Approximately 20-30% of neurons in the chick cochlear nucleus, Nucleus magnocellularis (NM) die following deafferentation (i.e. 
In the avian brainstem, Nucleus magnocellularis (NM) projects bilaterally to nucleus laminaris (NL) in a pathway that facilitates sound localization.
Approximately 20-30% of neurons in the avian cochlear nucleus, Nucleus magnocellularis (NM) die following deafferentation (i.e., deafness produced by cochlea removal).
Mid-line injections resulted in stable labelling of neurons of the Nucleus magnocellularis (NM), whereas injections into the SON retrogradely labelled neurons of the nucleus laminaris (NL).
All five NMDA subunits were expressed in the auditory brainstem before embryonic day (E) 10, when electrical activity and synaptic responses appear in the Nucleus magnocellularis (NM) and the nucleus laminaris (NL).
Primary cultures of neurons from Nucleus magnocellularis and nucleus laminaris were prepared from embryonic day 6.5 chicken.
Mature Nucleus magnocellularis (NM) neurons, the avian homolog of bushy cells of the mammalian anteroventral cochlear nucleus, maintain high [ Cl-]i and depolarize in response to GABA.
The development of synaptic function was examined at auditory nerve synapses in the rostromedial region of the cochlear Nucleus magnocellularis of the chick.
GABAergic transmission in the avian cochlear Nucleus magnocellularis (NM) of the chick is subject to modulation by gamma-aminobutyric acid type B (GABA(B)) autoreceptors.
One population was situated within the nucleus reticularis gigantocellularis (NRGc) and Nucleus magnocellularis (Mc) in the rostro-ventral medulla; this group of neurons extended caudally to the ventral portion of the nucleus paramedianus reticularis (nPR).
In the avian auditory system, the neural network for computing the localization of sound in space begins with bilateral innervation of nucleus laminaris (NL) by Nucleus magnocellularis (NM) neurons.
In the medulla of 7- and 8-day embryos, we identified four response areas, corresponding to ipsilateral Nucleus magnocellularis (NM) and Nucleus angularis (NA), which receive the auditory afferents, and ipsi- and contralateral Nucleus laminaris (NL), which receive projections from NM.
Nucleus magnocellularis (NM) is one of the subnuclei of the avian cochlear nucleus and has a role of extracting the temporal information of sound from the auditory nerve fibers (ANFs).
Labeling in the cochlear nucleus, Nucleus magnocellularis, on opposite sides of the same tissue sections were compared by densitometry. The results showed a dramatic increase in reactive oxygen species in the deafferented Nucleus magnocellularis by 6 h following cochlea removal.
Its b-isoform is found in Nucleus magnocellularis, which receives the cochlear input, both before and after the establishment of synaptic connections. We show here that this subunit translocates from the perinuclear cytoplasm to the cell membrane domain in Nucleus magnocellularis at the time that cochlear nerve endings emerge as endbulbs of Held (E17).
The NL and Nucleus magnocellularis (NM) neurons were strongly immunoreactive for parvalbumin, a calcium-binding protein.
Approximately 20-30% of neurons in the avian cochlear nucleus (Nucleus magnocellularis) die following deafferentation (i.e. Five days following surgery, the Nucleus magnocellularis neurons were counted stereologically on opposite sides of the same brains. Chronic administration of lithium dramatically increased the expression of bcl-2 protein in Nucleus magnocellularis neurons.
The ipsilateral feedback circuits allow Mn2+ to reach all main Song Control Nuclei after stereotaxic injection of very small doses of MnCl2 (10 nl of 10 mM) into HVC of one and MAN (Nucleus magnocellularis nidopallii anterioris) of the other hemisphere.
Avian Nucleus magnocellularis (NM) spikes provide a temporal code representing sound arrival times to downstream neurons that compute sound source location.
The contralateral projection from the cochlear nucleus, Nucleus magnocellularis (NM), to nucleus laminaris (NL) forms a delay line as it proceeds from medial to lateral across NL.
Nucleus magnocellularis (NM), nucleus angularis (NA), and nucleus laminaris (NL), second- and third-order auditory neurons in the avian brainstem, receive GABAergic input primarily from the superior olivary nucleus (SON).
Previously we reported morphological effects of prenatal auditory stimulation by species-specific and sitar musical sounds on the chick brainstem auditory nuclei-Nucleus magnocellularis and nucleus laminaris.
In the chicken auditory system, cochlear nucleus (Nucleus magnocellularis, NM) neurons receive their only excitatory input from the ipsilateral cochlea.
Extensive naturally occurring cochlear damage is found in some aged chickens, despite their regenerative capacity, providing the opportunity to examine the effects of this type of deafferentation on the avian cochlear nucleus (Nucleus magnocellularis, NM).
Premotor trigeminal as well as premotor hypoglossal neurons were located in the ventro-medial medullary reticular formation in a region corresponding to the Nucleus magnocellularis (Mc) and the ventral aspect of the nucleus reticularis gigantocellularis (NRGc).
One possible exception to this parallel organization is the inhibitory input provided by the superior olivary nucleus (SON) to nucleus angularis (NA), Nucleus magnocellularis (NM), and nucleus laminaris (NL) and contralateral SON (SONc).
Neurons of Nucleus magnocellularis (NM), a division of avian cochlear nucleus that performs precise temporal encoding, receive glutamatergic excitatory input solely from the eighth nerve and GABAergic inhibitory input primarily from the ipsilateral superior olivary nucleus.
To understand the cellular mechanism of response to prenatal auditory stimulation, we studied the expression of c-Fos and c-Jun in brainstem auditory nuclei, Nucleus magnocellularis, and nucleus laminaris of the domestic chick.
Using whole cell patch-clamp recordings, we pharmacologically characterized the voltage-gated Ca2+ channel (VGCC) currents of chicken Nucleus magnocellularis (NM) neurons using barium as the charge carrier.
Recent work examining the effects of age and cochlear degeneration on avian cochlear nucleus (Nucleus magnocellularis, NM) metabolism showed that changes in metabolic activity occur with age and cochlear damage [ Hear.
Nucleus magnocellularis (NM) is a division of the avian cochlear nucleus that extracts the timing of auditory signals.
Elimination of eighth-nerve activity results in the death of 30% of the neurons in the chick cochlear nucleus, Nucleus magnocellularis (NM).
In the chick, the auditory nerve transmits auditory information from the cochlea to Nucleus magnocellularis (NM).
SPO mRNA was found in moderate levels in the HVC, in low levels in the lateral Nucleus magnocellularis (lMAN) and Area X, and was absent in the RA.
NR1-ir first appeared in the Nucleus magnocellularis (NM) and nucleus laminaris (NL) at E10.
Specificity is exemplified at cellular and subcellular levels in the chick auditory brainstem, where Nucleus magnocellularis (NM) neurons project bilaterally to nucleus laminaris (NL).
Unilateral removal of the avian cochlea leads to rapid and dramatic reduction in the expression of both proteins in the Nucleus magnocellularis (NM; a division of the avian cochlear nucleus) neurons as detected by immunocytochemistry.
This series of experiments examined the arrival and organization of cochlear nerve axons in the primary auditory brainstem nucleus, Nucleus magnocellularis (NM), of the chick.
We examined the effects of temperature on acuity of coincidence detection in chick NL, by utilizing whole-cell and cell-attached recording techniques in brain slices while applying electrical stimuli bilaterally to axonal projections from the Nucleus magnocellularis to NL.
During development, a subpopulation (approximately 30%) of neurons in the avian cochlear nucleus, Nucleus magnocellularis (NM), dies following removal of the cochlea.
KCNC1b specific staining has a late onset with immunostaining first appearing in the regions that map high frequencies in Nucleus magnocellularis (NM) and nucleus laminaris (NL).
Neurons in the avian cochlear nucleus, Nucleus magnocellularis (NM), are highly sensitive to manipulations of afferent input, and removal of afferent activity through cochlear ablation results in the death of approximately 20-40% of ipsilateral NM neurons.
Cell number counts of the visual Nucleus isthmi (Ni) versus the vestibular Nucleus magnocellularis (Nm) revealed that in experimental animals total cell number was decreased in the Ni, possibly due to retarded growth as a result of the lack of visual input whereas no effect was observed in the Nm.
Synapse counting was undertaken by conventional electron microscopy in primary vestibular integration centers (i.e., Nucleus descendens, Nd, and Nucleus magnocellularis, Nm, of the brainstem Area octavolateralis) and in the diencephalic visual Nucleus corticalis (Nc) of spaceflown neonate swordtail fish Xiphophorus helleri as well as in 1 g control siblings.
Then, the metabolic activity of cochlear nucleus (Nucleus magnocellularis, NM) neurons in 15-19, 30, 39, 40, and 65-66 week old broiler chickens was examined using cytochrome oxidase histochemistry and compared to the degree of cochlear abnormality.
Here we have examined a specific case of how synaptic plasticity can affect temporal coincidence detection, by experimentally characterizing synaptic depression at the synapse between neurons in the Nucleus magnocellularis and coincidence detection neurons in the nucleus laminaris in the chick auditory brainstem.
We have determined the consequence of increased auditory stimulation on the developmental profile of synaptic proteins, synaptophysin and syntaxin 1, in the chick brainstem auditory nuclei, Nucleus magnocellularis and nucleus laminaris, by immunohistochemistry and western blotting techniques. During normal synaptogenesis of Nucleus magnocellularis and nucleus laminaris, synaptophysin immunoreactivity increased significantly from E8 to E20, in parallel with synapse formation, and reduced at hatching.
Brainstem auditory neurons in chicken Nucleus magnocellularis (NM), which receive their sole excitatory afferent input from the cochlea, were examined for evidence of mitosis during ototoxin-induced loss and regeneration of cochlear hair cells.
We used mRNA analysis and immunoblotting to contrast the development of AMPA receptor structure in the chick cochlear nucleus [ Nucleus magnocellularis (NM)] with that of the slowly desensitizing and calcium-impermeable AMPA receptors of brainstem motor neurons in the nucleus of the glossopharyngeal/vagal nerves.
Nucleus magnocellularis (NM) in the avian auditory brainstem receives auditory input from nerve the VIIIth and projects bilaterally to nucleus laminaris (NL).
In this study, we examined cell number and size, and volume of auditory nuclei, specifically in Nucleus magnocellularis and nucleus laminaris in Belgian Waterslager canaries.
In the posthatch chick, approximately 30% of the neurons in the avian cochlear nucleus, Nucleus magnocellularis (NM) die following elimination of VIIIth nerve activity.
Ghrelin immunoreactivity was also present in clusters of large ovoid magnocellular cells in the Nucleus magnocellularis preopticus pars medialis, Nucleus magnocellularis preopticus supraopticus and in the chiasmaopticus.
OBJECTIVE: To determine whether cholinergic neurons in the basal Nucleus magnocellularis (NBM) and the medial septum are affected in transgenic mice overexpressing human amyloid precursor protein 770 (APP770).
Neurons of the avian Nucleus magnocellularis transmit phase-locked action potentials of the auditory nerve in a pathway that contributes to sound localization based on interaural timing differences. Together, these factors improve the ability of cochlear Nucleus magnocellularis neurons to faithfully transmit timing information encoded by the auditory nerve..
Since chick cochlear nucleus neurons depend upon synaptic activation of metabotropic glutamate receptors (mGluRs) for maintenance and survival, the goal of this study was to determine (1) if zinc is released from the eighth nerve calyces onto Nucleus magnocellularis (NM) neurons in the chick cochlear nucleus, and, if so, (2) what effect it has on group I mGluR-mediated calcium homeostasis of these neurons.
Focal injections of horseradish peroxidase or neurobiotin were placed either in the NA or in the cochlear Nucleus magnocellularis, labeling small groups of auditory nerve fibers of known characteristic frequency (CF) from 0.25 to 9.6 kHz.
Neurons of the chick Nucleus magnocellularis (NM) receive depolarizing GABAergic input from the superior olivary nucleus (SON).
Transmission at the end-bulb synapse formed by auditory nerve terminals onto the soma of neurons in the avian Nucleus magnocellularis is characterized by high transmitter release probability and strong synaptic depression.
Positive end-bulbs made contact on somata in the Nucleus magnocellularis cochlearis.
In both barn owls and chickens, Kv3.1 mRNA was expressed in the cochlear Nucleus magnocellularis (NM) and the nucleus laminaris (NL).
In the avian auditory brainstem, Nucleus magnocellularis (NM) functions to relay phase-locked signals to nucleus laminaris for binaural coincidence detection.
NA forms a column of cells in the dorsolateral brainstem that partly overlaps with, and is rostral and lateral to, the cochlear Nucleus magnocellularis (NM).
nucleus descendens and Nucleus magnocellularis of the brainstem area octavolateralis) and in the diencephalic visual nucleus corticalis of spaceflown neonate swordtail fish Xiphophorus helleri as well as in 1 g control siblings. No effect of microg, however, was observed in the visual nucleus corticalis and in the vestibular Nucleus magnocellularis which is situated in the close vicinity of the nucleus descendens. In contrast to the latter, the Nucleus magnocellularis does not receive exclusively vestibular input, but inputs from the lateral line as well, possibly providing sufficient input at microgravity..
axonal degeneration on gliosis, the current study examines the astrocyte response to cochlea removal in two different breeds of adult chickens, one of which exhibits neuronal cell death within the brainstem Nucleus magnocellularis (NM) following the lesion and one which does not.
The avian auditory brainstem nuclei Nucleus magnocellularis (NM) and nucleus laminaris (NL) display highly precise patterns of neuronal connectivity.
Nucleus magnocellularis (NM) and nucleus angularis receive tonotopically ordered cochlear input.
The expression of the calcium-binding protein calretinin (CR) in the chick cochlear nucleus, Nucleus magnocellularis (NM), was examined after unilateral cochlea removal in hatchlings and 3-week-old birds.
After synapse formation in the avian Nucleus magnocellularis (nMag) in vivo, the rate of receptor desensitization increased threefold, sensitivity to channel block by polyamines increased, and sensitivity to cyclothiazide, an inhibitor of desensitization, increased, indicating a reduction in glutamate receptor subunit 2 and of flip splice variants.
Following cochlea removal, there is a marked increase within the auditory brainstem nucleus, Nucleus magnocellularis (NM), in both in the number of SHP-1-positive astrocytes and the length of their immunopositive fibers.
Neurons of the chick cochlear nucleus, Nucleus magnocellularis (NM), require eighth nerve activation of metabotropic glutamate receptors (mGluRs) for maintenance of intracellular calcium homeostasis.
Brainstem auditory neurons in the chick Nucleus magnocellularis (NM) express high levels of the neuron-specific calcium-binding protein calretinin (CR).
The results indicate that the AMPA receptors of the cochlear ganglion, Nucleus magnocellularis and nucleus laminaris share a number of structural and functional properties that distinguish them from the AMPA receptors of brainstem motor neurons, namely a lower relative abundance of glutamate receptor (GluR)2 transcript and much lower levels of GluR2 immunoreactivity, higher relative levels of GluR3 flop and GluR4 flop, lower relative abundance of the C-terminal splice variants GluR4c and 4d, less R/G editing of GluR2 and 3, greater permeability to calcium, predominantly inwardly rectifying I-V relationships, and greater susceptibility to block by Joro spider toxin.
The role of glutamate transporters in the regulation of synaptic depression was examined in the avian Nucleus magnocellularis.
The pigeon cochlear nucleus angularis (NA) and Nucleus magnocellularis (NM) were analyzed with Golgi and Nissl techniques.
We have investigated the developmental appearance of potassium currents in cell cultures from Nucleus magnocellularis and its precursor neuroblasts from the acoustico-vestibular anlage of the chicken. These findings suggest that the Shaw subfamily of channels in Nucleus magnocellularis may be involved in early neuronal development, as well as in synaptic function later on..
In the hindbrain, CR-IR was first observed in the rostromedial regions of the cochlear Nucleus magnocellularis and the nucleus laminaris, and in the dorsal regions of the nucleus angularis and in the nucleus of the lateral lemniscus.
This region, which encompasses the ventral portion of the nucleus reticularis gigantocellularis and the Nucleus magnocellularis, corresponds to the rostral portion of the classic inhibitory region of.
During early brainstem development, trkB and trkC are localized in the neuronal cell bodies and in the surrounding neuropil of Nucleus magnocellularis (NM) and nucleus laminaris (NL).
Stimulation of the Nucleus magnocellularis (NMC) of the medulla produces changes in locomotion, muscle tone, heart rate, and blood pressure.
Neurons of the avian cochlear nucleus, Nucleus magnocellularis (NM), are activated by glutamate released from auditory nerve terminals.
Located in the ventrolateral region of the avian brainstem, the superior olivary nucleus (SON) receives inputs from nucleus angularis (NA) and nucleus laminaris (NL) and projects back to NA, NL, and Nucleus magnocellularis (NM).
Age-dependent neuronal cell death and shrinkage has been documented in second order auditory neurons in the chick brainstem (Nucleus magnocellularis, NM) following cochlea removal (Born and Rubel, 1985.
Second-order auditory neurons in Nucleus magnocellularis (NM) are sensitive to changes in input from the cochlea.
Characterization of outward currents in neurons of the avian Nucleus magnocellularis. Neurons of the Nucleus magnocellularis (NM) preserve the timing of auditory signals through the convergence of a variety of voltage- and ligand-gated ion channels.
Elimination of auditory nerve activity results in atrophy and death of Nucleus magnocellularis (NM) neurons in the chick.
NL not only receives excitatory projections from the ipsi- and contralateral Nucleus magnocellularis, but also receives inhibitory (GABAergic) input.
Neurons of the avian cochlear nucleus, Nucleus magnocellularis (NM), are stimulated by glutamate, released from the auditory nerve, and GABA, released from both interneurons surrounding NM and from cells located in the superior olivary nucleus.
AMPA receptor specific antibodies were used to study the distribution and development of glutamate receptor subtypes (GluR1-4) in Nucleus magnocellularis, angularis, laminaris, and the superior olive of the barn owl.
Neurons of the cochlear nucleus, Nucleus magnocellularis (NM), of young chicks require excitatory afferent input from the eighth nerve for maintenance and survival.
The novel discovery that auditory nerve terminals in the chick cochlear Nucleus magnocellularis (NM) are immunoreactive for the opioid peptide dynorphin (DYN) was recently reported [ 3].
Anatomical studies and stimulation studies in the decerebrate animal have suggested that the muscle atonia of rapid eye movement (REM) sleep is mediated by a projection from cholinoceptive glutamatergic neurons in the pons to the Nucleus magnocellularis (NMC) of medulla.
Anatomical studies and stimulation studies in the decerebrate animal have suggested that the muscle atonia of rapid eye movement (REM) sleep is mediated by a projection from cholinoceptive glutamatergic neurons in the pons to the Nucleus magnocellularis (NMC) of medulla.
The present investigation considered the effects of cochlear damage caused by exposure to intense sound on the Nucleus magnocellularis of the chick. The brain stem region containing the Nucleus magnocellularis (NM) was serially sectioned in the coronal plane.
In the chicken brainstem cochlear nucleus, the Nucleus magnocellularis (NM), deprivation of auditory input via unilateral cochlea removal or silencing the eighth nerve with tetrodotoxin leads to a loss of 25-30% of the neurons and the atrophy of surviving neurons.
The role of mitochondria and the endoplasmic reticulum in buffering [ Ca2+]i in response to imposed calcium loads in neurons of the chick cochlear nucleus, Nucleus magnocellularis (NM), was examined.
The octavolateralis area of Dorosoma is composed of the nuclei that have been observed in other teleosts: nucleus medialis, the descending and anterior octaval nuclei, Nucleus magnocellularis, nucleus tangentialis, and a caudal granular-cell region that likely represents nucleus caudalis and the posterior octaval nucleus.
These results demonstrate that stereotactic recordings of field potentials from the Nucleus magnocellularis/angularis region are a suitable alternative to reliably monitor the condition of the inner ear when round window electrodes cannot be used..
CNQX, given from E8 to E15 or only from E8 to E10, also blocked the 33% neuronal loss in the Nucleus magnocellularis (NM) that follows surgical destruction of the otocyst on E3, a procedure that deafferents NM neurons by preventing formation of the cochlear nerve.
Neurons in Nucleus magnocellularis (NM) and nucleus laminaris (NL) of the chick brainstem auditory system show an unusual physiological response to GABA.
In the cochlear nucleus angularis (NA) and Nucleus magnocellularis (NM), 30% to 40% of the neurons die after otocyst removal, the survivors are shrunken, and some neurons in the NA migrate to an abnormal position in the brain stem.
For direct comparison in the same individuals, recordings were also obtained from the relevant next higher center, the Nucleus magnocellularis (NM).
Elimination of auditory nerve activity results in death and atrophy of neurons in the cochlear nucleus, Nucleus magnocellularis (NM), of the chick.
The cytology of the Nucleus magnocellularis and the nucleus laminaris in the barn owl, as well as the axonal pathways connecting them, were studied. The Nucleus magnocellularis contains a distinct stellate cell type in the low-frequency region, in addition to neurons classified as a small version of the principal cell. The low-frequency projections from the Nucleus magnocellularis showed two terminal fields in the nucleus laminaris: one containing a rough tonotopic representation and a second one where all low-frequency projections converged.
In the auditory brainstem, levels of GluR2/3 and GluR4 were very high in the cochlear Nucleus magnocellularis and the nucleus laminaris.
Previous studies in our laboratory have demonstrated that microinjection of N-methyl-D-aspartate (NMDA) agonist into the Nucleus magnocellularis (NMC) of the medial medulla increases muscle tone and/or produces locomotion, while injection of corticotropin-releasing factor (CRF) and non-NMDA agonists into the same or nearby sites suppresses muscle tone.
Auditory nerve and Nucleus magnocellularis units were distinguished by physiological criteria, with the use of the response latency to clicks, the spontaneous discharge rate, and the pattern of characteristic frequencies encountered along an electrode track. The response latency to click stimulation decreased in a logarithmic fashion with increasing characteristic frequency for both auditory nerve and Nucleus magnocellularis units. Average spontaneous rate was 72.2 spikes/s in the auditory nerve and 219.4 spikes/s for Nucleus magnocellularis. This large difference, together with the known properties of endbulb-of-Held synapses, suggests a convergence of approximately 2-4 auditory nerve fibers onto one Nucleus magnocellularis neuron. Some auditory nerve fibers as well as Nucleus magnocellularis units showed a quasiperiodic spontaneous discharge with preferred intervals in the time-interval histogram.
A detailed analysis of the binding capacity for [ 125I]CLO was performed for parts of several functional systems: hypothalamic structures (nucleus inferior hypothalami, Nucleus magnocellularis preopticus, nucleus paraventricularis), limbic system (habenula, nucleus septalis lateralis, nucleus striae terminalis), circumventricular organs (organum pineale, organum subfornicale, plexus choroidei ventriculi tertii and ventriculi lateralis), visual system (hyperstriatum accessorium, nucleus reticularis superior, tectum opticum), and associative cortex (hyperstriatum ventrale).
This regulation involves the construction and growth of song control structures: the high vocal center (HVC), nucleus robustus archistrialis (RA), Nucleus magnocellularis anterior (MAN), and Area X.
Neurons in the cochlear nucleus, Nucleus magnocellularis (NM), of embryonic and neonatal chicks are dependent on eighth nerve activity for their maintenance and survival.
We have found changes in postsynaptic AMPA receptor sensitivity in neurons of the chick cochlear nucleus, the Nucleus magnocellularis (nMAG), by photolysis of caged glutamate immediately after activation of a single synaptic input.
DYN-I, however, was especially prominent in the cochlear Nucleus magnocellularis (NM).
The part of the rhombic lip that forms Nucleus magnocellularis (homologue of the mammalian anteroventral cochlear nucleus) was explanted from white leghorn chicken embryos at Hamburger-Hamilton stage 28 (E5.5), the time when precursors of the magnocellularis bushy cells migrate and begin to differentiate in situ.
By using a brain slice preparation, neurons in the chick Nucleus magnocellularis (nMAG) were voltage clamped and individual presynaptic axons were stimulated to evoke excitatory postsynaptic currents (EPSCs).
120:463-473) reported finding a projection of lagenar fibers to parts of the cochlear nuclei (Nucleus magnocellularis and nucleus angularis).
We have used Golgi and ultrastructural techniques to analyze the development of the connections and cell types of the Nucleus magnocellularis (NM) and the nucleus laminaris (NL) with reference to the growth of the head.
Avian cochlear neurons of the Nucleus magnocellularis (NMC) are known to encode temporal information of sound.
Following cochlea removal in developing chicks, about 30% of the neurons in the ipsilateral second-order auditory nucleus, Nucleus magnocellularis, undergo cell death. In this study, we examined whether the chloramphenicol enhancement of deafferentation-induced cell death reveals the same ultrastructural characteristics that are seen in degenerating Nucleus magnocellularis neurons after cochlea removal alone. Two ultrastructurally different types of neuronal degeneration were observed in the deafferented Nucleus magnocellularis neurons: an early onset electron-lucent type that always involved ribosomal dissociation and a late-onset electron-dense type displaying nuclear pyknosis and severely damaged mitochondria. The percentage of Nucleus magnocellularis neurons displaying ribosomal disintegration following cochlea removal was found to be markedly increased after chloramphenicol treatment.
The part of the rhombic lip that forms Nucleus magnocellularis (homologue of the mammalian anteroventral cochlear nucleus) was explanted from white leghorn chicken embryos at Hamburger-Hamilton stage 28 (E5.5), the time when precursors of the magnocellularis bushy cells migrate and begin to differentiate in situ.
Computer-controlled intracellular current injection was used to mimic postsynaptic currents or conductances (PSCs) generated in NL neurons by the firing of Nucleus magnocellularis (NM) neurons during acoustic stimulation.
The mitochondrial enzyme, cytochrome oxidase, was localized cytochemically in the Nucleus magnocellularis, a primary relay nucleus of vestibular information within the area octavolateralis in the fish brain.
Neurons in Nucleus magnocellularis (NM) and nucleus laminaris (NL), second and third order auditory nuclei, discharge spontaneously in synchronous bursts at periodic intervals.
We have examined the mechanisms underlying the voltage sensitivity of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptors in voltage-clamped outside-out patches and whole cells taken from the Nucleus magnocellularis of the chick.
Ratiometric fura-2 imaging was used to measure the intracellular calcium concentration ([ Ca2+]i) of neurons in the embryonic avian cochlear nucleus, Nucleus magnocellularis (NM), after an in ovo unilateral cochlea removal (deafferentation).
Removal or blockade of nerve VIII input results in the death of 20-40% of neurons in the cochlear nucleus, Nucleus magnocellularis (NM), of the 10-14 days posthatch chick.
As regards the cochlear nuclei, we found that nucleus angularis derives from r3 to r6, nucleus laminaris from r5 to r6, Nucleus magnocellularis from r6 to r7 and nucleus olivaris superior from r5.
Nucleus magnocellularis medialis consists of a homogeneous population of neurons called "lesser ovoid" cells. Nucleus magnocellularis lateralis consists of "greater ovoid" and "small" cells. In Nucleus magnocellularis medialis and nucleus angularis medialis, primary afferents form both chemical and electrical synapses with resident neurons.
Loss of afferent innervation via unilateral cochlea removal results in the death of 20-40% of neurons in the neonatal chick cochlear nucleus, Nucleus magnocellularis (NM).
The auditory nerve serves as the only excitatory input to neurons in the avian cochlear nucleus, Nucleus magnocellularis (NM).
Higher resonant frequencies tended to predominate at relatively lower stations in the auditory pathway (approximately 100 Hz in the Nucleus magnocellularis, 24 Hz in the nucleus laminaris, 6 Hz in the nucleus ovoidalis).
Elimination of auditory nerve activity results in rapid metabolic changes, cell atrophy, and cell death in Nucleus magnocellularis (NM), the cochlear nucleus of the chick.
Anterogradely labelled axon terminals were found in the ipsilateral Nucleus magnocellularis, the contralateral intermediate nucleus of the lateral lemniscus, and the shell portion of the central nucleus of the inferior colliculus.
The permeability of AMPA (alpha-amino-3-hydroxy-5-methyl-4- isoxazolepropionate) receptors in the chick cochlear nucleus, the Nucleus magnocellularis (nMAG), was examined by measuring the shift in reversal potential (Erev) of current through glutamate or neurotransmitter-gated channels in solutions of different ionic composition.
We have examined responses of AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate) receptors in the chick Nucleus magnocellularis to pairs of pulses of glutamate and determined the extent of desensitization and the rate of recovery.
We assessed the effect a sound-induced cochlear lesion had on the tonotopic organization of the Nucleus magnocellularis (NM) immediately after acoustic overexposure and following a twelve day recovery period.
In addition, the penetration angle permitted recordings from units in both cochlear nuclei, Nucleus magnocellularis and nucleus angularis (probably mostly cochlear afferents), in the same animal.
Some of these terminals originate from cells surrounding Nucleus magnocellularis.
Astrocytes in Nucleus magnocellularis (NM) of the chick respond to afferent activity blockade with increased immunoreactivity for glial fibrillary acidic protein (GFAP).
The properties of evoked excitatory postsynaptic currents (EPSCs) and spontaneous miniature excitatory postsynaptic currents (mEPSCs) have been studied in neurons of the Nucleus magnocellularis (nMAG), one of the avian cochlear nuclei which receive somatic, calyceal innervation from auditory nerve fibres.
HVc received projections from medial Nucleus magnocellularis of the anterior neostriatum, nucleus interfacialis of midneostriatum, telencephalic auditory nucleus-field L, nucleus uvaeformis of the thalamus, and locus ceruleus of the pons.
Neurons of the avian Nucleus magnocellularis (NM) relay auditory information from the VIIIth nerve to other parts of the auditory system.
We have previously demonstrated rapid increases (< 6 hours) in GFAP-immunoreactive and silver-impregnated glial processes in the chick cochlear nucleus, Nucleus magnocellularis (NM), following cochlea removal or activity blockade of the eighth nerve.
The activation of current-clamped neurons in the chick Nucleus magnocellularis (nMAG) by eighth nerve stimulation has been studied in a brain slice preparation using patch electrodes.
Neurons of the Nucleus magnocellularis (nMAG) of the chick express AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate) receptors displaying unusually rapid kinetics of desensitization (Raman and Trussell, 1992a).
Following loss of eighth nerve input, 20-40% of neurons in the neonatal chick cochlear nucleus, Nucleus magnocellularis (NM), undergo cell death.
Microelectrode recordings of spontaneous multiple unit activity were made from Nucleus magnocellularis (NM) and nucleus laminaris (NL), second- and third-order nuclei in the chick auditory system, between 14 and 19 d of incubation (E14-E19).
Occasionally, small ChAT-I cells were found in the crossed dorsal cochlear tract and in the medial vestibular nucleus near the dorsal border of the caudal Nucleus magnocellularis (NM).
They were followed to their terminal sites in the hearing organ (basilar papilla), confirming that they were auditory, and to the cochlear Nucleus magnocellularis. The terminal sites of low-frequency fibers within Nucleus magnocellularis always included an area previously described as the lagenar part, i.e., an area receiving primary input which is probably only vestibular. Furthermore, a number of differences were recognized between these low-frequency (up to 0.64 kHz) and the high-frequency (1.8 kHz and above) auditory nerve projections to Nucleus magnocellularis. Nucleus magnocellularis is the first station in a brainstem auditory pathway processing stimulus timing information, coded through neuronal phase locking.
Second-order auditory neurons in Nucleus magnocellularis (NM) of the chick brainstem undergo a series of rapid metabolic changes following unilateral cochlea removal, culminating in the death of 25% of NM neurons.
Second-order auditory neurons in Nucleus magnocellularis (NM) of the chick brainstem undergo a series of rapid metabolic changes following unilateral cochlea removal, culminating in the death of 25% of NM neurons.
Nucleus magnocellularis receives a diffuse projection from all of the endorgans.
Published and preliminary data raise the possibility of several types of encephalic photoreceptor photopigment (cone-like, rod-like or different from both), and depending on species at least two types of photoreceptor cell: CSF-contacting neurons (larval lamprey, reptiles and birds) and classical neurosecretory neurons within the Nucleus magnocellularis preopticus (NMPO)(fish and amphibians)..
Surgical destruction of the otocyst in chick embryos prevents formation of the *** ear, abolishes normal cochlear input to the cochlear nucleus (Nucleus magnocellularis, NM) and results in axons from the contralateral NM forming (in addition to their normal bilateral endings in nucleus laminaris, NL) a novel and functional aberrant projection to the deafferented NM.
The metabolism of second order auditory neurons in Nucleus magnocellularis (NM) in the chick brainstem can be profoundly altered when excitatory input from the cochlea is removed.
The mitochondrial enzyme, cytochrome oxidase, was localized cytochemically in the Nucleus magnocellularis, a primary relay nucleus of vestibular information within the area octavolateralis in the fish brain. Hyper-g-exposure of the larvae for 8 days (centrifuge) caused a further augmentation of cytochrome oxidase activity in the perikarya within the Nucleus magnocellularis.
As each animal was removed from the exposure, it was anesthetized and an electrode was placed in the Nucleus magnocellularis.
The circuit from the cochlear Nucleus magnocellularis to the nucleus laminaris supports the encoding and measurement of interaural time differences in the auditory brainstem.
The afferents to NL were activated by electrical stimulation of Nucleus magnocellularis (NM) or the auditory nerve.
Of the two cochlear nuclei, angularis showed more intense staining than Nucleus magnocellularis.
The nucleus isthmo-opticus, Nucleus magnocellularis cochlearis, and nucleus laminaris all express high levels of SERCA2 but with different ratios of SERCA2b and SERCA2a.
Evoked potentials recorded from the Nucleus magnocellularis were used to measure threshold sensitivity and peak-to-peak response amplitude as a function of stimulus intensity.
Spectral response plots from single cells in the chick Nucleus magnocellularis were obtained following a 48 h exposure to a 0.9 kHz pure tone at 120 dB sound pressure level and after a recovery period of 12 days. Immediately after removal from the exposure, a variety of changes in the spectral response patterns of Nucleus magnocellularis cells were noted.
Neurons in the Nucleus magnocellularis (nMAG) of the chicken precisely transmit auditory nerve activity via glutamatergic synapses.
The developmental pharmacology of excitatory amino acid (EAA) receptors in the chick cochlear nucleus (Nucleus magnocellularis, NM) was studied by means of bath application of drugs and recording of synaptically-evoked field potentials in brain slices taken from chicks aged embryonic day (E) 14 through hatching (E21).
Since this conclusion is at odds with a number of studies suggesting that rapid excitatory neurotransmission in the CNS is mediated by alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-preferring non-NMDA receptors, we re-examined the pharmacology of synaptic transmission between the cochlear nerve and Nucleus magnocellularis (NM) in chickens, using bath application of drugs and recording of field potentials evoked in NM by electrical stimulation of the cochlear nerve in vitro.
Previous studies in our laboratory have found that muscle atonia could be triggered by two distinct areas of the medial medulla, a caudal region, corresponding to the nucleus paramedianus (NPM) and a rostral region, corresponding to the Nucleus magnocellularis (NMC).
Afferents from second-order neurons in the ipsilateral Nucleus magnocellularis (NM) innervate the dorsal dendrites of NL neurons, distributing processes of approximately equal length to NL neurons along an isofrequency band (roughly caudomedial to rostrolateral).
The nature of the enhancement and suppression of the click evoked AEPs during continuous pure tones was clearly different from those in recordings from the Nucleus magnocellularis, nucleus angularis and Field L in respect to the probability of occurrence of enhancement and suppression..
In the hypothalamus, alpha 2-adrenoceptors were detected in the antidiuretic hormone-synthesizing nucleus paraventricularis, the nucleus praeopticus medialis, the nucleus anterior medialis hypothalami, the Nucleus magnocellularis praeopticus, the nucleus commissurae pallii, the nucleus inferior hypothalami and the regio lateralis hypothalami.
These immunoreactive cells filled and outlined the boundaries of the hyperstriatum ventrale, pars caudalis, Nucleus magnocellularis neostriatalis anterioris (both in the lateral and medial subdivisions), and nucleus robustus archistriatalis.
Glutamate microinjection in both PIA and Nucleus magnocellularis (NMC) of the medial medulla also produces muscle atonia.
Nucleus magnocellularis (NM), a second-order nucleus in the chick auditory system, is topographically and tonotopically organized.
Ultrastructural peculiarities of synaptic contact formation in gravity-related integration centers (Nucleus magnocellularis) were found.
Each auditory nerve fiber enters the brain and divides to terminate in both the cochlear nucleus angularis and the cochlear Nucleus magnocellularis. The medial branch of the auditory nerve conveys phase information to the cells of the Nucleus magnocellularis via large axosomatic endings or end bulbs of Held.
This investigation assessed the effects of noise-induced hearing loss on the avian Nucleus magnocellularis, the homologue of the mammalian cochlear nucleus. Nucleus magnocellularis was assessed with thin-section electron microscopy and freeze-fracture techniques.
Microinjection of non-NMDA agonists into peri-locus coeruleus alpha (peri-LC alpha) and Nucleus magnocellularis (NMC) suppressed muscle tone, while injection of NMDA agonists at the same sites increased muscle tone and produced locomotion.
The goals of the studies presented here were to examine changes in the electrical activity of Nucleus magnocellularis cells and their afferents following removal of the cochlea and to determine if these changes were similar in adult and neonatal animals.
A monoclonal antibody to the GABAR/benzodiazepine/chloride channel complex and radiolabeled ligand binding using [ 3H]-muscimol, a GABA agonist, revealed labeling in Nucleus magnocellularis (NM), nucleus laminaris (NL), nucleus angularis (NA), and the superior olive (SO) in both posthatch and embryonic chicks.
These cells were noncholinergic and were localized to ventromedial and caudal portions of the Nucleus magnocellularis.
The effect of aminoglycoside intoxication on the cross-sectional area of neurons in Nucleus magnocellularis (NM) was studied in neonatal chickens.
In contrast, the nuclei with essentially or exclusively sensory components (i.e., nucleus angularis, nucleus laminaris, Nucleus magnocellularis) arise from the alar plate.
The effects of unilateral cochlea removal on GABA-immunoreactive (GABA-I) terminals in Nucleus magnocellularis (NM) of the chick were assessed by immunocytochemical (ICC) techniques.
Axons of the cochlear Nucleus magnocellularis, and their targets in the binaural nucleus laminaris, form the circuit responsible for encoding these interaural time differences. The nucleus laminaris receives bilateral inputs from the cochlear Nucleus magnocellularis such that axons from the ipsilateral cochlear nucleus enter the nucleus laminaris dorsally, while contralateral axons enter from the ventral side.
Electrical and chemical (glutamate) stimulations of the Nucleus magnocellularis (MC) enhanced ACh release in FTD and shortened PS latency.
Five nuclei of the song system (Area X [ X], Nucleus magnocellularis of the anterior neostriatum [ MAN], nucleus robustus archistriatalis [ RA], nucleus intercollicularis [ ICo], hyperstriatum ventrale, pars caudalis [ HVc]) and three preoptic-hypothalamic areas (preoptic anterior [ POA], periventricular magnocellular nucleus [ PVM], and posterior medial hypothalamic nucleus [ PMH]) were studied as well as other limbic and control non-steroid-sensitive areas.
The neuroblasts forming Nucleus magnocellularis, the avian homologue of the mammalian ventral cochlear nucleus, migrate by growth and elongation of their leading processes and by perikaryal translocation through these processes from the matrix zone of the rhombic lip to the acoustico-vestibular anlage.
Because such changes in the central nervous system are often associated with changes in local blood flow, we examined blood flow in second-order auditory Nucleus magnocellularis (NM) and third-order nucleus laminaris (NL). Nucleus magnocellularis receives its only excitatory input from the ipsilateral cochlea via the eighth nerve.
Neurons whose peripheral processes contacted tectorial hair cells in the cochlea projected to three divisions of the cochlear nucleus: Nucleus magnocellularis lateralis (NML), Nucleus magnocellularis medialis (NMM), and nucleus angularis lateralis (NAL).
Nissl-stained sections of adult male and female quail brains were examined for possible sex differences in the sizes of nuclei implicated in reproductive function or known to be dimorphic in songbirds, including Nucleus magnocellularis preopticus, two additional preoptic nuclei, n.
AChE positive neurons and neuropil were observed in all ChAT-IR regions and, in addition, in the vocal motor nuclei nucleus hyperstriatum ventrale pars caudalis (HVc), Nucleus magnocellularis in the anterior neostriatum (MAN), nucleus interfacialis (NIF) and RA.
Physiological recordings were made from single units in the two divisions of the chick cochlear nucleus-nucleus angularis (NA) and Nucleus magnocellularis (NM).
Surgical removal of the otocyst in chick embryos induces axons from the contralateral cochlear nucleus (Nucleus magnocellularis, NM) to form, in addition to their normal endings in nucleus laminaris (NL), anomalous and persistent functional contacts in the ipsilateral NM (Jackson and Parks, 1988).
The second- and third-order auditory nuclei in the brainstem of the chicken, Nucleus magnocellularis (NM) and nucleus laminaris (NL), receive afferents that are immunoreactive to gamma-aminobutyric acid (GABA).
In the time pathway, all the cells of the cochlear Nucleus magnocellularis and nucleus laminaris receive perisomatic GABAergic terminals, and small numbers of GABAergic neurons surround both nuclei.
Each brain slice contained portions of the auditory nerve and the second-order auditory nucleus, Nucleus magnocellularis (NM), bilaterally.
The development of gamma-aminobutyric acid-immunoreactivity (GABA-I) in Nucleus magnocellularis (NM) and nucleus laminaris (NL) of the chick was studied by using an antiserum to GABA.
During embryonic development, little Gly-I is present in Nucleus magnocellularis (NM), nucleus laminaris (NL), or nucleus angularis (NA).
We now report that glutamate-induced lesions of the medial medulla, including the Nucleus magnocellularis, caudal nucleus gigantocellularis and rostral nucleus paramedianus, produce REM sleep without atonia.
laminaris neurons in the chick auditory system are segregated into dorsal and ventral dendritic tufts, which receive spatially separated innervation from the ipsilateral and contralateral Nucleus magnocellularis, respectively.
The computation of ITD begins with preservation of the phase angle of spectral components by eighth-nerve fibers and by cells of the Nucleus magnocellularis.
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