic input within the DCN of aged rats. This reduced inhibition may contribute to functional deficits, particularly in activities that require precise timing of events such as response to speech-like stimuli.
The Auditory Cortex
Author: Jeffery A. WinerPublisher: Springer Science & Business Media
ISBN: 1441900748
Category : Science
Languages : en
Pages : 711
Book Description
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.
Development of Auditory and Vestibular Systems
Author: Raymond RomandPublisher: Academic Press
ISBN: 0124081088
Category : Science
Languages : en
Pages : 563
Book Description
Development of Auditory and Vestibular Systems fourth edition presents a global and synthetic view of the main aspects of the development of the stato-acoustic system. Unique to this volume is the joint discussion of two sensory systems that, although close at the embryological stage, present divergences during development and later reveal conspicuous functional differences at the adult stage. This work covers the development of auditory receptors up to the central auditory system from several animal models, including humans. Coverage of the vestibular system, spanning amphibians to effects of altered gravity during development in different species, offers examples of the diversity and complexity of life at all levels, from genes through anatomical form and function to, ultimately, behavior. The new edition of Development of Auditory and Vestibular Systems will continue to be an indispensable resource for beginning scientists in this area and experienced researchers alike. - Full-color figures illustrate the development of the stato-acoustic system pathway - Covers a broad range of species, from drosophila to humans, demonstrating the diversity of morphological development despite similarities in molecular processes involved at the cellular level - Discusses a variety of approaches, from genetic-molecular biology to psychophysics, enabling the investigation of ontogenesis and functional development
The Inferior Colliculus
Author: Jeffery A. WinerPublisher: Springer Science & Business Media
ISBN: 0387270833
Category : Science
Languages : en
Pages : 720
Book Description
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.
Basic Aspects of Hearing
Author: Brian C.J. MoorePublisher: Springer Science & Business Media
ISBN: 146141590X
Category : Medical
Languages : en
Pages : 545
Book Description
The International Symposium on Hearing is a highly-prestigious, triennial event where world-class scientists present and discuss the most recent advances in the field of hearing research in animals and humans. Presented papers range from basic to applied research, and are of interest neuroscientists, otolaryngologists, psychologists, and artificial intelligence researchers. Basic Aspects of Hearing: Physiology and Perception includes the best papers from the 2012 International Symposium on Hearing. Over 50 chapters focus on the relationship between auditory physiology, psychoacoustics, and computational modeling.
Cumulated Index Medicus
Author: Rhythms of the Brain
Author: G. BuzsákiPublisher: Oxford University Press
ISBN: 0199828237
Category : Medical
Languages : en
Pages : 465
Book Description
Studies of mechanisms in the brain that allow complicated things to happen in a coordinated fashion have produced some of the most spectacular discoveries in neuroscience. This book provides eloquent support for the idea that spontaneous neuron activity, far from being mere noise, is actually the source of our cognitive abilities. It takes a fresh look at the coevolution of structure and function in the mammalian brain, illustrating how self-emerged oscillatory timing is the brain's fundamental organizer of neuronal information. The small-world-like connectivity of the cerebral cortex allows for global computation on multiple spatial and temporal scales. The perpetual interactions among the multiple network oscillators keep cortical systems in a highly sensitive "metastable" state and provide energy-efficient synchronizing mechanisms via weak links. In a sequence of "cycles," György Buzsáki guides the reader from the physics of oscillations through neuronal assembly organization to complex cognitive processing and memory storage. His clear, fluid writing-accessible to any reader with some scientific knowledge-is supplemented by extensive footnotes and references that make it just as gratifying and instructive a read for the specialist. The coherent view of a single author who has been at the forefront of research in this exciting field, this volume is essential reading for anyone interested in our rapidly evolving understanding of the brain.