Dorsal Cochlear Nucleus

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Eric D. Young - One of the best experts on this subject based on the ideXlab platform.

  • nonlinear temporal receptive fields of neurons in the Dorsal Cochlear Nucleus
    Journal of Neurophysiology, 2013
    Co-Authors: Sharba Bandyopadhyay, Eric D. Young
    Abstract:

    Studies of the Dorsal Cochlear Nucleus (DCN) have focused on spectral processing because of the complex spectral receptive fields of the DCN. However, temporal fluctuations in natural signals convey important information, including information about moving sound sources or movements of the external ear in animals like cats. Here, we investigate the temporal filtering properties of DCN principal neurons through the use of temporal weighting functions that allow flexible analysis of nonlinearities and time variation in temporal response properties. First-order temporal receptive fields derived from the neurons are sufficient to characterize their response properties to low-contrast (3-dB standard deviation) stimuli. Larger contrasts require the second-order terms. Allowing temporal variation of the parameters of the first-order model or adding a component representing refractoriness improves predictions by the model by relatively small amounts. The importance of second-order components of the model is shown through simulations of nonlinear envelope synchronization behavior across sound level. The temporal model can be combined with a spectral model to predict tuning to the speed and direction of moving sounds.

  • 2001) Proprioceptive information from the pinna provides somatosensory input to cat Dorsal Cochlear Nucleus
    2013
    Co-Authors: Patrick O. Kanold, Eric D. Young
    Abstract:

    The Dorsal Cochlear Nucleus (DCN) is a second-order auditory structure that also receives nonauditory information, including somatosensory inputs from the Dorsal column and spinal trigeminal nuclei. Here we investigate the peripheral sources of the somatosensory inputs to DCN. Electrical stimulation was applied to cervical nerves C1–C8, branches of C2, branches of the trigeminal nerve, and hindlimb nerves. The largest evoked potentials in the DCN were produced by C2 stimulation and by stimulation of its branches that innervate the pinna. Electrical stimulation of C2 produced a pattern of inhibition and excitation of DCN principal cells comparable with that seen in previous studies with stimulation of the primary somatosensory nuclei, suggesting that the same pathway was activated. Because C2 contains both proprioceptive and cutaneous fibers, we applied peripheral somatosensory stimulation to identify the effective somatosensory modalities. Only stimuli that activate pinna muscle receptors, such as stretch or vibration of the muscles connected to the pinna, were effective in driving DCN units, whereas cutaneous stimuli such as light touch, brushing of hairs, and stretching of skin were ineffective. These results suggest that the largest somatosensory inputs to the DCN originate from muscle receptors associated with the pinna. They support the hypothesis that a role of the DCN in hearing is to coordinate pinna orientation to sounds or to support correction for the effects of pinna orientation on sound-localization cues. Key words: auditory; somatosensory; Dorsal Cochlear Nucleus; cat; pinna; multisensory; sound localization The output neurons of the Dorsal Cochlear Nucleus (DCN) are sensitive to both auditory and somatosensory stimuli (Saadé et al., 1989; Young et al., 1995), suggesting a cross-modal associative role for the DCN. The somatosensory inputs to the DCN originate predominantly from the ipsilateral Dorsal column and spinal trigeminal nuclei (abbreviated MSN for medullary somatosensor

  • Receptive field for Dorsal Cochlear Nucleus neurons at multiple sound levels.
    Journal of neurophysiology, 2007
    Co-Authors: Sharba Bandyopadhyay, Lina A. J. Reiss, Eric D. Young
    Abstract:

    Neurons in the Dorsal Cochlear Nucleus (DCN) exhibit nonlinearities in spectral processing, which make it difficult to predict the neurons’ responses to stimuli. Here, we consider two possible sour...

  • Effects of Stimulus Spectral Contrast on Receptive Fields of Dorsal Cochlear Nucleus Neurons
    Journal of neurophysiology, 2007
    Co-Authors: Lina A. J. Reiss, Sharba Bandyopadhyay, Eric D. Young
    Abstract:

    Neurons in the Dorsal Cochlear Nucleus (DCN) exhibit strong nonlinearities in spectral processing. Low-order models that transform the stimulus spectrum into discharge rate using a combination of f...

  • Circuitry and Function of the Dorsal Cochlear Nucleus
    Integrative Functions in the Mammalian Auditory Pathway, 2002
    Co-Authors: Eric D. Young, Kevin A. Davis
    Abstract:

    In Chapter 2 of this volume, Smith and Spirou describe the wonderful complexity of the brainstem auditory system. This system forms a collection of parallel pathways that diverge at the first auditory synapse in the brainstem, in the Cochlear Nucleus (CN), and then converge again, at least in a gross anatomical sense, in the inferior colliculus (for abbreviations, see Table 5.1). The CN is a well-studied collection of neural circuits that are diverse both in anatomical and physiological terms (reviewed by Cant 1992; Rhode and Greenberg 1992; Young 1998). These vary from the simplest system, the bushy cells of the ventral Cochlear Nucleus (VCN; see Yin, Chapter 4), to the most complex, in the Dorsal Cochlear Nucleus (DCN). The DCN differs from other parts of the CN by having an extensive internal neuropil formed by groups of interneurons (Lorente de No 1981; Osen et al. 1990). As a result, the DCN makes significant changes in the auditory representation from its inputs to its outputs. In this chapter, the neural organization of the DCN is reviewed, paying most attention to data from the cat. The response properties of DCN neurons are discussed in the context of its neural organization and related to data on the functional role of the DCN in hearing.

Laurence O Trussell - One of the best experts on this subject based on the ideXlab platform.

  • Microcircuits of the Dorsal Cochlear Nucleus
    The Mammalian Auditory Pathways, 2018
    Co-Authors: Laurence O Trussell, Donata Oertel
    Abstract:

    The Dorsal Cochlear Nucleus (DCN) integrates excitatory input from auditory and nonauditory sources. Auditory signals are conveyed to the deep layer by the auditory nerve and by excitatory interneurons in the ventral Cochlear Nucleus (VCN). Signals from diverse auditory, somatosensory, proprioceptive, and vestibular sources arrive through mossy fibers in the molecular layer. Thus the DCN is a multisensory integrator. Auditory and mossy inputs are processed through separate microcircuits and are then integrated and conveyed to the inferior colliculus by fusiform cells. Signals arriving from the auditory nerve and VCN in the DCN deep layer are refined by inhibitory neurons that give the acoustic responses of the principal cells a striking nonlinearity as a function of sound intensity and inhibitory sidebands in the spectral domain. Mossy inputs are preprocessed by local circuits in a granule cell region and further refined in the molecular layer. Unlike the auditory signals in the deep layer, signals in the molecular layer exhibit diverse forms of long-term synaptic plasticity. The function of the DCN is not fully understood. The sensitivity of the DCN to spectral notches suggests a role in sound localization using monoaural cues. Input associated with pinna muscles and the trigeminal nerve suggests that the DCN relates head orientation to incoming sounds. The anatomical and physiological similarity of the DCN to structures in electric fish that sensitize the fish to novel signals in the environment has led to the idea that the DCN cancels self-generated and expected features of sounds.

  • Superficial stellate cells of the Dorsal Cochlear Nucleus
    Frontiers in neural circuits, 2014
    Co-Authors: Pierre F. Apostolides, Laurence O Trussell
    Abstract:

    The Dorsal Cochlear Nucleus (DCN) integrates auditory and multisensory signals at the earliest levels of auditory processing. Proposed roles for this region include sound localization in the vertical plane, head orientation to sounds of interest, and suppression of sensitivity to expected sounds. Auditory and non-auditory information streams to the DCN are refined by a remarkably complex array of inhibitory and excitatory interneurons, and the role of each cell type is gaining increasing attention. One inhibitory neuron that has been poorly appreciated to date is the superficial stellate cell. Here we review previous studies and describe new results that reveal the surprisingly rich interactions that this tiny interneuron has with its neighbors, interactions which enable it to respond to both multisensory and auditory afferents.

  • Chemical synaptic transmission onto superficial stellate cells of the mouse Dorsal Cochlear Nucleus.
    Journal of neurophysiology, 2014
    Co-Authors: Pierre F. Apostolides, Laurence O Trussell
    Abstract:

    The Dorsal Cochlear Nucleus (DCN) is a cerebellum-like auditory brain stem region whose functions include sound localization and multisensory integration. Although previous in vivo studies have sho...

  • Synaptic inputs to granule cells of the Dorsal Cochlear Nucleus.
    Journal of neurophysiology, 2007
    Co-Authors: Veeramuthu Balakrishnan, Laurence O Trussell
    Abstract:

    The mammalian Dorsal Cochlear Nucleus (DCN) integrates auditory nerve input with nonauditory signals via a cerebellar-like granule cell circuit. Although granule cells carry nonauditory information...

  • ion channels generating complex spikes in cartwheel cells of the Dorsal Cochlear Nucleus
    Journal of Neurophysiology, 2007
    Co-Authors: Laurence O Trussell
    Abstract:

    Cartwheel cells are glycinergic interneurons that modify somatosensory input to the Dorsal Cochlear Nucleus. They are characterized by firing of mixtures of both simple and complex action potential...

Herbert Voigt - One of the best experts on this subject based on the ideXlab platform.

Thanos Tzounopoulos - One of the best experts on this subject based on the ideXlab platform.

  • mechanisms of synaptic zinc plasticity at mouse Dorsal Cochlear Nucleus glutamatergic synapses
    bioRxiv, 2018
    Co-Authors: Nathan W Vogler, Thanos Tzounopoulos
    Abstract:

    In many excitatory synapses, synaptic zinc is co-released with glutamate to modulate neurotransmission. Synaptic zinc modulates the responsiveness of auditory cortex to sound, and synaptic zinc levels and signaling are modulated by sensory experience, termed zinc plasticity. The mechanisms underlying zinc plasticity remain unknown. We discovered that high- and low-frequency electrical stimulation of Dorsal Cochlear Nucleus synapses reduces and increases synaptic zinc signaling, respectively. This bidirectional zinc plasticity is evidenced by changes in zinc inhibition of AMPA and NMDA receptor activity. Increases and decreases in zinc signaling require activation of Group 1 metabotropic glutamate receptors (mGluRs). Activation of Group 1 mGluRs with a higher agonist concentration increases presynaptic zinc levels and postsynaptic zinc signaling, whereas activation with a lower concentration reduces zinc levels and signaling. Sound-induced zinc plasticity also requires Group 1 mGluRs. Our results reveal the mechanisms underlying synaptic zinc plasticity, elicited by either synaptic activity or sound experience.

  • Mice with behavioral evidence of tinnitus exhibit Dorsal Cochlear Nucleus hyperactivity because of decreased GABAergic inhibition
    Proceedings of the National Academy of Sciences of the United States of America, 2011
    Co-Authors: Jason W. Middleton, Taro Kiritani, Courtney Pedersen, Jeremy G. Turner, Gordon M. Shepherd, Thanos Tzounopoulos
    Abstract:

    Tinnitus has been associated with increased spontaneous and evoked activity, increased neural synchrony, and reorganization of tonotopic maps of auditory nuclei. However, the neurotransmitter systems mediating these changes are poorly understood. Here, we developed an in vitro assay that allows us to evaluate the roles of excitation and inhibition in determining the neural correlates of tinnitus. To measure the magnitude and spatial spread of evoked circuit activity, we used flavoprotein autofluorescence (FA) imaging, a metabolic indicator of neuronal activity. We measured FA responses after electrical stimulation of glutamatergic axons in slices containing the Dorsal Cochlear Nucleus, an auditory brainstem Nucleus hypothesized to be crucial in the triggering and modulation of tinnitus. FA imaging in Dorsal Cochlear Nucleus brain slices from mice with behavioral evidence of tinnitus (tinnitus mice) revealed enhanced evoked FA response at the site of stimulation and enhanced spatial propagation of FA response to surrounding sites. Blockers of GABAergic inhibition enhanced FA response to a greater extent in control mice than in tinnitus mice. Blockers of excitation decreased FA response to a similar extent in tinnitus and control mice. These findings indicate that auditory circuits in mice with behavioral evidence of tinnitus respond to stimuli in a more robust and spatially distributed manner because of a decrease in GABAergic inhibition.

  • Cell-specific, spike timing–dependent plasticities in the Dorsal Cochlear Nucleus
    Nature Neuroscience, 2004
    Co-Authors: Thanos Tzounopoulos, Donata Oertel, Yuil Kim, Laurence O Trussell
    Abstract:

    In the Dorsal Cochlear Nucleus, long-term synaptic plasticity can be induced at the parallel fiber inputs that synapse onto both fusiform principal neurons and cartwheel feedforward inhibitory interneurons. Here we report that in mouse fusiform cells, spikes evoked 5 ms after parallel-fiber excitatory postsynaptic potentials (EPSPs) led to long-term potentiation (LTP), whereas spikes evoked 5 ms before EPSPs led to long-term depression (LTD) of the synapse. The EPSP-spike protocol led to LTD in cartwheel cells, but no synaptic changes resulted from the reverse sequence (spike-EPSP). Plasticity in fusiform and cartwheel cells therefore followed Hebbian and anti-Hebbian learning rules, respectively. Similarly, spikes generated by summing EPSPs from different groups of parallel fibers produced LTP in fusiform cells, and LTD in cartwheel cells. LTD could also be induced in glutamatergic inputs of cartwheel cells by pairing parallel-fiber EPSPs with depolarizing glycinergic PSPs from neighboring cartwheel cells. Thus, synaptic learning rules vary with the postsynaptic cell, and may require the interaction of different transmitter systems.

  • cell specific spike timing dependent plasticities in the Dorsal Cochlear Nucleus
    Nature Neuroscience, 2004
    Co-Authors: Thanos Tzounopoulos, Donata Oertel, Yuil Kim, Laurence O Trussell
    Abstract:

    In the Dorsal Cochlear Nucleus, long-term synaptic plasticity can be induced at the parallel fiber inputs that synapse onto both fusiform principal neurons and cartwheel feedforward inhibitory interneurons. Here we report that in mouse fusiform cells, spikes evoked 5 ms after parallel-fiber excitatory postsynaptic potentials (EPSPs) led to long-term potentiation (LTP), whereas spikes evoked 5 ms before EPSPs led to long-term depression (LTD) of the synapse. The EPSP-spike protocol led to LTD in cartwheel cells, but no synaptic changes resulted from the reverse sequence (spike-EPSP). Plasticity in fusiform and cartwheel cells therefore followed Hebbian and anti-Hebbian learning rules, respectively. Similarly, spikes generated by summing EPSPs from different groups of parallel fibers produced LTP in fusiform cells, and LTD in cartwheel cells. LTD could also be induced in glutamatergic inputs of cartwheel cells by pairing parallel-fiber EPSPs with depolarizing glycinergic PSPs from neighboring cartwheel cells. Thus, synaptic learning rules vary with the postsynaptic cell, and may require the interaction of different transmitter systems.

David K Ryugo - One of the best experts on this subject based on the ideXlab platform.

  • Glycine immunoreactivity of multipolar neurons in the ventral Cochlear Nucleus which project to the Dorsal Cochlear Nucleus.
    The Journal of comparative neurology, 1999
    Co-Authors: John R. Doucet, Adam T. Ross, M. Boyd Gillespie, David K Ryugo
    Abstract:

    Certain distinct populations of neurons in the Dorsal Cochlear Nucleus are inhibited by a neural source that is responsive to a wide range of acoustic frequencies. In this study, we examined the glycine immunoreactivity of two types of ventral Cochlear Nucleus neurons (planar and radiate) in the rat which project to the Dorsal Cochlear Nucleus (DCN) and thus, might be responsible for this inhibition. Previously, we proposed that planar neurons provided a tonotopic and narrowly tuned input to the DCN, whereas radiate neurons provided a broadly tuned input and thus, were strong candidates as the source of broadband inhibition (Doucet and Ryugo [1997] J. Comp. Neurol. 385:245‐264). We tested this idea by combining retrograde labeling and glycine immunohistochemical protocols. Planar and radiate neurons were first retrogradely labeled by injecting biotinylated dextran amine into a restricted region of the Dorsal Cochlear Nucleus. The labeled cells were visualized using streptavidin conjugated to indocarbocyanine (Cy3), a fluorescent marker. Sections that contained planar or radiate neurons were then processed for glycine immunocytochemistry using diaminobenzidine as the chromogen. Immunostaining of planar neurons was light, comparable to that of excitatory neurons (pyramidal neurons in the DCN), whereas immunostaining of radiate neurons was dark, comparable to that of glycinergic neurons (cartwheel cells in the Dorsal Cochlear Nucleus and principal cells in the medial Nucleus of the trapezoid body). These results are consistent with the hypothesis that radiate neurons in the ventral Cochlear Nucleus subserve the wideband inhibition observed in the Dorsal Cochlear Nucleus. J. Comp. Neurol. 408:515‐531, 1999. r 1999 Wiley-Liss, Inc. Indexing terms: auditory system; biotinylated dextran amine; hearing; inhibition

  • Projections from the ventral Cochlear Nucleus to the Dorsal Cochlear Nucleus in rats
    The Journal of comparative neurology, 1997
    Co-Authors: John R. Doucet, David K Ryugo
    Abstract:

    Local circuit interactions between the Dorsal and ventral divisions of the Cochlear Nucleus are known to influence the evoked responses of the resident neurons to sound. In the present study, we examined the projections of neurons in the ventral Cochlear Nucleus to the Dorsal Cochlear Nucleus by using retrograde transport of biotinylated dextran amine injected into restricted but different regions of the Dorsal Cochlear Nucleus. In all cases, we found retrogradely labeled granule, unipolar brush, and chestnut cells in the granule cell domain, and retrogradely labeled multipolar cells in the magnocellular core of the ventral Cochlear Nucleus. A small number of the labeled multipolar cells were found along the margins of the ventral Cochlear Nucleus, usually near the boundaries of the granule cell domain. Spherical bushy, globular bushy, and octopus cells were not labeled. Retrogradely-labeled auditory nerve fibers and the majority of labeled multipolar neurons formed a narrow sheet extending across the medial-to-lateral extent of the ventral Cochlear Nucleus whose dorsoventral position was topographically related to the injection site. Labeled multipolar cells within the core of the ventral Cochlear Nucleus could be divided into at least two distinct groups. Planar neurons were most numerous, their somata found within the associated band of labeled fibers, and their dendrites oriented within this band. This arrangement mimics the organization of isofrequency contours and implies that planar neurons respond best to a narrow range of frequencies. In contrast, radiate neurons were infrequent, found scattered throughout the ventral Cochlear Nucleus, and had long dendrites oriented perpendicular to the isofrequency contours. This dendritic orientation suggests that radiate neurons are sensitive to a broad range of frequencies. These structural differences between planar and radiate neurons suggest that they subserve separate functions in acoustic processing. J. Comp. Neurol. 385:245‐264, 1997. r 1997 Wiley-Liss, Inc.

  • immunocytochemical localization of glycine in a subset of cartwheel cells of the Dorsal Cochlear Nucleus in rats
    Hearing Research, 1996
    Co-Authors: Troy S Gates, Diana L Weedman, Tan Pongstaporn, David K Ryugo
    Abstract:

    Abstract Glycine is an inhibitory neurotransmitter and a glutamate cofactor for N -methyl- d -aspartate (NMDA) receptors in the central nervous system. The distribution of glycine in the auditory system will therefore provide clues as to synaptic mechanisms underlying auditory signal processing. Previous studies have reported the immunocytochemical presence of glycine in the Dorsal Cochlear Nucleus of a variety of mammals, but the specificity with respect to particular cell types has proven elusive at the light microscopic level. We sought to identify cell types in the superficial regions of the Dorsal Cochlear Nucleus that were immunoreactive to glycine using light and electron microscopy in the rat. At the light microscopic level, glycine immunoreactivity was present in some but not all medium-sized cells in layers I and II. The somata of pyramidal and granule cells were not stained. At the electron microscopic level, using previously published ultrastructural criteria, we examined the glycine-labeled cells and determined that many but not all cartwheel cells were labeled. We also observed unlabeled unipolar brush cells, Golgi cells, and stellate cells. As some of the labeled cells could not be identified, we could not determine whether unipolar brush cells, Golgi cells or stellate cells had both labeled and unlabeled subpopulations. Our observations indicate that within the population of cartwheel cells, only a subset are glycine-immunoreactive.

  • Immunocytochemical localization of the mGluR1α metabotropic glutamate receptor in the Dorsal Cochlear Nucleus
    The Journal of comparative neurology, 1996
    Co-Authors: Debora D. Wright, Craig Blackstone, Richard L. Huganir, David K Ryugo
    Abstract:

    We demonstrate that the metabotropic glutamate receptor mGluR1α is enriched in two interneuron cell populations in the Dorsal division of the Cochlear Nucleus. Electron microscopic analysis confirms that mGluR1α immunoreactivity is concentrated in the dendritic spines of cartwheel cells and in dendrites of the recently described unipolar brush cells. The cartwheel cells, which have many similarities to the Purkinje cells of the cerebellum, participate in a local neuronal circuit that modulates the output of the Dorsal Cochlear Nucleus. Immunostained unipolar brush cells were observed in granule cell regions of the Cochlear Nucleus and the vestibulocerebellum. The presence of analogous cell types with similar patterns of immunolabeling in the cerebellum and in the Dorsal Cochlear Nucleus suggests that a shared but as yet unknown mode of processing may occur in both structures. © 1996 Wiley-Liss, Inc.

  • Inositol 1,4,5-trisphosphate receptors: immunocytochemical localization in the Dorsal Cochlear Nucleus.
    The Journal of comparative neurology, 1995
    Co-Authors: David K Ryugo, Tan Pongstaporn, Debora D. Wright, Alan H. Sharp
    Abstract:

    In the Cochlear Nucleus of mammals, the relatively homogeneous responses of auditory nerve fibers are transformed into a variety of different response patterns by the different classes of resident neurons. The spectrum of these responses is hypothesized to depend on the types and distribution of receptors, ion channels, G proteins, and second messengers that form the signaling capabilities in each cell class. In the present study, we examined the immunocytochemical distribution of the inositol 1,4,5-trisphosphate (IP3) receptor in the Dorsal Cochlear Nucleus to better understand how this second messenger might be involved in shaping the neural signals evoked by sound. Affinity-purified polyclonal antibodies directed against the IP3 receptor labeled a homogeneous population of neurons in the Dorsal Cochlear Nucleus of rats, guinea pigs, mustache bats, cats, New World owl monkeys, rhesus monkeys, and humans. These cells were all darkly immunostained except in the human where the labeling was less intense. Immunoblots of Dorsal Cochlear Nucleus tissue from the rat revealed a single band of protein of molecular weight ∼260 kD, which is the same size as the purified receptor, indicating that our antibodies reacted specifically with the IP3 receptor. These immunolabeled neurons were identified as cartwheel cells on the basis of shared characteristics across species, including cell body size and distribution, the presence of a highly invaginated. Nucleus, and a well-developed systain of cisternae. Reaction product was localized along the membranes of rough and smooth endoplasmic reticulum, subsurface cisternae, and the nuclear envelope. This label was distributed throughout the cartwheel cell body and dendritic shafts but not within dendritic spines, axons, or axon terminals. The regular pattern of immunolabeling across mammals suggests that IP3 and cartwheel cells are conserved in evolution and that both play an important but as yet unknown role in hearing. © 1995 Wiley-Liss, Inc.

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