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Results for “Vestibular Nucleus, Lateral”

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At least 19 recordsLinked to original sources

PubMed1984

Electrophysiological and HRP studies on feedback loop between inferior olivary nucleus and lateral vestibular nucleus in the cat.

The role of input from the inferior olivary nucleus (IO) of decerebellate cats were studied on the lateral vestibular nucleus (LVN) neurons which were monosynaptically activated by vestibular nerve stimulation. Out of 168 monosynaptic neurons, test stimuli to the contralateral IO elicited a monosynaptic spike in 43 neurons and an antidromic spike in 9 neurons. Conditioning stimulus applied to the IO preceding vestibular nerve stimulation produced an inhibition of spike generation in 22 other LVN neurons upon the nerve stimulation. When horseradish peroxidase (HRP) was iontophoretically applied into the immediate vicinity of the LVN monosynaptic neurons, HRP-reactive cells were found in the dorsal cap and beta-nucleus of the contralateral IO. These results suggest that the LVN neurons monosynaptically activated by vestibular nerve stimulation receive both excitation and inhibition from the IO.

Action Potentials↗

PubMed1995

Spinovestibular projections in the rat, with particular reference to projections from the central cervical nucleus to the lateral vestibular nucleus.

Projections from the spinal cord to the vestibular nuclei were examined following injections of Phaseolus vulgaris-leucoagglutinin, cholera toxin subunit B, or biotinylated dextran at various levels of the spinal cord in the rat. Labeled terminals were abundant after injections of the tracers into the C2 and C3 segments containing the central cervical nucleus. Labeled terminals were seen in the descending vestibular nucleus and the parvocellular, magnocellular, and caudal parts of the medial vestibular nucleus throughout its rostrocaudal extent. Labeled terminals were most numerous in the lateral vestibular nucleus throughout its rostrocaudal extent. The projections from the central cervical nucleus to the vestibular nuclei were exclusively contralateral to the cells of origin because the axons of the central cervical nucleus neurons cross in the spinal cord. Following tracer injections in the cervical enlargement, many labeled terminals were seen in the magnocellular part of the medial vestibular nucleus, but a few were seen in the lateral and the descending vestibular nucleus. Injections into more caudal segments resulted in sporadic terminal labeling in the magnocellular part of the medial vestibular nucleus, the descending vestibular nucleus, and the caudal part of the lateral vestibular nucleus. The results indicate that primary neck afferent input relayed at the central cervical nucleus is mediated directly to the contralateral vestibular nuclei. It is suggested that this projection serves as an important linkage from the upper cervical segments to the lateral vestibulospinal tract in the tonic neck reflex.

Animals↗

PubMed1995

Connections of the lateral reticular nucleus to the lateral vestibular nucleus in the rat. An anterograde tracing study with Phaseolus vulgaris leucoagglutinin.

Efferent projections from the lateral reticular nucleus in the rat were investigated with anterograde transport of Phaseolus vulgaris leucoagglutinin. Besides the well known mossy fibre connections to the cerebellar cortex and collaterals to the cerebellar nuclei, a substantial bilateral projection to the lateral vestibular nucleus was found. Terminal arborizations found within this nucleus appeared to detach from the reticulocerebellar fibres in the cerebellar white matter and enter the lateral vestibular nucleus from dorsally. This projection may have functional relevance for the control, by ascending spinal pathways, of the descending lateral vestibulospinal tract.

Animals↗

PubMed1990

Immunohistochemical evidence for GABAergic cell bodies in the medial nucleus of the trapezoid body and in the lateral vestibular nucleus in the guinea pig brainstem.

The presence of gamma-aminobutyric acid (GABA) in two brainstem nuclei is demonstrated by using a pre-embedding immunohistochemical procedure followed by staining intensification. Firstly, immunoreactivity was found in numerous cell bodies and profiles of the medial nucleus of the trapezoid body (MNTB). Secondly, numerous neurons including giant Deiters' cells, terminals and fibers were strongly labelled within the lateral vestibular nucleus (LVN). These observations suggest that the inhibitory part of the efferent innervation of outer hair cells in the cochlea can originate from the MNTB, and that GABAergic neurons in the LVN may contribute to information processing within this nucleus.

Animals↗

PubMed1984

[Antidromic and synaptic potentials of neurons of the lateral vestibular nucleus of the cat evoked by stimulation of the interstitial nucleus of Cajal and the nucleus of Darkschewitsch].

Effects of stimulation of the Cajal interstitial nucleus and Darkschewitsch nucleus on the activity of neurons of the lateral vestibular nucleus of Deiters was studied in experiments on cats anesthetized with nembutal. It was shown that stimulation of the mentioned structures lead to antidromic and synaptic activation of Deiters neurons. Ascending axon collaterals of vestibular neurons to the marked brain stem structures were revealed. Stimulation of both Cajal and Darkschewitsch nuclei evoked mono- and polysynaptic EPSP and IPSP in Deiters neurons. The convergence of influences from both nuclei on the investigated neurons was shown. Peculiarities and functional significance of the indicated influences are discussed.

Animals↗

PubMed1992

Organization of afferent projections to the ventral and dorsal regions of the cat lateral vestibular nucleus: an HRP study.

Topical organization of afferent projections to Deiters' nucleus originating from cortical, subcortical, brainstem, and spinal cord structures has been revealed in the cat by microiontophoretic injection of horseradish peroxidase (HRP) into the ventral (NVLV) and dorsal (NVLD) regions of the nucleus and subsequent study of retrograde axonal transport of the enzyme. Differences between afferent inputs to the ventral and dorsal parts of the nucleus, considered as representative of the forelimb and hindlimb regions of the structure, have been observed. The trajectories of labeled fiber systems of the nucleus mentioned have been described. Computer reconstruction of the cat lateral vestibular nucleus (NVL) according the contours drawn from frontal sections of the brain has been carried out.

Afferent Pathways↗

PubMedDate not supplied

Electrophysiologic evidence for involvement of acetylcholine as a neurotransmitter in the lateral vestibular nucleus.

Monosynaptic spike generation of lateral vestibular nucleus (LVN) neurons with vestibular nerve stimulation in cats was inhibited by microiontophoretic atropine and gamma-aminobutyric acid (GABA). Spontaneous firing of the LVN monosynaptic neuron was increased by iontophoretic acetylcholine and glutamate. Atropine inhibited acetylcholine-induced firing without affecting glutamate-induced firing, while GABA blocked spike generation produced by acetylcholine and glutamate. Acetylcholine probably plays a role in transmission from the vestibular nerve to the LVN monosynaptic neurons.

Acetylcholine↗

PubMed2002

Ascending and descending projections of the lateral vestibular nucleus in the rat.

The tracer neurobiotin was injected into the lateral vestibular nucleus in rat and the efferent fiber connections of the nucleus were studied. The labeled fibers reached the diencephalon rostrally and the sacral segments of the spinal cord caudally. In the diencephalon, the ventral posteromedial and the gustatory nuclei received the most numerous labeled fibers. In the mesencephalon, the inferior colliculus, the interstitial nucleus of Cajal, the nucleus of Darkschewitch, the periaqueductal gray matter and the red nucleus received large numbers of labeled fibers. In the rhombencephalon, commissural and internuclear connections originated from the lateral vestibular nucleus to all other vestibular nuclei. The medioventral (motor) part of the reticular formation was richly supplied, whereas fewer fibers were seen in the lateral (vegetative) part. In the spinal cord, the descending fibers were densely packed in the anterior funiculus and in the ventral part of the lateral funiculus. Collaterals invaded the entire gray matter from lamina IX up to lamina III; the fibers and terminals were most numerous in laminae VII and VIII. Collateral projections were rich in the cervical and lumbosacral segments, whereas they were relatively poor in the thoracic segments of the spinal cord. It was concluded that the fiber projection in the rostral direction was primarily aimed at sensory-motor centers; in the rhombencephalon and spinal cord, fibers projected onto structures subserving various motor functions.

Afferent Pathways↗

PubMed1980

Locus coeruleus-induced inhibition of dorsal cochlear nucleus neurons in comparison with lateral vestibular nucleus neurons.

The effects of conditioning stimulation of the locus coeruleus (LC) on the neuron activity of dorsal cochlear nucleus (DCN), which is rich in noradrenergic nerve terminals, were compared with those on the lateral vestibular nucleus (LVN), devoid of such terminals, to determine whether or not noradrenaline is responsible for the LC-induced inhibition. The conditioning stimuli applied to the LC had no effect on either the field potential or the spike generation of mono- and polysynaptic neurons in the LVN elicited by VIIIth cranial nerve stimulation. In contrast, the spike firing of the DCN neurons with VIIIth cranial nerve stimulation was significantly inhibited by LC conditioning stimulation. The inhibition of spike generation was mainly observed in the DCN neurons which fired spikes with a longer latency. The inhibition of DCN neurons by LC conditioning stimulation did not occur in the cats pretreated with reserpine; however, a rapid recovery of the inhibition was produced by intraventricular application of noradrenaline. These results are in good agreement with the histochemical findings and support our previous conclusion that noradrenaline acts as an inhibitory transmitter or modulator on the nuclei where noradrenergic nerve terminals derived from the LC are located. In addition, the vestibular input in the primary relay nucleus is apparently not regulated by noradrenaline originating in the LC.

Animals↗

PubMed1977

Facilitation of the lordosis reflex in female rats by electrical stimulation of the lateral vestibular nucleus.

(1) Electrical stimulation of the lateral vestibular nucleus (LVN) facilitated lordosis reflex responses to somatosensory stimulation, in estrogen-primed female rats. (2) Unilateral LVN stimulation was sufficient for this effect. Currents as low as 10muA could be used. (3) With the stimulus parameters used, the effect develops within 5 min of LVN stimulation and decays within 10 min following cessation of stimulation. (4) Together with previous evidence that LVN lesions disrupt lordosis, these results suggest LVN facilitation of spinal reflex mechanisms for lordosis.

Animals↗

PubMed1983

Electrophysiological analysis of cerebellar corticovestibular and fastigiovestibular projections to the lateral vestibular nucleus in the cat.

In the lateral vestibular nucleus, vestibulospinal tract (VST) neurons were surveyed with microelectrodes in cats anesthetized with sodium pentobarbital. The VST neurons (n = 450) were classified by their properties; axonal courses (LVST and MVST). spinal segmental levels of their axonal termination (C1-3, C4-8, T1-13, L1-4, and L5-neurons), their orthodromic activation by the primary vestibular nerve (second-order and non-second-order vestibular neurons), and their location in the LVN. Inhibitory and excitatory effects of cerebellar stimulation on these classified VST neurons were investigated. 84% (259/308) neurons were observed to receive cerebellar corticovestibular inhibition. The rate was high, and almost the same among classified neurons; C1-3 to L5-neurons, and second-order and non-second-order neurons. However, the rate with MVST neurons (69%) was significantly lower than with LVST cells (87%). These neurons which received cerebellar inhibition were distributed in all areas even deep in the rostroventral region of the LVN, while neurons which did not receive were distributed in the ventral region of the LVN. Electrical stimulation of ipsi- and contralateral fastigial nuclei evoked monosynaptic excitation of the classified VST neurons. Rate of occurrence of crossed fastigiovestibular excitation was higher with cervical neurons (86%) than with lumbar neurons (43%), and higher with second-order neurons (78%) than with non-second-order neurons (41%). Neurons which received monosynaptic excitation from crossed fastigiovestibular fibers were distributed in the ventral region of the LVN. In total, 73% of the neurons were identified to receive either ipsi- or contralateral fastigiovestibular excitation. The results indicated that there was relative scarcity of fastigiovestibular projections in the dorsal region of the LVN. Spinovestibular and other afferents to the LVN were also investigated.

Animals↗

PubMed1990

Effects of motor cortex and single muscle stimulation on neurons of the lateral vestibular nucleus in the rat.

The neuronal responses to stimulation of motor cortical sites and of forelimb single muscles were studied in the lateral vestibular nucleus of anaesthetized rats. Of the 228 neurons tested for response to stimulation of contralateral motor cortex, 63% responded to cortical sites controlling extensor muscles and 30% to those controlling flexors. The corresponding figures for responders to ipsilateral stimulation were 34 and 21%. Vestibulospinal units responded to cortical sites controlling extensor and flexor muscles whereas the remaining lateral vestibular nucleus neurons, very reactive to cortical sites controlling extensor muscles, responded little to contralateral and not at all to ipsilateral cortical sites controlling flexor muscles. The effects evoked by contralateral cortical sites controlling extensors varied, those induced by cortical sites controlling flexors were inhibitory in 77% of cases. The responses to ipsilateral motor cortex stimulation differed not so much by cortical sites controlling extensor or flexor muscles as by whether the neuron was in the dorsal or ventral zone of the lateral vestibular nucleus: mixed in the former, all inhibitory in the latter. Of the lateral vestibular nucleus units tested for response to stimulation of ipsilateral or contralateral forelimb distal muscles, only 11% responded. All the vestibulospinal units responsive to muscle stimulation lay in the dorsal zone of the nucleus. The remainder, dorsal or ventral, were not responsive to contralateral muscles. Single lateral vestibular nucleus cells influenced both by ipsilateral muscle and by contralateral motor cortex made up 24% of the pool, vestibulospinal and non-vestibulospinal. They fell into three groups: responsive to one or both structures but responding more strongly to combined stimulation; responsive to each of the two structures but showing a response to combined stimulation not significantly different from that evoked by the cortex alone; responsive only to combined stimulation. The lateral vestibular nucleus units included in these three groups accounted for 29% of those tested for response to extensor muscles and cortical sites controlling extensors and 15% of those tested for response to flexor muscles and cortical sites controlling flexors. Twenty-five per cent of the vestibulospinal neurons responded both to contralateral muscles and to ipsilateral motor cortex stimulation but none of the non-vestibulospinal neurons responded to both. All the responders to both were in the dorsal zone of the lateral vestibular nucleus and responded to extensor stimuli, always in the same way. These results indicate that motor cortex output exerts a major influence on lateral vestibular nucleus discharges, while the muscle afferents have a modulatory influence on the lateral vestibular nucleus responses to cortex.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗

PubMed1997

Development of the human lateral vestibular nucleus: a morphometric evaluation.

The development of the human lateral vestibular nucleus was studied on serial sections of the brain of 8 fetuses and neonates at 12-40 weeks of gestation, an infant at 2 months of age and an adult of 63 years using a microscope with a drawing tube and an image-analysing computer system. A morphometric analysis revealed that the lateral vestibular nucleus, whose neurons were distinguished from glia after 16 weeks of gestation, divided cytoarchitectonically into the medial and the lateral subnuclei at 21 weeks of gestation onwards, and showed the moderate development in terms of the columnar length and volume, neuronal size and neuropil.

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PubMed1988

[Afferent connections of the lateral vestibular nucleus in the cat].

Localization of labelled neurons (sources of projections to the lateral vestibular nucleus) in the brain was studied by means of microiontophoretic injections of horseradish peroxidase. Bilateral projections of the midbrain structures to all parts of the nucleus mentioned (field of Forel, interstitial nucleus of Cajal, oculomotor nerve nucleus and red nucleus) were found. There have been also shown: bilateral projections from more caudally localized structures of the superior, medial and inferior (descending) vestibular nuclei, group "Y" of the vestibular nuclear complex, facial nucleus and hypoglossi, nucleus prepositus nervi hypoglossi and spinal trigeminal nucleus; ipsilateral projections from crus IIa of lobulus ansiformus of the cerebellar hemisphere; contralateral projections from lateral reticular nucleus of medulla oblongata and Deiters' nucleus. Trajectories of the labelled fibre system projecting to Deiters' nucleus are described.

Afferent Pathways↗

PubMed1975

The occurrence of dark neurons in the normal and deafferentated lateral vestibular nucleus in the rat: observations by light and electron microscopy.

The lateral vestibular nucleus was studied by light and electron microscopy in normal rats as well as in rats in which the anterior cerebellar vermis was destroyed. Dark neurons were seen in many of the operated rats but were rarely found in normal control animals. The dark neurons were not seen in adjacent nuclei. In additional rats, it was found that anoxia, extra anaesthetic, postmortem rough handling, and sham operations did not increase the frequency of dark neurons. These data indicate that dark neurons might not always be artifactual and that the lateral vestibular nucleus appears to be a focal point for their occurrence.

Animals↗

PubMed1987

Integration of cortical and peripheral information in the lateral vestibular nucleus in the cat.

Neuronal discharges in the lateral vestibular nucleus (LVN) of the cat were studied during stimulation of a forelimb muscle and of a site in the contralateral motor cortex (area 4) capable of activating the same muscle. About one third of the LVN units were reactive to both stimulations or at least responded to one (cortex or muscle) but modified the response pattern when the other was stimulated also. The patterns evoked by a muscle were mostly enhanced on simultaneous stimulation of the cortical zone controlling the same muscle and vice versa. Only in the dorsal division the excitatory responses to muscle stimulation were depressed by simultaneous cortical stimulation. Some functional implications are proposed.

Afferent Pathways↗

PubMed1994

Neurofibrillary tangles without cell loss in the lateral vestibular nucleus of patients with Alzheimer's disease.

The lateral vestibular nucleus (LVN, nucleus of Deiters) was examined in the brains of four control subjects and four patients with dementia of the Alzheimer type (DAT). Neuronal counts on sections stained with silver and a polyclonal antibody to human choline acetyltransferase (ChAT) revealed an undiminished number of LVN neurons in patients with DAT. Numerous silver-stained neurofibrillary tangles (NFTs) were found in the DAT group, some also in the LVN of controls. These findings suggest that DAT affects LVN neurons, however without causing neuronal loss.

Aged↗

PubMed1989

Age related changes in neuron number in the mouse lateral vestibular nucleus.

The number of large neurons in the lateral vestibular nucleus of the mouse brain decreases in number after 25 months of age, from 488 at 25 months to 298 at 31 months. The number of small neurons in the nucleus remains constant up to 31 months of age. Large neurons accumulate lipofuscin from 25 months and their mean nuclear diameter increases significantly between 25 and 28 months of age. Small neurons contain very little lipofuscin even at 31 months of age and their mean nuclear diameter remains constant between 6 and 31 months. The difference in response of the two types of neurons to ageing may be due to their connections. Large neurons project to spinal motor neurons which decline in number with age and they receive projections from Purkinje cells in the anterior lobe of the cerebellum which also decline in number with age. Small neurons mainly project to the oculogyric nuclei in at least one of which (the abducens) there is no loss of neurons up to 31 months of age.

Aging↗