The presence and nature of a descending projection from the ventral nucleus of the Lateral Lemniscus (LLV) to the cochlear Nuclei (NA, NM) and the third-order nucleus laminaris (NL) was investigated in a songbird using tract tracing and GAD immunohistochemistry. 
(2) SPON axons are relatively thick (diameter >1.2 microm), ascend to the midbrain tectum in the medial aspect of the Lateral Lemniscus, and, for the most part, do not innervate the Nuclei of the Lateral Lemniscus.
This study examined features and mechanisms associated with low-frequency (LF) suppression among neurons of the lateral lemniscal Nuclei (NLL). We obtained extracellular recordings from neurons in the intermediate and ventral Nuclei of the Lateral Lemniscus, observing different forms of LF suppression related to the two above-cited frequency bands.
The ascending projections to the lateral lemniscal Nuclei and the inferior colliculus were investigated in the albino rat by using Fluoro-Gold, either alone or in combination with other retrograde tract tracers. The DNLL receives a similar pattern of projections from the auditory lower brainstem Nuclei.
Nitrergic and cholinergic cells were segregated within the telencephalon, in both dorsal and ventral areas, and co-distributed in some Nuclei of the diencephalon, mesencephalon, rhombencephalon, and spinal cord. Double-labeling experiments revealed nNOS/ChAT-positive cells in (1) the diencephalon: the preoptic and suprachiasmatic Nuclei, the habenula, the dorsal thalamus, and the nucleus of the medial longitudinal fasciculus; (2) the mesencephalon: the optic tectum, the mesencephalic portion of the trigeminal nucleus, the oculomotor and trochlear Nuclei, and the Edinger-Westphal nucleus; and (3) the rhombencephalon: the secondary gustatory nucleus, the nucleus isthmi, the Lateral Lemniscus nucleus, the cerebellum, the reticular formation, different Nuclei of the octaval column, the motor zone of the vagal lobe, and the trigeminal, facial, abducens, glosso-pharyngeal, vagal, and hypobranchial motor Nuclei. Because double-labeled cells were more abundant in those Nuclei involved with sensory and motor physiological processes, we suggest the involvement of both nitric oxide and acetylcholine in these neural functions in fish..
The MPL has afferent neuronal connections distinct from adjacent brain regions including major inputs from the auditory cortex, medial part of the medial geniculate body, superior colliculus, external and dorsal cortices of the inferior colliculus, periolivary area, lateral preoptic area, hypothalamic ventromedial nucleus, lateral and dorsal hypothalamic areas, subparafascicular and posterior intralaminar thalamic Nuclei, periaqueductal gray, and cuneiform nucleus.
We used broadband noise stimuli to investigate the interaural-delay sensitivity of low-frequency neurons in two midbrain Nuclei: the inferior colliculus (IC) and the dorsal nucleus of the Lateral Lemniscus.
Using histochemical and immunohistochemical techniques, distribution of activity of oxidative mitochondrial enzyme cytochrome oxidase (CO) and of immunoreactivity to calcium-binding proteins has been studied in spiral ganglion and auditory Nuclei of brainstem in two turtle species. It has been shown that immunoreactivity to calbindin, parvalbumin, and calretinin in neurons and neuropil of Nuclei of cochlear and superior olivary complexes, in nucleus of lateral lemniscus, and in spiral ganglion neurons coincides topographically with the high CO activity.
Wfs1 expression was also detected in numerous brainstem Nuclei and in laminae VIII and IX of the spinal cord.
The fact that all midbrain regions we stimulated, which includes three distinctly different Nuclei, exhibited similar loudness summation effects (i.e.
ChAT-immunoreactive (IR) cells comprise several prominent groups, including the pedunculopontine tegmental nucleus, laterodorsal tegmental nucleus, and parabigeminal nucleus, as well as the cranial nerve somatic motor and parasympathetic Nuclei. Additional concentrations are present in the parabrachial Nuclei and superior colliculus. Among auditory Nuclei, the majority of ChAT-IR cells are in the superior olive, particularly in and around the lateral superior olive, the ventral nucleus of the trapezoid body and the superior paraolivary nucleus.
METHODS: We performed a detailed pathoanatomical investigation of unconventionally thick tissue sections through the auditory brainstem Nuclei (that is, nucleus of the inferior colliculus, Nuclei of the Lateral Lemniscus, superior olive, cochlear Nuclei) and auditory brainstem fibre tracts (that is, lateral lemniscus, trapezoid body, dorsal acoustic stria, cochlear portion of the vestibulocochlear nerve) of clinically diagnosed and genetically confirmed SCA2, SCA3 and SCA7 patients. RESULTS: Examination of unconventionally thick serial brainstem sections stained for lipofuscin pigment and Nissl material revealed a consistent and widespread involvement of the auditory brainstem Nuclei in the SCA2, SCA3 and SCA7 patients studied.
The distribution of KCNQ5 was analyzed in auditory Nuclei of the rat brainstem by high-resolution immunocytochemistry. Double labeling with anti-KCNQ5 antibodies and anti-synaptophysin or anti-syntaxin, which mark synaptic endings, or anti-microtubule-associated protein 2 (MAP2) antibodies, which mark dendrites, were used to analyze the subcellular distribution of KCNQ5 in neurons in the cochlear nucleus, superior olivary complex, Nuclei of the Lateral Lemniscus, and inferior colliculus. An abundance of KCNQ5 labeling in punctate structures throughout auditory brainstem Nuclei along with colocalization with such synaptic markers suggests that a preferred localization of KCNQ5 is in synaptic endings in these auditory Nuclei. These findings predict pre- and postsynaptic roles for KCNQ5 in excitability regulation in auditory brainstem Nuclei, at the level of glutamatergic excitatory endings and in dendrites..
The dorsal nucleus of the Lateral Lemniscus (DNLL) receives afferent inputs from many brain stem Nuclei and, in turn, is a major source of inhibitory inputs to the inferior colliculus (IC).
One part (zone 1) receives almost all of its ascending input from the cochlear Nuclei, the Nuclei of the Lateral Lemniscus, and the main Nuclei of the superior olivary complex; the other part (zone 2) receives inputs from the cochlear Nuclei and Nuclei of the Lateral Lemniscus but few or no inputs from the main olivary Nuclei.
OBJECTIVE: The purpose of this study is to investigate the early myelination patterns of brainstem auditory Nuclei and pathway on magnetic resonance imaging compared with past histological research. We aimed to identify the time course difference in myelination of the brainstem auditory Nuclei and pathway between magnetic resonance imaging and histological research results. In four sites (cochlear nucleus, superior olivary nucleus, lateral lemniscus, inferior colliculus) of the brainstem auditory Nuclei and pathway on four cross-sections obtained perpendicular to the long axis of the brainstem, signal changes of T1- and T2-weighted magnetic resonance images were analyzed using a region-of-interest methodology according to corrected postnatal age.
However, the identification of neurons in the cochlear Nuclei participating in this reflex has not been fully elucidated. Transynaptically labeled neurons were observed bilaterally in the dorsal and dorso-medial parts of ventral cochlear Nuclei as early as 48 h after virus injection, and had morphological features of radiate multipolar cells. After >or=69 h, labeled cells of different types were observed in all cochlear Nuclei. Based on the temporal course of viral replication, our data strongly suggest the presence of a direct projection of neurons from the ventral cochlear Nuclei bilaterally to the TT motoneuron pool in rats. The influence of neurons in the cochlear Nuclei upon TT activity through direct and indirect pathways may account for multifunctional roles of this muscle in auditory functions..
Axonal projections from the lateral superior olivary Nuclei (LSO), as well as from the dorsal cochlear nucleus (DCN) and dorsal nucleus of the Lateral Lemniscus (DNLL), converge in frequency-ordered layers in the central nucleus of the inferior colliculus (IC) where they distribute among different synaptic compartments. The results indicated that projections from all three Nuclei are present at birth, but are not segregated into bands.
Inactivation of either the HVI region of the cerebellar cortex or the cerebellar interposed Nuclei (IN) during learning is known to prevent CR acquisition. In addition, a functional test of TTX diffusion around the BC indicated that the inactivation did not affect other known parts of eyeblink circuits, such as the cerebellar interposed Nuclei, the middle cerebellar peduncle or the contralateral red nucleus.
Notably, particularly high levels of Cbln mRNAs were expressed in some Nuclei and neurons, whereas their postsynaptic targets often lacked or were low for any Cbln mRNAs, as seen for cerebellar granule cells/Purkinje cells, entorhinal cortex/hippocampus, intralaminar group of thalamic Nuclei/caudate-putamen, and dorsal nucleus of the Lateral Lemniscus/central nucleus of the inferior colliculus.
The function of the ventral and intermediate Nuclei of the Lateral Lemniscus (VNLL and INLL), collectively termed ventral complex of the Lateral Lemniscus (VCLL), is unclear.
The present study examined the neural projection from the inferior colliculus to the pontine Nuclei in guinea pig. Ultimately, we wanted to determine if the pontine Nuclei could be a component of the descending auditory system from the inferior colliculus to the cochlear nucleus. The anterograde tracer Phaseolus vulgaris leucoagglutinin (PHA-L) was injected into one inferior colliculus of 10 animals and the pontine Nuclei examined under a light microscope to detect PHA-L-labeled fibers. PHA-L-labeled fibers were observed in the ipsilateral pontine Nuclei in 70% of the animals. While the majority of labeled fibers were smooth in appearance, a few fibers with en passant type varicosities (indicating synapses) were observed in the dorsolateral area of the pontine Nuclei, adjacent to the Lateral Lemniscus. These findings do not support a robust projection from the inferior colliculus to the pontine Nuclei in guinea pig.
Thus, immunoreactive fibers were found in Nuclei close to the midline (centrum medianum/parafascicular complex), in the ventrolateral thalamus (medial geniculate nucleus, inferior pulvinar nucleus), and in the dorsolateral thalamus (lateral posterior nucleus, pulvinar nucleus).
The inferior colliculus (IC) receives its major ascending input from the cochlear Nuclei, the superior olivary complex, and the Nuclei of the Lateral Lemniscus. The cases could be divided into three groups based on counts of labeled cells in brainstem auditory Nuclei. Group 1 cases had labeled cells in both the cochlear Nuclei and the lateral and medial superior olivary Nuclei. Group 2 cases had labeled cells in the cochlear Nuclei but few or none in the lateral and medial superior olivary Nuclei. Both groups had labeled cells in the Nuclei of the Lateral Lemniscus and the superior paraolivary nucleus.
Anterograde projections could be traced into all cranial motor and sensory Nuclei involved in phonation, that is, the nucleus ambiguus, facial, hypoglossal and trigeminal motor Nuclei, the motorneuron column in the ventral gray substance innervating the extrinsic laryngeal muscles, the nucleus retroambiguus, solitary tract and spinal trigeminal Nuclei. Projections were also found into a number of auditory Nuclei, namely the nucleus cochlearis-complex, superior olive, ventral and dorsal Nuclei of the Lateral Lemniscus and inferior colliculus. Furthermore, there were projections into the reticular formation of the lateral and dorsocaudal medulla and lateral pons, into nucleus gracilis, inferior and medial vestibular Nuclei, lateral reticular nucleus, ventral raphe, pontine gray, superior colliculus, PAG and mediodorsal thalamic nucleus.
Here we report on response properties and the roles of inhibition in three brain stem Nuclei of Mexican-free tailed bats: the inferior colliculus (IC), the dorsal nucleus of the Lateral Lemniscus (DNLL) and the intermediate nucleus of the Lateral Lemniscus (INLL).
In the present study, we characterized the normal distribution of TH as well as changes following deafness (bilateral cochlear ablation) in the IC and Nuclei of the Lateral Lemniscus. Many TH immunoreactive fibers and puncta were identified in the IC and Nuclei of the Lateral Lemniscus of normal hearing animals and labeling was most dense in the external cortex of the IC.
Densitometry also was used to quantify levels of parvalbumin immunostaining within neurons and fibers in auditory Nuclei. In addition, an increase was noted in the size of spiral ganglion cells as well as a decrease in the volume and cell size of the cochlear nucleus (CN), the superior olivary complex Nuclei (SOC), and the Nuclei of the Lateral Lemniscus (LL) and the inferior colliculus (IC).
No collaterals were seen innervating any olivary complex Nuclei.
We investigated functional activation of central auditory brainstem Nuclei in response to direct electrical stimulation of the cochlear nerve using c-Fos immunoreactivity as a marker for functional mapping. In a control group, bilateral cochlectomy was performed in order to assess the basal expression of c-Fos in the auditory brainstem Nuclei. The completeness of cochlear ablations and the response of auditory brainstem Nuclei to electrical stimulation were electrophysiologically verified. Contralateral inhibition of the Nuclei of the trapezoid body (TB) was observed. Our data show that unilateral electrical stimulation of the cochlear nerve leads to increased expression of c-Fos in most auditory brainstem Nuclei, similar to monaural auditory stimulation. They also confirm previous studies suggesting inhibitory connections between the cochlear Nuclei.
The responses of dorsal column Nuclei neurones to MN stimuli were of similar latency, but the latencies of antidromic responses to ML stimuli were variable.
The distribution and quantity of the alpha 7 nicotinic acetylcholine receptor (nAChR) were mapped in the Nuclei of the superior olivary complex, lateral lemniscus, and inferior colliculus in the developing and mature rat brain. More moderate levels of transcript and protein were measured in the ventral, intermediate, and dorsal Nuclei of the Lateral Lemniscus, lateral and medial ventral posterior olivary Nuclei, rostral periolivary region, lateral periolivary nucleus, caudal periolivary region, ventral and dorsal trapezoid Nuclei, medial superior olive, and the lateral superior olive.
Two previous studies have investigated the development of auditory Nuclei projections and lateral lemniscal nuclear projections in embryonic rats, respectively. Overall, the developmental progression of projections follows that of terminal mitoses in various Nuclei, suggesting the consistent use of a developmental timetable at a given nucleus, independent of that of other Nuclei. These projections develop approximately a day before the reciprocal connections between the MGB and IC and before development of projections from the auditory Nuclei to the IC. Brainstem nuclear projections to the IC arrive first from the Lateral Lemniscus Nuclei then the superior olive and finally the cochlear Nuclei.
The majority of these boutons were of the "large round" type and corresponded to the terminals of cochlear Nuclei. Part of these boutons appeared to arise from Nuclei of the Lateral Lemniscus and the superior olive, and a certain percentage likely represented endings of inhibitory interneurons..
Detectable levels of biotin were primarily found caudal to the diencephalon, with greatest expression in the cerebellar motor system and several brainstem auditory Nuclei. Biotin was detected in cells of the spiral ganglion, somata and proximal dendrites of cells in the cochlear Nuclei, superior olivary Nuclei, medial nucleus of the trapezoid body, and nucleus of the Lateral Lemniscus. Biotin was further found in pontine Nuclei and fiber tracts, the substantia nigra pars reticulata, lateral mammillary nucleus, and a small number of hippocampal interneurons.
Three main relay Nuclei are located between the auditory nerve and the primary auditory cerebral cortex: 1- the cochlear nucleus, 2- the contralateral inferior colliculus and 3- the contralateral medial geniculate body. Some fibers of this main ascending pathway branch off to other Nuclei such as the Nuclei of the superior olivary complex and the nucleus of the Lateral Lemniscus.
Following bilateral lesions of the medial subparafascicular area including the subparafascicular nucleus, TIP39-immunoreactive fibers almost completely disappeared from forebrain regions including the anterior limbic cortical areas, the shell and cone portions of the nucleus accumbens, the lateral septum, the bed nucleus of the stria terminalis, the amygdaloid Nuclei, the fundus striati, the subiculum, the thalamic paraventricular nucleus, and the hypothalamic paraventricular, dorsomedial and arcuate Nuclei. Following lesions of the medial paralemniscal nucleus, TIP39-immunoreactive fibers disappeared from the medial geniculate body, the periaqueductal gray, the deep layers of the superior colliculus, the external cortex of the inferior colliculus, the cuneiform nucleus, the Nuclei of the Lateral Lemniscus, the lateral parabrachial nucleus, the locus coeruleus, the subcoeruleus area, the medial nucleus of the trapezoid body, the periolivary Nuclei, and the spinal cord, suggesting that these regions receive TIP39-containing fibers from the medial paralemniscal nucleus, and unilateral lesions demonstrated that the projections are ipsilateral.
The use of 100 microm serial sections through the SCA2 patient's central somatosensory components showed that obvious neuronal loss occurred in nearly all of the relay stations of this system (Clarke's column; cuneate, external cuneate and gracile Nuclei; spinal, principal and mesencephalic trigeminal Nuclei; ventral posterior lateral and ventral posterior medial Nuclei of the thalamus), whereas the majority of interconnecting fibre tracts (dorsal spinocerebellar tract; cuneate and gracile fascicles; medial lemniscus; spinal trigeminal tract, trigeminal nerve and mesencephalic trigeminal tract) displayed signs of atrophy accompanied by demyelinization. Moreover, together with the lesions seen in the motor cerebellothalamocortical feedback loop (pontine Nuclei, deep cerebellar Nuclei and cerebellar cortex, ventral lateral nucleus of the thalamus), they also account for the somatomotor deficits that were observed in the young woman (gait, stance, and limb ataxia, falls, and impaired writing).
The cochlear nuclear complex gives rise to widespread projections to Nuclei throughout the brainstem. Globular bushy cells and two types of spherical bushy cells project to Nuclei in the superior olivary complex that play roles in sound localization based on binaural cues. Octopus cells convey precisely timed information to Nuclei in the superior olivary complex and lateral lemniscus that, in turn, send inhibitory input to the inferior colliculus. Type II multipolar cells send inhibitory projections to the contralateral cochlear Nuclei.
The purpose of the present study was to compare information about the distribution of neurons expressing the KV 1.1 in the brainstem auditory Nuclei with the distribution of neurons with known functional properties in the auditory system of the big brown bat, Eptesicus fuscus. We used immunocytochemistry and light microscopy to look at the distribution of Kv1.1 subunits in the brainstem auditory Nuclei.
Both Nuclei presented strong ir-GHRH projections extending rostro-ventrally.
Immunoreactive staining for both calbindin and parvalbumin was reduced in the cochlear Nuclei and the superior olivary complex in jj rats. By contrast, immunoreactive staining in other brainstem areas (e.g., dorsal and ventral Nuclei of the Lateral Lemniscus, inferior colliculus), thalamic (medial geniculate body) auditory areas, and neighboring non-auditory structures was similar in jaundiced and control rats. Calbindin-immunoreactive staining in the superior paraolivary and medial superior olivary Nuclei in Nj rats was associated with myelinated axons, whereas parvalbumin-immunoreactive staining was localized postsynaptically in neuronal somata and dendrites. Immunoreactive staining for the calcium-binding proteins calbindin and parvalbumin in lower brainstem auditory Nuclei shows abnormalities in areas susceptible to the effects of hyperbilirubinemia and provides a sensitive new way to assess bilirubin toxicity in the auditory system..
We therefore propose a mechanism of integration across frequency channels that may originate within the inferior colliculus and/or the Nuclei of the Lateral Lemniscus.
It was observed that only a specific BDP deflection recorded at the level at which lemniscal fibers terminate in the Nuclei of LL coincided in time with the most prominent BDP in the cat's vertex-recorded ABRs, the BDP in their wave P4.
The three Nuclei are intimately linked through a complex arrangement of excitatory and inhibitory connections.
To this end, we have employed unbiased stereological methods to estimate neuron number in the cochlear Nuclei, superior olivary complex, lateral lemniscus, inferior colliculus and medial geniculate body. The utility of unbiased stereological estimates of auditory Nuclei is discussed in the context of various experimental paradigms..
High levels were found in most cortical areas, many thalamic Nuclei, some subNuclei of the amygdaloid complex, the hypothalamus and the nucleus of the stria terminalis, the nucleus of the solitary tract, the parabrachial nucleus, and the inferior olive.
Novel AT(1) binding sites were discovered in the pituitary, retrorubral field, periolivary region, dorsolateral nucleus of the Lateral Lemniscus, dorsal raphe, and laterodorsal tegmental Nuclei.
In the cochlear Nuclei (CN), c-Fos activation was scarce in isolated rats and increased strongly following sound stimulation. Following unilateral cochlear lesions, acoustically driven expression was decreased in some, but not all superior olivary Nuclei in both the lesioned and the untreated sides. Following unilateral cochlear lesion, acoustically driven expression decreased bilaterally in all Nuclei.
We explored a detailed hybridohistochemical expression pattern of the nociceptin precursor mRNA in the mouse brainstem, and identified positive cells in several auditory brainstem Nuclei. Positive cells were seen in the dorsal and ventral Nuclei of the Lateral Lemniscus, the rostral periolivary region, the lateroventral and medioventral periolivary Nuclei, the dorsal periolivary region, the superior paraolivary nucleus, and the external cortex and dorsal cortex of the inferior colliculus. Of these, the medioventral and lateroventral periolivary Nuclei, the major sites of origin of olivocochlear bundle, were most populated by positive cells..
To address this question, we used a two-tone paradigm to examine responses of single units to combination stimuli in a brainstem structure, the Nuclei of the Lateral Lemniscus (NLL).
In the rostral auditory Nuclei (Nuclei of the Lateral Lemniscus and inferior colliculus), the alpha1 subunit transcript appears later (P8) than in the caudal Nuclei (cochlear nuclear complex and superior olivary complex; P0). However, alpha2 subunit mRNA is present at high levels in other neonatal brainstem structures, such as cranial motor Nuclei.
This task is ascribed to a group of central nervous system Nuclei in the dorsal midbrain or torus semicircularis, homologous to the inferior colliculus of mammals. We have mapped the connections of the subNuclei of the torus semicircularis in Xenopus laevis to determine which receive auditory and which receive lateral line information. The principal and magnocellular Nuclei receive their input from the lateral line nucleus of the medulla. All three Nuclei of the torus also have reciprocal connections with the superior olive and the nucleus of the Lateral Lemniscus. Ascending efferents from all three Nuclei of the torus innervate central and lateral thalamic Nuclei, and all have a weak reciprocal connection with the posterior thalamus. The laminar and magnocellular Nuclei have reciprocal connections with the ventral thalamus, and all three Nuclei of the torus receive descending input from the anterior entopeduncular nucleus. The laminar and magnocellular Nuclei also receive descending input from the preoptic area. Based on our identification of toral Nuclei and these results we assign a major function for the detection of water-borne sounds to the laminar nucleus and a major function for the detection of near field disturbances in water pressure to the principal and magnocellular Nuclei..
The distribution of stained somata and neuropil varied across auditory Nuclei and correlated with the distribution of Kv3.1 mRNA-expressing neurons and their terminal arborizations, respectively.
vestibular and cochlear Nuclei, cells and fibers at the floor of the fourth ventricle with morphologic features of tanycytes, parabrachial Nuclei (PBN), medial lemniscus, lateral lemniscus, inferior cerebellar peduncle and cerebellar white matter, central tegmental tract, and the capsule of the red nucleus.
An injection of CTB into PE produced dense retrograde labeling of the contralateral dorsal column Nuclei and anterograde labeling of the ipsilateral lateral and dorsolateral nucleus basalis.
The thalamus displayed GAL-ir neurons within the anterodorsal, paraventricular, central lateral, paracentral, and central medial Nuclei. In the medulla oblongata, GAL-ir neurons appear in the anterodorsal and dorsal cochlear Nuclei, salivatory nucleus, A5 noradrenergic cells, gigantocellular nucleus, inferior olive, solitary tract nucleus, dorsal vagal motor and hypoglossal Nuclei.
Here we describe, using in situ hybridization, the subunit expression patterns of GABA(A) receptors in the rat cochlear nucleus, superior olivary complex, and dorsal and ventral Nuclei of the Lateral Lemniscus. In both the dorsal and ventral Nuclei of the Lateral Lemniscus, alpha1, beta3 and gamma2L are the main subunit messenger RNAs; the ventral nucleus also expresses the delta subunit. We have mapped, using in situ hybridization, the subunit expression patterns of the GABA(A) receptor in the auditory brainstem Nuclei. In contrast to many brain regions, the beta2 subunit gene and gamma2S splice forms are not highly expressed in auditory brainstem Nuclei.
Moderate levels of Y1 immunoreactivity were found the in the main olfactory bulb, dorsomedial part of suprachiasmatic nucleus, paraventricular hypothalamic nucleus, ventral nucleus of lateral lemniscus, pontine Nuclei, mesencephalic trigeminal nucleus, external cuneate nucleus, area postrema, and nucleus tractus solitarius.
This information is sent primarily to the subdivisions of the inferior colliculus and to the Nuclei of the Lateral Lemniscus. Little is known about the transmitter types used by olivary projections to the Nuclei of the Lateral Lemniscus, but they are presumed to be similar to the collicular projections. Olivary efferents to the Nuclei of the Lateral Lemniscus are also key components of ascending pathways that inhibit neurons in the midbrain..
In the diencephalon, labeled cells were present in all the mid-line and intralaminar thalamic Nuclei; the lateral posterior, pulvinar and suprageniculate Nuclei; the ventral nucleus of the lateral geniculate body and the medial geniculate body. Variable densities of labeled fibers were also seen in all these Nuclei except in the medial geniculate body and in most areas of the lateral posterior and pulvinar Nuclei. In the mesencephalon, positive cells were found in the periaqueductal gray, the Edinger-Westphal and interpeduncular Nuclei, delimited areas of the superior and inferior colliculi and the ventral tegmental area. In the rhombencephalon, labeled cells were seen in the majority of the Nuclei in the latero-dorsal pontine tegmentum, the Nuclei of the Lateral Lemniscus, the trapezoid, vestibular medial, vestibular inferior and cochlear Nuclei, the prepositus hypoglossal, the nucleus of the solitary tract and the dorsal motor nucleus of the vagus, the infratrigeminal nucleus and the caudal part of the spinal trigeminal nucleus and in the rhombencephalic reticular formation. The distribution of fibers included additionally the substantia nigra, all the trigeminal nerve Nuclei, the facial nucleus and a restricted portion of the inferior olive.
This study determined if an asymmetric hearing loss, due to unilateral cochlear ablation, could induce the regulation of intracellular AMPA receptors in brain stem auditory Nuclei. Between 7 and 147 days, most SOC Nuclei exhibited transient, temporally synchronized postlesion deficits in binding.
In the mustached bat, we have discovered a population of such FM selective cells in an area interposed between the central nucleus of the inferior colliculus (ICC) and the Nuclei of the Lateral Lemniscus (NLL). To describe FM selectivity of neurons in the ICXv and to compare it to other midbrain Nuclei, up- and down-sweeping linear FM stimuli were presented at different modulation rates.
In contrast, the alpha3 and beta4 nicotinic subunits are expressed in the embryo and early in postnatal development in the CN and IC, but not other brainstem Nuclei.
All investigated auditory fields send axons to the suprageniculate, posterior limitans, laterodorsal and lateral posterior thalamic Nuclei, with strongest projections from DP and VP, as well as to the reticular and subgeniculate thalamic Nuclei. They also project to the deep and intermediate layers of the ipsilateral superior colliculus, with strongest projections from DP and VP to the lateral and basolateral amygdaloid Nuclei, the caudate putamen, globus pallidus and the pontine Nuclei.
Transneuronal atrophy occurred in neurons of the dorsal column (DCN) and ventral posterior lateral thalamic (VPL) Nuclei in monkeys subjected to cervical and upper thoracic dorsal rhizotomies for 13-21 years and that had shown extensive representational plasticity in somatosensory cortex and thalamus in other experiments. In the affected Nuclei, neurons were progressively shrunken with increasing survival time, and their packing density increased, but there was relatively little loss of neurons (10-16%). There was evidence for loss of axons of atrophic CN cells in the medial lemniscus and in the thalamus, with accompanying severe disorganization of the parts of the ventral posterior Nuclei representing the normally innervated face and the deafferented upper limb.
The methodology used clearly indicates sequential signal propagation from the dorsal and ventral Nuclei of the Lateral Lemniscus up to the inferior colliculus..
KCNQ4 is also expressed in neurons of many, but not all, Nuclei of the central auditory pathway, and is absent from most other brain regions. It is present, e.g., in the cochlear Nuclei, the Nuclei of the Lateral Lemniscus, and the inferior colliculus.
Terminal fields are identified in the medulla (ventral SO, RF), isthmus (nucleus praeeminentialis), midbrain (nucleus of the Lateral Lemniscus, medial pretoral nucleus, contralateral NC, tectum), diencephalon (lateral preglomerular, central posterior, and anterior tuber Nuclei), and telencephalon (area ventralis).
This region, which we identify as VMpo, is located posteromedial to the ventral posterior lateral (VPL) and ventral posterior medial (VPM) Nuclei, ventral to the anterior pulvinar and centre médian Nuclei, lateral to the limitans and parafascicular Nuclei and dorsal to the medial geniculate nucleus. CGRP immunoreactivity is also present over small, non-clustered neurons in the calbindin-negative area that separates VMpo from the VPL and VPM Nuclei, which we denote as the posterior nucleus (Po).
Extratelencephalic projections of rostral HA traveled in the septomesencephalic tract (TSM) and gave rise to nuclear-specific terminal fields in the precerebellar medial spiriform nucleus of the posterior thalamus, the red nucleus in the mesencephalon, the medial pontine nucleus in the pons, and the subtrigeminal, external cuneate, cuneate, gracile, and inferior olivary Nuclei in the medulla. There was also a sparse projection to the dorsal thalamic nucleus intermedius ventralis anterior, which supplies the somatosensory input to the rostral Wulst, and distinct projections to the intercollicular region surrounding the central nucleus of the inferior colliculus, where they partly overlapped the projections of the dorsal column Nuclei.
By immunostaining, neurons expressing peptides (dynorphin and corticotropin-releasing factor, CRF) and glutamate decarboxylase (GAD), a GABA-synthesizing enzyme, were precisely mapped in the rat lateral lemniscal Nuclei. While GAD neurons were numerous and preferably localized in the dorsal (DLL) and ventral (VLL) Nuclei, neurons expressing these peptides were less numerous and localized primarily in the intermediate (ILL) nucleus of the Lateral Lemniscus.
The early development of calretinin immunoreactivity (CR-IR) was described in the auditory Nuclei of the brainstem of the barn owl. In each of the auditory Nuclei studied, CR-IR did not develop homogeneously, but began in the regions that map high best frequencies in the adult barn owl. The edge of these gradients moved along the future tonotopic axes during the development of all Nuclei studied, until adult patterns of CR-IR were achieved about a week after hatching..
Notably, CRNs apparently do not innervate any of the Nuclei of the auditory brainstem, as usually defined, even though their axons pass through or in close proximity to them.
Our intent is to understand how the steady state behavior arises from the cell properties in and connectional patterns from lower brainstem Nuclei.
Many immunoreactive puncta surrounded the neuronal somata in the cochlear nuclear complex, the superior olivary complex, and the Nuclei of the Lateral Lemniscus. Thereafter, a decrease occurred until about postnatal day 21, when the mature pattern was established in most Nuclei.
Considering both the density of labeled neurons per region and their intensity of labeling, the distribution of prepronociceptin messenger RNA-containing neurons can be summarized as follows: the highest level of prepronociceptin messenger RNA expression was detected in the septohippocampal nucleus, bed nucleus of the stria terminalis, central amygdaloid nucleus, and in selective thalamic Nuclei such as the parafascicular, reticular, ventral lateral geniculate and zona incerta. High to moderate levels of prepronociceptin messenger RNA expression were detected in the lateral, ventral and medial septum, and were evident in brainstem structures implicated in descending antinociceptive pathways (e.g., the gigantocellular nucleus, raphe magnus nucleus, periaqueductal gray matter), and also observed in association with auditory relay Nuclei such as the inferior colliculi, lateral lemniscus nucleus, medioventral preolivary nucleus and lateral superior nucleus. A weak level of prepronociceptin messenger RNA expression was present in some areas, such as the cerebral cortex, endopiriform cortex, hippocampal formation, medial amygdaloid nucleus, anterior hypothalamic area, medial mammillary hypothalamic Nuclei, retrorubral field and substantia nigra pars compacta.
In most Nuclei containing labeled cells, there was a single focus of labeling in regions thought to be responsive to high-frequency sounds. More complex labeling patterns were observed in three Nuclei. In both Nuclei, multiple foci of labeling occurred. Thus, one or more of these three Nuclei may provide low-frequency input to high-frequency-sensitive cells in the ICC, creating FM-FM responses. If the spectral integration of FM-FM neurons is created at the level of the ICC, these results suggest that neurons of the anteroventral cochlear nucleus or monaural Nuclei of the Lateral Lemniscus may provide the essential low-frequency input.
AT2 mRNA is detected beginning at E15 in the subthalamic and hypoglossus Nuclei; at E17 in the pedunculopontine nucleus, cerebellum, motor facial nucleus, and the inferior olivary complex; at E19 in the thalamus, bed nucleus of the supraoptic decussation, interstitial nucleus of Cajal, Nuclei of the Lateral Lemniscus, locus coeruleus, and supragenual nucleus; and at E21 in the lateral septal and medial amygdaloid Nuclei, medial geniculate body, and the superior colliculus. The substantia nigra and many telencephalic and medullary Nuclei express AT2 mRNA only after birth. In conclusion, during brain development, expression of AT2 mRNA appears early at E13, is strongly but transiently expressed in certain structures, and is high and persists until brain maturity in Nuclei involved in motor functions and sensory integration.
We investigated whether acoustic brainstem Nuclei express Fos-like immunoreactivity (FLI) after flurothyl-induced generalized seizures in rats. Because this pattern of FLI closely resembles that observed after AS in previous studies, these results suggest that Fos expression in acoustic brainstem Nuclei is not specific for AS..
The monaural Nuclei of the Lateral Lemniscus, whose roles are not understood (although they are ubiquitous in higher vertebrates), receive input from multiple pathways that encode timing with precision, some through calyceal endings..
Both retrograde and anterograde labelings were mainly found in: 1) the deep cerebellar Nuclei; 2) the Lateral Lemniscus and paralemniscal Nuclei, deep gray, and white intermediate layers of the superior colliculus, tegmental (laterodorsal and microcellular) Nuclei, and central gray; and 3) the septohypothalamic nucleus, and lateral and posterior hypothalamic areas. The FR-labeled terminal-like elements were found in: 1) Crus 2 of the ansiform lobule, and the simple, 2, and 3 cerebellar lobules; 2) the subcoeruleus, deep mesencephalic, and Edinger-Westphal Nuclei; and 3) the premammillary, lateral, and medial mammillary Nuclei, retrochiasmatic part of the supraoptic nucleus, and the zona incerta. The FB-labeled neurons were found in: 1) the parapedunculopontine tegmental and cuneiform Nuclei, caudal linear nucleus of the raphe, and adjacent area of the cerebral peduncle; 2) the thalamic posterior nuclear group and subparafascicular, parafascicular, and gelatinosus thalamic Nuclei; 3) the parastrial amygdaloid and subthalamic Nuclei; and 4) the olfactory tubercle, granular, and agranular insular cortex, parietal and lateral orbital cortices.
Here we have studied age-dependent changes in the expression of alpha-amino-3-hydroxy-5-methyl-4-isoxazole (AMPA) and N-methyl-D-aspartate (NMDA) receptor subunits in the cochlear nucleus complex (CN), the superior olivary complex (SOC), the Nuclei of the Lateral Lemniscus, and the inferior colliculus of the developing rat. In contrast, the adult pattern of the distribution of AMPA receptor subunits emerged gradually in most of the other auditory Nuclei. Thus, progressive as well as regressive events characterized AMPA receptor development in some Nuclei, while a monotonically maturation was seen in other regions.
In some brain areas, induced expression manifested a clear tonotopic organization, i.e., in dorsal, posteroventral, and anteroventral cochlear Nuclei, and in the medial nucleus of the trapezoid body. Although expression was present, tonotopy was not evident in periolivary Nuclei or in the ventral or intermediate Nuclei of the Lateral Lemniscus. Free-field diotic stimulation did not induce c-fos mRNA expression in the medial or lateral superior olivary Nuclei.
Previous evidence suggests that the Nuclei of the Lateral Lemniscus play an important role in processing timing information that is essential for target range determination in echolocation.
Neurons in the Nuclei of the Lateral Lemniscus (NLL) of the big brown bat, Eptesicus fuscus, show several distinctive patterns of response to unmodulated tones.
Furthermore, in nociceptive neurons with TP input recorded from nucleus centralis lateralis (CL) and parafascicularis (Pf) of the intralaminar Nuclei, intravenous morphine suppressed responses both to stimulation of the mesencephalic reticular formation (MRF) as well as TP stimulation. Results suggest that intravenous morphine suppresses synaptic transmission of nociceptive impulses in the intralaminar Nuclei as well as in the lower brain stem but not in the VPM..
The ventral complex of the Lateral Lemniscus (VCLL, i.e., the ventral and intermediate Nuclei) is composed of cells embedded in the fibers of the Lateral Lemniscus. Whereas tonotopic organization is a feature of all other Nuclei of the auditory system, this functional principle is debated in the VCLL. We conclude that the clusters may represent discontinuous frequency-band compartments as a counterpart to the continuous laminar compartments in the remaining auditory Nuclei.
From the diencephalon, it receives afferents from the dorsomedial anterior and medial posterior thalamic Nuclei, and from several hypothalamic Nuclei. The afferents to the thalamic Nuclei that project to the PDVR have also been studied. The dorsomedial anterior thalamic nucleus receives projections mainly from limbic structures, whereas the medial posterior thalamic nucleus is the target of projections from structures with a clear sensory significance (optic tectum, torus semicircularis, Nuclei of the lateral and spinal lemniscus, superior olive and trigeminal complex).
Anatomical pathway tracing uncovered a bilateral array of both first- and second-order medullary Nuclei and a perilemniscal nucleus. Medullary Nuclei projected to the auditory midbrain by means of the Lateral Lemniscus. Midbrain auditory areas projected to both ipsilateral and contralateral optic tecta and to an array of three Nuclei in the auditory thalamus.
Vestibulospinal neurons are located in the descending, magnocellular, and tangential octaval Nuclei, as well as in the medial octavolateralis nucleus of the lateral line system. More rostrally, cells of the ventrolateral thalamus, dorsal periventricular hypothalamus, central pretectal and magnocellular preoptic Nuclei also project to the cord.
Here we tested the hypothesis that responses to SAM in the mustache bat IC are shaped by the same mechanism that shapes responses to SAM in the two lower Nuclei.
Five possible sources for the inhibition are considered: the auditory nerve, intrinsic circuits in the cochlear nucleus, medial and lateral Nuclei of the trapezoid body inhibition to the medial superior olive, dorsal nucleus of the Lateral Lemniscus (DNLL) inhibition to the ICC, and intrinsic circuits in the ICC itself..
One class of cerebrospinal projection Nuclei (represented by the nucleus of the medial longitudinal fascicle, the intermediate reticular formation, and the magnocellular octaval nucleus) showed a robust regenerative response after both types of lesions as determined by retrograde tracing and/or in situ hybridization for GAP-43. After distal lesion, upregulation of L1.1 and L1.2 mRNAs, but not NCAM mRNA expression, was observed in the first class of Nuclei. The second class of Nuclei did not show any changes in their mRNA expression after distal lesion. After proximal lesion, both classes of brain Nuclei upregulated L1.1 mRNA expression (L1.2 and NCAM were not tested after proximal lesion).
The thick myelinated axon originated from the cell body and innervated Nuclei exclusively in the ipsilateral auditory brain stem. These include the lateral superior olive (LSO), ventral nucleus of the Lateral Lemniscus, medial superior olive, dorsomedial and ventromedial periolivary Nuclei, and the MNTB itself. This MNTB cell output then becomes an important inhibitory input to a number of ipsilateral auditory brain stem Nuclei..
In contrast to the ease of finding tonotopicity in other Nuclei, both anatomical and electrophysiological methods have failed to demonstrate a clear and simple tonotopic map within the ventral nucleus of the Lateral Lemniscus (VLL). Since the same organization of ascending frequencies present in the cochlea is maintained in these fibers as well as in all main auditory Nuclei, demonstration of a similar organization of frequencies in VLL would be evidence of the cochleo- or tono-topicity of this nucleus. Using triple injection of 3 different fluorescent dyes in inferior colliculus to study efferents, orderly and tonotopic cell-labeling is found in each of the brainstem auditory Nuclei, with the notable exception of VLL. Using the 2-deoxyglucose (2-DG) method, during stimulation at 6 different frequencies, afferent orderliness, indeed, tonotopicity is found in all major brainstem auditory Nuclei, again with the notable exception of VLL.
Results show an attenuation of Fos expression following TMR in the dorsal and ventral cochlear Nuclei, ventral nucleus of the Lateral Lemniscus and medial geniculate nucleus.
The objective of the present study was to provide direct evidence regarding GABAergic projections from the Nuclei of the Lateral Lemniscus to the central nucleus of the inferior colliculus (ICC), and from the ICC to the opposite ICC. GABA immunostaining alone showed substantial numbers of GABA positive neurons in the Nuclei of the Lateral Lemniscus and the inferior colliculus. FG and GABA double-labeled neurons were present in all Nuclei of the Lateral Lemniscus that project to the ICC.
The paralemniscal tegmental area is situated in the dorsolateral tegmentum ventral to the inferior colliculus and rostral and medial to the dorsal and intermediate Nuclei of the Lateral Lemniscus.
The intermediate and ventral Nuclei of the Lateral Lemniscus (INLL and VNLL) were also labeled ipsilaterally and exhibited a distribution of tracer that depended on the frequency of the injection site: the low frequency projection was banded but the high frequency projection was more evenly distributed..
Input projections were observed contralaterally from: all three divisions of cochlear nucleus; intermediate and dorsal Nuclei of the Lateral Lemniscus (LL); and the central nucleus, external nucleus and dorsal cortex of the IC. Input projections were observed ipsilaterally from: the medial and lateral superior olivary Nuclei; the superior paraolivary nucleus; the dorsolateral and anterolateral periolivary Nuclei; the dorsal and ventral divisions of the ventral nucleus of LL; the dorsal and intermediate Nuclei of LL; the central nucleus, external nucleus and dorsal cortex of the IC outside the injection site; and small projections from central gray and the medial geniculate body.
Microtubule-associated protein 2 immunoreactivity revealed differential vulnerability of the acoustic relay Nuclei in the brainstem. We also demonstrated a close relationship between the reversibility of ischemia-induced changes on brainstem auditory evoked potential and ischemic lesions of these relay Nuclei.
To identify possible neural correlates of this interference, we recorded responses of single units in the Nuclei of the Lateral Lemniscus to combinations of a broad-band click and a test signal (pure tones or frequency-modulated sweeps).
After labeling predominately cells of the core and multipolar regions, varicose fibers were observed in a variety of auditory Nuclei. These regions included bilaterally the principal Nuclei of the superior olivary complex, some periolivary regions, and the sagulum, as well as the ipsilateral intermediate and dorsal nucleus of the Lateral Lemniscus, inferior colliculus, and lateral pontine nucleus.
We have used retrograde labelling techniques in ferrets to examine the sources and pattern of innervation from auditory brainstem Nuclei. After multiple injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) into the SC, the heaviest concentrations of labelled cells were found in the nucleus of the brachium (BIN) and external nucleus of the inferior colliculus, with much weaker labelling in the nucleus sagulum, dorsal, intermediate and ventral Nuclei of the Lateral Lemniscus, paralemniscal regions, and periolivary Nuclei. However, no clear segregation was apparent in the BIN after injections into the medial and lateral regions or in any of the other Nuclei after either injection paradigm. These data suggest that converging inputs from several auditory brainstem Nuclei contribute to the construction of the auditory space map in the SC, although information about sound azimuth may be conveyed to this nucleus via a spatially ordered projection from the ipsilateral BIN..
The three Nuclei of the cat lateral lemniscus (dorsal, intermediate, and ventral) were distinguished by their immunoreactivities for the putative inhibitory transmitters, gamma-aminobutyric acid (GABA) and glycine. Neurons in the ventral nucleus had fewer immunoreactive perisomatic puncta than neurons in either the dorsal or the intermediate Nuclei. These differences in neuronal immunoreactivity and in the relative abundance of GABA-and glycine-immunoreactive perisomatic puncta among the three Nuclei of the Lateral Lemniscus support connectional and electrophysiological evidence that each nucleus has a different functional role in auditory processing. In particular, this study demonstrates that the intermediate nucleus of the cat is cytochemically distinct from the dorsal and ventral Nuclei in terms of the somatic and perisomatic immunoreactivity of its neurons for these two important inhibitory transmitters and may provide novel inputs to the inferior colliculus..
Second, a number of auditory structures (cochlear Nuclei, superior olivary complex, Nuclei of the Lateral Lemniscus, inferior colliculus and the medial division of the medial geniculate body) displayed a clear intensity-dependent increase in c-fos induction. Particularly intense c-fos induction was observed in the bed nucleus of the stria terminalis, especially its anterior medial and ventral aspects, the septohypothalamic nucleus, the ventral lateral septum, the ventral portion of the dentate gyrus, a number of hypothalamic Nuclei including the lateral preoptic area, the medial preoptic nucleus and the paraventricular nucleus, the median raphe and the pedunculopontine tegmental nucleus.
Locations of brain Nuclei showing fos-like immunoreactive (FLI) neurons following AS with and without seizures were mapped. Unexpectedly, the cochlear Nuclei and the central nucleus of the inferior colliculi (ICc), both of which are requisite for AGS initiation, exhibited a diminished fos expression in animals having seizures compared to AS controls. Other Nuclei, known to be involved in auditory transmission (i.e., superior olivary complex; trapezoid nucleus; dorsal nucleus of the Lateral Lemniscus, DNLL), did not show differential FLI densities between seizure and AS control animals. In contrast, seizure-induced FLI was observed in many nonauditory brain Nuclei. Other brain stem Nuclei showing differential fos expression between GEPRs and AS control rats are also described..
Although there is little evidence for such a projection in other sensory thalamic Nuclei, a GABAergic, ascending auditory projection was reported recently in the cat.
When PHAL was injected into the SpVe, labeled ascending fibers ran along the Lateral Lemniscus forming a loose bundle, and terminated in the medial part of the rostrocaudal extent of the medial geniculate body, and the posterior and ventral thalamic Nuclei.
Dense fibre labelling and varicosities were also apparent for both peptides immediately medial to the ventral and dorsal Nuclei of the Lateral Lemniscus, and in the external cortex and dorsomedial zones of the inferior colliculus (IC). Neuronal somata immuno-reactive for somatostatin were found in anteroventral and posteroventral cochlear Nuclei (AVCN and PVCN) and the A5 and A7 cell groups adjacent to the LSO and the VNLL and DNLL and in all subdivisions of the inferior colliculus (IC).
This review explores the questions of how spike trains that originate from lower auditory Nuclei interact in the inferior colliculus to produce an output that synthesizes the information from all these sources.
Furthermore, the results in the patients with thalamic lesions suggest that the lateral Nuclei of the thalamus, other than the ventral posterolateral nucleus and probably including the ventrolateral nucleus, have an important function in the processing of peripheral sensory input for tuning motor cortical excitability..
Under control conditions (a and b), scattered labeled neurons were found in the ventral periolivary nucleus, lateral lemniscus Nuclei, inferior colliculus, medial nucleus of the medial geniculate body, and in three divisions of the temporal auditory cortex. Sound stimulation (c) increased the number of fos-like-immunoreactive (FLI) Nuclei in all the auditory pathway structures. FLI Nuclei were strong in the dorsal cochlear nucleus, anterior and posterior ventral cochlear Nuclei, all the superior olivary complex Nuclei, lateral lemniscus Nuclei, all areas of the inferior colliculus, medial geniculate body, and the three temporal auditory areas, which showed a barrel pattern.
The SFM-selective neurons in the IC responded to a lower and more limited range of SFM rates than do neurons in the Nuclei of the Lateral Lemniscus of this bat.
AMPA receptor subunit-specific antibodies were used to determine if the distribution of excitatory amino acid receptors in the owl's auditory brainstem and midbrain Nuclei reflected specializations for temporal processing. In the lemniscal Nuclei, most neurons contained low levels of GluR1, and dense GluR2/3 and GluR4 immunoreactivity, with high levels of GluR4 in the dendrites.
Thus, we wondered if the Nuclei-specific differences in LCGU could be explained by localized differences in rate of brain heating during the two hyperthermic treatments.
The cochleotopic map projected, from apex to base, on the ventral-to-dorsal axes of the cochlear Nuclei. Terminal axonal degeneration in Nuclei of the superior olivary complex, lateral lemniscus, and inferior colliculus was interpreted as transynaptic, since degenerated axons could not be traced to these locations from the cochlear nerve or trapezoid body. Moreover, biotinylated dextran amine injection in the basal turn of scala media of a normal cochlea labeled cochlear nerve fibers projecting to the high-frequency regions of the cochlear Nuclei and to the flocculus, but not to more central auditory Nuclei.
By week 26, ascending axons have begun to form plexuses of terminal neuropil within all of the brainstem auditory Nuclei.
To a lesser extent it was found in the nucleus sagulum and in the area medial to the lemniscal Nuclei.
Nuclei that surround the main relay Nuclei of the ascending auditory pathway lacked labeling. In addition, since their axons are also selectively stained, auditory Nuclei can further be compartmentalized based on different terminal fields.
This model has been developed by reviewing quantitative studies of human brain stem Nuclei, results of intrasurgical recordings, studies of correlation of pathology with ABR waveform alterations, and findings from direct stimulation of the human cochlear Nuclei through a brain stem implant device. It was further assumed that wave III is generated by axons emerging from the cochlear Nuclei in the ventral acoustic stria and that waves IV and V reflect activity in parallel subpopulations of these ascending axons at a higher brain stem level. Beyond the cochlear nucleus, the largest component of the brain stem auditory pathway consists of axons projecting without interruption from the cochlear Nuclei to the contralateral lateral lemniscus and inferior colliculus.
Some Nuclei projected to one or the other DNLL division, but not to both. Other lower Nuclei projected to both DNLL divisions.
The results indicated that CRT1 mRNA is widely distributed in auditory Nuclei, including the fusiform and deep layers of the dorsal cochlear nucleus, the ventral cochlear nucleus, the superior olivary complex, the Nuclei of the Lateral Lemniscus and the inferior colliculus. Although most auditory Nuclei express CRT1 mRNA, the quantity of CRT1 mRNA varies among auditory Nuclei, indicating that many auditory Nuclei have high and fluctuating energy requirements.
Single HRP-labeled and double (HRP-GABA)-labeled neurons were systematically counted in all brainstem auditory Nuclei. Our results revealed that the IC receives GABAergic afferent connections from ipsi- and contralateral brainstem auditory Nuclei. In the superior olivary complex, a smaller number of neurons, which lie mainly in the periolivary Nuclei, display double labeling. In the contralateral cochlear Nuclei, only a few of the retrogradely labeled neurons were GABA immunoreactive.
the Lateral Lemniscus contains relay Nuclei of the auditory pathway in which the neurons have been grouped into dorsal and ventral (VNLL) Nuclei.
Neurons with similar perineuronal proteoglycans are also recognized in the extrapyramidal system (superior colliculus, red nucleus, reticular formation, vestibular Nuclei and cerebellar Nuclei), in the secondary auditory system (cochlear Nuclei, nucleus of trapezoid body, inferior colliculus and nucleus of lateral lemniscus), in the vestibulo-ocular reflex system (vestibular Nuclei and extraocular motor Nuclei), and in the pupillary reflex system. The neurons with perineuronal sulfated proteoglycans in the cerebral cortices and hippocampal subiculum are usually labeled with the lectin Vicia villosa agglutinin, though those in the cerebellar, vestibular and cochlear Nuclei may not be reactive to this lectin. Double staining of the retrosplenial cortex, hippocampal subiculum and cerebellar Nuclei with Golgi's silver nitrate and cationic iron colloid indicates that the perineuronal sulfated proteoglycans are identical with the Golgi's reticular coating or glial nets..
Thus, substantial overlap exists in the connections of the two facial subsystems; i.e., the solitary chemoreceptor information is not processed in Nuclei distinct from those making up the usual gustatory lemniscus..
Prominent intrasomal AMGBi was observed in Nuclei containing large cell bodies, including cranial motor neurons innervating somatic muscle, lateral vestibular and red nucleus and pontine/medullary reticular Nuclei. In the hypothalamus, the supraoptic and paraventricular Nuclei demonstrated the densest AMGBi. Neuropil of subcortical auditory Nuclei (cochlear nucleus, trapezoid body, lateral lemniscus and nucleus of lateral lemniscus, medial geniculate nucleus and inferior colliculus) had a high density of AMGBi.
Under this condition, application of baclofen decreased the amplitude of the medial lemniscus- and optic tract-evoked excitatory postsynaptic potentials in the two thalamic Nuclei investigated. These receptors are tonically activated by endogenous GABA, at least in vitro, and provide a negative control mechanism by which the excitatory amino acid-mediated transmission within these Nuclei can be regulated.
All three of these STT/SHT neurons projected to the intralaminar Nuclei (parafascicular or central lateral Nuclei) of the thalamus.
Several Nuclei of the lemniscal auditory pathway (dorsal nucleus of the Lateral Lemniscus, central nucleus of the inferior colliculus, lateral superior olive) as well as the nucleus of the central acoustic tract appear to project to the paralemniscal tegmentum.
Labelling observed in the ventral nucleus of the Lateral Lemniscus, and to a lesser extent in the dorsal nucleus of the Lateral Lemniscus, was accompanied by retrogradely labelled somata and therefore we cannot conclude unequivocally that the CNIC projects to these lemniscal Nuclei. Our findings are consistent with the existence of tonotopically organised feedback projections from the CNIC to the brainstem Nuclei that project to it..
A mixture of these tracers was injected iontophoretically into the VNTB and the results analyzed by first assessing magnitudes of autoradiographic signal in Nuclei receiving projections and then identifying the axons and terminals responsible for this signal in parallel sets of sections processed for BDA. Other sites receiving projections from the VNTB included the VNTB itself and the Nuclei of the Lateral Lemniscus. Significantly, the relative magnitudes of labeling within the Nuclei receiving inputs from the VNTB varied consistently as a function of the dorsoventral location of the injection site, confirming previous work showing that there is a partial segregation within this nucleus of neurons according to their projections. Our data also revealed an orderly topographic pattern of projections to the cochlear Nuclei, lateral superior olive and the inferior colliculus which is consistent with the known tonotopic organization both of the VNTB and these projection targets.
These areas included hippocampus (dentate gyrus and C1, -2, and -3), cerebral cortex (predominantly layer 3), arcuate nucleus, median eminence, medial geniculate nucleus, tegmental bundle, medial and lateral lemniscus, Purkinje layer of the cerebellum, and several brain stem Nuclei. In addition, the specificity of distribution of TR beta2 mRNA to certain brain Nuclei, particularly those involved in hearing, implies a specific functional role of this receptor subtype and provides a physiological basis to understand the effects of hypothyroidism on brain development..
Within the rat auditory system, CB is transiently expressed in several Nuclei during the period of synapse refinement, indicating a specific function of CB during development, yet little is known in this regard about PV and CR. In the adult, PV was heavily present in somata and neuropil of all Nuclei and in fibers of all tracts. CR was found in somata of the cochlear nucleus and peripheral aspects of the inferior colliculus as well as in fibers extending into the superior olivary complex and the Nuclei of the Lateral Lemniscus. In contrast, CR immunoreactivity was already strong two days before birth, yet the number and intensity of labeled neurons subsequently decreased and CR disappeared almost completely in the superior olivary complex, Nuclei of the Lateral Lemniscus, and central aspects of the inferior colliculus.
For the most part, jaw, tongue, and tracheosyringeal motor Nuclei did not receive terminations. Results also show that the auditory component of NB is not directly linked to the vocal control system at telencephalic levels, but the possibility remains that the lingual, beak, and auditory parts of NB play a role in vocalization by multisynaptic influences on cranial nerve motor Nuclei innervating various parts of the vocal tract..
The presence of perineuronal nets could not be correlated with any single class of neurons; however a few functionally related groups (e.g., motor and motor-related structures: motor neurons both in the spinal cord and in the efferent somatic Nuclei of the brainstem, deep cerebellar Nuclei, vestibular Nuclei; red nucleus, reticular formation; central auditory pathway: ventral cochlear nucleus, trapezoid body, superior olive, nucleus of the Lateral Lemniscus, inferior colliculus, medial geniculate body) were the main components of the neuronal subpopulation displaying chondroitin unsulfated proteoglycans in the surrounding extracellular matrix.
All superior olivary and periolivary Nuclei showed NA innervation by mainly fine, weakly staining fibres. Both Nuclei of the LL were also found to contain D beta H-positive fibres.
In the same Nuclei, FLI was increased even by short durations of stimulation (5 and 10 min) as compared to control rats, although FLI progressively increased for longer stimulation (20 and 45 min). In other auditory Nuclei, such as the inferior colliculus and the nucleus of the Lateral Lemniscus, there was no simple relation between the density of FLI and the three tested experimental parameters. Thus, the distribution and density of FLI did not vary in parallel in the various Nuclei of the auditory pathway as a function of the tested experimental parameters; different patterns of FLI changes were instead observed in different auditory Nuclei..
Labeled terminals were observed ipsilaterally in the parabigeminal nucleus, superficial layers of the superior colliculus, dorsal and lateral terminal Nuclei of the accessory optic system and pretectal Nuclei and contralaterally in the NOT and superficial layers of the superior colliculus.
At mesencephalic levels, the medial lemniscus innervates the lateral part of the torus semicircularis as well as various tegmental Nuclei.
Fibres with varicosities were observed in discrete areas of the thalamus (central lateral, posterior complex), hypothalamus (lateral, posterior and ventromedial), zona incerta, parvocellular red nucleus, intermediate and deep layers of the superior colliculus, central grey, deep mesencephalon, pontine parabrachial region, and pontine Nuclei.
Cells expressing mRNA for glutamic acid decarboxylase were most prominent in the inferior colliculus, but were also present in all lower auditory brainstem Nuclei, except the medial superior olivary nucleus and medial nucleus of trapezoid body. There were also differences in the pattern of expression of these mRNAs in the various brainstem auditory Nuclei; there was no preprotachykinin mRNA in any part of the superior olivary complex, only somatostatin mRNA was found in the ventral cochlear nucleus, and expression of preproenkephalin mRNA was pronounced in the ventral nucleus of the trapezoid body and the rostral periolivary zone.
These findings provide immunocytochemical and electrophysiological evidence that the various Nuclei of the auditory pathway are activated by electrical stimulation of the cochlea..
A recent neurophysiological study demonstrated that areas adjacent to the medial vestibular nucleus apparently to participate in the production of OKN, because both the slow component and after-nystagmus similar to OKN and optokinetic after nystagmus were elicited by stimulation of the vestibular Nuclei. The present study shows that this direct projection from the NOT to the vestibular Nuclei may serve to drive velocity storage in the vestibular Nuclei..
In addition, H-FABP was present in the thalamus, entorhinal and piriform cortex, and throughout the pontine and medullary Nuclei.
Interrhombomeric cell migration was either sparse or restricted to specific Nuclei. The cranial nerve motor Nuclei showed rhombomeric origins consistent with the patterns described in early embryos. 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. The Nuclei of the Lateral Lemniscus originated between r1 and r3. There were consistently some interrhombomeric neuronal migrations inside the vestibular column, some motor Nuclei and the reticular formation, involving only one rhombomere length. The pontine Nuclei, which extended from r1 to r7, showed neuronal migrations that crossed several rhombomeres.
It is expressed in: (1) motor Nuclei such as the oculomotor nucleus, trochlear nucleus, motor trigeminal nucleus, abducens nucleus, facial nucleus, ambiguus nucleus, dorsal motor nucleus of vagus and hypoglossal nucleus; (2) several sensory-related Nuclei like the mesencephalic trigeminal nucleus, ventral nucleus of the Lateral Lemniscus, lateral and spinal vestibular Nuclei, ventral and dorsal cochlear Nuclei and nucleus of the trapezoid body; and (3) other regions such as the red nucleus, dorsal raphe nucleus, pontine Nuclei, three cerebellar Nuclei (medial, interposed and lateral), Purkinje cells, cells in the granular layer of the cerebellum, locus coeruleus, several areas of the reticular nucleus and area postrema..
The Nuclei of the Lateral Lemniscus in the echolocating bat, Eptesicus fuscus, are large and highly differentiated. To determine whether the dissimilar response properties are due in part to differential ascending input, we examined the retrograde transport from small deposits of horseradish peroxidase (HRP) or HRP conjugated with wheat germ agglutinin (WGA-HRP) in the Nuclei of the Lateral Lemniscus. The intermediate nucleus (INLL) and the two divisions of the ventral nucleus (VNLL) receive almost exclusively monaural input from the anteroventral and posteroventral cochlear Nuclei and from the medial nucleus of the trapezoid body. Although the three monaural Nuclei of the Lateral Lemniscus all receive input from the same set of Nuclei, and from the same identified cell types in the cochlear nucleus, there is a difference in the relative proportions of input from these sources. The differences in response properties between monaural Nuclei, however, are not due to input from different Nuclei or cell types but may be influenced by differing magnitudes of the constituent ascending projections..
Nuclei in the descending pain modulating system were not relatively depressed..
KV3.1b subunits are expressed in specific neuronal populations of the rat brain, such as cerebellar granule cells, projecting neurons of deep cerebellar Nuclei, the substantia nigra pars-reticulata, the globus pallidus, and the ventral thalamus (reticular thalamic nucleus, ventral lateral geniculate and zona incerta). The KV3.1b protein is also present in various neuronal populations involved in the processing of auditory signals, including the inferior colliculus, the Nuclei of the Lateral Lemniscus, the superior olive, and some parts of the cochlear Nuclei; as well as in several other neuronal groups in the brainstem (e.g., in the oculomotor nucleus, the pontine Nuclei, the reticulotegmental nucleus of the pons, trigeminal and vestibular Nuclei, and the reticular formation) and subsets of neurons in the neocortex, the hippocampus and the caudate-putamen shown by double staining to correspond to neurons containing parvalbumin.
The goals of the study were (1) to compare and contrast the location of GABAergic and glycinergic neurons and puncta, (2) to determine whether Nuclei containing immunoreactive neurons likewise have a similar concentration of puncta, (3) to assess the uniformity of immunostaining within a nucleus and to consider regional differences that were related to or independent of cytoarchitecture, and (4) to compare the patterns recognized in this bat with those in other mammals. (3) Some Nuclei have GABAergic or glycinergic neurons exclusively; a few have neither. (5) Even Nuclei devoid of or with few GABAergic or glycinergic neurons contain relatively abundant numbers of puncta; some neurons receive axosomatic terminals of each type. (6) In a few Nuclei there are physiological subregions with specific local patterns of immunostaining. (7) The patterns of immunostaining resemble those in other mammals; the principal exceptions are in Nuclei that, in the bat, are hypertrophied (such as those of the Lateral Lemniscus) and in the medial geniculate body. (8) Cellular colocalization of GABA and Gly is specific to only a few Nuclei.
The aim of the present study was to describe the spatiotemporal pattern of somatostatin and leu-enkephalin immunoreactivity in the auditory brainstem Nuclei of the developing rat and to correlate it with other developmental events. Somatostatin immunoreactivity (SIR) was found in all Nuclei of the auditory brainstem, yet it was temporally restricted in most Nuclei. As these Nuclei receive direct input from VCN neurons, and as the distribution and morphology of the somatostatinergic fibers in the superior olivary complex (SOC) was like that of axons from VCN neurons, these findings suggest a transient somatostatinergic connection within the auditory system. Aside from the LSO, MSO, and MNTB, labeled fibers were found to a smaller extent in all other auditory brainstem Nuclei. After P7, the SIR decreased and only a few immunoreactive elements were found in the adult auditory brainstem Nuclei, indicating that somatostatin is transiently expressed in the rat auditory brainstem.
Several auditory brainstem Nuclei, including the superior paraolivary nucleus, the medial superior olive, the lateral and ventral trapezoid Nuclei, and the central nucleus, as well as the external cortex of the inferior colliculus, were entirely devoid of FGF-2-IR. In the dorsal cochlear nucleus, the lateral superior olive, and the Nuclei of the Lateral Lemniscus, FGF-2-IR was not detectable in nerve cell bodies prior to adult age.
Projections to the OS originate bilaterally in the cochlear Nuclei (nucleus angularis) and the nucleus laminaris.
CN efferents projected heavily to the lateral superior olive (LSO) ipsilaterally, the medial superior olive (MSO) bilaterally, and contralaterally to the medial (MNTB) and ventral (VNTB) Nuclei of the trapezoid body, the ventral (VNLL) and intermediate Nuclei of the Lateral Lemniscus and the central nucleus of the inferior colliculus (ICc). There were smaller projections to the lateral nucleus of the trapezoid body ipsilaterally, the dorsal and dorsomedial periolivary Nuclei bilaterally, and the dorsal nucleus of the Lateral Lemniscus contralaterally. CN ablation depressed D-[ 3H]Asp release in the MSO bilaterally and in the contralateral MNTB and VNLL, suggesting that the CN efferents to these Nuclei may use glutamate or aspartate as a transmitter.
Micropunch and microdissection procedures provided fresh samples of these auditory Nuclei for the measurement of the high-affinity uptake and electrically evoked release of exogenous D-[ 3H]ASP. The study also determined if the LSO and MSO contain glycinergic synaptic endings by measuring uptake and release of [ 14C]Gly in these Nuclei, and whether the MNTB, VNLL, and ICc contain GABAergic endings by assessing the uptake and release of [ 14C]GABA in these structures. Each of these Nuclei manifested the high-affinity uptake and the evoked Ca(2+)-dependent release of D-[ 3H]Asp, suggesting the presence of synaptic endings that may use Glu or Asp as a transmitter.
In the cerebellum, Golgi cells in the granule cell layer as well as a subpopulation of neurons in the interposed Nuclei were consistently labelled. In the brainstem, where the bulk of the labelling was concentrated, several Nuclei showed a high level of transcript expression, including the superior olivary complex, nucleus of the trapezoid body and the ventral nucleus of the Lateral Lemniscus.
The present investigation used an antibody directed against the extracellular domain of the signal transducing nerve growth factor receptor, trkA, to reveal immunoreactive perikarya or fibers within the olfactory bulb and tubercle, cingulate cortex, nucleus accumbens, striatum, endopiriform nucleus, septal/diagonal band complex, nucleus basalis, hippocampal complex, thalamic paraventricular and reuniens Nuclei, periventricular hypothalamus, interpeduncular nucleus, mesencephalic nucleus of the fifth nerve, dorsal nucleus of the Lateral Lemniscus, prepositus hypoglossal nucleus, ventral cochlear nucleus, ventral lateral tegmentum, medial vestibular nucleus, spinal trigeminal nucleus oralis, nucleus of the solitary tract, raphe Nuclei, and spinal cord. Sections stained with a pan-trk antibody that recognizes primarily trkA, as well as trkB and trkC, labeled neurons within all of these regions as well as within the hypothalamic arcuate, supramammilary, and supraoptic Nuclei, hippocampus, inferior and superior colliculus, substantia nigra, ventral tegmental area of T'sai, and cerebellular Purkinje cells.
C-fos immunocytochemistry was used as a rapid and sensitive technique for identification of sound activated neurons in the cerebral cortex, the cerebellum and subcortical Nuclei of the big brown bat, Eptesicus fuscus. When bats were stimulated with sounds under the both-ears opened conditions, Fos-like immunoreactive neurons were bilaterally and symmetrically distributed in all subcortical auditory Nuclei, the auditory cortex, the superior colliculus, the pontine Nuclei and the cerebellar deep Nuclei. They were predominantly distributed in all contralateral auditory Nuclei from the level of the nucleus of the Lateral Lemniscus down and in all ipsilateral auditory Nuclei from the level of inferior colliculus up as well as in the contralateral superior colliculus, pontine Nuclei and cerebellar deep Nuclei.
With the exception of the lateral superior olive, the ventral and the intermediate Nuclei of the Lateral Lemniscus, and the auditory cortex, which already express CaBP prenatally, CaBP immunoreactivity is not present before postnatal day 2 (P2). There was no detectable sequence in CaBP development from lower to higher stations in the auditory pathway, i.e., the different Nuclei appear to express CaBP independently of each other, indicating that intrinsic, rather than peripheral, maturation processes may predominantly influence CaBP expression. Neurons in four brainstem Nuclei (the lateral superior olive, the ventral and intermediate Nuclei of the Lateral Lemniscus, and the central nucleus of the inferior colliculus) express CaBP only transiently. In these Nuclei, CaBP immunoreactivity peaks between P6 and P18, which coincides with the period of synapse stabilization.
NOS-positive cells in the caudal brainstem were found in the cerebellar Nuclei, in the superior vestibular nucleus, in the reticular Nuclei, ventrolateral to the nucleus of the solitary tract, in the perihypoglossal, and in the dorsal funicular nucleus.
The densest clusters of immunoreactive perikarya were found in the inferior and superior colliculi, the inferior olive, the periaqueductal gray, the central tegmental field and the substantia nigra, whereas the central linear nucleus, the locus coeruleus, the nucleus incertus, the dorsal and ventral Nuclei of the Lateral Lemniscus, the cuneiform nucleus, the pontine gray, the Kölliker-Fuse nucleus, the dorsal motor nucleus of the vagus and the medial nucleus of the solitary tract had the lowest density. A high density of immunoreactive fibers was observed in the substantia nigra, the nucleus ruber, the superior and inferior colliculi, the periaqueductal gray, the interpeduncular nucleus, the central, magnocellular and lateral tegmental fields, the marginal nucleus of the brachium conjunctivum, the postpyramidal nucleus of the raphe, the inferior olive, the internal division of the lateral reticular nucleus and the medial and lateral Nuclei of the superior olive. A moderate density of calbindin-immunoreactive fibers was found in the retrorubral nucleus, the central linear nucleus, the locus coeruleus, the nucleus sagulum, the dorsal nucleus of the raphe, the cuneiform nucleus, the ventral and dorsal Nuclei of the Lateral Lemniscus, the medial nucleus of the solitary tract, the dorsal motor nucleus of the vagus, and the cuneate nucleus.
The objective of the present study was, by using the Mongolian gerbil (Meriones unguiculatus) as an animal model, to provide data on the growth dynamics of central auditory and visual Nuclei and to relate the growth of these structures to the growth of the entire brain. Increases in volumes of Nuclei and changes in their shape were analyzed for animals at the day of birth (P0); at postnatal days P7, P15, P22, P28; and in the third month (P90). The auditory Nuclei investigated were the cochlear nucleus, the superior olivary complex, the Nuclei of the Lateral Lemniscus, the inferior colliculus, and the medial geniculate body. At P15 (shortly after the onset of central auditory responsiveness), the volumes of all auditory Nuclei examined reached only 60-70% of their adult sizes; i.e., they showed considerable growth afterwards. At the same time (shortly before the animals open their eyes), the visual Nuclei had almost reached their adult sizes (superior colliculus, 91%; lateral geniculate nucleus, 97%). These data demonstrate that different sensory Nuclei contribute in highly different fashions to brain growth. There are system-specific differences in growth dynamics between central auditory and visual Nuclei. However, the absolute growth of Nuclei in both sensory systems relates to the brain regions. The data do not support the idea of a peripheral-to-central gradient in the growth of central auditory Nuclei..
The intense oxidase reactions were present in the red nucleus, oculomotor nucleus, trochlear nucleus, ventral nucleus of the Lateral Lemniscus, dorsal and ventral cochlear Nuclei, vestibular Nuclei, Nuclei of posterior funiculus, nucleus of the spinal tract of the trigeminal nerve, lateral reticular nucleus, inferior olivary nucleus, and hypoglossal nucleus.
This study was designed to determine if there are age-related alterations in the bio-synthetic enzyme glutamic acid decarboxylase (GAD), the degradative enzyme GABA-transaminase (GABA-T), and the uptake system for GABA in the central nucleus of the inferior colliculus (CIC), the cochlear nucleus (CN), and/or Nuclei of the Lateral Lemniscus (NLL) of Fischer-344 rats. CN) integrative Nuclei, demonstrate selective, age-related neurochemical deficits; and 3) age-related neurochemical changes in central auditory structures may contribute substantially to the abnormal perception of signals in noise and loss of speech discrimination observed in neural presbycusis..
To determine the level at which certain response characteristics originate, we compared monaural auditory responses of neurons in ventral cochlear nucleus, Nuclei of lateral lemniscus and inferior colliculus. Exceptionally broad tuning curves were found in the Nuclei of the Lateral Lemniscus, while exceptionally narrow tuning curves were found in the inferior colliculus. Neither specialized tuning characteristic was found in the ventral cochlear Nuclei. Range of latencies across neurons was small in the ventral cochlear nucleus (1.3-5.7 ms), intermediate in the Nuclei of the Lateral Lemniscus (1.7-19.8 ms) and greatest in the inferior colliculus (2.9-42.0 ms). We conclude that, in the Nuclei of the Lateral Lemniscus and in the inferior colliculus, unique tuning and timing properties are built up from ascending inputs..
Quantitative receptor autoradiography in the rat brain revealed [ 125I-Tyr]hCGRP8-37 binding sites mostly concentrated in the nucleus accumbens (shell), caudate putamen (tail), amygdaloid body, pontine Nuclei, cerebellum and inferior olive, whereas lower quantities of sites were present in the olfactory tubercle, nucleus accumbens (core), medial geniculate, superior colliculus, temporal cortex, inferior colliculus, lateral lemniscus, vestibular Nuclei and principal sensory trigeminal nucleus..
3) Calretinin label is abundant but more restricted to subsets of auditory Nuclei or subpopulations of cells than parvalbumin. 4) Calcium-binding proteins are useful markers to define particular subregions or cell types in auditory Nuclei: for example, i) different labeling patterns are obtained within the Nuclei of the Lateral Lemniscus and adjacent tegmental zones; ii) in the inferior colliculus both calbindin- and calretinin-antisera yield similar regional specific staining patterns, but label different cell types; iii) subregions of the medial geniculate body have characteristic profiles of calcium-binding proteins; and iv) analyses of different Nuclei showed that there is no simple common denominator for cells characterized by the expression of particular calcium-binding proteins, nor does labeling correspond in a straightforward way with specific functional systems.
Our observations demonstrate convergent, bilateral input from several auditory brainstem Nuclei to the PnC, predominantly originating from neurons in the cochlear nuclear complex and the superior olivary complex. Almost no input neurons were found in the Nuclei of the Lateral Lemniscus. As the relatively long neuronal response latencies in several of these auditory Nuclei appear to be incompatible with the primary ASR, we conclude that neurons in the cochlear root Nuclei most likely provide the auditory input to PnC neurons that is required to elicit the ASR.
Sparse FLI was detected in the superior olivary complex, the pontine Nuclei and the ipsilateral dorsal nucleus of the Lateral Lemniscus, whereas the contralateral dorsal nucleus of the Lateral Lemniscus was moderately labeled.
No ChAT-I neurons or fibers were observed in NM, nucleus angularis, nucleus laminaris, in the Nuclei of the Lateral Lemniscus, or in the nucleus mesencephalicus lateralis pars dorsalis.
The densest network of immunoreactive fibres was visualized in the interpeduncular nucleus, marginal nucleus of the brachium conjunctivum, alaminar and laminar spinal trigeminal Nuclei and in the substantia nigra.
In rat brain, positive neurons were located in the cerebral cortex, subiculum, amygdala, thalamic reticular nucleus, Nuclei of the inferior colliculus, Nuclei of the trapezoid body, and vestibular Nuclei. They were also scattered in the hypothalamus, substantia nigra pars reticularis, red nucleus, parabrachial Nuclei, brainstem reticular nuclear group, ventral cochlear nucleus, Nuclei of lateral lemniscus, and deep cerebellar Nuclei.
Immunohistochemical and ligand-binding techniques were used to visualize the neurotransmitter serotonin and one of its receptors, the 5-HT1A subtype, in auditory Nuclei of the brainstem. Serotonergic fibers and terminal endings were found in all auditory Nuclei extending from the cochlear nucleus to the inferior colliculus, including the superior olivary complex and the Nuclei of the Lateral Lemniscus. All serotonergic cell bodies were located outside the auditory Nuclei. With no serotonergic cell bodies present in the auditory Nuclei, the present neuroanatomic and neurochemical findings support behavioral and neurophysiologic findings that the serotonergic system may modulate central auditory processing..
Seizures were also blocked with lesions located between the external and central Nuclei of the IC.
With respect to control rats, in the NGF-treated cases Fos-ir cells were more numerous in the anterior olfactory nucleus, in the medial prefrontal and anterior cingulate cortices, in the basal forebrain, in the preoptic and ventromedial Nuclei of the hypothalamus, as well as anterior hypothalamic area, in the thalamic midline Nuclei, and in some brainstem structures, such as the parabrachial nucleus. These included: frontoparietal and occipital cortical fields, the hypothalamic arcuate nucleus, and many brainstem structures, such as the dorsal nucleus of the Lateral Lemniscus, posterodorsal tegmental, medial and lateral vestibular, ventral cochlear, and prepositus hypoglossal Nuclei.
Thresholds for triggering summed auditory evoked responses (ERs) were measured in non-auditory (= extralemniscal--EL) Nuclei receiving direct auditory projections from the Lateral Lemniscus. Primary EL ERs with onset latency of 3-6 ms reflecting activation of direct EL projections of lemniscal auditory Nuclei were registered in caudal pontine reticular nucleus (CPRN), in deep layers of superior colliculus (SC) and in ventromedial hypothalamus (VMH). Secondary EL ERs (waves of EL ERs with onset latency above 10 ms) reflecting diffuse auditory EL co-activation of the brain, were registered besides the above mentioned Nuclei also in the medial amygdala (MA). Threshold sound intensities for evoking primary EL ERs in CPRN, SC and VMH, for secondary EL ERs in all extralemniscal Nuclei tested, and for conditioned avoidance behavior in a two-way shuttle box, were compared mutually. There were no significant mutual differences among thresholds for inducing secondary EL ERs in all EL Nuclei tested. The results suggest that auditory EL projections into SC and/or VMH (but not into CPRN) might represent the primary triggering source for secondary EL ERs in various extralemniscal Nuclei.
Inferior colliculus neurons were found to project to many Nuclei and regions of the hindbrain where olivocochlear neurons reside.
In general, both the Nuclei lateralis and centralis of the torus semicircularis showed a high density of immunoreactive fibers from rostral to caudal levels. The localization of neuropeptide Y-like immunoreactivity in both Nuclei--lateralis and centralis--of the carp torus semicircularis suggests that this peptide is involved in the control of visual, auditive, and lateral line mechanisms, as well as in the control of feeding..
Several neurons from different Nuclei give rise to descending spinal tracts and project to various levels in the spinal cord of goldfish, Carassius auratus. As many as 16 brain Nuclei or neuronal aggregations and the Mauthner cells project posteriorly up to the 20th spinal segment.
Bushy cells in the anteroventral cochlear nucleus (AVCN) receive their principal excitatory input from the auditory nerve and are the primary source of excitatory input to more centrally located brainstem auditory Nuclei. Despite this pivotal position in the auditory pathway, details of the basic physiological information being carried by axons of these cells and their projections to more central auditory Nuclei have not been fully explored.
Although other auditory Nuclei in the brain-stem, the ventral nucleus of the Lateral Lemniscus, the trapezoid body and the auditory nerve responded to transient stimuli with an amplitude larger than that of the IC, no amplification occurred with 50 Hz stimuli in these Nuclei.
Evoked potentials and single neuron activity with diminished responses to the second of paired tones were recorded in the brainstem reticular formation in the paragigantocellular region at the caudal level of the pons, but diminished responses were not observed in the primary auditory relay Nuclei. Stimulation of the auditory Nuclei up to the level of the Lateral Lemniscus, but not the superior colliculus, was also able to substitute for an auditory stimulus to produce sensory gating in the hippocampus.
PL is located ventral to DPL and medial to the intermediate and ventral Nuclei of the Lateral Lemniscus; in PL 88% (14/16) of neurons were binaural.
We examined the organization of descending projections from the inferior colliculus (IC) to auditory brainstem Nuclei and to pontine and reticular Nuclei in the rat by employing the anterograde axonal tracer Phaseolus vulgaris-leucoagglutinin (PHA-L). Small PHA-L injections into cytologically defined subNuclei of the IC revealed that each subnucleus has a unique pattern of efferent projections. Minor projections were found to pontine and reticular Nuclei. Efferent fibers from the dorsal cortex of the IC terminate mainly in the Sag, while other Nuclei of the auditory and extra-auditory brainstem receive only minor projections. The intercollicular zone sends a moderate number of fibers to the DLL and very few, if any, to the remaining auditory brainstem Nuclei. The present data demonstrate that the four subNuclei of the IC have a differential pattern of descending projections to Nuclei in the pontine and medullary brainstem.
Although the connections of the auditory brainstem Nuclei are well described in adult mammals, almost nothing is known concerning how and when these connections develop. Axons traverse Nuclei in the superior olivary complex and the Lateral Lemniscus and finally grow up into the inferior colliculus, but axon collaterals do not form during this period. The second period (E18-P5) is marked by pronounced collateral branching of CN fibers in auditory brainstem Nuclei. The remaining auditory Nuclei become successively innervated, as indicated by collaterals found in them.
Neurons located in the trigeminal sensory complex (TSC) and the lateral pontine tegmentum (LPT) have been reported to project to both the accessory abducens and the facial Nuclei, which innervate the retractor bulbi and orbicularis oculi muscles respectively, in order to control the nictitating membrane (NM) and eyelid defensive reflex. Only a few scattered neurons were found in the principal and spinal trigeminal Nuclei.
Hybridization was most dense in neurons of the motor and autonomic cranial nerve Nuclei including the oculomotor, Edinger-Westphal, and trochlear Nuclei of the midbrain, the abducens, superior salivatory, trigeminal, facial and accessory facial Nuclei of the pons, and the hypoglossal, vagus, and solitary Nuclei and nucleus ambiguous of the medulla. In addition, numerous cells in the pedunculopontine and laterodorsal tegmental Nuclei, the ventral nucleus of the Lateral Lemniscus, the medial and lateral divisions of the parabrachial nucleus, and the medial and lateral superior olive were labeled. Occasional labeled neurons were distributed in the giantocellular, intermediate, and parvocellular reticular Nuclei, and the raphe magnus nucleus.
Each IC was divided into a dorsal piece, which contained the dorsal cortex and dorsomedial nucleus, and a ventral piece, which contained the central and lateral Nuclei.
The medial nucleus of the trapezoid body (MNTB) is one of several principal Nuclei in the superior olivary complex (SOC) of mammals. It is classically thought to function as a relay station between the contralateral ventral cochlear nucleus and the lateral superior olive (LSO), playing a role among those brainstem Nuclei that are involved in binaural hearing. All cells (n = 10) projected exclusively ipsilaterally and had terminal axonal arbors in a variety of auditory brainstem Nuclei.
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