Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Cochlear Nucleus”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,117 records · Page 62Linked to original sources
PubMed1975

[Karyometric studies of the ventral cochlear nucleus in kanamycin treated guinea pigs (author's transl)].

The aim of these investigations was to study the effect of kanamycin on the nucleus ventralis cochleae in guinea pigs. The evaluation of the results was based on the karyometric method which is a very sensitive criterion of the cell activity. In the same animals, the microphonic potential (PM) and the nerve action potential (AP) were measured in order to detect changes in the peripheral auditory system. The results were statistically analysed. The studies showed that despite marked changes in the PM and AP values, there were no changes in the cell volume in the nucleus ventralis cochleae. The findings indicate that the injuries induced by kanamycin are localized peripherally and the later central morphological changes reported in the literature can be assumed to be secondary resulting from the damage to the peripheral auditory system by kanamycin.

Animals↗
PubMed1994

Determination of the position of nucleus cochlear implant electrodes in the inner ear.

Accurate determination of intracochlear electrode position in patients with cochlear implants could provide a basis for detecting migration of the implant and could aid in the selection of stimulation parameters for sound processor programming. New computer algorithms for submillimeter resolution and 3-D reconstruction from spiral computed tomographic (CT) scans now make it possible to accurately determine the position of implanted electrodes within the cochlear canal. The accuracy of these algorithms was tested using an electrode array placed in a phantom model. Measurements of electrode length and interelectrode distance from spiral CT scan reconstructions were in close agreement with those from stereo microscopy. Although apparent electrode width was increased on CT scans due to partial volume averaging, a correction factor was developed for measurements from conventional radiographs and an expanded CT absorption value scale added to detect the presence of platinum electrodes and wires. The length of the cochlear canal was calculated from preoperative spiral CT scans for one patient, and the length of insertion of the electrode array was calculated from her postoperative spiral CT scans. The cross-sectional position of electrodes in relation to the outer bony wall and modiolus was measured and plotted as a function of distance with the electrode width correction applied.

Adult↗
PubMed2004

Alterations in calretinin immunostaining in the ferret superior olivary complex after cochlear ablation.

In this study, we used image analysis to assess changes in calretinin immunoreactivity in the lateral (LSO) and medial (MSO) superior olivary nuclei in ferrets 2 months after unilateral cochlear ablations at 30-40 days of age, soon after hearing onset. These two nuclei are the first significant sites of binaural convergence in the ascending auditory system, and both receive direct projections from the deafferented cochlear nucleus. Cochlear ablation results in a decrease in the overall level of calretinin immunostaining within the LSO ipsilaterally compared with the contralateral side and with control animals and within the MSO bilaterally compared with control ferrets. In addition, the level of calretinin immunostaining ipsilaterally within neurons in the LSO was significantly less in cochlear ablated than control animals. In contrast, there was no effect of cochlear ablation on the level of calretinin immunostaining within neurons either in the contralateral LSO or in the MSO. These results are consistent with a downregulation in calretinin within the neuropil of MSO bilaterally and LSO ipsilaterally, as well as a downregulation in calretinin within somata in the ipsilateral LSO as a result of unilateral cochlear ablation soon after hearing onset. Thus, cochlear-driven activity appears to affect calcium binding protein levels in both neuropil and neurons within the superior olivary complex.

Animals↗
PubMed1997

Brain monoamines and optokinetic performances in pigmented and albino rats.

The aim of this study was two-fold: 1) To provide in DA-HAN rats the basic brain monoamine data useful for later investigations of the neurochemical effects of sensory alterations and 2) to assess whether there is a relationship between the monoaminergic pattern in medial vestibular nuclei and optokinetic performances. We comparatively studied the regional brain monoamine distribution and the optokinetic performances in pigmented DA-HAN and albino Sprague-Dawley rats. As expected, the optokinetic responses and vestibulo-ocular reflex gain were by far more efficient in DA-HAN rats. Norepinephrine (NE), dopamine (DA), serotonin (5-HT) and their metabolites were determined in retina, brainstem nuclei and dopaminergic areas. DA-HAN rats exhibited an increased noradrenergic activity in the medial vestibular nuclei, locus coeruleus and anteroventral cochlear nucleus, an extended decrease of serotonergic activity in brainstem nuclei and increased DA stores with a reduced dopaminergic activity in most dopaminergic areas. These data confirm and extend the general findings that biochemical data obtained in one strain cannot be extrapolated to another strain. The possible role of the morphological neuronal abnormalities and functional impairment induced by albinism has been discussed especially in medial vestibular nucleus, cochlear nuclei and retina. Alternatively, behavioral factors may also explain some of the observed neurochemical differences.

Albinism↗
PubMed1994

Cholinergic neurons in the ventral trapezoid nucleus project to the cochlear nuclei in the rat.

A combination of retrograde axonal tract tracing and choline acetyltransferase immunocytochemistry was used to determine the cells of origin of the cholinergic innervation of the rat cochlear nucleus. The results showed that the cochlear nucleus receives a major cholinergic input from a group of small cells found in the ventral trapezoid nucleus. Experiments using an anterograde tracer confirmed the presence of a neuronal pathway from the ventral trapezoid nucleus to the cochlear nucleus and showed that this pathway travels via the trapezoid body.

Animals↗
PubMed2002

Immunolocalization of PICK1 in the ascending auditory pathways of the adult rat.

Protein that interacts with C-kinase alpha (PICK1) is a PDZ domain protein that interacts with many binding partners in the central nervous system (CNS), including activated protein kinase Calpha and subunits of the AMPA subtype of glutamate receptor. Almost nothing is known about the anatomic distribution of PICK1 in the intact adult CNS. By using PICK1 antisera and peroxidase immunocytochemistry, we report on the distribution of PICK1 in the ascending pathways of the central auditory system of the adult rat. PICK1-immunoreactivity (ir) was observed in many component nuclei of the central auditory system, including the dorsal cochlear nucleus, anteroventral cochlear nucleus, posteroventral cochlear nucleus, some divisions of the superior olivary complex, inferior colliculus, medial geniculate body, and primary auditory cortex. The general staining pattern for PICK1-immunoreactivity was somatodendritic with scattered puncta in neuropil and somatodendritic regions. The distribution of PICK1 partially overlaps with PKCalpha and glutamate receptor subunits such as GluR2. These data suggest that PICK1 may function in the regulation of PKCalpha and GluR2 localization in components of the rat auditory system, which may be a fundamental mechanism of synaptic transmission and/or plasticity. J. Comp. Neurol.

Animals↗
PubMed1994

mu-Opioid receptor mRNA expression in the rat CNS: comparison to mu-receptor binding.

The distribution of cells expressing mu-receptor mRNA and mu-receptor binding sites were compared in brain and spinal cord tissue sections using a combination of in situ hybridization and receptor autoradiographic techniques. mu-Receptor mRNA was visualized with a 35S-labeled cRNA probe directed to transmembrane III-VI of the rat mu-receptor, while mu-receptor binding sites were labeled with the mu-selective ligand [3H]DAMGO. A high correspondence between the mu-receptor mRNA and receptor binding distributions was observed in the nucleus of the accessory olfactory bulb, anterior olfactory nuclei, striatal patches of the nucleus accumbens and caudate-putamen, endopiriform nucleus, claustrum, diagonal band of Broca, globus pallidus, ventral pallidum, bed nucleus of stria terminalis, most thalamic nuclei, medial and posteriocortical medial amygdala, lateral, dorsomedial, posterior and mammillary nuclei of the hypothalamus, presubiculum, subiculum, rostral interpeduncular nucleus, median raphe, inferior colliculus, parabrachial nucleus, locus coeruleus, central grey, nucleus ambiguus, nucleus of the solitary tract, nucleus gracilis, nucleus cuneatus, and the dorsal motor nucleus of vagus. Differences in mu-receptor mRNA and receptor binding distributions were observed in several regions, including the olfactory bulb, cortex, hippocampus, superior colliculus, spinal trigeminal nucleus, cochlear nucleus and spinal cord, and may be due to mu-receptor transport to presynaptic terminals.

Animals↗
PubMedDate not supplied

Calcitonin gene-related peptide: detailed immunohistochemical distribution in the central nervous system.

With the use of an antiserum generated in rabbits against synthetic human calcitonin gene-related peptide (CGRP) the distribution of CGRP-like immunoreactive cell bodies and nerve fibers was studied in the rat central nervous system. A detailed stereotaxic atlas of CGRP-like neurons was prepared. CGRP-like immunoreactivity was widely distributed in the rat central nervous system. CGRP positive cell bodies were observed in the preoptic area and hypothalamus (medial preoptic, periventricular, anterior hypothalamic nuclei, perifornical area, medial forebrain bundle), premamillary nucleus, amygdala medialis, hippocampus and dentate gyrus, central gray and the ventromedial nucleus of the thalamus. In the midbrain a large cluster of cells was contained in the peripeduncular area ventral to the medial geniculate body. In the hindbrain cholinergic motor nuclei (III, IV, V, VI, VII XII) contained CGRP-immunoreactivity. Cell bodies were also observed in the ventral tegmental nucleus, the parabrachial nuclei, superior olive and nucleus ambiguus. The ventral horn cells of the spinal cord, the trigeminal and dorsal root ganglia also contained CGRP-immunoreactivity. Dense accumulations of fibers were observed in the amydala centralis, caudal portion of the caudate putamen, sensory trigeminal area, substantia gelatinosa, dorsal horn of the spinal cord (laminae I and II). Other areas containing CGRP-immunoreactive fibers are the septal area, nucleus of the stria terminalis, preoptic and hypothalamic nuclei (e.g., medial preoptic, periventricular, dorsomedial, median eminence), medial forebrain bundle, central gray, medial geniculate body, peripeduncular area, interpeduncular nucleus, cochlear nucleus, parabrachial nuclei, superior olive, nucleus tractus solitarii, and in the confines of clusters of cell bodies. Some fibers were also noted in the anterior and posterior pituitary and the sensory ganglia. As with other newly described brain neuropeptides it can only be conjectured that CGRP has a neuroregulatory action on a variety of functions throughout the brain and spinal cord.

Animals↗
PubMed2004

Reactive astrocytes express PARP in the central nervous system of SOD(G93A) transgenic mice.

In the present study, we used the transgenic mice expressing a human Cu/Zn SOD mutation (SOD1(G93A)) as an in vivo model of amyotrophic lateral sclerosis (ALS) and performed immunohistochemical studies to investigate the changes of poly(ADP-ribose) polymerase (PARP) in the central nervous system. In the spinal cord of symptomatic transgenic mice, immunohistochemistry showed intensely stained PARP-immunoreactive glial cells with the appearance of astrocytes, which were confirmed as astrocytes by double-immunofluorescences. In the brainstem and cerebellum, PARP-immunoreactive astrocytes were observed in the medullary and pontine reticular formation, hypoglossal nucleus, vestibular nucleus, cochlear nucleus and cerebellar nuclei. On the contrary, no PARP-immunoreactive glial cells were observed in control mice although PARP-immunoreactive motor neurons were found. In presymptomatic transgenic mice, a few moderately stained neurons were observed, whereas PARP-immunoreactive astrocytes were not detected. The present study provides the first evidence that PARP-immunoreactive astrocytes were found in the central nervous system of symptomatic SOD1(G93A) transgenic mice, suggesting that reactive astrocytes may play an important role in the pathogenesis and progress of ALS.

Animals↗