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Js Yeomans - One of the best experts on this subject based on the ideXlab platform.

  • Kynurenate in the pontine reticular formation inhibits acoustic and trigeminal nucleus-evoked startle, but not vestibular nucleus-evoked startle
    neuroscience, 2004
    Co-Authors: Steidl S, Li L, Faerman P, Js Yeomans
    Abstract:

    The startle reflex is elicited by acoustic, trigeminal or vestibular stimulation, or by combinations of these stimuli. Acoustic startle is mediated largely by ibotenate-sensitive neurons in the ventrocaudal pontine reticular formation (PnC). In these studies we tested whether startle elicited by stimulation of different modalities is affected by infusion of the non-selective glutamate antagonist, kynurenate, into the PnC. In awake rats, startle responses evoked by either acoustic or spinal trigeminal nucleus stimulation were inhibited by kynurenate, but not saline, infusions, with the most effective placements nearest PnC. In chloral hydrate-anesthetized rats, kynurenate in the PnC reduced trigeminal nucleus-evoked hindlimb EMG responses, but not vestibular nucleus-evoked startle. Kynurenate in the vestibular nucleus had no effect on trigeminal nucleus-evoked startle. These results indicate that trigeminal nucleus stimulation evokes startle largely through glutamate receptors in the PnC, similarly to acoustic startle, but vestibular nucleus-evoked startle is mediated through other pathways, such as the Vestibulospinal Tract. (C) 2004 IBRO. Published by Elsevier Ltd. All rights reserved.NeurosciencesSCI(E)1ARTICLE1127-13612

  • Tactile, acoustic and vestibular systems sum to elicit the startle reflex
    神经学与生物行为评论, 2002
    Co-Authors: Js Yeomans, Li L, Bw Scott, Pw Frankland
    Abstract:

    The startle reflex is elicited by intense tactile, acoustic or vestibular stimuli. Fast mechanoreceptors in each modality can respond to skin or head displacement. In each modality, stimulation of cranial nerves or primary sensory nuclei evokes startle-like responses. The most sensitive sites in rats are found in the ventral spinal trigeminal pathway, corresponding to inputs from the dorsal face. Cross-modal summation is stronger than intramodal temporal summation, suggesting that the convergence of acoustic, vestibular and tactile information is important for eliciting startle. This summation declines sharply if the cross-modal stimuli are not synchronous. Head impact stimuli activate trigeminal, acoustic and vestibular systems together, suggesting that the startle response protects the body from impact stimuli. In each primary sensory nucleus, large, second-order neurons project to pontine reticular formation giant neurons critical for the acoustic startle reflex. In vestibular nucleus sites, startle-like responses appear to be mediated mainly via the Vestibulospinal Tract, not the reticulospinal Tract. Summation between Vestibulospinal and reticulospinal pathways mediating startle is proposed to occur in the ventral spinal cord. (C) 2002 Elsevier Science Ltd. All rights reserved.Behavioral SciencesNeurosciencesSCI(E)50REVIEW11-112

  • Contributions of the vestibular nucleus and Vestibulospinal Tract to the startle reflex
    neuroscience, 2001
    Co-Authors: Li L, Steidl S, Js Yeomans
    Abstract:

    The startle reflex is elicited by strong and sudden acoustic, vestibular or trigeminal stimuli. The caudal pontine reticular nucleus, which mediates acoustic startle via the reticulospinal Tract, receives further anatomical connections from vestibular and trigeminal nuclei, and can be activated by vestibular and tactile stimuli, suggesting that this pontine reticular structure could mediate vestibular and trigeminal startle. The vestibular nucleus, however, also projects to the spinal cord directly via the Vestibulospinal Tracts, and therefore may mediate vestibular startle via additional faster routes without a synaptic relay in the hindbrain. In the present study, the timing properties of the vestibular efferent pathways mediating startle-like responses were examined in rats using electrical stimulation techniques. Transient single- or win-pulse electrical stimulation of the vestibular nucleus evoked bilateral, startle-Eke responses with short refractory periods. In chloral hydrate-anesthetized rats, hindlimb electromyogram latencies recorded from the anterior biceps femoris muscle were shorter than those for stimulation of the trigeminal nucleus, and similar to those for stimulation of the caudal pontine reticular nucleus or ventromedial medulla. In awake rats, combining vestibular nucleus stimulation with either acoustic stimulation or trigeminal nucleus stimulation enhanced the whole-body startle-like responses and led to strong cross-modal summation without collision effects. In both chloral hydrate-anesthetized and awake rats, combining vestibular nucleus stimulation with ventromedial medulla stimulation produced a symmetrical collision effect, i.e. a loss of summation at the same positive and negative stimulus intervals, indicating a continuous connection between the vestibular nucleus and ventromedial medulla in mediating vestibular startle. By contrast, combining trigeminal nucleus stimulation with ventromedial medulla stimulation resulted in an asymmetric collision effect when the trigeminal nucleus stimulation preceded ventromedial medulla stimulation by 0.5 ms, suggesting that a monosynaptic connection between the trigeminal nucleus and ventromedial medulla mediates trigeminal startle. We propose that the Vestibulospinal Tracts participate strongly in mediating startle produced by activation of the vestibular nucleus. The convergence of the Vestibulospinal Tracts with the reticulospinal Tract within the spinal cord therefore provides the neural basis of cross-modal summation of startling stimuli. (C) 2001 IBRO. Published by Elsevier Science Ltd. All rights reserved.NeurosciencesSCI(E)PubMed16ARTICLE4811-82110

Barry W. Peterson - One of the best experts on this subject based on the ideXlab platform.

  • Relation Between Axon Morphology in C1 Spinal Cord and Spatial Properties of Medial Vestibulospinal Tract Neurons in the Cat
    Journal of Neurophysiology, 1998
    Co-Authors: S. I. Perlmutter, James F Baker, Y. Iwamoto, L. F. Barke, Barry W. Peterson
    Abstract:

    Perlmutter, S. I., Y. Iwamoto, L. F. Barke, J. F. Baker, and B. W. Peterson. Relation between axon morphology in C1 spinal cord and spatial properties of medial Vestibulospinal Tract neurons in the...

  • Interdependence of Spatial Properties and Projection Patterns of Medial Vestibulospinal Tract Neurons in the Cat
    Journal of neurophysiology, 1998
    Co-Authors: S. I. Perlmutter, James F Baker, Y. Iwamoto, Barry W. Peterson
    Abstract:

    Perlmutter, S. I., Y. Iwamoto, J. F. Baker, and B. W. Peterson. Interdependence of spatial properties and projection patterns of medial Vestibulospinal Tract neurons in the cat. J. Neurophysiol. 79...

  • spatial coordination by descending vestibular signals 2 response properties of medial and lateral Vestibulospinal Tract neurons in alert and decerebrate cats
    Experimental Brain Research, 1996
    Co-Authors: Y. Iwamoto, Steve I. Perlmutter, James F Baker, Barry W. Peterson
    Abstract:

    Spatial response properties of medial (MVST) and lateral (LVST) Vestibulospinal Tract neurons were studied in alert and decerebrate cats during sinusoidal angular rotations of the whole body in the horizontal and many vertical planes. Of 220 Vestibulospinal neurons with activity modulated during 0.5-Hz sinusoidal rotations, 200 neurons exhibited response gains that varied as a cosine function of stimulus orientation and phases that were near head velocity for rotation planes far from the minimum response plane. A maximum activation direction vector (MAD), which represents the axis and direction of rotation that maximally excites the neuron, was calculated for these neurons. Spatial properties of secondary MVST neurons in alert and decerebrate animals were similar. The responses of 88 of 134 neurons (66%) could be accounted for by input from one semicircular canal pair. Of these, 84 had responses consistent with excitation from the ipsilateral canal of the pair (13 horizontal, 27 anterior, 44 posterior) and 4 with excitation from the contralateral horizontal canal. The responses of the remaining 46 (34%) neurons suggested convergent inputs. The activity of 38 of these was significantly modulated by both horizontal and vertical rotations. Twelve neurons (9%) had responses that were consistent with input from both vertical canal pairs, including 9 cells with MADs near the roll axis. Thirty-two secondary MVST neurons (24%) had type II yaw and/or roll responses. The spatial response properties of 18 secondary LVST neurons, all studied in decerebrate animals, were different from those of secondary MVST neurons. Sixteen neurons (89%) had type II yaw and/or roll responses, and 12 (67%) appeared to receive convergent canal pair input. Convergent input was more common on higher-order Vestibulospinal neurons than on secondary neurons. These results suggest that MVST and LVST neurons and previously reported vestibulo-ocular neurons transmit functionally different signals. LVST neurons, particularly those with MADs close to the roll axis, may be involved in the vestibular-limb reflex. The combination of vertical and ipsilateral horizontal canal input on many secondary MVST neurons suggests a contribution to the vestibulocollic reflex. However, in contrast to most neck muscles, very few neurons had maximum vertical responses near pitch.

John S. Yeomans - One of the best experts on this subject based on the ideXlab platform.

  • Kynurenate in the pontine reticular formation inhibits acoustic and trigeminal nucleus-evoked startle, but not vestibular nucleus-evoked startle
    Neuroscience, 2004
    Co-Authors: Stephan Steidl, P Faerman, John S. Yeomans
    Abstract:

    The startle reflex is elicited by acoustic, trigeminal or vestibular stimulation, or by combinations of these stimuli. Acoustic startle is mediated largely by ibotenate-sensitive neurons in the ventrocaudal pontine reticular formation (PnC). In these studies we tested whether startle elicited by stimulation of different modalities is affected by infusion of the non-selective glutamate antagonist, kynurenate, into the PnC. In awake rats, startle responses evoked by either acoustic or spinal trigeminal nucleus stimulation were inhibited by kynurenate, but not saline, infusions, with the most effective placements nearest PnC. In chloral hydrate-anesthetized rats, kynurenate in the PnC reduced trigeminal nucleus-evoked hindlimb EMG responses, but not vestibular nucleus-evoked startle. Kynurenate in the vestibular nucleus had no effect on trigeminal nucleus-evoked startle. These results indicate that trigeminal nucleus stimulation evokes startle largely through glutamate receptors in the PnC, similarly to acoustic startle, but vestibular nucleus-evoked startle is mediated through other pathways, such as the Vestibulospinal Tract.

  • tactile acoustic and vestibular systems sum to elicit the startle reflex
    Neuroscience & Biobehavioral Reviews, 2002
    Co-Authors: John S. Yeomans, Brian W Scott, Paul W. Frankland
    Abstract:

    The startle reflex is elicited by intense tactile, acoustic or vestibular stimuli. Fast mechanoreceptors in each modality can respond to skin or head displacement. In each modality, stimulation of cranial nerves or primary sensory nuclei evokes startle-like responses. The most sensitive sites in rats are found in the ventral spinal trigeminal pathway, corresponding to inputs from the dorsal face. Cross-modal summation is stronger than intramodal temporal summation, suggesting that the convergence of acoustic, vestibular and tactile information is important for eliciting startle. This summation declines sharply if the cross-modal stimuli are not synchronous. Head impact stimuli activate trigeminal, acoustic and vestibular systems together, suggesting that the startle response protects the body from impact stimuli. In each primary sensory nucleus, large, second-order neurons project to pontine reticular formation giant neurons critical for the acoustic startle reflex. In vestibular nucleus sites, startle-like responses appear to be mediated mainly via the Vestibulospinal Tract, not the reticulospinal Tract. Summation between Vestibulospinal and reticulospinal pathways mediating startle is proposed to occur in the ventral spinal cord.

Jan Voogd - One of the best experts on this subject based on the ideXlab platform.

  • Deiters’ Nucleus. Its Role in Cerebellar Ideogenesis
    The Cerebellum, 2016
    Co-Authors: Jan Voogd
    Abstract:

    Otto Deiters (1834–1863) was a promising neuroscientist who, like Ferdinando Rossi, died too young. His notes and drawings were posthumously published by Max Schultze in the book “Untersuchungen über Gehirn und Rückenmark.” The book is well-known for his dissections of nerve cells, showing the presence of multiple dendrites and a single axon. Deiters also made beautiful drawings of microscopical sections through the spinal cord and the brain stem, the latter showing the lateral vestibular nucleus which received his name. This nucleus, however, should be considered as a cerebellar nucleus because it receives Purkinje cell axons from the vermal B zone in its dorsal portion. Afferents from the labyrinth occur in its ventral part. The nucleus gives rise to the lateral Vestibulospinal Tract. The cerebellar B module of which Deiters’ nucleus is the target nucleus was used in many innovative studies of the cerebellum on the zonal organization of the olivocerebellar projection, its somatotopical organization, its microzones, and its role in posture and movement that are the subject of this review.

  • Connections of the Lateral Reticular Nucleus to the Lateral Vestibular Nucleus in the Rat. An Anterograde Tracing Study with Phaseolus vulgaris Leucoagglutinin
    European Journal of Neuroscience, 1995
    Co-Authors: Tom J H Ruigrok, Federico Cella, Jan Voogd
    Abstract:

    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.

Sang Seok Yeo - One of the best experts on this subject based on the ideXlab platform.

  • Injury of the lateral Vestibulospinal Tract in a patient with the lateral medullary syndrome: Case report.
    Medicine, 2020
    Co-Authors: Sung Ho Jang, Ga Young Park, In Hee Cho, Sang Seok Yeo
    Abstract:

    Rationale Lateral medullary syndrome is a central vestibular disorder characterized by vertigo and ataxia. We report on a patient with injury of the lateral Vestibulospinal Tract (VST) following lateral medullary syndrome, detected on diffusion tensor Tractography (DTT). Patient concerns A 56-year-old male patient was diagnosed with lateral medullary syndrome due to an infarction in the posterior inferior cerebellar artery area. Diagnoses Two weeks following the infarction, he was transferred to the rehabilitation department of the same university hospital with severe vertigo, ataxia (Berg balance scale: 16 point), and dysphasia. In contrast, he maintained good motor power and cognitive function (Mini-mental state test: 26 points). Interventions N/A OUTCOMES:: Both the patient's medial VSTs and left lateral VST were well-reconstructed. In contrast, the right lateral VST was not reconstructed. On DTT parameters of the VST, the patient's medial VSTs and left lateral VST did not differ significantly from the control subjects. Lessons An injury of the right lateral VST was demonstrated in a patient with lateral medullary syndrome. We believe that the result will be helpful in clinical management and research for patients with lateral medullary syndrome.

  • Lateral Medullary Syndrome Following Injury of Lateral Vestibulospinal Tract: Diffusion Tensor Imaging Study.
    Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association, 2020
    Co-Authors: Sung Ho Jang, Sang Seok Yeo
    Abstract:

    AbsTract Background Unilateral lesions of vestibular nucleus can cause lateral medullary syndrome. Little is known about injury of medial and lateral Vestibulospinal Tract (VST) after dorsolateral medullary infarct. We investigated injury of the lateral VST in patients with typical central vestibular disorder using diffusion tensor Tractography (DTT). Methods Seven patients with lateral medullary syndrome and ten control subjects were recruited. For the medial VST, we determined seed region of interest (ROI) as medial vestibular nuclei of pons and target ROI on posteromedial medulla. For the lateral VST, the seed ROI was placed on lateral vestibular nuclei of pons, and the target ROI on posterolateral medulla. Fractional anisotropy (FA), mean diffusivity (MD), and Tract volume were measured. Result Reconstructed lateral VST on both sides had significantly lower FA values in patients than controls (p 0.05). Conclusion Injury of the lateral VST was demonstrated in patients with lateral vestibular syndrome following dorsolateral medullary infarct. Analysis of the lateral VST using DTT would be helpful in evaluation of patients with lateral medullary syndrome.

  • Associations between Age-Related Changes in the Core Vestibular Projection Pathway and Balance Ability: A Diffusion Tensor Imaging Study
    'Hindawi Limited', 2020
    Co-Authors: Sang Seok Yeo, Jung Won Kwon, In Hee Cho
    Abstract:

    Objective. We investigated the changes of the Vestibulospinal Tract (VST) and parietoinsular vestibular cortex (PIVC) using diffusion tensor imaging (DTI) and relation to balance between old and young healthy adults. Methods. This study recruited eleven old adults (6 males, 5 females; mean age 63.36±4.25 years) and 12 young adults (7 males, 5 females; mean age 28.42±4.40 years). The lateral and medial VST and PIVC were reconstructed using DTI. Fractional anisotropy (FA), mean diffusivity (MD), and Tract volume were measured. The six-minute walk test (6-MWT), the timed up and go test (TUG), and the Berg balance scale (BBS) were conducted. Spatiotemporal parameters during tandem gait and values of sway during one-leg standing using the wearable sensors were measured. All parameters between two groups were analyzed by the Mann-Whitney U test and independent t-test. Results. Statistically significant decrease in old adults was detected in the Tract volume of lateral (p=0.005) and medial VST (p≤0.001) and PIVC (p=0.020). A significant decrease in FA of lateral VST (p=0.044) and MD of medial VST (p=0.001) was seen in old adults. Stride length (p=0.003) and velocity (p=0.001) during tandem gait in old adults were significantly decreased. 6MWT (p≤0.001) showed significant decrease, while TUG (p≤0.001) showed significant increase in old adults. However, mean BSS (p=0.296) was nonsignificantly different. In eyes-open condition during one-leg standing, all parameters except for reciprocal compensatory index (RCI) values were significantly decreased in old adults. The RCI in the anteroposterior (AP) direction (p≤0.001) was increased in old adults; however, the mediolateral direction (p=0.301) was nonsignificantly different between the two groups. In eye-closed condition, the changes of ankle (p=0.031) and hip (p=0.004) sway and the center of mass in the AP direction (p=0.014) showed to be significantly higher in old adults than in young adults. Conclusion. The results suggested that there was a relationship between DTI parameters in the vestibular neural pathway and balance according to aging