Superior Vestibular Nucleus


Clinicoanatomic correlation in this patient suggests that a lesion of the superior vestibular nucleus and its efferent crossing ventral tegmental tract could be responsible for the PPUN.  

Furthermore, there is now accumulating evidence that the CVTT pathway emerging from the superior vestibular nucleus (SVN) also plays an important role in the mediation of excitatory upward EP and VEM signals to the III.  

From retrograde injections into the both the flocculus and uvula-nodulus, numerous cells were found in the superior vestibular nucleus (VeS), the cerebellovestibular process (pcv), the descending vestibular nucleus (VeD), and the medial vestibular nucleus (VeM).  

RESULTS: Three types of labeled neurons were observed: (1) neurons only retrogradely microfluorosphere-labeled that were mainly located in the medial vestibular nucleus, lateral vestibular nucleus, superior vestibular nucleus and parvicellular reticular nucleus on the ipsilateral side of the injection; (2) neurons that were both immunolabeled with CGRP and also retrogradedly labeled with microfluorospheres, indicating that they are CGRP cells projecting to the area of vestibular efferent nucleus, these cells were mainly distributed in the superior vestibular nucleus and dorsal vestibular nucleus, and (3) cells only immunolabeled for CGRP that were scattered extensively in the brainstem.  

One terminal field was located primarily ipsilateral to the injection site and involved rostrodorsal aspects of the vestibular nuclei, including superior vestibular nucleus and rostral portions of the medial vestibular nucleus (MVN) and lateral vestibular nucleus (LVN).  

The characteristics of the baseline spike activity of neurons in the superior vestibular nucleus of rats were studied after exposure to vibration for five, 10, and 15 days using a computerized method for recording and analyzing interspike intervals. The results demonstrate changes in the level of the functional state of neurons in the superior vestibular nucleus after exposure to vibration.  

The tracing experiments showed that Purkinje cells of zone 1 projected to the parvicellular part of lateral cerebellar nucleus and superior vestibular nucleus, while Purkinje cells of zone 3 projected to group Y and the superior vestibular nucleus.  

The results of vibration action (5, 10 and 15 daily) on spontaneous neuronal activity of superior vestibular nucleus were studied using software for biological signals. The results have demonstated that neurons of superior vestibular nucleus have mean frequency 14.0 +/- 1.4 Hz. The results obtained suggest significant reconstruction of spontaneous impulse activity in neurons of the superior vestibular nucleus within postvibration period..  

One of the major differences between the connections of these nuclei was found at the level of the mesencephalon: the eye-moving cranial nerve nuclei received the densest projection from the superior vestibular nucleus (SVN).  

Otolith-activated vestibular neurons in the superior vestibular nucleus were extremely rare.  

Thirty-seven neurons were recorded in the superior vestibular nucleus (SVN) of two cynomolgus monkeys 1-2 yr after bilateral lateral canal nerve section to test whether the central neurons had spatially adapted for the loss of lateral canal input.  

NOS I-positive neurons and fibres were found in all parts of VNCc: medial vestibular nucleus (MVN); lateral vestibular nucleus (LVN); superior vestibular nucleus (SVN); inferior vestibular nucleus (IVN); X, Y, Z groups and Cajal's nucleus.  

UBN due to pontine lesions could result from damage to the ventral tegmental tract (VTT), originating in the superior vestibular nucleus (SVN), coursing through the ventral pons and transmitting excitatory upward vestibular signals to the third nerve nucleus.  

2) Laterally placed vestibular complex injections that included the central superior vestibular nucleus labeled projections only in twitch motoneuron subgroups.  

Ascending branch ramifications terminated in the superior vestibular nucleus, the magnocellular and parvicellular medial vestibular nuclei, and the cerebellum.  

Previous anatomical studies in rabbits and rats have shown that the superior vestibular nucleus (SVN), medial vestibular nucleus (MVN) and inferior vestibular nucleus (IVN) project to the parabrachial nucleus (PBN) and K├Âlliker-Fuse (KF) nucleus.  

The principal brainstem areas of saccular nerve termination were lateral, particularly the spinal vestibular nucleus, the lateral portion of the superior vestibular nucleus, ventral nucleus y, the external cuneate nucleus, and cell group l. Principle brainstem areas of termination of the utricular nerve were the lateral/dorsal medial vestibular nucleus, ventral and lateral portions of the superior vestibular nucleus, and rostral portion of the spinal vestibular nucleus.  

The t(-Y) zone also projected to the pcv, but more ventrally on the border with the superior vestibular nucleus (VeS).  

The density of serotonin transporter-immunopositive fibers is greatest in the superior vestibular nucleus and the medial vestibular nucleus, especially along the border of the fourth ventricle; it declines in more lateral and caudal regions of the vestibular nuclear complex.  

Both TrkA- and TrkB-immunostained cells were widely distributed in the lateral, medial and spinal vestibular nuclei, and were less frequently seen in the superior vestibular nucleus, x and y subnuclei.  

Utricular and lagenar nerve-evoked activation maps overlapped strongly in the lateral and descending vestibular nuclei, whereas lagenar amplitudes were greater in the superior vestibular nucleus.  

In the brainstem of normal rats subjected to OVAR, a high density of Fos-immunoreactive (Fos-ir) neurons was found in the vestibular nuclear complex (namely, spinal vestibular nucleus, SpVe; medial vestibular nucleus, Mve; superior vestibular nucleus, SuVe) and subnuclei (namely, group x and group y), whereas a lower density was found in the lateral vestibular nucleus (LVe).  

The rostral group extended from rhombomeres 1-4 (r1-r4) and was restricted mainly to the superior vestibular nucleus.  

After iontophoretic injections of tracers into the rH45c zones, heavy anterograde labeling was found in the infracerebellar nucleus and the medial margin of the superior vestibular nucleus. After injections into the rVA zones, heavy anterograde labeling was found in the medial and descending vestibular nuclei, the nucleus prepositus hypoglossi, and the central region of the superior vestibular nucleus.  

Units that responded during rotation were located in lateral and medial PBN and KF caudal to the trochlear nerve at sites that were confirmed anatomically to receive superior vestibular nucleus afferents.  

Twelve of 27 commissural neurons were located in the medial vestibular nucleus, 5 were in the lateral vestibular nucleus, 10 were in the descending vestibular nucleus, and no commissural neurons were recorded in the superior vestibular nucleus.  

UT-activated vestibulothalamic neurons were recorded in the medial vestibular nucleus (MVN; 24/40), the lateral vestibular nucleus (LVN; 9/40), the descending vestibular nucleus (DVN; 6/40), and the superior vestibular nucleus (SVN; 1/40).  

The superior vestibular nucleus was relatively free of dye-coupled vestibular neurons.  

No significant difference was detected between neuronal responses in the lateral and the superior vestibular nucleus.  

Mapping these results onto adult anuran vestibular organization indicates that the superior vestibular nucleus derives from larval r1/2, the lateral vestibular nucleus from r3/4, and the major portions of the medial and descending vestibular nuclei from r5-8.  

Anterior vertical canal signals peaked in the superior vestibular nucleus, posterior vertical canal signals peaked in the descending and in the dorsal part of the lateral vestibular nucleus, whereas horizontal canal signals peaked in the descending and in the ventral part of the lateral vestibular nucleus.  

The remaining neurons were located in group X (two neurons) and the superior vestibular nucleus (three neurons).  

The distribution of retrogradely labeled Purkinje cells revealed that efferent projections from the dorsal surface of the flocculus and the ventral paraflocculus to the superior vestibular nucleus, rostral medial vestibular nucleus, ventral lateral vestibular nucleus, and caudal aspect of the vestibular nuclear complex (caudal medial vestibular nucleus, inferior vestibular nucleus and nucleus prepositus hypoglossi) tended to correspond to previously identified climbing fiber zones [ Ruigrok et al.  

Labeled terminals of Purkinje cell axons of lobule X were numerous in the superior vestibular nucleus (SV), medial parts of the parvocellular (MVpc) and the caudal part (MVc) of the medial vestibular nucleus (MV), and group y.  

Labeled terminals of Purkinje cell axons were numerous in the superior vestibular nucleus, the parvocellular (MVpc) and the caudal part (MVc) of the medial vestibular nucleus (MV), and group y.  

A lateral descending noradrenergic bundle (LDB) projects from LC to the superior vestibular nucleus (SVN) and rostral lateral vestibular nucleus (LVN).  

A moderate amount of terminal labeling was found in the medial cerebellar nucleus, the superior vestibular nucleus (laterally, dorsally, and medially), and the descending vestibular nucleus, particularly in the lateral half. Injections into the rotation zone resulted in heavy terminal labeling in the superior vestibular nucleus (particularly dorsally and medially), the descending vestibular nucleus (particularly medially), and the medial vestibular nucleus.  

The results showed that the superior vestibular nucleus and the medial vestibular nucleus, especially its rostral-to-middle parts, project to the lateral part of the parafascicular thalamic nucleus (corresponding to the centromedian nucleus in primates), the transitional zone between the ventrolateral thalamic nucleus (VL) and the ventral posterolateral thalamic nucleus (VPL) (the region considered to be the nucleus ventralis intermedius of Vogt [ Vogt C.  

The results show that neurons in the caudal part of the trigeminal mesencephalic nucleus project mainly to the medial, inferior and lateral vestibular nuclei and moderately to the peripheral part of the superior vestibular nucleus.  

The spatial distribution of ChAT-Ir within the VN of control cats showed darkly stained neurons and varicosities mainly located in the caudal parts of the medial (MVN) and inferior (IVN) VN, the nucleus prepositus hypoglossi (PH) and, to a lesser extent, in the medial part of the superior vestibular nucleus (SVN).  

No abnormalities were observed in the volume or length of the vestibular nuclei, except for a decrease in both dimensions in the superior vestibular nucleus (SNV).  

When the tracer covered the FL, labeled axon terminals were located within the medial and ventrolateral parts of the medial vestibular nucleus, superior vestibular nucleus and y-group. When the tracer covered the VP, labeled axon terminals were located within the caudo-ventral part of posterior interpositus and dentate nuclei, in addition to the medial and ventrolateral parts of the medial vestibular nucleus, superior vestibular nucleus and y-group.  

The caudomedial subdivision of the nucleus projected ipsilaterally to the dorsal and medial parts of the superior vestibular nucleus (Su Ve), the dorsomedial part of the lateral vestibular nucleus (LVe), and the dorsal parts of the medial (MVe) and spinal (Sp Ve) vestibular nuclei, and projected contralaterally to the ventrolateral corners of the Su Ve and LVe, the ventral part of the MVe, and the lateral part of the Sp Ve.  

Neuronal loss as a percentage of the total number of neurons was greatest in the superior vestibular nucleus and least in the medial vestibular nucleus.  

Many fibers were labeled in the vestibular nerve and in fascicles of the descending vestibular nucleus, as well as ascending fibers in the superior vestibular nucleus and fibers directed to the medial vestibular nucleus. Labeled terminals were present in the medial vestibular nucleus, especially along the ventricular border, in the neuropil of the superior vestibular nucleus, and scattered in the descending and ventral portions of the lateral vestibular nucleus.  

Beak NB also received a projection from a paralateral lemniscal nucleus, and the dorsocaudal part of auditory NB and the medially adjacent neostriatum also received a projection from a lateral subnucleus of the superior vestibular nucleus (VS).  

In the hindbrain, immunoreactive neurons were found in the nucleus of the solitary tract, and varicose fibers were observed in the superior vestibular nucleus and the subventricular area.  

Neuronal activity was investigated in the left superior vestibular nucleus (SVN), lateral vestibular nucleus (LVN), and rostral part of the medial vestibular nucleus (MVN) in the alert guinea pig after a unilateral (left) labyrinthectomy was performed.  

1 h after unilateral labyrinthectomy, increased levels of astroglial S100 immunoreactivity were found in the superior vestibular nucleus and in the medial/lateral vestibular nucleus border region on the side contralateral to the deafferentation.  

The depletion of the visual following eye velocity signal on superior vestibular nucleus (SVN) FTNs accompanied a small but consistent decrease of visual following eye velocity amplitude.  

Using single-unit recording and microstimulation methods, a group of flocculus target neurons (FTNs) were identified in the superior vestibular nucleus (SVN) and were studied using visual-vestibular interaction paradigms in alert squirrel monkeys.  

5:279-283) that Purkinje cells of the rabbit flocculus projecting to the medial vestibular nucleus are located in two discrete zones, FZII and FZIV, that alternate with two other Purkinje cell zones, FZI and FZIII, projecting to the superior vestibular nucleus. Purkinje cell axons from FZI and FZIII occupy the FC1 and FC3 compartments, respectively, and terminate in the superior vestibular nucleus.  

Studies of the pathways involved in the vestibulo-ocular reflex have suggested that the projection from the superior vestibular nucleus to the ipsilateral oculomotor nucleus is inhibitory, whereas the medial vestibular nucleus, the abducens nucleus and the contralateral superior vestibular nucleus most likely exert excitatory effects on oculomotor neurons. The superior vestibular nucleus projected bilaterally to the superior rectus and inferior oblique subdivisions, and ipsilaterally to the inferior rectus and medial rectus subdivision; the medial vestibular nucleus projected bilaterally to the medial rectus, inferior oblique, inferior rectus and superior rectus subdivisions with a strong contralateral predominance. More than 90% of all the anterogradely labeled terminals from the ipsilateral superior vestibular nucleus were GABAergic. All terminals derived from the medial vestibular nucleus the abducens nucleus and the contralateral superior vestibular nucleus were non-GABAergic. The present study provides the first direct anatomical evidence that most, if not all, of the synaptic input from the superior vestibular nucleus to the ipsilateral oculomotor nucleus is GABAergic, and that the medial rectus subdivision is included in the termination area. Furthermore, it confirms that the projections from the medial vestibular nucleus, the abducens nucleus and the contralateral superior vestibular nucleus are exclusively non-GABAergic..  

We believe that this input originates in the brain stem, probably in the superior vestibular nucleus.  

Purkinje cells in the next zone respond best to optokinetic stimulation about an axis approximately perpendicular to the ipsilateral anterior canal; they project to the periinterposed white matter, dorsal group y, the superior vestibular nucleus, and the medial vestibular nucleus.  

Collectively, Purkinje cells of zone 1 projected to the ventral dentate nucleus, dorsal group y, and superior vestibular nucleus; Purkinje cells of zones 2 and 4 projected to the magnocellular and parvicellular parts of the medial vestibular nucleus; Purkinje cells of zone 3 projected to dorsal group y, ventral group y, and the superior vestibular nucleus; and Purkinje cells of zone C2 projected to the interposed posterior nucleus and dorsal group y. Branching axons from zone 1 either innervated both the ventral dentate nucleus and the superior vestibular nucleus or both dorsal group y and the superior vestibular nucleus. Branching axons from zone 3 innervated both dorsal group y and the superior vestibular nucleus, or both ventral group y and the superior vestibular nucleus. Other target nuclei (e.g., superior vestibular nucleus and medial vestibular nucleus) do not project back to the olivary subnuclei that innervate the flocculus and are part of an open olivofloccular pathway.  

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.  

Tracer injections in the rostral dorsal cap and ventrolateral outgrowth produced a sparse bilateral distribution of labeled neurons in the superior vestibular nucleus and an almost exclusively ipsilateral pattern of labeled neurons in caudal pars alpha of the lateral vestibular nucleus.  

Injecting into the oculomotor/trochlear nuclei and nearby tissue labeled cells in SC, INC, riMLF, FN, IN, MVN, and superior vestibular nucleus (SVN).  

Major sources of such projections include the caudal half of the medial and inferior vestibular nuclei, and the dorsal half of the superior vestibular nucleus.  

Cell somata of the extra-MLF anterior canal neurons were located in the superior vestibular nucleus.  

The superior vestibular nucleus (SV) and the medial vestibular nucleus (MV) receive projections exclusively from RPc and RGc, whereas the lateral reticular nucleus (LV) and the inferior vestibular nucleus (IV) receive additional projections from the remaining RF nuclei.  

Properties of superior vestibular nucleus (SVN) neurons and their projection to the cerebellar flocculus were studied in alert squirrel monkeys by using chronic unit and eye movement recording and microstimulation techniques.  

Microiontophoretic ejection (10-100 nA) of serotonin (5-hydroxytryptamine) into the superior vestibular nucleus induced modifications of the mean firing rate in 87% of the neurons examined. These results support the hypothesis that 5-hydroxytryptamine exerts various functions throughout the superior vestibular nucleus by various receptors and that the inhibitory action is limited to an area of it..  

A lateral descending noradrenergic bundle provides input from LC to the superior vestibular nucleus (SVN), the cochlear nuclei, and the cerebellar cortex.  

The superior vestibular nucleus (SN) originated ventromedial to the mesencephalic tract and nuclei of the trigeminal nerve.  

Our sample included neurons in the lateral vestibular nucleus, the ventrolateral portion of the medial vestibular nucleus, and the superior vestibular nucleus.  

In the hindbrain, neurons of the cranial nerve motor nuclei, neurons of the superior vestibular nucleus, giant cells of the reticular formation, and preganglionic parasympathetic neurons of the superior salivatory nucleus were stained.  

A previous study measured the relative contributions made by regularly and irregularly discharging afferents to the monosynaptic vestibular nerve (Vi) input of individual secondary neurons located in and around the superior vestibular nucleus of barbiturate-anesthetized squirrel monkeys.  

The fibers passing through the subnucleus y divided into two bundles; one bundle coursed rostrally to terminate in the lateral and ventral parts of the superior vestibular nucleus, while the other bundle passed through the lateral and then ventral parts of the lateral vestibular nucleus, supplying a few terminals to these regions, to terminate sparsely in the rostral to intermediate part of the medial vestibular nucleus and the rostroventral part of the spinal vestibular nucleus. Some fibers passing through the lateral vestibular nucleus coursed rostrally to terminate in the medial part of the superior vestibular nucleus.  

Activity of "vestibular only" (VO) and "vestibular plus saccade" (VPS) units was recorded in the rostral part of the medial vestibular nucleus and caudal part of the superior vestibular nucleus of alert rhesus monkeys.  

They lay in caudal ventral superior vestibular nucleus (SVN), dorsal portions of central medial vestibular nucleus (MVN) caudal to the abducens nuclei and in adjacent lateral vestibular nucleus (LVN).  

Posterior, as well as anterior and lateral ampullary fibers were found to project extensively to the superior vestibular nucleus, but also reached the other main vestibular nuclei.  

In the superior vestibular nucleus a statistically significant difference in the proportion of double-labeled neurons was found between cases with injections in the flocculus (1%) and the caudal vermis (9%). Statistically significant laterality preferences were found in the superior vestibular nucleus for the contralateral flocculus..  

The present results demonstrated a muscarinic receptor supersensitivity in the deafferented side in the superior vestibular nucleus 90 days after surgery.  

Unilateral OMC injections labeled cells ipsilaterally in the RiMLF, contralaterally in the pretectal olivary nucleus, the interstitial nucleus of Cajal and the infracerebellar nucleus and bilaterally in the superior vestibular nucleus, none of which were ChAT-IR.  

The superior vestibular nucleus appeared to have little G6PD activity in either the neuron cell bodies or the surrounding parenchyma.  

Thus the infracerebellar nucleus projects exclusively, and the superior vestibular nucleus predominantly, upon oculomotor (mIII, mIV) nuclei; VDL projects predominantly upon the neck motor nucleus, whereas the interstitial vestibular regions (medial Ta, rostral VeD, intermediate VeM) project upon both collimotor and oculomotor neurons.  

Projections from the auricle and adjacent lateral unfoliated cortex (F zone) focus upon the infracerebellar nucleus, the medial tangential nucleus, and the medial division of the superior vestibular nucleus.  

Moreover, the WGA-HRP and rhodamine methods (known to be more sensitive than the HRP method) revealed several afferent sources not shown by HRP: the anterior hypothalamic area, ventral tegmental area, lateral division of the superior vestibular nucleus, nucleus interpositus, and the nucleus praepositus hypoglossi.  

Mercury staining was first detected after 10 days in cell bodies of five specific areas of the brain stem: the mesencephalic nucleus of the trigeminal nerve, the red nuclei, the ventral cochlear nucleus, the superior vestibular nucleus, and the nucleus reticularis pontis caudalis.  

Target neurons of rostral zone inhibition in the superior vestibular nucleus (SV) were identified by observing cessation of spontaneous discharges after rostral zone stimulation.  

A number of PC cells had MADs centered around the MAD of the superior oblique muscle, and 2/3 AC cells recorded in the superior vestibular nucleus had MADs near that of the inferior oblique.  

The ascending branch extended rostrally and gave off one or two collaterals in the superior vestibular nucleus (SVN), although some of the ascending branches further ran rostrally into the cerebellum.  

The corticovestibular fibers from sublobule a terminated in the dorsal and rostral parts of the superior vestibular nucleus, the dorsal part of the lateral vestibular nucleus, and the caudomedial part of the spinal vestibular nucleus.  

Ipsilateral injections of 200 ng bicuculline methiodide into an area immediately dorsal to the superior cerebellar peduncle or the dorsal aspect of the superior vestibular nucleus reversibly attenuated the nodulus-uvula evoked depression.  

On the other hand, major sources projecting to the ventral uvula were the caudal aspect of the medial and inferior vestibular nuclei, the x- and f-groups of the vestibular nuclei, the dorsal and central aspect of the superior vestibular nucleus, the rostral dorsomedial aspect of the paramedian nucleus of the pontine nuclei, the caudal aspect of the prepositus hypoglossal nucleus, and the infratrigeminal nucleus.  

Major sources projecting to the ventral uvula include the caudal parts of the medial and inferior vestibular nuclei, the x- and f-groups of the vestibular nuclei, the dorsal and central parts of the superior vestibular nucleus, the rostral dorsomedial part of the paramedian nucleus of the pontine nuclei, the caudal part of the prepositus hypoglossal nucleus, and the infratrigeminal nucleus.  

Vestibulo-ocular (VO) neurons in the superior vestibular nucleus (SVN) were labeled with horseradish peroxidase (HRP) and studied quantitatively in the electron microscope to determine the morphologic correlates of vestibular compensation.  

All five vestibular nuclei received primary afferents, but there were extensive areas of them that received very little or no projections at all, such as the rostral part of the superior vestibular nucleus, the dorsocaudal part of the lateral vestibular nucleus, the caudal half of the medial vestibular nucleus and the caudalmost aspect of the dorsal vestibular nucleus..  

No conclusive evidence was found supporting the presence of substantial direct spinal projections to the lateral vestibular nucleus, superior vestibular nucleus, or group z.  

Following small dorsal thalamic injections, labeled neurons were located predominantly in rostroventrolateral regions of the superior vestibular nucleus, less numerously within the ventral part of the lateral vestibular nucleus, and least numerously within the medial vestibular nucleus.  

Injections placed in the rostral MVN, lateral vestibular nucleus, y group, and superior vestibular nucleus resulted in a distribution of labeled cells similar to that seen following global vestibular injections, but these cells were fewer in number.  

Fibers (1) ascend in the superior fascicle, with flocculo-vestibular projections, to the superior vestibular nucleus, (2) enter the medial fascicle, with flocculo-vestibular fibers, and course along the dorsolateral border of the 4th ventricle to innervate a distinct rostral subdivision of the medial vestibular nucleus, and (3) enter the lateral fascicle, with flocculo-vestibular fibers, to terminate in pars alpha and beta of the lateral vestibular nucleus and the caudal subdivision of the medial vestibular nucleus. Comparison of different injection cases indicate that the caudal half to two-thirds of the dorsal cap contributes projections to the rostral medial vestibular nucleus, centrolateral and dorsomedial aspects of the superior vestibular nucleus, and a projection to both central and dorsal aspects of the caudal medial vestibular nucleus. By contrast, the rostral third to half of the dorsal cap-ventrolateral outgrowth projects sparsely to the rostral medial vestibular nucleus, contributing dense projections to the central aspect of the superior vestibular nucleus and dorsomedial and lateral regions in the caudal medial vestibular nucleus.(ABSTRACT TRUNCATED AT 400 WORDS).  

Vestibulo-ocular (VO) neurons in the superior vestibular nucleus were labeled retrogradely with horseradish peroxidase and studied quantitatively using electron microscopy to determine the morphologic correlates of vestibular compensation.  

A third group of cells (N = 4) were located in the superior vestibular nucleus, generated bursts of spikes during upward saccades, and increased their tonic firing rate during upward eye positions.  

Intracellular recordings were made from neurons located in the superior vestibular nucleus or the rostral parts of the medical or lateral vestibular nuclei.  

The neurons were located in the superior vestibular nucleus (SVN) or in the rostral parts of the medical or lateral (LVN) vestibular nuclei.  

Findings indicate a zonal organization in the uvula and nodulus projecting to the vestibular nuclei as follows; the Purkinje cells located in the medial half of the uvula except for the area along the posterolateral fissure project to the middle part of the inferior vestibular nucleus (IV) (middle IV zone); those in the lateral half of the uvula other than the laterocaudal part project to the caudal part of the IV (caudal IV zone); those in the mediorostral part of the nodulus and the middle part of the nodulus project to the middle part of the medial vestibular nucleus (MV) (middle MV zone); those in the lateral part of the nodulus project to the caudal part of the MV (caudal MV zone); those in the medial part of the uvula and nodulus along the posterolateral fissure project to the dorsal peripheral part of the superior vestibular nucleus (SV) (SV zone).  

Furthermore, a hitherto undescribed cell cluster found dorsal to the dorsal border of the superior vestibular nucleus is presented.  

In addition to these neurons, we found the parvalbumin-like immunoreactivity in the large neurons of the superior vestibular nucleus and the neurons of the medial superior olive nucleus.  

Smaller numbers of WGA-HRP labeled cells appeared in bed nucleus of stria terminalis, diagonal band of Broca, cuneiform nucleus, superior vestibular nucleus, pontine periventricular gray, and some hypothalamic and reticular areas.  

Major commissural transport was to all parts of the opposite medial vestibular nucleus (MVN) and to peripheral parts of the superior vestibular nucleus (SVN), but some transport was present in all contralateral VN, including ventral cell group y.  

Attempts were made to determine brainstem and cerebellar afferent and efferent projections of the superior vestibular nucleus (SVN) and cell group 'y' ('y') in the cat using axoplasmic tracers.  

The following vestibular nuclei can be identified by the fact that they receive primary vestibular afferents: the ventral vestibular nucleus, medial vestibular nucleus, descending vestibular nucleus, superior vestibular nucleus, and cerebellar nucleus.  

Other, notably thicker, axons of this group continued rostrally and medially to terminate chiefly in the large-cell core of the superior vestibular nucleus.  

There were neurons labeled bilaterally throughout all the vestibular nuclei except the lateral vestibular nucleus, but most of the labeled neurons were in the caudal parts of the medial and inferior vestibular nuclei and in the central part of the superior vestibular nucleus; the nucleus prepositus was also labeled bilaterally, primarily caudally.  

Cells exhibiting both retrograde fluorescent label and GAD-positive immunoreactivity were observed in the cerebellar cortex, the striatum and the ventrobasal complex following injections of DY into the superior vestibular nucleus, substantia nigra and dorsal thalamus.  

Following injections in the superior vestibular nucleus and group Y, weaker termination, also patchlike, was observed in the same tegmental nuclei, and in addition in the dorsomedial pontine nuclei proper.  

The lateral vestibular nucleus contained numerous coarse GAD-immunoreactive fibers surrounding Deiters' neurons, while substance P-immunoreactive and Leu-enkephalin-immunoreactive fibers were rather poorly distributed in this nucleus as well as in the superior vestibular nucleus..  

All of the VO neurones in the superior vestibular nucleus (n = 19) were inhibited from the flocculus while the activities of three-fourths of the VO neurones (36/48) in the other vestibular nuclei were not suppressed by floccular stimulation.  

The superior vestibular nucleus contained VO neurons that were activated mono- and polysynaptically following ACN stimulation..  

Our results for neurons projecting to the spinal cord (spinal-projecting neurons) from the nucleus ambiuus, dorsal motor nucleus of the vagus, superior vestibular nucleus and nucleus f, nucleus Darshevch, nucleus Rolleri, nucleus prepositus hypoglossi, and nucleus of the posterior commissure have been reported before in other mammals but not in rats. With only a few exceptions (e.g., the superior vestibular nucleus) most of the spinal-projecting neurons are bilaterally distributed, some with contralateral and others with ipsilateral predominance..  

A correlation is most evident in the superior vestibular nucleus, and is rather clear in the medial and lateral vestibular nuclei and for the groups f,x,y, and z, whereas no such correlation can be found in the descending (inferior) nucleus.  

Stimulation of the superior vestibular nucleus and the anterior canal nerve evoked mono- and disynaptic excitatory postsynaptic potentials, respectively, in contralateral inferior oblique motoneurones of the cat. Combined stimulation revealed that the superior vestibular nucleus relayed excitatory anterior canal signals to the motoneurones.  

Small fibers were also seen in the brachium conjunctivum oriented towards the cerebellum, from the superior vestibular nucleus.  

Two major terminating axon fields were observed, one caudal and one rostral to the entrance of the VIII nerve, corresponding to the ventral vestibular nucleus and superior vestibular nucleus, respectively.  

Contralateral afferents to MVN arise from (1) the nuclei prepositus (NPP) and intercalatus (NIC), (2) all parts of MVN and cell group 'y' and (3) parts of the superior vestibular nucleus (SVN), IVN and the fastigial nucleus (FN).  

Light microscopy of antidromically identified injected cells demonstrated that these cells are predominantly located at the central levels of the superior vestibular nucleus along the incoming vestibular nerve fibers but a few are found at more caudal levels.  

The neurons are located in the periphery of the superior vestibular nucleus.  

Specifically: (1) the superior vestibular nucleus is topographically and reciprocally related to the spinal (spr) and medial vestibular nuclei (mv); (2) the lateral vestibular nucleus (lv) is reciprocally related to the mv, and (3) the lv receives afferent fibers from the spv but does not reciprocate this input..  

Transverse cryostat sections (-15 degrees C) of the brainstem were cut alternately at 200 and 20 microns from the nucleus gracilis caudally through the superior vestibular nucleus rostrally.  

HRP-positive neurons in these cases were localized principally to the ventral lateral vestibular nucleus and adjacent superior vestibular nucleus ipsilateral to the thalamic injection, evidence that vestibulothalamic neurons in these nuclei may project to the thalamus over the unlesioned ATD.  

The ascending branch distributed terminals mainly in the middle part of the superior vestibular nucleus.  

It was found that there existed three-dimensional zones which were perpendicular to the long axis of the folia in the ipsilateral flocculus; Purkinje cells projecting to the superior vestibular nucleus were distributed in the rostral zone, those to the medial vestibular nucleus in the middle zone.  

The superior vestibular nucleus projects mainly to lobule X.  

The central band, 500-750 micrometer wide, projects to the medial vestibular nucleus, while the two adjacent bands, each 300-500 micrometer wide, innervate the superior vestibular nucleus.  

It was also found that neurons activated by antidromic stimulation of ipsilateral medial longitudinal fasciculus were located in the superior vestibular nucleus, some of which made direct inhibitory connections to the target extraocular motoneurons.  

Recent studies of the vestibulo-ocular reflex have revealed a distinct pathway from the anterior semicircular canal to the contralateral oculomotor nucleus via the superior vestibular nucleus.  

Labeled neurons with HRP were recognized in the medial and the superior vestibular nucleus. Electrical stimulation of the medial or the superior vestibular nucleus elicited orthodromic evoked potentials and unitary responses in the caudal part of the DNR.  

The later production of neurons of the superior vestibular nucleus may reflect the subsequent differentiation of the circuit from the rotational receptors (semicircular canals) to the neurons of the brain stem controlling eye movements.  

The cells of the superior vestibular nucleus showed a predominant excitatory response, the neurons of the medial vestibular nucleus displayed different combinations of excitatory and inhibitory effects, while those of the descending vestibular nucleus responded with excitation followed by inhibition.  

A second projection originates mainly in the superior vestibular nucleus (S) and in cell group y and terminates mainly in the contralateral nucleus centralis lateralis (CL) and the adjoining nucleus paracentralis (Pc).  

The superior vestibular nucleus of the cat and its primary vestibular efferents were examined by light and electron microscopy.  

The superior vestibular nucleus sends commissural fibres to the superior, medial, and descending nuclei and to Deiters' complex.  

Ipsilateral afferents from the superior vestibular nucleus and bilateral connections from the medial vestibular nucleus and the y-group were prominent.  

The following pathway seems to be the simplest which would account for these findings: anterior semicircular canal leads to superior vestibular nucleus leads to brachium conjunctivum leads to oculomotor nucleus leads to superior rectus muscle (ipsilateral) and inferior oblique muscle (contralateral)..  

By lesioning the MLF or brachium conjunctivum immediately after iontophoresis it was demonstrated that positive cells in the dorsum of the superior vestibular nucleus are backfilled via their axons which ascend in the brachium conjunctivum. Recording extracellularly with glass microelectrodes filled with fast green FCF the only cells both ortho- and antidromically activated were localized to the dorsum of the superior vestibular nucleus.  

The response to constant angular acceleration of type I neurons in the superior vestibular nucleus was studied in pentobarbital-anesthetized, cerebellectomized squirrel monkeys.  

Electroencephalographic activity of the frontal cortex, cerebellar vermis, and superior vestibular nucleus was recorded in awake rats during the high pressure nervous syndrome (HPNS) by means of permanently implanted electrodes.  

The response to angular acceleration of units in the superior vestibular nucleus (SVN) of barbiturate-anesthetized, cerebellectomized squirrel monkeys was used to study the distribution of semicircualr-canal inputs to the nucleus.  

Axons of fastigial origin also distribute to the superior vestibular nucleus, to subnuclei "f" and "x" and to the parasolitary region.  

We conclude that inhibitory vestibular neurons eminating from the superior vestibular nucleus terminate on trochlear motoneurons with Type II boutons and excitatory vestibular neurons from the contralateral medial vestibular nucleus end on trochlear motoneurons with Type III boutons..  

(2) Average sized neurones of the superior vestibular nucleus show a significant increase in the number of dendritic spines between birth and the age of 3 days.  

Lesions of the deep cerebellar nuclei, inferior olive, medial vestibular nucleus, and superior vestibular nucleus did not produce significant effects.  

Lesions of the lateral vestibular nucleus, superior vestibular nucleus, or inferior olive produced severe disturbances of posture and movement.  

superior vestibular nucleus (SVN) stimulation induced monosynaptic IPSPs.  

These neurons were found in all of the four main vestibular nuclei, but were less prevalent in dorsal Deiters' nucleus and in the central region of the superior vestibular nucleus than elsewhere.  

Isolated fresh cat trochlear and oculomotor nuclei, which contain the axon terminals of inhibitory neurons whose cell bodies are in the superior vestibular nucleus (SVN), actively synthesize and store [ 3H]GABA, [ 14C]acetylcholine, [ 3H]dopamine and [ 3H]tyramine from labeled precursors of these compounds. Twelve to 14 days following lesions of the ipsilateral superior vestibular nucleus or its efferent pathway to the oculomotor and trochlear nuclei, at a time when there is extensive degeneration of superior vestibular nucleus axon terminals in these nuclei, the synthesis and storage of GABA in the ipsilateral trochlear nucleus is markedly reduced compared to that in the contralateral trochlear nucleus; the synthesis of acetylcholine, dopamine and tyramine is not measurably affected. The data support the identity of GABA as an inhibitory transmitter in the superior vestibular nucleus-trochlear nucleus pathway..  


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