In this paper, we studied RLFs of neurons in ventral cochlear nucleus (VCN) of the cat after acoustic trauma. 
Neurons in the ventral cochlear nucleus (VCN) that respond primarily at the onset of a pure tone stimulus show diversity in terms of peri-stimulus-time-histograms (PSTHs), rate-level functions, frequency tuning, and also their responses to broad band noise.
The spatial organization of projections from the ventral cochlear nucleus (VCN) to the ventral nucleus of the lateral lemniscus (VNLL) and from the VNLL to the central nucleus of the inferior colliculus (CNIC) was investigated by using neuroanatomical tracing methods in the gerbil.
We propose a relatively low-level neuronal explanation for this grouping effect: the captor reduces the neural response to the leading segment of the asynchronous component by activating across-frequency suppression, either from the cochlea, or acting via a wideband inhibitor in the ventral cochlear nucleus. Using a simplified paradigm we show that both primary-like and chopper units in the ventral cochlear nucleus of the anesthetized guinea pig may show a rebound in excitation when a captor is positioned so as to stimulate the suppressive sidebands in its receptive field.
Principal cells of the medial nucleus of the trapezoid body (MNTB) receive their excitatory input through large somatic terminals, the calyces of Held, which arise from axons of globular bushy cells located in the contralateral ventral cochlear nucleus.
Principal cells of the ventral cochlear nucleus (VCN) differ in the magnitudes of low-voltage-activated potassium (gKL) and hyperpolarization-activated (gh) conductances that determine the time course of signaling.
UBCs and granules are also present in regions previously not included in the GCS, namely the rostrodorsal magnocellular portions of ventral cochlear nucleus, vestibular nerve root, trapezoid body, spinal tract and sensory and principal nuclei of the trigeminal nerve, and cerebellar peduncles.
The strength of synapses between auditory nerve (AN) fibers and ventral cochlear nucleus (VCN) neurons is an important factor in determining the nature of neural integration in VCN neurons of different response types.
In this study we have investigated the effects of continuous background noise without and with MOC system activation, on responses of different neuron types in the ventral cochlear nucleus of the guinea pig.
Klüver-Barrera and neuronal nuclei (NeuN) staining showed a decrease in neuronal density in the ventral cochlear nucleus, but not in the dorsal cochlear nucleus.
We examine the general influence of IKLT on spike encoding of stochastic stimuli using a pattern classification analysis between spike responses from a ventral cochlear nucleus (VCN) model containing IKLT, and the same model with the IKLT dynamics removed.
In both normal and deaf mice, the ipsilateral projections from the anteroventral cochlear nucleus (AVCN) to the lateral superior olive (LSO), and the contralateral projections from the AVCN to the medial nucleus of the trapezoid body (MNTB) were intact. There was electrophysiological evidence of in vivo spontaneous ventral cochlear nucleus activity in normal and deaf animals, indicating that this activity may be responsible for the appropriate connectivity in the deaf mice.
In the adult hindbrain, the cytoplasmic Math5-lacZ reporter is expressed within the ventral cochlear nucleus (VCN), in a subpopulation of neurons that project to medial nucleus of the trapezoid body (MNTB), lateral superior olive (LSO), and lateral lemniscus (LL).
Multichannel techniques were used to assess the frequency specificity of activation in the central nucleus of the inferior colliculus (CIC) produced by electrical stimulation of localized regions within the ventral cochlear nucleus (VCN).
Spike trains were recorded from single units in the ventral cochlear nucleus of the anaesthetised guinea-pig in response to dynamic iterated rippled noise with positive and negative gain.
Octopus cells, neurons in the most posterior and dorsal part of the mammalian ventral cochlear nucleus, convey the timing of synchronous firing of auditory nerve fibers to targets in the contralateral superior paraolivary nucleus and ventral nucleus of the lateral lemniscus.
The ventral cochlear nucleus, medial geniculate, CA1 hippocampus, and perirhinal cortex showed modified metabolic capacity due to latent inhibition.
ventral cochlear nucleus (VCN) axons normally project to the medial nucleus of the trapezoid body (MNTB) only on the contralateral side.
In the auditory brainstem the neurons whose axons traverse the midline in the ventral acoustic stria (VAS) are primarily located in the ventral cochlear nucleus (VCN) and project bilaterally to the superior olivary complex (SOC).
Until recently, the target region for ABI implantation has been the ventral cochlear nucleus (CN).
Low-order models that transform the stimulus spectrum into discharge rate using a combination of first- and second-order weighting of the spectrum (quadratic models) usually fail to predict responses to novel stimuli for principal neurons in the DCN, even though they work well in ventral cochlear nucleus.
The lateral superior olivary nucleus (LSO) is an auditory relay centre within the brain stem that encodes interaural level differences for sound localization by integrating GABA/glycinergic input from the contralateral ear via the medial nucleus of the trapezoid body (MNTB), and glutamatergic input from the ipsilateral ear via the ventral cochlear nucleus (VCN).
Acoustically evoked responses from intracranial electrodes chronically implanted bilaterally into the ventral cochlear nucleus were used to assess acoustic sensitivity alterations.
A central auditory prosthesis based on microstimulation within the ventral cochlear nucleus (VCN) offers a means of restoring hearing to persons whose auditory nerve has been destroyed bilaterally and cannot benefit from cochlear implants.
Using receptor autoradiography, GABAB receptor expression in the anterior ventral cochlear nucleus was revealed.
Bushy cells in the ventral cochlear nucleus convey firing of auditory nerve fibers to neurons in the superior olivary complex that compare the timing and intensity of sounds at the two ears and enable animals to localize sound sources in the horizontal plane.
Effects of intensity of repetitive acoustic stimuli on neural adaptation in the ventral cochlear nucleus of the rat. Again, auditory near-field evoked potentials (ANEPs) were recorded in response to 250-ms trains of clicks from an electrode chronically implanted in the ventral cochlear nucleus (VCN).
MEMRI indicated: (1) In rats with evidence of tinnitus, activity was generally elevated in the auditory brainstem, with significant elevation in the cerebellar paraflocculus, the posterior ventral cochlear nucleus, and the inferior colliculus; in general forebrain structures showed decreased activity, although MEMRI may be a less sensitive indicator of forebrain activity than brainstem activity; (2) in normal rats exposed to a tinnitus-like sound, a similar pattern of elevated brainstem activity and decreased forebrain activity was evident, with the notable exception of the paraflocculus, where artificial tinnitus had no effect and (3) vigabatrin, decreased brainstem activity to control levels, in rats with prior evidence of tinnitus, and decreased forebrain activity to below control levels.
Following salicylate injections that induced the behavioural manifestations of tinnitus, the number of principal neurons in the ventral cochlear nucleus expressing CB1 receptors significantly decreased, while the number of CB1-positive principal neurons in the dorsal cochlear nucleus did not change significantly. These results suggest that CB1 receptors in the cochlear nucleus may be important for auditory function and that a down-regulation of CB1 receptors in the ventral cochlear nucleus may be related to the development of tinnitus..
In order to understand whether glutamatergic excitatory presynaptic input is an absolute requirement for the adult regulation of postsynaptic glutamate receptors we analyzed if a period of 11 days of excitatory deprivation affects the expression, distribution and Ca(2+) permeability of AMPA receptor subunits in the ventral cochlear nucleus of the rat.
Among the neuronal groups proposed to both receive, and contribute to, commissural input is the bushy cell population in the ventral cochlear nucleus (VCN).
The bushy cells of the anterior ventral cochlear nucleus (AVCN) preserve or improve the temporal coding of sound information arriving from auditory nerve fibers (ANF).
The anterior ventral cochlear nucleus (AVCN), posterior ventral cochlear nucleus (PVCN) and dorsal cochlear nucleus (DCN) each contain predominant populations of neurons that have been well characterized regarding their morphological and electrophysiological properties.
A computer model of sustained chopper neurons in the ventral cochlear nucleus is presented and investigated.
The data provide the basis for a new computer model of sustained chopper neurons in the ventral cochlear nucleus.
We found that a unilateral cochlear lesion led within 1 week to a rise of choline acetyltransferase (ChAT) immunoreactivity in the ventral cochlear nucleus of the affected side, matching the lesion-induced expression of growth-associated protein 43 (GAP-43) previously described.
In the auditory brainstem, the ventral cochlear nucleus (VCN) projects to the contralateral but not ipsilateral medial nucleus of the trapezoid body (MNTB).
The three types of principal cells of the ventral cochlear nucleus (VCN), bushy, octopus, and T stellate, differ in the detection of coincidence among synaptic inputs.
Responses to noise were recorded in ventral cochlear nucleus (VCN) neurons of anesthetized chinchillas and cats, then analyzed using Wiener-kernel theory.
The ventral cochlear nucleus is positioned on the lateral surface of the inferior cerebellar peduncle where it often straddles the anterior edge of the foramen of Luschka at the junction of the lateral recess and cerebellopontine angle and produces less of a prominence on the surface of the brainstem than on the dorsal nucleus. The ventral cochlear nucleus is positioned so that it would be vulnerable to damage by tumors within or operative approaches to the cerebellopontine angle. The dorsal cochlear nucleus and the adjacent intraventricular part of the ventral cochlear nucleus have anatomic characteristics that make them the preferable site of placement for the auditory brain stem implant..
The ventral cochlear nucleus (VCN) stellate cell population comprises two clusters: narrowly-tuned, excitatory T stellate neurons, and D stellate neurons, a broadly-tuned population of inhibitory cells.
Preliminary findings using surgical transection and focal lesioning of the auditory brainstem to interrupt the MEM reflexes suggest that MEM reflex interneurons are located in the ventral cochlear nucleus..
Multipolar cells in the ventral cochlear nucleus (VCN) are a structurally and functionally diverse group of projection neurons.
A plant lectin, Wisteria floribunda agglutinin, that recognizes specific carbohydrate residues in the extracellular matrix binds to some cell types in the ventral cochlear nucleus but not to cells in the dorsal cochlear nucleus. In the ventral cochlear nucleus, the most intensely labeled cells are octopus cells, a subset of multipolar cells and cochlear root neurons.
The ventral cochlear nucleus is the principal nucleus for transmission of neural impulses from the VIII par and form the main ascendant route of the cochlear nerve.
The presence of both thick and thin fibers within the acoustic striae following these injections suggests that large and small fibers/boutons within these bands may originate from different neuronal types in the dorsal and ventral cochlear nucleus.
Fusiform cells, major DCN output neurons, receive focused glycinergic inputs from tonotopically aligned vertical cells that also project to the ventral cochlear nucleus.
Auditory nerve fibers (ANFs) were labeled by injecting DiI into the cochlea, and the contralateral projection to the medial nucleus of the trapezoid body (MNTB) by injecting DiI and GFP into the ventral cochlear nucleus.
Both of these response properties have been reported for some cells in the ventral cochlear nucleus in the auditory brainstem..
A more caudal Math1-dependent cochlear extramural stream (CES) generates the ventral cochlear nucleus and cochlear granule neurons.
The differing biophysical properties of neurons the axons of which form the different pathways from the ventral cochlear nucleus (VCN) determine what acoustic information they can convey.
In normal hearing animals, contralateral sound produces an inhibitory response to broadband noise in approximately one third of ventral cochlear nucleus (VCN) neurons.
We found that: (1) cochleotomy or severe noise trauma both lead to a considerable increase of immunoreactivity of the growth-associated protein GAP-43 in the ventral cochlear nucleus (VCN) of the affected side; (2) the expression of GAP-43 in VCN is restricted to presynaptic endings and short fiber segments; (3) axon collaterals of the cholinergic medial olivocochlear (MOC) neurons are the path along which GAP-43 reaches VCN; (4) partial cochlear lesions induce the emergence of GAP-43 positive presynaptic endings only in regions tonotopically corresponding to the extent of the lesion; (5) judging from the presence of immature fibers and growth cones in VCN on the deafened side, at least part of the GAP-43 positive presynaptic endings appear to be newly formed neuronal contacts following axonal sprouting while others may be modified pre-existing contacts; and (6) GAP-43 positive synapses are formed only on specific postsynaptic profiles, i.e., glutamatergic, glycinergic and calretinin containing cell bodies, but not GABAergic cell bodies.
The results suggest that axons from the ipsilateral or contralateral cortex contact fusiform and giant cells in the dorsal cochlear nucleus and multipolar cells in the ventral cochlear nucleus that project directly to the inferior colliculus.
Our experimental results demonstrated that microstimulation of both the dorsal and ventral cochlear nucleus (DCN and VCN) could access the cortical ampli-tonotopic organization as acoustic stimuli did.
RESULTS: Among the auditory nuclei, only the posterior ventral cochlear nucleus (PVCN) showed age-related changes.
Computer-assisted microdensitometric image analysis revealed higher levels of specific mean gray values of FGF-2 immunoreactivity in the trapezoid body and ventral cochlear nucleus and also in the spiral ganglion and inner hair cells.
In this study, we examined synaptic transmission at the endbulb of Held synapse between auditory nerve fibers and bushy cells in the anterior ventral cochlear nucleus (AVCN).
5-HTT immunoreactivity (5-HTT-IR) was first observed in P8 mice and was localized to cell bodies in the ventral cochlear nucleus (VCN) and principal nuclei of the superior olivary complex, including the medial nucleus of the trapezoid body.
ventral cochlear nucleus stellate cells respond to characteristic frequency (CF) tones with sustained (C(S)), transient (C(T)) or onset chopping (O(C)) activity.
We show that each of three voltage-sensitive conductances of octopus cells of the mammalian ventral cochlear nucleus (VCN) is affected differently by changes in temperature.
In this report we partially characterize a pathway projecting to the posterior ventral cochlear nucleus (PVCN) of the rat brain that transiently expresses a high level of acetylcholinesterase (AChE).
In anaesthetized animals with unilateral electrical stimulation of the cochlear nerve, increased expression of c-Fos was detected in the ipsilateral ventral cochlear nucleus (VCN), in the dorsal cochlear nucleus bilaterally (DCN), in the ipsilateral lateral superior olive (LSO) and in the contralateral inferior colliculus (IC).
Labeled boutons were also present in the ventral cochlear nucleus, where they were located in the small cell cap as well as magnocellular parts of both posteroventral and anteroventral cochlear nucleus.
Bushy cells of the ventral cochlear nucleus produce a single, short latency action potential at the beginning of long depolarisations.
The dorsal cochlear nucleus also forms a feed-forward circuit, which receives cochlear input and projects to the ventral cochlear nucleus by a tuberculo-ventral tract. Biotinylated dextran injections into the dorsal cochlear nucleus anterogradely labeled the tuberculo-ventral tract and its endings in the anteroventral cochlear nucleus but also retrogradely filled cochlear nerve fibers and their terminals in the same regions.
Labeled mossy fibers were seen in 9.0% of mossy fibers detected after tracer injection into the ipsilateral anteroventral cochlear nucleus, in 7.3% of mossy fibers after contralateral collicular injection, and 13.2% after contralateral cochlear nucleus injection. Most of the anterograde-labeled ipsilateral mossy fibers containing small round synaptic vesicles, are probably derived from multipolar neurons within the ipsilateral anteroventral cochlear nucleus. The latter would suggest the presence of an amplification pathway within the DCN, from collateral axons of pyramidal or stellate cells of the ipsilateral ventral cochlear nucleus to form glomeruli with granule-unipolar brush cells. After injection into the contralateral cochlear nucleus, it was not possible to distinguish between commissural mossy fibers and those derived from ipsilateral recurrent axon-terminals of commissural neurons within the DCN or the ventral cochlear nucleus.
Model responses were compared directly to published physiological data at three levels: the auditory nerve, ventral cochlear nucleus, and inferior colliculus.
In the ipsilateral dorsal cochlear nucleus, ipsilateral posterior ventral cochlear nucleus and bilateral inferior colliculus, Fos-like immunoreactive neurons were observed as a distinct banding pattern.
We demonstrated previously that the trigeminal ganglion projects to CN, with terminal labeling most dense in the marginal cell area and secondarily in the magnocellular area of the ventral cochlear nucleus (VCN).
At the same postoperative time, the ES cells had migrated into the brain stem close to the ventral cochlear nucleus.
Sindbis or Semliki Forest viruses encoding enhanced green fluorescent protein (EGFP) were injected into the ventral cochlear nucleus (VCN) of rats (postnatal days 7-21) and yielded bright fluorescence in cells of the VCN, including globular bushy cells with their axon and calyx terminal.
Considerable circumstantial evidence suggests that cells in the ventral cochlear nucleus, that respond predominantly to the onset of pure tone bursts, have a stellate morphology and project, among other places, to the dorsal cochlear nucleus. They also provide widespread local innervation of the anteroventral cochlear nucleus and a small innervation of the posteroventral cochlear nucleus.
In ventral cochlear nucleus, c-fos IRN were always found after stimulation and often also after saline injections, whereas none were present when injecting salicylate.
Loss of neurons was found in two nuclei of the auditory pathway of aged ASA(-/-) mice (ventral cochlear nucleus and nucleus of trapezoid body).
Strong HCN1 staining was present on octopus and bushy cells of the ventral cochlear nucleus, principal neurons of the lateral and medial superior olive, and neurons of the ventral nucleus of the lateral lemniscus. Strong HCN2 antibody labelling was also observed in bushy cells of the ventral cochlear nucleus.
A unilateral cochlear lesion induces expression of the growth and plasticity-associated protein 43 (GAP-43) in fibers and their varicosities on specific types of postsynaptic profiles in the ventral cochlear nucleus (VCN), suggesting the induction of synaptic remodeling.
Following surgery, GAP-43 re-emerged in the ipsilateral anterior ventral cochlear nucleus (AVCN) and the immunoreactivity reached a climax around postoperative day (POD) 8; the same expression pattern as that reported in the previous literature is the indicator of synaptogenesis.
In vivo intracellular recordings from the ventral cochlear nucleus (VCN) showed that, when tones were presented above or below the characteristic frequency (CF) of a T stellate neuron, they were inhibited during depolarization.
To investigate neural adaptive properties, near-field evoked potentials were recorded from a chronically implanted electrode in the ventral cochlear nucleus in awake Long-Evans rats exposed to acoustic stimuli or receiving intracochlear electric stimulation.
AAE effects on the number of surviving neurons (age 12-14 months) in the anterior ventral cochlear nucleus (AVCN) depended on sex.
The current modeling study investigates the possible role of populations of sustained chopper (Chop-S) units located in the mammalian ventral cochlear nucleus (VCN) in this process. It is proposed that Chop-S units in the ventral cochlear nucleus may play an important role in pitch extraction: They can convert a purely temporal pitch code as observed in the auditory nerve into a temporal place code of pitch in populations of cochlear-nucleus, Chop-S with different characteristic frequencies, and chopping rates.
These experiments examined the coding of the voice onset time (VOT) of six naturally spoken syllables, presented at a number of intensities, by ventral cochlear nucleus (VCN) neurons in rats anesthetized with urethane.
A projection from the trigeminal ganglion to the ventral cochlear nucleus (VCN) of the guinea pig was recently described. Stimulation of this projection has been shown to result in activation of neurons of the ventral cochlear nucleus.
Trk A, Trk B and Trk C expression has been reported in the rat ventral cochlear nucleus.
To study neural adaptation as a function of stimulus intensity, auditory near-field evoked potentials were recorded from the ventral cochlear nucleus in awake Long Evans rats. These results indicate that adaptation patterns obtained in the ventral cochlear nucleus by using near-field evoked potentials exhibit properties comparable to those already present at the level of the auditory nerve..
The voltage-gated potassium (Kv) channel subunit Kv1.1, encoded by the Kcna1 gene, is expressed strongly in the ventral cochlear nucleus (VCN) and the medial nucleus of the trapezoid body (MNTB) of the auditory pathway.
Stellate cells within the ventral cochlear nucleus (VCN) are a diverse cell group that have been classified according to their size and morphology.
At low stimulation rates (200-300 pps), the discharges of AN fibers and a large proportion of principal cells (bushy, octopus, stellate) in the ventral cochlear nucleus (VCN) followed with high probability each pulse in the train, resulting in synchronization of discharges within large populations of AN fibers and CN cells.
A direct commissural connection between cochlear nuclei provides a pathway by which binaural input can influence the processing of acoustic information through the ventral cochlear nucleus.
The trigeminal ganglion sends a projection to the granule and magnocellular regions of the ventral cochlear nucleus (VCN; [ J Comp Neurol 419 (2000) 271]), as well as to the cochlea ([ Neuroscience 79 (1997) 605; Neuroscience 84 (1998a) 559]).
A massive reduction of cochlear nerve fibers in the ventral cochlear nucleus (VCN) was demonstrated by tracing them from the cochlea of rats that survived acoustic overstimulation for 1 year or longer.
The projections of nine distinguishable cell types in the cochlear nucleus-seven in the ventral cochlear nucleus and two in the dorsal cochlear nucleus-are described in this review.
Using kinetic data from three different K+ currents in acutely isolated neurons, a single electrical compartment representing the soma of a ventral cochlear nucleus (VCN) neuron was created.
Neurons in the ventral cochlear nucleus (VCN) express three distinct K+ currents that differ in their voltage and time dependence, and in their inactivation behavior.
In the ventral cochlear nucleus (VCN), neurons transform information from auditory nerve fibers into a set of parallel ascending pathways, each emphasizing different aspects of the acoustic environment.
This report describes a source of input to the LSO that complements bushy cell projections from the ventral cochlear nucleus (VCN).
Neurons in the ventral cochlear nucleus and inferior colliculus show a sustained Krox-20 expression.
Ventrotubercular cells are multipolar cells in the ventral cochlear nucleus (VCN) that project a collateral axon to the ipsilateral dorsal cochlear nucleus (DCN).
Cells in the octopus cell area of the rat ventral cochlear nucleus have been connected to the monaural interpretation of spectral patterns of sound such as those derived from speech. The cytological characteristics that make these large cells able to perform such a function have been studied with ultrastructural immunocytochemistry for glycine, GABA and glutamate, and compared to that of other multipolar neurons of other regions of the ventral cochlear nucleus.
Since no GABA labelled cells in both the dorsal and ventral cochlear nucleus were retrograde labelled from the colliculus, the source of these intrinsic anterograde labelled boutons must be external to the cochlear nucleus.
In the present study, gerbils were deafened at postnatal day 9, an age at which there is no deafferentation-induced cell death of ventral cochlear nucleus neurons.
We demonstrate that the dorsal cochlear nucleus and the small cell cap of the ventral cochlear nucleus have a direct projection to the medial division of the medial geniculate body.
The volumes of the ventral cochlear nucleus (VCN) and dorsal cochlear nucleus (DCN), and the maximal cross-sectional area and densities of cell bodies in the anterior ventral cochlear nucleus (AVCN) were measured bilaterally by light microscopy assisted by the Neurolucida 2000 image analysis system.
We have monitored the spectrum of the (spontaneous) neural noise at the round window (RW) and on the surface of the antero-ventral cochlear nucleus (CN) and the dorsal CN (DCN) of anaesthetised guinea pigs.
Results indicate low, but detectable expression of biotinidase throughout the brain, but increased concentrations of biotinidase within the dorsal cochlear nucleus, ventral cochlear nucleus, and superior olivary complex of the brainstem, as well as, in the hair cells and spiral ganglion of the cochlea.
An unequivocal rise in GAP-43 immunoreactivity was also found in the neuropil of the inferior colliculus and the ventral cochlear nucleus, both preferentially on the acoustically damaged side.
To achieve this purpose, near-field evoked potentials were picked up from the ventral cochlear nucleus in awake animals. The results were comparable to those obtained in previous studies in the auditory nerve and suggest that the adaptation recorded in the ventral cochlear nucleus by using near-field evoked potentials reflects the adaptive properties of auditory nerve fibers..
This study characterized the morphology of octopus cell (OC) somata in the posterior-ventral cochlear nucleus and of synaptic terminals on the OC somata in 8-week-old B6 and B6Cast mice, and the immunolocalization of antibodies to GluR1 (glutamate receptor subunit 1) and GRIP-C (glutamate receptor interacting protein-C terminus).
Whole cell patch recordings in slices show that the probability of firing of action potentials in octopus cells of the ventral cochlear nucleus depends on the dynamic properties of depolarization.
We have examined the temporal discharge patterns of single units from the ventral cochlear nucleus (VCN) of anaesthetized guinea-pigs in response to iterated rippled noise (IRN).
The representation of Schroeder-phase harmonic complex sounds in the ventral cochlear nucleus (VCN) of the anesthetized chinchilla was studied.
Some labelled neurons in the ipsilateral ventral cochlear nucleus were found as a result. The latter show an ultrastructure and axo-somatic profile similar to that of glycinergic commissural neurons in the dorsal and ventral cochlear nucleus. The present study is in accordance with previous tract-tracing light microscopic studies which have indicated that large glycinergic neurons in the ventral cochlear nucleus act as broad-band inhibitory neurons in microcircuits of the dorsal cochlear nucleus and contralateral cochlear nucleus..
The main source of excitation to the ventral cochlear nucleus (VCN) is from glutamatergic auditory nerve afferents, but the VCN is also innervated by two groups of cholinergic efferents from the ventral nucleus of the trapezoid body.
Responses were more diverse than those observed with similar stimuli in a previous study in the ventral cochlear nucleus (Pressnitzer et al., 2000).
We have measured the responses of single units from one of the earliest stages in the ascending auditory pathway, the ventral cochlear nucleus, where across frequency processing may take place.
The terminals are confined to those parts of the GCD immediately surrounding the ventral cochlear nucleus.
Similarities to staining patterns in other mammals included a higher density of serotonergic fibers in the dorsal cochlear nucleus and in granule cell regions than in the ventral cochlear nucleus, a high density of fibers in some periolivary nuclei of the superior olive, and a higher density of fibers in peripheral regions of the inferior colliculus compared with its core.
The type of synaptic terminals from the cochlear nucleus and inferior colliculus that terminate in the contralateral ventral cochlear nucleus are not known. The tracer anterogradely labelled boutons onto the main neurons of the contralateral ventral cochlear nucleus. After injection of the tracer into the contralateral inferior colliculus few anterogradely labelled boutons were seen on spherical and multipolar cells of type II in the anteroventral cochlear nucleus. Rare labelled boutons were present on multipolar cells of type I and II, globular neurons and octopus cells in the posteroventral cochlear nucleus. After injection into the contralateral dorsal and ventral cochlear nucleus labelled boutons were seen more frequently than after injection into the inferior colliculus.
Immunohistochemistry indicates that one or both of the receptor subtypes are expressed in the dorsal raphe, the lateral dorsal tegmental (LDT), the pedunculo pontine (PPT), the locus coeruleus (LC), the locus subcoeruleus, pontis oralis, Barrington's, the trigeminal complex (mesencephalic trigeminal and motor nucleus of the trigeminal nerve), the dorsal tegmental nucleus of Gudden (DTG), the ventral cochlear nucleus (VCA), trapezoid nucleus (TZ), pontine raphe nucleus and the pontine reticular formation.
The discharge patterns of single units in the ventral cochlear nucleus (VCN) of anesthetized guinea pigs were examined in response to iterated rippled noise (IRN) as a function of the IRN delay (which determines the IRN pitch) and the IRN sound level.
In the ventral cochlear nucleus, octopus cells express alpha1, beta3, gamma2L and delta. Both dorsal and ventral cochlear nucleus granule cells express alpha1, alpha6, beta3 and gamma2L; unlike their cerebellar granule cell counterparts, they do not express beta2, gamma2S or the delta subunit genes.
Within the ventral cochlear nucleus, a large fraction of principal cells were immunopositive for both NOS-I and sGCbeta; these cells could be seen at times receiving contacts from NOS-I-positive fibers. Multiple labeling revealed that almost all sGC-positive neurons also accumulated cGMP both in the ventral cochlear nucleus and in the granule cell domain.
Expression of mRNAs encoding ionotropic glutamate receptor subunits such as alpha-amino-3-hydroxy-5-methyl-4-isoxazole (AMPA) and N-methyl-D-aspartate (NMDA), and gamma-aminobutyric acid type A (GABA(A)) receptor subunits was assessed by in situ hybridization in the dorsal (DCN) and the ventral cochlear nucleus (VCN) and in the central nucleus of the inferior colliculus (CNIC).
The expression of mRNAs encoding N-methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazole (AMPA) and gamma-aminobutyric acid type A (GABA(A)) receptor subunits was then studied by in situ hybridization in the dorsal and ventral cochlear nucleus and in the central nucleus of the inferior colliculus (CNIC).
Octopus cells occupy a sharply defined region of the most caudal and dorsal part of the mammalian ventral cochlear nucleus.
This study was conducted to help to establish the feasibility of a multi-channel auditory prosthesis based on microstimulation within the human ventral cochlear nucleus, and to define the range of stimulus parameters that can be used safely with such a device. We chronically implanted activated iridium microelectrodes into the feline ventral cochlear nucleus and, beginning 80-250 days after implantation, they were pulsed for 7 h/day, on up to 21 successive days.
Here we show that an asymmetry also occurs in the physiological responses of most units in the ventral cochlear nucleus to these same sounds. If primary-like units are assumed to reflect the activity in primary auditory nerve fibres, then there is enhancement of temporal asymmetry in the ventral cochlear nucleus by both onset and chopper units..
When cochlear pathology impairs the afferent innervation of the ventral cochlear nucleus (VCN), electrical responses of the auditory brainstem are altered and changes in cell and synaptic morphology are observed.
HCN1 expression is highly enriched in cerebral cortex, hippocampus, cerebellum, and facial motor nucleus; HCN2 is highly abundant in mamillary bodies, pontine nucleus, ventral cochlear nucleus, and nucleus of the trapezoid body; HCN3 expression is most pronounced in supraoptic nucleus of hypothalamus; and HCN4 expression is most abundant in medial habenula and anterior and principal relay nuclei of the thalamus.
To explore the role of PKC in central auditory plasticity, we studied the effect of auditory deafferentation on the expression of PKC betaI, betaII, gamma, and delta in the rat dorsal (DCN) and ventral cochlear nucleus (VCN), using immunocytochemistry.
Tuberculo-ventral neurons of the dorsal cochlear nucleus send isofrequency inhibitory inputs to bushy cells of the ventral cochlear nucleus. Injection of wheat germ agglutinin conjugated to horseradish peroxidase into the rat ventral cochlear nucleus, labelled tuberculo-ventral neurons retrogradely in the deep polymorphic layer of the ipsilateral dorsal cochlear nucleus.
Responses of neurons in the ventral cochlear nucleus (VCN) of anesthetized chinchillas to six synthetic vowel sounds (/a/, /e/, /epsilon/, /i/, /o/ and /u/) were recorded at several intensity levels.
This increase was associated with an up- and downregulation of the mRNA coding for GAP-43 in the ipsilateral ventral cochlear nucleus and in the ipsilateral superior olive, respectively.
By injecting the fluorescent retrograde axonal tracers diamidino yellow and fast blue into the cochlea and the ventral cochlear nucleus (VCN), we studied the distribution and number of olivocochlear neurons with and without axon collaterals into the VCN of the rat.
Granule cells located between the dorsal and ventral cochlear nucleus had moderate expression of alpha 3 and beta subunits and no detectable alpha1 expression.
The changes of the cross-sectional areas of anteroventral cochlear nucleus (AVCN) and posteroventral cochlear nucleus (PVCN) were studied in neonatal and adult guinea pigs after monaural cochlear ablation with computer imaging analysis system.
Terminal labeling after biocytin and BDA injections into the ganglion was found to be most dense in the marginal cell area and secondarily in the magnocellular area of the ventral cochlear nucleus (VCN).
The autoradiographs revealed that the lactate dehydrogenase-1 messenger RNA is highly expressed in a variety of brain structures, including the main olfactory bulb, the piriform cortex, several thalamic and hypothalamic nuclei, the pontine nuclei, the ventral cochlear nucleus, the trigeminal nerve and the solitary tractus nucleus.
We tested two hypotheses to determine whether dorsal cochlear nucleus (DCN) neurons are specialized to derive directionality from spectral notches: DCN neurons exhibit greater spectral-dependent directionality than ventral cochlear nucleus (VCN) neurons, and spectral-dependent directionality depends on response minima (nulls) produced by coincidence of best frequency (BF) and spectral-notch center frequency.
The medium multipolar cells were most common, and resembled the multipolar cells of the mammalian ventral cochlear nucleus.
During this procedure, the ventral cochlear nucleus (VCN) can easily be damaged.
At the same time, calbindin-positive astrocytes emerged in the dorsal and ventral cochlear nucleus.
Bushy, octopus, and T-stellate cells of the ventral cochlear nucleus (VCN) and tuberculoventral cells of the dorsal cochlear nucleus (DCN) receive most of their excitatory input from the auditory nerve; fusiform cells receive excitatory inputs from both the auditory nerve and parallel fibers; cartwheel cells receive excitatory input from parallel fibers alone.
OBJECT: The development of appropriate methods to stimulate the dorsal and ventral cochlear nucleus by means of an auditory brainstem implant in patients with acquired bilateral anacusis requires a detailed topoanatomical knowledge both of the location and extension of the nuclear surface in the fourth ventricle and lateral recess and of its variability. CONCLUSIONS: The midline approach would provide an opportunity to stimulate the whole area of the dorsal as well as the ventral cochlear nucleus with an auditory brainstem implant..
Other axons were thicker, gnarly, less frequently observed and probably originated from the ventral cochlear nucleus.
The weak responses of type II units to broadband stimuli are unusual for neurons in the lower auditory system and suggest that these units receive strong inhibitory inputs, most likely from onset-C neurons of the ventral cochlear nucleus.
The total number of neurons was determined in both the ventral cochlear nucleus (VCN) and the dorsal cochlear nucleus (DCN) to compare the right and left sides.
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. 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..
Intracellular responses of onset chopper neurons in the ventral cochlear nucleus to tones: evidence for dual-component processing. The ventral cochlear nucleus (VCN) contains a heterogeneous collection of cell types reflecting the multiple processing tasks undertaken by this nucleus.
After postoperative intervals of 1 day to 3 months, the cochlear tract was examined by an anterograde tracing method using wheat germ aggulutinin-conjugated horseradish peroxidase (WGA-HRP) injected unilaterally in the ventral cochlear nucleus (VCN) ipsilateral to the lesion.
No significant increase of FLI was observed in the central nucleus of the IC, ventral and dorsal parts of the MGB, dorsal nucleus of the lateral lemniscus, or ventral cochlear nucleus.
Octopus cells of the mammalian ventral cochlear nucleus form a pathway that encodes the timing of firing of groups of auditory nerve fibers with exceptional precision.
Anatomical and electrophysiological specializations for conveying precise timing, including calyceal synaptic terminals and matching axonal conduction times, are evident in several of the major ascending auditory pathways through the ventral cochlear nucleus and its nonmammalian homologues.
CD15 immunoreactivity was first observed in the ventral cochlear nucleus at 10 weeks of gestation, whereas the dorsal cochlear nucleus became positive from 13 weeks of gestation. In many of the auditory pathway structures (e.g., ventral cochlear nucleus and central nucleus of the inferior colliculus), a heterogeneous pattern of CD15 expression in the form of repeating parallel bands, possibly related to tonotopic organization, became transiently apparent around 23 weeks of gestation, whereas in the magnocellular part of the medial geniculate nucleus, a striking modular or compartmental arrangement of immunoreactive structures (which could also be associated with tonotopic organization) was also noted at about 23 weeks of gestation.
NADPH-diaphorase activity also was observed in the lateral and medial superior olive (LSO and MSO, respectively), the superior periolivary nucleus (SPN), the ventral and lateral nuclei of the trapezoid body (VNTB and LNTB, respectively), and the ventral cochlear nucleus (VCN).
In the hindbrain, Fkh5/Mf3 is a longitudinal marker (as opposed to a transverse or rhombomeric one), since it labels nuclei belonging to the somatic afferent zone (ventral cochlear nucleus, cuneate and external cuneate nuclei, principal and spinal nuclei of the trigeminal).
The functionality of such a device is dependent on its ability to access the tonotopic axis of the human ventral cochlear nucleus in an orderly fashion. In anesthetized cats, stimuli were delivered to three or four locations along the dorsal-to-ventral axis of the posteroventral cochlear nucleus (PVCN), and for each stimulus location, we recorded the multiunit neuronal activity and the field potentials at 20 or more locations along the dorsolateral-ventromedial (tonotopic) axis of the IC.
Medium to large-giant multipolar neurons in the rat ventral cochlear nucleus were retrograde labelled after injection of the tracer Wheat Germ Agglutinin conjugated to Horse Radish Peroxidase into the contralateral cochlear nucleus. A little less than the remaining 2/3rds of the whole commissural population in the postero-ventral cochlear nucleus presented a surface which was 65-85% covered with synaptic boutons, among which some also appeared labelled. Spherical bushy cells in the rat anteroventral cochlear nucleus lack the nuclear capping of rough endoplasmic reticulum observed in the cat, and none was labelled after injection into the contralateral cochlear nucleus.
Neurons in the rat ventral cochlear nucleus which project to the inferior colliculus were identified after retrograde labelling of the neural tracer wheat germ agglutinin conjugated to horse radish peroxidase. In the acoustic root area and posterior ventral cochlear nucleus, most of the body surface of the neurons projecting to the inferior colliculus was 10-30% covered by axo-somatic boutons and appeared as multipolar cells of type I. In the anteroventral cochlear nucleus, labelled multipolar type I and II showed similar immunocytological and ultrastructural characteristics to those in the posteroventral cochlear nucleus but their dimension was smaller.
Cell bodies, dendrites, and terminals for all seven labeled cells were restricted to the narrow plane of the superficial granule cell domain over the ventral cochlear nucleus.
Although forward masking occurs in the auditory nerve, that observed in the ventral cochlear nucleus (VCN) more closely resembles psychophysical forward masking.
At approximately the onset of hearing (postnatal day 12-14), some cells of the dorsal cochlear nucleus and small cells of the ventral cochlear nucleus gained adult-like GABA-staining properties. Almost adult-like labelling intensity was observed in glycine-immunoreactive cells of the deep dorsal cochlear nucleus and in some small cells of the ventral cochlear nucleus.
NT3-like immunoreactivity was clearly population-specific, with some cell groups heavily (various small neurons and granule cells) or moderately (large neurons of the ventral cochlear nucleus) stained, while others remained negative (a major fraction of medium and large neurons of the dorsal cochlear nucleus).
Meanwhile, myelinated nerve fiber degeneration in the cochlea extended basally, followed 2 weeks to 2 months later by spread of axonal degeneration into the corresponding high-frequency region of the ventral cochlear nucleus. Axonal degeneration occurred early in the low-frequency region of the ventral cochlear nucleus, followed 2-4 weeks later by spread of myelinated fiber degeneration into more apical regions of the cochlea. New degeneration of axons in the cochlear nerve and in the ventral cochlear nucleus continued to occur for up to 8 months after stimulation.
Glycine plays an important role as an inhibitory neurotransmitter in the ventral cochlear nucleus. The present study examines the kinetics of the native inhibitory glycine receptors in neurons of the ventral cochlear nucleus, using outside-out patches from acutely dissociated cells and a fast flow system.
Single-unit responses were studied in the ventral cochlear nucleus (VCN) of cats as formant and trough features of the vowel /epsilon/ were shifted in the frequency domain to each unit's best frequency (BF; the frequency of greatest sensitivity).
In the ventral cochlear nucleus, synaptophysin-labelled boutons were clearly defined in contact with spherical, globular, multipolar, octopus and cochlear-nerve root neurons.
Responses of the principal unit types in the ventral cochlear nucleus of the chinchilla were studied with a single-formant stimulus set that covered fundamental frequency (f0) from 100 Hz to 200 Hz and formant center frequency (F1) from 256 to 782 Hz.
Robust labeling occurred in the dorsal cochlear nucleus and small cell shell, with less in the ventral cochlear nucleus.
The antero-ventral cochlear nucleus, however, almost doubled in volume after the onset of hearing, reaching a maximum in 4-month-old animals. To further assess which elements contribute to the growth of the antero-ventral cochlear nucleus after the onset of hearing, we analysed the somal size of the neurones. We conclude that the growth of the antero-ventral cochlear nucleus after the onset of hearing is due to changes in the neuropil..
Anterograde and retrograde transport of fluorogold was used to trace input to the superficial granule cell layer of the ventral cochlear nucleus in the guinea pig. Infusion of fluorogold into the labyrinth resulted in heavy labeling of eighth nerve axons and their terminals in the ventral cochlear nucleus, but only a few labeled axons entered the granule cell layer. Labeled neurons were also present in the ipsilateral ventral cochlear nucleus, but this may be due to interruption of axons of passage in the lateral ventrotubercular tract.
Auditory brainstem response thresholds, histopathology [ cytocochleograms for hair cells, the packing density of spiral ganglion cells (SGCs), the number of neurons and overall size of the anterior ventral cochlear nucleus (AVCN)], and behavioral paradigms (prepulse inhibition, fear-potentiated startle) were compared with previous data from C57BL/6J (C57) and DBA/2J (DBA) mouse strains.
The glycinergic interneurons that mediate the series of IPSPs are intrinsic to the ventral cochlear nucleus because long series of IPSPs were recorded from T stellate cells in slices in which the DCN was removed.
We used an in vitro slice preparation of the rat ventral cochlear nucleus to make whole-cell recordings from these cells.
We report that the entire populations of ventral cochlear nucleus bushy and multipolar cells, but not octopus cells, express this peptide in their somata and dendrites. There are many more immunostained neurons in lateral than in medial periolivary cell groups, but their combined numbers are dwarfed by the numbers of immunolabeled cells in the ventral cochlear nucleus. Since ventral cochlear nucleus bushy cells comprise the predominant input to principal nuclei of the superior olive, and the entire bushy cell population is immunolabeled by PEP-19 antiserum, the numbers and distribution of their inputs can be quantified. Thus, this antiserum represents a useful tool for investigating the distribution of ventral cochlear nucleus fibers and synaptic terminals within their target nuclei in the superior olive..
To investigate the potential role of neurotrophins in the mature cochlear nucleus, we determined the expression of the three major neurotrophin tyrosine kinase receptors (Trk) in the adult rat ventral cochlear nucleus, as revealed by antibodies against the full-Trk proteins. The abundant and widespread neuronal distribution of signal-transducing forms of TrkA, TrkB and TrkC predicts that their cognate ligands may exert significant effects on a large proportion of neurons within the mature ventral cochlear nucleus..
Senktide induced increased numbers of Fos-LI neurones in the following brain areas: frontal, parietal and piriform cortex, the lateral septum, the CA1, CA2, subiculum and dentate gyrus of the hippocampus, most areas in the amygdala, thalamus and hypothalamus, medial geniculate nucleus and the ventral cochlear nucleus. Pretreatment with SR142801, but not with SR142806, before administration of senktide inhibited Fos-LI expression in the cingulate cortex, dentate gyrus of the hippocampus, some regions of the thalamus, hypothalamus and amygdala and the ventral cochlear nucleus.
Postnatal development of the gerbil ventral cochlear nucleus (VCN) was studied quantitatively under the light microscope in Nissl-stained serial sections at postnatal day 0 (P0), P5, P7, P10, P12, P15, and P140.
The transcript for the alpha 3-subunit is transiently expressed in the ventral cochlear nucleus (VCN).
Prominent alpha1A hybridization signal was also seen in the neocortex, claustrum, lateral amygdala, ventral cochlear nucleus, raphe magnus, and in the ventral horn of thoracic spinal cord.
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. 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. In contrast, radiate neurons were infrequent, found scattered throughout the ventral cochlear nucleus, and had long dendrites oriented perpendicular to the isofrequency contours.
To investigate the neuronal populations contributing to the ABR under these stimulation conditions, we measured the extracellular responses of ventral cochlear nucleus (VCN) units in the urethane-anaesthetised guinea pig.
In the cochlear nucleus, immunoreactive perineuronal nets were found around a small number of neurons and immunoreactive nerve fibers were scattered in the anterior ventral cochlear nucleus.
Chopper units of the ventral cochlear nucleus (VCN) provide a rare representation of stimulus spectrum and a temporal representation of fundamental frequency (F0).
The goal was to test the model (adapted from cat) that its principal cells (type III and type IV units) receive three sources of shared auditory input: excitatory input from the auditory nerve; inhibitory input from DCN interneurons (vertical cells; type II and type II-i units) that respond vigorously to tones; and inhibitory input from ventral cochlear nucleus principal cells (D-stellate cells; wideband inhibitors) that conversely respond vigorously to noise.
The anteroventral cochlear nucleus on the deprived side was reduced in volume when the deprivation started before the age of 3 months. c-fos expression was also dramatically reduced in the ventral cochlear nucleus, regardless of age at the onset of hearing loss..
The age-related changes in the ventral cochlear nucleus (VCN) as revealed by glial fibrillary acid protein (GFAP) immunoreactivity were analyzed in the following age groups: 3-, 6-, 12-, 18-, and 24-month-old Sprague-Dawley rats.
In the current study, Cat-301 staining is first seen at 7 days after birth in the anterior ventral cochlear nucleus (AVCN), the posterior VCN (PVCN), and the medial nucleus of the trapezoid body (MNTB) shortly before the onset of sound-evoked activity.
The expression of the inducible transcription factors (ITF) c-Fos and JunB was investigated in the dorsal cochlear nucleus (DCN), ventral cochlear nucleus (VCN) and inferior colliculus (IC) of juvenile and adult rats following deprivation and repetitive stimulation paradigms using 8 kHz tone bursts at 5 min duration and 70 dB, 90 dB or 120 dB sound pressure level (SPL).
Following an injection of Phaseolus vulgaris-leucoagglutinin into the ventral cochlear nucleus, most of the axons on the contralateral side and all of the axons on the ipsilateral side are thin.
As in other mammals, the ventral cochlear nucleus contains a few large single-glycine-immunoreactive cells and scattered double-labeled cells.
The cochleotopic pattern of terminal degeneration in the ventral cochlear nucleus correlated with the sites of myelinated fiber and inner-hair-cell loss: this correlation was less rigorous with outer-hair-cell loss, especially in the dorsal cochlear nucleus.
Immunostaining for axonal neurofilaments in an age-graded series of fetal brains demonstrates that a small number of cochlear nerve axons have invaded the ventral cochlear nucleus by the 16th fetal week.
Multipolar cells in the ventral cochlear nucleus are the source of projections to numerous brainstem auditory nuclei, including the contralateral and ipsilateral inferior colliculi and the contralateral cochlear nucleus. Following injections of different tracers into each target, the ventral cochlear nucleus was examined for the presence of cells that contained more than one tracer. The distribution and somatic morphology of cells in the ventral cochlear nucleus that project to each of the three targets were examined. On the basis of these results, we conclude that projections from the ventral cochlear nucleus to the ipsilateral and contralateral inferior colliculi and to the contralateral cochlear nucleus arise in three different populations of multipolar cells..
Also branches of the same cochlear nerve axons projecting to the octopus, stellate, and bushy cells of the ventral cochlear nucleus can use N-methyl-D-aspartate receptor, while their branches to fusiform cells cannot.
-
[ View All ]
