Cellular Mechanisms of Inhibition in Sound Localization Circuits PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Cellular Mechanisms of Inhibition in Sound Localization Circuits PDF full book. Access full book title Cellular Mechanisms of Inhibition in Sound Localization Circuits by Rebecca J. Curry. Download full books in PDF and EPUB format.
Author: Rebecca J. Curry Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
The ability to localize sound in space is an important task for communication and survival in complex acoustic environments for both humans and animals. For localizing sound in the horizontal plane, differences in sound information received by each ear generates binaural cues, such as the interaural level difference (ILD). Using whole-cell recordings in brain slices, this work focuses on the basic properties of synaptic inhibition in the avian ILD circuit, as well as the modulation of inhibition in the mammalian ILD circuit, both of which are critical for understanding the range of cellular sound localization coding solutions. In birds, the posterior portion of the dorsal nucleus of the lateral lemniscus (LLDp) encodes the ILD, but little is known about the mechanisms of synaptic inhibition underlying the ILD coding. Here, I provide the first evidence confirming a monosynaptic inhibition driven by direct electrical and chemical stimulation of the contralateral LLDp. Additionally, inhibition to LLDp neurons was largely GABAergic, although there is evidence for a glycinergic component, and the low internal chloride concentration suggests a hyperpolarizing action of inhibition in this circuit. In mammals, the medial nucleus of the trapezoid body (MNTB) provides synaptic inhibition to many auditory brainstem nuclei including the mammalian ILD encoding nucleus, and thus contributes to ILD coding. However, not much is understood of the synaptic inhibition the MNTB itself receives and it remains entirely unknown how this inhibition is regulated. Here, I investigated group I metabotropic glutamate receptor (mGluR I) modulation of the glycinergic and GABAergic inputs to MNTB neurons in both wildtype (WT) mice and a fragile X syndrome (FXS) mouse model, in which the fragile X mental retardation gene 1 is knocked out (Fmr1 KO). Loss of the FMR protein results in exaggerated activity of mGluR I, allowing for comparisons of mGluR I function under normal and disordered conditions. Activation of group I mGluRs by 3,5-DHPG (200 ℗æM) increased sIPSC frequency and amplitude in both WT and Fmr1 KO neurons in a voltage-gated sodium channel dependent fashion for glycinergic transmission, but did not modulate glycinergic eIPSCs. For GABAergic transmission, 3,5-DHPG did not increase sIPSC frequency or amplitude, but did suppress eIPSCs in WT neurons. These findings suggest differential modulation by mGluR I on specific inhibitory neurotransmitters and specific neurotransmitter release modes. Together, the results provide new insight to the role of synaptic inhibition in the computation of sound localization across animal models, establishing a working cellular model for avian ILD coding and laying the foundation for the role of mGluR I modulation in the mammalian MNTB under normal and disease states.
Author: Rebecca J. Curry Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
The ability to localize sound in space is an important task for communication and survival in complex acoustic environments for both humans and animals. For localizing sound in the horizontal plane, differences in sound information received by each ear generates binaural cues, such as the interaural level difference (ILD). Using whole-cell recordings in brain slices, this work focuses on the basic properties of synaptic inhibition in the avian ILD circuit, as well as the modulation of inhibition in the mammalian ILD circuit, both of which are critical for understanding the range of cellular sound localization coding solutions. In birds, the posterior portion of the dorsal nucleus of the lateral lemniscus (LLDp) encodes the ILD, but little is known about the mechanisms of synaptic inhibition underlying the ILD coding. Here, I provide the first evidence confirming a monosynaptic inhibition driven by direct electrical and chemical stimulation of the contralateral LLDp. Additionally, inhibition to LLDp neurons was largely GABAergic, although there is evidence for a glycinergic component, and the low internal chloride concentration suggests a hyperpolarizing action of inhibition in this circuit. In mammals, the medial nucleus of the trapezoid body (MNTB) provides synaptic inhibition to many auditory brainstem nuclei including the mammalian ILD encoding nucleus, and thus contributes to ILD coding. However, not much is understood of the synaptic inhibition the MNTB itself receives and it remains entirely unknown how this inhibition is regulated. Here, I investigated group I metabotropic glutamate receptor (mGluR I) modulation of the glycinergic and GABAergic inputs to MNTB neurons in both wildtype (WT) mice and a fragile X syndrome (FXS) mouse model, in which the fragile X mental retardation gene 1 is knocked out (Fmr1 KO). Loss of the FMR protein results in exaggerated activity of mGluR I, allowing for comparisons of mGluR I function under normal and disordered conditions. Activation of group I mGluRs by 3,5-DHPG (200 ℗æM) increased sIPSC frequency and amplitude in both WT and Fmr1 KO neurons in a voltage-gated sodium channel dependent fashion for glycinergic transmission, but did not modulate glycinergic eIPSCs. For GABAergic transmission, 3,5-DHPG did not increase sIPSC frequency or amplitude, but did suppress eIPSCs in WT neurons. These findings suggest differential modulation by mGluR I on specific inhibitory neurotransmitters and specific neurotransmitter release modes. Together, the results provide new insight to the role of synaptic inhibition in the computation of sound localization across animal models, establishing a working cellular model for avian ILD coding and laying the foundation for the role of mGluR I modulation in the mammalian MNTB under normal and disease states.
Author: R. Michael Burger Publisher: Frontiers Media SA ISBN: 2889196674 Category : Auditory perception Languages : en Pages : 233
Book Description
There seems little doubt that from the earliest evolutionary beginnings, inhibition has been a fundamental feature of neuronal circuits - even the simplest life forms sense and interact with their environment, orienting or approaching positive stimuli while avoiding aversive stimuli. This requires internal signals that both drive and suppress behavior. Traditional descriptions of inhibition sometimes limit its role to the suppression of action potential generation. This view fails to capture the vast breadth of inhibitory function now known to exist in neural circuits. A modern perspective on inhibitory signaling comprises a multitude of mechanisms. For example, inhibition can act via a shunting mechanism to speed the membrane time constant and reduce synaptic integration time. It can act via G-protein coupled receptors to initiate second messenger cascades that influence synaptic strength. Inhibition contributes to rhythm generation and can even activate ion channels that mediate inward currents to drive action potential generation. Inhibition also appears to play a role in shaping the properties of neural circuitry over longer time scales. Experience-dependent synaptic plasticity in developing and mature neural circuits underlies behavioral memory and has been intensively studied over the past decade. At excitatory synapses, adjustments of synaptic efficacy are regulated predominantly by changes in the number and function of postsynaptic glutamate receptors. There is, however, increasing evidence for inhibitory modulation of target neuron excitability playing key roles in experience-dependent plasticity. One reason for our limited knowledge about plasticity at inhibitory synapses is that in most circuits, neurons receive convergent inputs from disparate sources. This problem can be overcome by investigating inhibitory circuits in a system with well-defined inhibitory nuclei and projections, each with a known computational function. Compared to other sensory systems, the auditory system has evolved a large number of subthalamic nuclei each devoted to processing distinct features of sound stimuli. This information once extracted is then re-assembled to form the percept the acoustic world around us. The well-understood function of many of these auditory nuclei has enhanced our understanding of inhibition's role in shaping their responses from easily distinguished inhibitory inputs. In particular, neurons devoted to processing the location of sound sources receive a complement of discrete inputs for which in vivo activity and function are well understood. Investigation of these areas has led to significant advances in understanding the development, physiology, and mechanistic underpinnings of inhibition that apply broadly to neuroscience. In this series of papers, we provide an authoritative resource for those interested in exploring the variety of inhibitory circuits and their function in auditory processing. We present original research and focused reviews touching on development, plasticity, anatomy, and evolution of inhibitory circuitry. We hope our readers will find these papers valuable and inspirational to their own research endeavors.
Author: Mei Lian Tan Publisher: ISBN: 9789090244549 Category : Languages : en Pages : 166
Book Description
In this thesis, different aspects of central auditory processing in the inferior colliculus (IC) of young-adult mice and rats are described. With the in vivo patch-clampʺ technique we investigated the contribution of membrane properties and synaptic integration of excitatory and inhibitory inputs to sound processing in an intact auditory system. We describe how biocytin cell injections and vesicular glutamate transporter -1 and -2 stainings can be used to confirm localization of measured cells and to identify the central nucleus of the IC. Next, constant current injections were used to characterize the firing patterns and basic membrane properties of IC neurons. New findings include the presence of electrical synapses (spikelets), the absence of onset firing, the absence of a classic pause in buildup neurons and a description of accelerating cells. In addition, spontaneous excitatory synaptic potentials contributed to the irregularity of spike patterns! . The clearest mechanism in duration tuning seems to be synaptic integration of excitatory and inhibitory inputs and synaptic adaptation, while AM tuning seems to be more influenced by the presence of calcium-dependent potassium channels and the absence of adaptation. Hyperpolarization-activated voltage-dependent sodium/potassium channel Ih can additionally shape the incoming auditory signal. FM tuning is largely determined by the synaptic integration of excitatory and inhibitory inputs, while membrane properties and ion-channels play a lesser role. By showing how the diversity in membrane properties and synaptic inputs can lead to specific tuning for complex sounds, we provide a cellular explanation for the contribution of the IC to central auditory processing..
Author: John van Opstal Publisher: Academic Press ISBN: 0128017252 Category : Science Languages : en Pages : 438
Book Description
The Auditory System and Human Sound-Localization Behavior provides a comprehensive account of the full action-perception cycle underlying spatial hearing. It highlights the interesting properties of the auditory system, such as its organization in azimuth and elevation coordinates. Readers will appreciate that sound localization is inherently a neuro-computational process (it needs to process on implicit and independent acoustic cues). The localization problem of which sound location gave rise to a particular sensory acoustic input cannot be uniquely solved, and therefore requires some clever strategies to cope with everyday situations. The reader is guided through the full interdisciplinary repertoire of the natural sciences: not only neurobiology, but also physics and mathematics, and current theories on sensorimotor integration (e.g. Bayesian approaches to deal with uncertain information) and neural encoding. - Quantitative, model-driven approaches to the full action-perception cycle of sound-localization behavior and eye-head gaze control - Comprehensive introduction to acoustics, systems analysis, computational models, and neurophysiology of the auditory system - Full account of gaze-control paradigms that probe the acoustic action-perception cycle, including multisensory integration, auditory plasticity, and hearing impaired
Author: Jan Schnupp Publisher: MIT Press ISBN: 0262518023 Category : Medical Languages : en Pages : 367
Book Description
An integrated overview of hearing and the interplay of physical, biological, and psychological processes underlying it. Every time we listen—to speech, to music, to footsteps approaching or retreating—our auditory perception is the result of a long chain of diverse and intricate processes that unfold within the source of the sound itself, in the air, in our ears, and, most of all, in our brains. Hearing is an "everyday miracle" that, despite its staggering complexity, seems effortless. This book offers an integrated account of hearing in terms of the neural processes that take place in different parts of the auditory system. Because hearing results from the interplay of so many physical, biological, and psychological processes, the book pulls together the different aspects of hearing—including acoustics, the mathematics of signal processing, the physiology of the ear and central auditory pathways, psychoacoustics, speech, and music—into a coherent whole.
Author: Jeffery A. Winer Publisher: 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.
Author: Edwin W. Rubel Publisher: Springer ISBN: 9781461274506 Category : Science Languages : en Pages : 0
Book Description
The contributors to this volume have provided a detailed and integrated introduction to the behavioural, anatomical, and physiological changes that occur in the auditory system of developing animals. Edwin W Rubel is Virginia Merrill Bloedel Professor of Hearing Sciences at the Virginia Merrill Bloedel Hearing Research Center at the University of Washington, Arthur N. Popper is Professor and Chair of the Department of Zoology at the University of Maryland, while Richard R. Fay is Associate Director of the Parmly Hearing Institute and Professor of Psychology at Loyola University of Chicago. Each volume in this series is independent and authoritative; taken as a set, the series will be the definitive resource in the field.
Author: Donata Oertel Publisher: Springer Science & Business Media ISBN: 9780387989037 Category : Medical Languages : en Pages : 450
Book Description
A summary of how the electrical signals used to represent sounds are encoded and interpreted through the integrated roles of various nuclei. This volume builds on the information about the anatomy and physiology of the auditory pathway found in volumes 1 and 2 of the SHAR series. While the first two volumes describe the structure and function of auditory pathways, this one explains how these pathways lead to an animal's ability to localize and interpret sounds.
Author: Rebecca J. Curry
Author: Rebecca J. Curry
Author: R. Michael Burger
Author: Briana J. Carroll
Author: J. A. Altman
Author: Mei Lian Tan
Author: John van Opstal
Author: Jan Schnupp
Author: Jeffery A. Winer
Author: Edwin W. Rubel
Author: Donata Oertel