Central distribution of vestibular afferents that innervate the anterior or lateral semicircular canal in the mongolian gerbil

2004 ◽  
Vol 14 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Golda Anne Kevetter ◽  
Robert B. Leonard ◽  
Shawn D. Newlands ◽  
Adrian A. Perachio
Keyword(s):  
Reticular Formation ◽  
Vestibular Nucleus ◽  
Direct Injection ◽  
Semicircular Canals ◽  
Vestibular Nuclei ◽  
Nerve Fibers ◽  
Crista Ampullaris ◽  
Prepositus Hypoglossi ◽  
Nucleus Cuneatus ◽  
Anterior Canal

The central distribution of afferents that innervate the crista ampullaris of the anterior or lateral semicircular canals was determined in gerbils following the direct injection of tracers into one sensory neuroepithelia. Labeled somata were scattered throughout the superior ganglion. The central distribution of fibers demonstrated extensive overlap. The central branch of afferents innervating either canal was located in the rostral part of the nerve. Nerve fibers divided into ascending and descending branches. Ascending branch ramifications terminated in the superior vestibular nucleus, the magnocellular and parvicellular medial vestibular nuclei, and the cerebellum. Cerebellar terminal areas include the flocculus, nodulus and uvula. Descending branch ramifications terminated in the caudal medial, parvicellular medial and descending vestibular nuclei, and the nucleus prepositus hypoglossi. Lateral canal afferents terminated sparsely in nucleus cuneatus. The anterior canal had sparse innervation in the paratrigeminal and gigantocellular reticular formation. This study has shown many similarities in the central distribution of fibers that innervate the anterior and lateral canals and a few areas of segregated input. Projections outside the vestibular nuclei are more extensive than previously determined, including afferents to prepositus hypoglossi, cochlear nuclei, and reticular formation. Projections to the flocculus appear as numerous as those to the vermis.

scholarly journals Convergence of linear acceleration and yaw rotation signals on non-eye movement neurons in the vestibular nucleus of macaques

2018 ◽  
Vol 119 (1) ◽  
pp. 73-83 ◽  
Author(s):  
Shawn D. Newlands ◽  
Ben Abbatematteo ◽  
Min Wei ◽  
Laurel H. Carney ◽  
Hongge Luan
Keyword(s):  
Eye Movement ◽  
Multisensory Integration ◽  
Vestibular Nucleus ◽  
Semicircular Canals ◽  
Linear Acceleration ◽  
Vestibular Nuclei ◽  
Otolith Organs ◽  
Angular Rotation ◽  
Sensory Signals ◽  
Nonlinear Integration

Roughly half of all vestibular nucleus neurons without eye movement sensitivity respond to both angular rotation and linear acceleration. Linear acceleration signals arise from otolith organs, and rotation signals arise from semicircular canals. In the vestibular nerve, these signals are carried by different afferents. Vestibular nucleus neurons represent the first point of convergence for these distinct sensory signals. This study systematically evaluated how rotational and translational signals interact in single neurons in the vestibular nuclei: multisensory integration at the first opportunity for convergence between these two independent vestibular sensory signals. Single-unit recordings were made from the vestibular nuclei of awake macaques during yaw rotation, translation in the horizontal plane, and combinations of rotation and translation at different frequencies. The overall response magnitude of the combined translation and rotation was generally less than the sum of the magnitudes in responses to the stimuli applied independently. However, we found that under conditions in which the peaks of the rotational and translational responses were coincident these signals were approximately additive. With presentation of rotation and translation at different frequencies, rotation was attenuated more than translation, regardless of which was at a higher frequency. These data suggest a nonlinear interaction between these two sensory modalities in the vestibular nuclei, in which coincident peak responses are proportionally stronger than other, off-peak interactions. These results are similar to those reported for other forms of multisensory integration, such as audio-visual integration in the superior colliculus. NEW & NOTEWORTHY This is the first study to systematically explore the interaction of rotational and translational signals in the vestibular nuclei through independent manipulation. The results of this study demonstrate nonlinear integration leading to maximum response amplitude when the timing and direction of peak rotational and translational responses are coincident.

Properties of projections from vestibular nuclei to medial reticular formation in the cat

1975 ◽  
Vol 38 (6) ◽  
pp. 1421-1435 ◽  
Author(s):  
B. W. Peterson ◽  
C. Abzug
Keyword(s):  
Reticular Formation ◽  
Central Region ◽  
Vestibular Nucleus ◽  
Extracellular Recording ◽  
Vestibular Nuclei ◽  
Medullary Reticular Formation ◽  
Pentobarbital Anesthesia ◽  
Antidromic Responses ◽  
Series Of Experiments ◽  
Stimulation Of

In one series of experiments, vestibular neurons that could be activated antidromically by stimulation of the contralateral medial reticular formation were studied with extracellular recording in cats under pentobarbital anesthesia. 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. Regions of the pontine and medullary reticular formation from which neurons in different vestibular nuclei were activated corresponded to the pattern of vestibuloreticular projections described by neuroanatomists. 2. Latencies of antidromic responses to stimulation of the contralateral reticular formation ranged from 0.6 to over 3 ms, indicating a relatively slow transfer of activity from vestibular nuclei to reticular formation.

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 Initial evaluation of vertigo

2006 ◽  
Vol 59 (11-12) ◽  
pp. 585-590 ◽  
Author(s):  
Slobodanka Lemajic-Komazec ◽  
Zoran Komazec
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Balance Control ◽  
Vestibular Nucleus ◽  
Sensory Information ◽  
Semicircular Canals ◽  
Vestibular Nuclei ◽  
Spontaneous Nystagmus ◽  
Medial Longitudinal Fasciculus ◽  
Slow Phase

Dizziness is one of the most common reasons patients visit their physicians. Balance control depends on receiving afferent sensory information from several sensory systems: vestibular, optical and proprioceptive. Bioelectric signals, generated by body movements in the semicircular canals and in the otolithic apparatus, are transported via the vestibular nerve to the vestibular nucleus. All four vestibular nuclei, located bilaterally in medial longitudinal fasciculus, are linked with central nervous system structures. These central nervous system structures are involved in maintaining visual stability, spatial orientation and balance control. Nystagmus is a result of afferent signals balance disorders. Nystagmus due to peripheral lesions is conjugate nystagmus, because there is a bilateral central connection. Lesions above the vestibular nuclei induce deficits in synchronization and conjugation of eye movements, thus the nystagmus is dissociated. This paper shows that in peripheral vestibular disorders spontaneous nystagmus is rhythmic, associated, horizontal-rotatory or horizontal, with subjective sensation of dizziness which decreases with time and harmonic signs whose direction coincides with the slow phase of nystagmus and it is associated with mild disorders during pendular stimulation with statistically significant vestibular hypofunction. Spontaneous nystagmus in central vestibular lesions is severe, dissociated, horizontal, rotatory or vertical, without changes related to optical suppression; if vestibular symptoms are present, they are non-harmonic. In central disorders, findings after thermal stimulation are either normal or pathological, with dysrhythmias and inhibition in pendular stimulation. This paper deals with differential diagnosis of vertigo based on anamnesis and clinical examination, as well as objective diagnostic tests. .

Response of vestibular neurons to head rotations in vertical planes. I. Response to vestibular stimulation

1988 ◽  
Vol 60 (5) ◽  
pp. 1753-1764 ◽  
Author(s):  
J. Kasper ◽  
R. H. Schor ◽  
V. J. Wilson
Keyword(s):  
Vestibular Nucleus ◽  
Semicircular Canals ◽  
Vestibular Nuclei ◽  
Vestibular Stimulation ◽  
Excitatory Input ◽  
Whole Body ◽  
Otolith Organs ◽  
Vertical Semicircular Canal ◽  
Vector Orientation ◽  
Response Vector

1. We have studied, in decerebrate cats, the responses of neurons in the lateral and descending vestibular nuclei to whole-body rotations in vertical planes that activated vertical semicircular canal and utricular receptors. Some neurons were identified as vestibulospinal by antidromic stimulation with floating electrodes placed in C4. 2. The direction of tilt that caused maximal excitation (response vector orientation) of each neuron was determined. Neuron dynamics were then studied with sinusoidal stimuli closely aligned with the response vector orientation, in the range 0.02-1 Hz. A few cells, for which we could not identify a response vector, probably had spatial-temporal convergence. 3. On the basis of dynamics, neurons were classified as receiving their input primarily from vertical semicircular canals, primarily from the otolith organs, or from canal+otolith convergence. 4. Response vector orientations of canal-driven neurons were often near +45 degrees or -45 degrees with respect to the transverse (roll) plane, suggesting these neurons received excitatory input from the ipsilateral anterior or posterior canal, respectively. Some neurons had canal-related dynamics but vector orientations near roll, presumably because they received convergent input from the ipsilateral anterior and posterior canals. Few neurons had their vectors near pitch. 5. In the lateral vestibular nucleus, neurons with otolith organ input (pure otolith or otolith+canal) tended to have vector orientations closer to roll than to pitch. In the descending nucleus the responses were evenly divided between the roll and pitch quadrants. 6. We conclude that most of our neurons have dynamics and response vector orientations that make them good candidates to participate in vestibulospinal reflexes acting on the limbs, but not those acting on the neck.

The perihypoglossal projection to the superior colliculus in the rhesus monkey

1990 ◽  
Vol 4 (1) ◽  
pp. 29-42 ◽  
Author(s):  
Rosi Hartwich-Young ◽  
Jon S. Nelson ◽  
David L. Sparks
Keyword(s):  
Rhesus Monkey ◽  
Superior Colliculus ◽  
Reticular Formation ◽  
Vestibular Nucleus ◽  
Retrograde Transport ◽  
Medial Vestibular Nucleus ◽  
Eye Position ◽  
Medullary Reticular Formation ◽  
Prepositus Hypoglossi ◽  
Motor Error

AbstractThe projection of the perihypoglossal (PH) complex to the superior colliculus (SC) in the rhesus monkey was investigated using the retrograde transport of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP). Following physiological identification by electrical stimulation and multiunit recording, small injections of the tracer were placed within the SC of three monkeys. The largest numbers of retrogradely labeled neurons within the PH complex were found in the contralateral nucleus prepositus hypoglossi (NPH), in the laterally adjacent medial vestibular nucleus, and in the ventrally adjacent reticular formation (the nucleus reticularis supragigantocellularis). These labeled neurons are strikingly heterogeneous in size and morphology. The nuclei supragenualis and intercalatus also contain numerous labeled neurons in the 2 cases in which the injections involve the caudal SC. Large numbers of retrogradely labeled neurons as well as anterogradely transported WGA-HRP are observed alo throughout the pontine and medullary reticular formation, including the midline raphe. The PH complex, particularly the NPH, is known to be involved in the coding of eye position and has been hypothesized to be a critical component of the “neural integrator.” Our data demonstrate the existence of a robust projection from the PH complex to the contralateral SC in the rhesus monkey. This projection may serve as the anatomical substrate by which a corollary of eye position could reach the SC. Such a signal is a prerequisite for the computation, at the collicular level, of saccadic motor error signals observed in the SC of rhesus monkeys.

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)

Discharge patterns in nucleus prepositus hypoglossi and adjacent medial vestibular nucleus during horizontal eye movement in behaving macaques

1992 ◽  
Vol 68 (1) ◽  
pp. 319-332 ◽  
Author(s):  
J. L. McFarland ◽  
A. F. Fuchs
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Smooth Pursuit ◽  
Vestibular Nucleus ◽  
Medial Vestibular Nucleus ◽  
Eye Position ◽  
Head Velocity ◽  
Firing Rates ◽  
Prepositus Hypoglossi ◽  
Eye Velocity

1. Monkeys were trained to perform a variety of horizontal eye tracking tasks designed to reveal possible eye movement and vestibular sensitivities of neurons in the medulla. To test eye movement sensitivity, we required stationary monkeys to track a small spot that moved horizontally. To test vestibular sensitivity, we rotated the monkeys about a vertical axis and required them to fixate a target rotating with them to suppress the vestibuloocular reflex (VOR). 2. All of the 100 units described in our study were recorded from regions of the medulla that were prominently labeled after injections of horseradish peroxidase into the abducens nucleus. These regions include the nucleus prepositus hypoglossi (NPH), the medial vestibular nucleus (MVN), and their common border (the “marginal zone”). We report here the activities of three different types of neurons recorded in these regions. 3. Two types responded only during eye movements per se. Their firing rates increased with eye position; 86% had ipsilateral “on” directions. Almost three quarters (73%) of these medullary neurons exhibited a burst-tonic discharge pattern that is qualitatively similar to that of abducens motoneurons. There were, however, quantitative differences in that these medullary burst-position neurons were less sensitive to eye position than were abducens motoneurons and often did not pause completely for saccades in the off direction. The burst of medullary burst position neurons preceded the saccade by an average of 7.6 +/- 1.7 (SD) ms and, on average, lasted the duration of the saccade. The number of spikes in the burst was well correlated with saccade size. The second type of eye movement neuron displayed either no discernible burst or an inconsistent one for on-direction saccades and will be referred to as medullary position neurons. Neither the burst-position nor the position neurons responded when the animals suppressed the VOR; hence, they displayed no vestibular sensitivity. 4. The third type of neuron was sensitive to both eye movement and vestibular stimulation. These neurons increased their firing rates during horizontal head rotation and smooth pursuit eye movements in the same direction; most (76%) preferred ipsilateral head and eye movements. Their firing rates were approximately in phase with eye velocity during sinusoidal smooth pursuit and with head velocity during VOR suppression; on average, their eye velocity sensitivity was 50% greater than their vestibular sensitivity. Sixty percent of these eye/head velocity cells were also sensitive to eye position. 5. The NPH/MVN region contains many neurons that could provide an eye position signal to abducens neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

Probing the human vestibular system with galvanic stimulation

2004 ◽  
Vol 96 (6) ◽  
pp. 2301-2316 ◽  
Author(s):  
Richard C. Fitzpatrick ◽  
Brian L. Day
Keyword(s):  
Balance Control ◽  
Semicircular Canals ◽  
Vestibular Nuclei ◽  
Vestibular Stimulation ◽  
Otolith Organs ◽  
Sources Of Information ◽  
Electrophysiological Studies ◽  
Human Balance ◽  
Cortical Inputs ◽  
Vestibular Organs

Galvanic vestibular stimulation (GVS) is a simple, safe, and specific way to elicit vestibular reflexes. Yet, despite a long history, it has only recently found popularity as a research tool and is rarely used clinically. The obstacle to advancing and exploiting GVS is that we cannot interpret the evoked responses with certainty because we do not understand how the stimulus acts as an input to the system. This paper examines the electrophysiology and anatomy of the vestibular organs and the effects of GVS on human balance control and develops a model that explains the observed balance responses. These responses are large and highly organized over all body segments and adapt to postural and balance requirements. To achieve this, neurons in the vestibular nuclei receive convergent signals from all vestibular receptors and somatosensory and cortical inputs. GVS sway responses are affected by other sources of information about balance but can appear as the sum of otolithic and semicircular canal responses. Electrophysiological studies showing similar activation of primary afferents from the otolith organs and canals and their convergence in the vestibular nuclei support this. On the basis of the morphology of the cristae and the alignment of the semicircular canals in the skull, rotational vectors calculated for every mode of GVS agree with the observed sway. However, vector summation of signals from all utricular afferents does not explain the observed sway. Thus we propose the hypothesis that the otolithic component of the balance response originates from only the pars medialis of the utricular macula.

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