Effect of Spinal Cord Transection on Spontaneous Activity Recorded from Type I Neurons of the Medial Vestibular Nucleus in Compensated Hemilabyrinthectomized Gerbils

1985 ◽  
Vol 93 (3) ◽  
pp. 414-418 ◽  
Author(s):  
Thomas J. Clegg ◽  
Adrian A. Perachio
Keyword(s):  
Spinal Cord ◽  
Spontaneous Activity ◽  
Inhibitory Control ◽  
Vestibular Nucleus ◽  
Vestibular Nuclei ◽  
Spinal Cord Transection ◽  
Medial Vestibular Nucleus ◽  
Type I ◽  
Intact Side ◽  
Injured Side

Spontaneous activity was recorded from type I neurons of the medial vestibular nuclei (MVN) in unanesthetized, decerebrate gerbils to determine the effect of spinal cord transection on compensation following labyrinthectomy. Immediately after labyrinthectomy there was an increase in activity of type I neurons on the intact side and an absence of activity on the injured side. Following compensation from labyrinthectomy, the distribution and activity rates approximated those of nonlabyrinthectomized animals. Spinal cord transection resulted in an increase in activity in type I MVN neurons contralateral to the labyrinthectomy in compensated animals and bilaterally in nonlabyrinthectomized animals. These results illustrate that type I neurons apparently are under an indirect inhibitory control from both the contralateral labyrinth and the spinal cord. In compensated animals spinal cord inhibition exists only on the intact side. This suggests that the symmetry in type I activity bilaterally in the compensated animal is in part the result of asymmetric spinal cord input.

Inputs from regularly and irregularly discharging vestibular nerve afferents to secondary neurons in squirrel monkey vestibular nuclei. III. Correlation with vestibulospinal and vestibuloocular output pathways

1992 ◽  
Vol 68 (2) ◽  
pp. 471-484 ◽  
Author(s):  
R. Boyle ◽  
J. M. Goldberg ◽  
S. M. Highstein
Keyword(s):  
Spinal Cord ◽  
Transition Zone ◽  
Vestibular Nucleus ◽  
Vestibular Nuclei ◽  
Vestibular Nerve ◽  
Descending Pathways ◽  
Relative Contribution ◽  
Antidromic Stimulation ◽  
Vestibulospinal Tract ◽  
Irregular Afferents

1. 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. Here, the analysis is extended to more caudal regions of the vestibular nuclei, which are a major source of both vestibuloocular and vestibulospinal pathways. As in the previous study, antidromic stimulation techniques are used to classify secondary neurons as oculomotor or spinal projecting. In addition, spinal-projecting neurons are distinguished by their descending pathways, their termination levels in the spinal cord, and their collateral projections to the IIIrd nucleus. 2. Monosynaptic excitatory postsynaptic potentials (EPSPs) were recorded intracellularly from secondary neurons as shocks of increasing strength were applied to Vi. Shocks were normalized in terms of the threshold (T) required to evoke field potentials in the vestibular nuclei. As shown previously, the relative contribution of irregular afferents to the total monosynaptic Vi input of each secondary neuron can be expressed as a %I index, the ratio (x100) of the relative sizes of the EPSPs evoked by shocks of 4 x T and 16 x T. 3. Antidromic stimulation was used to type secondary neurons as 1) medial vestibulospinal tract (MVST) cells projecting to spinal segments C1 or C6; 2) lateral vestibulospinal tract (LVST) cells projecting to C1, C6; or L1; 3) vestibulooculo-collic (VOC) cells projecting both to the IIIrd nucleus and by way of the MVST to C1 or C6; and 4) vestibuloocular (VOR) neurons projecting to the IIIrd nucleus but not to the spinal cord. Most of the neurons were located in the lateral vestibular nucleus (LV), including its dorsal (dLV) and ventral (vLV) divisions, and adjacent parts of the medial (MV) and descending nuclei (DV). Cells receiving quite different proportions of their direct inputs from regular and irregular afferents were intermingled in all regions explored. 4. LVST neurons are restricted to LV and DV and show a somatotopic organization. Those destined for the cervical and thoracic cord come from vLV, from a transition zone between vLV and DV, and to a lesser extent from dLV. Lumbar-projecting neurons are located more dorsally in dLV and more caudally in DV. MVST neurons reside in MV and in the vLV-DV transition zone.(ABSTRACT TRUNCATED AT 400 WORDS)

Inputs from regularly and irregularly discharging vestibular nerve afferents to secondary neurons in the vestibular nuclei of the squirrel monkey. II. Correlation with output pathways of secondary neurons

1987 ◽  
Vol 58 (4) ◽  
pp. 719-738 ◽  
Author(s):  
S. M. Highstein ◽  
J. M. Goldberg ◽  
A. K. Moschovakis ◽  
C. Fernandez
Keyword(s):  
Spinal Cord ◽  
Vestibular Nucleus ◽  
Preceding Paper ◽  
Vestibular Nuclei ◽  
Vestibular Nerve ◽  
Antidromic Activation ◽  
Mean Values ◽  
Postsynaptic Potentials ◽  
The Mean ◽  
Vestibular Nerve Afferents

1. Intracellular recordings were made from secondary neurons in the vestibular nuclei of barbiturate-anesthetized squirrel monkeys. Monosynaptic excitatory postsynaptic potentials (EPSPs) evoked by stimulation of the ipsilateral vestibular nerve (Vi) were measured. An electrophysiological paradigm, described in the preceding paper (26), was used to determine the proportion of irregularly (I) and regularly (R) discharging Vi afferents making direct connections with individual secondary neurons. The results were expressed as a % I index, an estimate for each neuron of the percentage of the total Vi monosynaptic input that was derived from I afferents. The secondary neurons were also classified as I, R, or M cells, depending on whether they received their direct Vi inputs predominantly from I or R afferents or else from a mixture (M) of both kinds of Vi fibers. The neurons were located in the superior vestibular nucleus (SVN) or in the rostral parts of the medical or lateral (LVN) vestibular nuclei. 2. Antidromic activation or reconstruction of axonal trajectories after intrasomatic injection of horseradish peroxidase (HRP) was used to identify three classes of secondary neurons in terms of their output pathways: 1) cerebellar-projecting (Fl) cells innervating the flocculus (n = 26); 2) rostrally projecting (Oc) cells whose axons ascended toward the oculomotor (IIIrd) nucleus (n = 27); and 3) caudally projecting (Sp) cells with axons descending toward the spinal cord (n = 13). Two additional neurons, out of 21 tested, could be antidromically activated both from the level of the IIIrd nucleus and from the spinal cord. 3. The Vi inputs to the various classes of relay neurons differed. As a class, Oc neurons received the most regular inputs. Sp neurons had more irregular inputs. Fl neurons were heterogeneous with similar numbers of R, M, and I neurons. The mean values (+/- SD) of the % I index for the Oc, Fl, and Sp neurons were 34.7 +/- 24.7, 51.9 +/- 30.4, and 61.8 +/- 18.0%, respectively. Only the Oc neurons had a % I index that was similar to the proportion of I afferents (34%) in the vestibular nerve (cf. Ref. 26). 4. The commissural inputs from the contralateral vestibular nerve (Vc) also differed for the three projection classes. Commissural inhibition was most common in Fl cells: 22/25 (88%) of the neurons had Vc inhibitory postsynaptic potentials (IPSPs) and 1/25 (4%) had a Vc EPSP. In contrast, Vc inputs were only observed in approximately half the Oc and Sp neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

Repair of spinal cord transection and its effects on muscle mass and myosin heavy chain isoform phenotype

2007 ◽  
Vol 103 (5) ◽  
pp. 1808-1814 ◽  
Author(s):  
Yu-Shang Lee ◽  
Ching-Yi Lin ◽  
Vincent J. Caiozzo ◽  
Richard T. Robertson ◽  
Jen Yu ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Myosin Heavy Chain ◽  
Muscle Mass ◽  
Muscle Fiber ◽  
Soleus Muscle ◽  
Heavy Chain ◽  
Combined Treatment ◽  
Spinal Cord Transection ◽  
Type I ◽  
Cord Injury

A number of significant advances have been developed for treating spinal cord injury during the past two decades. The combination of peripheral nerve grafts and acidic fibroblast growth factor (hereafter referred to as PNG) has been shown to partially restore hindlimb function. However, very little is known about the effects of such treatments in restoring normal muscle phenotype. The primary goal of the current study was to test the hypothesis that PNG would completely or partially restore 1) muscle mass and muscle fiber cross-sectional area and 2) the slow myosin heavy chain phenotype of the soleus muscle. To test this hypothesis, we assigned female Sprague-Dawley rats to three groups: 1) sham control, 2) spinal cord transection (Tx), and 3) spinal cord transection plus PNG (Tx+PNG). Six months following spinal cord transection, the open-field test was performed to assess locomotor function, and then the soleus muscles were harvested and analyzed. SDS-PAGE for single muscle fiber was used to evaluate the myosin heavy chain (MHC) isoform expression pattern following the injury and treatment. Immunohistochemistry was used to identify serotonin (5-HT) fibers in the spinal cord. Compared with the Tx group, the Tx+PNG group showed 1) significantly improved Basso, Beattie, and Bresnahan scores (hindlimb locomotion test), 2) less muscle atrophy, 3) a higher percentage of slow type I fibers, and 4) 5-HT fibers distal to the lesion site. We conclude that the combined treatment of PNG is partially effective in restoring the muscle mass and slow phenotype of the soleus muscle in a T-8 spinal cord-transected rat model.

scholarly journals Vestibular neurons with direct projections to the solitary nucleus in the rat

2019 ◽  
Vol 122 (2) ◽  
pp. 512-524 ◽  
Author(s):  
Amelia H. Gagliuso ◽  
Emily K. Chapman ◽  
Giorgio P. Martinelli ◽  
Gay R. Holstein
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Vestibular Nucleus ◽  
Vasovagal Syncope ◽  
Vestibular Nuclei ◽  
Medial Vestibular Nucleus ◽  
Postural Orthostatic Tachycardia Syndrome ◽  
Vestibular Neurons ◽  
Direct Demonstration ◽  
Vestibular Nuclear Neurons

Anterograde and retrograde tract tracing were combined with neurotransmitter and modulator immunolabeling to identify the chemical anatomy of vestibular nuclear neurons with direct projections to the solitary nucleus in rats. Direct, sparsely branched but highly varicose axonal projections from neurons in the caudal vestibular nuclei to the solitary nucleus were observed. The vestibular neurons giving rise to these projections were predominantly located in ipsilateral medial vestibular nucleus. The cell bodies were intensely glutamate immunofluorescent, and their axonal processes contained vesicular glutamate transporter 2, supporting the interpretation that the cells utilize glutamate for neurotransmission. The glutamate-immunofluorescent, retrogradely filled vestibular cells also contained the neuromodulator imidazoleacetic acid ribotide, which is an endogenous CNS ligand that participates in blood pressure regulation. The vestibulo-solitary neurons were encapsulated by axo-somatic GABAergic terminals, suggesting that they are under tight inhibitory control. The results establish a chemoanatomical basis for transient vestibular activation of the output pathways from the caudal and intermediate regions of the solitary nucleus. In this way, changes in static head position and movement of the head in space may directly influence heart rate, blood pressure, respiration, as well as gastrointestinal motility. This would provide one anatomical explanation for the synchronous heart rate and blood pressure responses observed after peripheral vestibular activation, as well as disorders ranging from neurogenic orthostatic hypotension, postural orthostatic tachycardia syndrome, and vasovagal syncope to the nausea and vomiting associated with motion sickness. NEW & NOTEWORTHY Vestibular neurons with direct projections to the solitary nucleus utilize glutamate for neurotransmission, modulated by imidazoleacetic acid ribotide. This is the first direct demonstration of the chemical neuroanatomy of the vestibulo-solitary pathway.

Discharge Dynamics of Oculomotor Neural Integrator Neurons During Conjugate and Disjunctive Saccades and Fixation

2003 ◽  
Vol 90 (2) ◽  
pp. 739-754 ◽  
Author(s):  
Pierre A. Sylvestre ◽  
Julia T. L. Choi ◽  
Kathleen E. Cullen
Keyword(s):  
Eye Movements ◽  
Vestibular Nucleus ◽  
Vestibular Nuclei ◽  
Medial Vestibular Nucleus ◽  
Eye Position ◽  
Neural Integrator ◽  
Abducens Nucleus ◽  
Nucleus Prepositus Hypoglossi ◽  
Prepositus Hypoglossi ◽  
Eye Velocity

Burst-tonic (BT) neurons in the prepositus hypoglossi and adjacent medial vestibular nuclei are important elements of the neural integrator for horizontal eye movements. While the metrics of their discharges have been studied during conjugate saccades (where the eyes rotate with similar dynamics), their role during disjunctive saccades (where the eyes rotate with markedly different dynamics to account for differences in depths between saccadic targets) remains completely unexplored. In this report, we provide the first detailed quantification of the discharge dynamics of BT neurons during conjugate saccades, disjunctive saccades, and disjunctive fixation. We show that these neurons carry both significant eye position and eye velocity-related signals during conjugate saccades as well as smaller, yet important, “slide” and eye acceleration terms. Further, we demonstrate that a majority of BT neurons, during disjunctive fixation and disjunctive saccades, preferentially encode the position and the velocity of a single eye; only few BT neurons equally encode the movements of both eyes (i.e., have conjugate sensitivities). We argue that BT neurons in the nucleus prepositus hypoglossi/medial vestibular nucleus play an important role in the generation of unequal eye movements during disjunctive saccades, and carry appropriate information to shape the saccadic discharges of the abducens nucleus neurons to which they project.

scholarly journals Modulation of spontaneous activity in the overactive bladder: the role of P2Y agonists

2012 ◽  
Vol 302 (11) ◽  
pp. F1447-F1454 ◽  
Author(s):  
C. H. Fry ◽  
J. S. Young ◽  
R. I. Jabr ◽  
C. McCarthy ◽  
Y. Ikeda ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Overactive Bladder ◽  
Spontaneous Activity ◽  
Fluorescence Imaging ◽  
Contractile Activity ◽  
Bladder Wall ◽  
Spinal Cord Transection ◽  
Thoracic Spinal Cord ◽  
Thoracic Spinal ◽  
Intact Mucosa

Spinal cord transection (SCT) leads to an increase in spontaneous contractile activity in the isolated bladder that is reminiscent of an overactive bladder syndrome in patients with similar damage to the central nervous system. An increase in interstitial cell number in the suburothelial space between the urothelium and detrusor smooth muscle layer occurs in SCT bladders, and these cells elicit excitatory responses to purines and pyrimidines such as ATP, ADP, and UTP. We have investigated the hypothesis that these agents underlie the increase in spontaneous activity. Rats underwent lower thoracic spinal cord transection, and their bladder sheets or strips, with intact mucosa except where specified, were used for experiments. Isometric tension was recorded and propagating Ca2+ and membrane potential ( Em) waves were recorded by fluorescence imaging using photodiode arrays. SCT bladders were associated with regular spontaneous contractions (2.9 ± 0.4/min); ADP, UTP, and UDP augmented the amplitude but not their frequency. With strips from such bladders, a P2Y6-selective agonist (PSB0474) exerted similar effects. Fluorescence imaging of bladder sheets showed that ADP or UTP increased the conduction velocity of Ca2+/ Em waves that were confined to regions of the bladder wall with an intact mucosa. When transverse bladder sections were used, Ca2+/ Em waves originated in the suburothelial space and propagated to the detrusor and urothelium. Analysis of wave propagation showed that the suburothelial space exhibited properties of an electrical syncitium. These experiments are consistent with the hypothesis that P2Y-receptor agonists increase spontaneous contractile activity by augmenting functional activity of the cellular syncitium in the suburothelial space.

The subdivisions of the guinea pig vestibular complex revealed by acetylcholinesterase staining

1999 ◽  
Vol 9 (2) ◽  
pp. 73-81
Author(s):  
Laurence Ris ◽  
Sven Saussez ◽  
Nicolaas Gerrits ◽  
Emile Godaux ◽  
Roland Pochet
Keyword(s):  
Guinea Pig ◽  
Vestibular Nucleus ◽  
Vestibular Nuclei ◽  
Medial Vestibular Nucleus ◽  
Cresyl Violet ◽  
Nuclear Complex ◽  
Cresyl Violet Staining ◽  
Vestibular Nuclear Complex ◽  
Acetylcholinesterase Staining ◽  
Vestibular Complex

A detailed map of the vestibular nuclear complex of the guinea pig has been established by Gstoettner and Burian (1987), using cytoarchitectonic (cresyl violet staining) and fiberarchitectonic criteria. However, the exact borders between the different subdivisions are not always evident in Nissl stained sections. In the present study, serial sections of the vestibular nuclei of the guinea pig were stained to visualize acetylcholinesterase (AChE) activity, and compared with corresponding sections stained with cresyl violet. All of the subdivisions of the vestibular nuclear complex previously described are more readily distinguished in AChE than in Nissl preparations. The AChE reactivity also shows that the medial vestibular nucleus extends more rostrally than previously described. Furthermore, it questions whether the area classically referred to as the rostral pole of the descending vestibular nucleus belongs to the descending vestibular nucleus or to the lateral vestibular nucleus (LV). Finally, a morphometric analysis performed on cresyl violet stained sections shows that (1) in the caudal LV, the neurons of the ventromedial extension are smaller than those of the dorsolateral extension and that (2) in the rostral LV, the ventromedial division contains a larger ratio of smaller neurons than the dorsolateral one.

Vestibular nuclear complex in cattle: Topography, morphology, cytoarchitecture and lumbo-sacral projections

2007 ◽  
Vol 17 (1) ◽  
pp. 9-24 ◽  
Author(s):  
Annamaria Grandis ◽  
Cristiano Bombardi ◽  
Beatrice Travostini ◽  
Arcangelo Gentile ◽  
Monica Joechler ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Vestibular Nucleus ◽  
Vestibular Nuclei ◽  
Analysis Software ◽  
Fluorescent Tracer ◽  
Minimum Diameter ◽  
Nuclear Complex ◽  
Dorsal Portion ◽  
Vestibular Nuclear Complex ◽  
Intermediate Size

The topography and the main characteristics of the vestibular nuclear complex (VNC) in cattle have been studied in serially transversally cut Nissl and Gles-stained sections. By using computerized image analysis software, the cell size, the maximum and minimum diameter of the neurons of each vestibular nucleus were obtained. These parameters were statistically analyzed by comparing the cell population from different nuclei and different parts of each nucleus. Furthermore, in order to investigate the lumbo-sacral projections, the fluorescent tracer Fast Blue was injected into the L6-S1 spinal cord of three calves. Among the vestibular nuclei, the superior was the least extensive rostro-caudally, the medial was the most extensive and contained the smallest cells, the lateral showed the largest neurons, and the descending nucleus contained cells of intermediate size which decreased in a rostrocaudal direction. Concerning the lumbo-sacral projections of the bovine VNC, the present study showed that only the fibers coming from the lateral vestibular nucleus reached the L6-S1 spinal cord. The labelled neurons were most heavily concentrated in the dorsal portion of this nucleus, but scattered neurons were also observed throughout the entire extension of the nucleus. The differences between the descriptions of cattle and other species were described.

scholarly journals Neural Stem Cell Transplantation Improves Locomotor Function in Spinal Cord Transection Rats Associated with Nerve Regeneration and IGF-1 R Expression

2019 ◽  
Vol 28 (9-10) ◽  
pp. 1197-1211 ◽  
Author(s):  
Xiao-Ming Zhao ◽  
Xiu-Ying He ◽  
Jia Liu ◽  
Yang Xu ◽  
Fei-Fei Xu ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Motor Function ◽  
Spinal Nerve ◽  
Nerve Fibers ◽  
Spinal Cord Transection ◽  
Type I ◽  
Locomotor Function ◽  
Cord Injury

Transplantation of neural stem cells (NSCs) is a potential strategy for the treatment of spinal cord transection (SCT). Here we investigated whether transplanted NSCs would improve motor function of rats with SCT and explored the underlying mechanism. First, the rats were divided into sham, SCT, and NSC groups. Rats in the SCT and NSC groups were all subjected to SCT in T10, and were administered with media and NSC transplantation into the lesion site, respectively. Immunohistochemistry was used to label Nestin-, TUNEL-, and NeuN-positive cells and reveal the expression and location of type I insulin-like growth factor receptor (IGF-1 R). Locomotor function of hind limbs was assessed by Basso, Beattie, Bresnahan (BBB) score and inclined plane test. The conduction velocity and amplitude of spinal nerve fibers were measured by electrophysiology and the anatomical changes were measured using magnetic resonance imaging. Moreover, expression of IGF-1 R was determined by real-time polymerase chain reaction and Western blotting. The results showed that NSCs could survive and differentiate into neurons in vitro and in vivo. SCT-induced deficits were reduced by NSC transplantation, including increase in NeuN-positive cells and decrease in apoptotic cells. Moreover, neurophysiological profiles indicated that the latent period was decreased and the peak-to-peak amplitude of spinal nerve fibers conduction was increased in transplanted rats, while morphological measures indicated that fractional anisotropy and the number of nerve fibers in the site of spinal cord injury were increased after NSC transplantation. In addition, mRNA and protein level of IGF-1 R were increased in the rostral segment in the NSC group, especially in neurons. Therefore, we concluded that NSC transplantation promotes motor function improvement of SCT, which might be associated with activated IGF-1 R, especially in the rostral site. All of the above suggests that this approach has potential for clinical treatment of spinal cord injury.

scholarly journals Sensorimotor Rehabilitation Promotes Vestibular Compensation in a Rodent Model of Acute Peripheral Vestibulopathy by Promoting Microgliogenesis in the Deafferented Vestibular Nuclei

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3377
Author(s):  
Emna Marouane ◽  
Nada El Mahmoudi ◽  
Guillaume Rastoldo ◽  
David Péricat ◽  
Isabelle Watabe ◽  
...  
Keyword(s):  
Vestibular Nucleus ◽  
Vestibular Nuclei ◽  
Original Data ◽  
Vestibular Rehabilitation ◽  
Cellular Level ◽  
Vestibular Compensation ◽  
Medial Vestibular Nucleus ◽  
Vestibular Neurectomy ◽  
Peripheral Vestibulopathy ◽  
The Impact

Acute peripheral vestibulopathy leads to a cascade of symptoms involving balance and gait disorders that are particularly disabling for vestibular patients. Vestibular rehabilitation protocols have proven to be effective in improving vestibular compensation in clinical practice. Yet, the underlying neurobiological correlates remain unknown. The aim of this study was to highlight the behavioural and cellular consequences of a vestibular rehabilitation protocol adapted to a rat model of unilateral vestibular neurectomy. We developed a progressive sensory-motor rehabilitation task, and the behavioural consequences were quantified using a weight-distribution device. This analysis method provides a precise and ecological analysis of posturolocomotor vestibular deficits. At the cellular level, we focused on the analysis of plasticity mechanisms expressed in the vestibular nuclei. The results obtained show that vestibular rehabilitation induces a faster recovery of posturolocomotor deficits during vestibular compensation associated with a decrease in neurogenesis and an increase in microgliogenesis in the deafferented medial vestibular nucleus. This study reveals for the first time a part of the underlying adaptative neuroplasticity mechanisms of vestibular rehabilitation. These original data incite further investigation of the impact of rehabilitation on animal models of vestibulopathy. This new line of research should improve the management of vestibular patients.

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