Body position with respect to the head or body position in space is coded by lumbar interneurons

1985 ◽  
Vol 54 (1) ◽  
pp. 123-133 ◽  
Author(s):  
I. Suzuki ◽  
S. J. Timerick ◽  
V. J. Wilson
Keyword(s):  
Body Position ◽  
Polarization Vector ◽  
Head Rotation ◽  
Vestibular Stimulation ◽  
Body Tilt ◽  
Whole Body ◽  
Vestibular Response ◽  
Maximal Sensitivity ◽  
Frequency Of Stimulation ◽  
Decerebrate Cats

In decerebrate cats, we have studied the response of neurons in the L3-L6 segments of the spinal cord to stimulation of neck and vestibular receptors. Neck receptors were stimulated by head rotation in labyrinthectomized cats or by body rotation with the head fixed in labyrinth-intact cats. Vestibular receptors were stimulated by whole-body tilt in the latter preparation. Most neurons were located outside the motoneuron nuclei and were arbitrarily classified as interneurons. Combinations of roll and pitch stimuli at frequencies of 0.1 or 0.05 Hz were used to determine the horizontal component of the polarization vector, i.e., the best direction of tilt, for each neuron. Two types of stimuli were used; rotation of a fixed angle of tilt around the head or body ("wobble," Ref. 22) or sinusoidal stimuli in several planes. Polarization vectors of the responses to neck stimulation were widely distributed; different neurons responded best to roll, pitch, and angles in between. For every neuron, the amplitude of the response decreased as the cosine of the angle between the direction of maximal sensitivity and the plane of the stimulus. The direction of the vector remained stable as the frequency of stimulation was varied. Neurons with different vectors had similar dynamics that resembled those of cervical interneurons (27). Many neurons responded to both neck and vestibular stimulation, although the vestibular response usually had a much lower gain. Neck and vestibular vectors were approximately opposite in direction. We suggest that neck responses originate in receptors, probably spindles, in perivertebral muscles. Each of these muscles presumably is best stretched by a particular direction of pull. It seems likely that convergence from receptors in selected muscles determines the direction of a spinal neuron's vector. Vestibular responses probably are due mainly to activity in otolith afferents.

Abstract 114: Effect of Body Position on Intracranial Pressure and Carotid Blood Flow During Extracorporeal Cardiopulmonary Resuscitation

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_4) ◽  
Author(s):  
Yaël Levy ◽  
Rocio Fernandez ◽  
Fanny Lidouren ◽  
Matthias Kohlhauer ◽  
Lionel Lamhaut ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Arrest ◽  
Intracranial Pressure ◽  
Cardiopulmonary Resuscitation ◽  
Body Position ◽  
Spontaneous Circulation ◽  
Systemic Hemodynamics ◽  
Body Tilt ◽  
Whole Body ◽  
Extracorporeal Cardiopulmonary Resuscitation

Introduction: Extracorporeal cardiopulmonary resuscitation (E-CPR) using extracorporeal membrane oxygenation (ECMO) is widely proposed for the treatment of refractory cardiac arrest. Hypothesis: Since cerebral autoregulation is altered in such conditions, body position may modify hemodynamics during ECPR. Our goal was to determine whether a whole body tilt-up challenge (TUC) could lower intracranial pressure (ICP) as previously shown with conventional CPR, without deteriorating cerebral blood flow (CBF). Methods: Pigs were anesthetized and instrumented for the continuous evaluation of CBF, ICP and systemic hemodynamics. After 15 min of untreated ventricular fibrillation they were treated with 30 min of E-CPR followed by sequential defibrillation shocks until resumption of spontaneous circulation (ROSC). ECMO was continued after ROSC to target a mean arterial pressure (MAP) >60 mmHg. Animals were maintained in the flat position (FP) throughout protocol, except during a 2 min TUC of the whole body (+30°) at baseline, during E-CPR and after-ROSC. Results: Four animals received the entire procedure and ROSC was obtained in 3/4. After cardiac arrest, E-CPR was delivered at 29±2 ml/kg/min to maintain a MAP of 57±8 mmHg in the FP. CBF was 28% of baseline and ICP remain stable (12±1 vs 13±1 mmHg during ECPR vs baseline, respectively). Under baseline pre-arrest conditions TUC resulted in a significant decrease in ICP (-63±7%) and CBF (-21±3%) versus the FP, with no significant effect on systemic hemodynamics. During E-CPR and after ROSC, TUC markedly reduced ICP but CBF remained unchanged vs the FP (Figure). Conclusion: During E-CPR whole body TUC reduced ICP without lowering CBF compared with E-CPR flat. Additional investigations with prolonged TUC and selective head and thorax elevation during E-CPR are warranted.

Responses of neurons of the cat central cervical nucleus to natural neck and vestibular stimulation

1996 ◽  
Vol 76 (4) ◽  
pp. 2786-2789 ◽  
Author(s):  
D. B. Thomson ◽  
N. Isu ◽  
V. J. Wilson
Keyword(s):  
Vestibular Nuclei ◽  
Vestibular Stimulation ◽  
Body Tilt ◽  
Whole Body ◽  
Vestibular Input ◽  
Preferred Direction ◽  
Central Cervical Nucleus ◽  
Neck Rotation ◽  
Vector Orientation ◽  
To Receive

1. The central cervical nucleus (CCN) is known to receive neck and vestibular input and to project to the contralateral cerebellum and vestibular nuclei. To investigate the processing of neck and vestibular input by cells in the CCN, we studied their responses to sinusoidal neck rotation and to whole-body tilt in vertical planes in decerebrate, paralyzed cats. CCN neurons were identified by antidromic stimulation with electrodes placed in or near the contralateral restiform body. 2. For every neuron, we first identified the preferred direction of neck rotation (response vector orientation), then studied the neuron's dynamics with rotations in a plane close to this direction at 0.05-1 Hz. 3. Responses of CCN neurons to neck rotation resembled those of previously studied neck spindle primary afferents in terms of their dynamics and nonlinear responses to stimuli of differing amplitudes. They also resembled the neck responses of Deiters' neurons studied in similar preparations. 4. The activity of two-thirds of CCN neurons also was modulated by natural vestibular stimulation. Orientation and dynamics of vestibular responses were characterized in the same way as neck responses. Labyrinthine input originated predominantly from the contralateral vertical canals, and there was no evidence of otolith input. Neck and vestibular inputs were always antagonistic, but the gain of the vestibular response was lower than that of the neck response at all frequencies studied. 5. The quantitative aspects of the interaction between neck and vestibular inputs can be expected to vary with the type of preparation and with stimulus parameters, and its functional significance remains to be investigated.

Neck muscle spindle activity in the decerebrate, unparalyzed cat: dynamics and influence of vestibular stimulation

1989 ◽  
Vol 62 (4) ◽  
pp. 917-923 ◽  
Author(s):  
J. Kasper ◽  
V. J. Wilson ◽  
Y. Yamagata ◽  
B. J. Yates
Keyword(s):  
Muscle Spindle ◽  
Muscle Spindles ◽  
Vestibular Stimulation ◽  
High Gain ◽  
Neck Muscles ◽  
Body Tilt ◽  
Whole Body ◽  
Neck Muscle ◽  
Response Dynamics ◽  
Decerebrate Cat

1. Using floating electrodes, we recorded from neck-muscle spindle afferents in the C2 dorsal root ganglion of the decerebrate cat. Nerves to dorsal neck muscles were cut so that the afferents presumably originated mainly from ventral and ventrolateral perivertebral muscles and sternocleidomastoid. One goal of our experiments was to study possible vestibular influence exerted on these spindles via the fusimotor system. Unparalyzed preparations were therefore used. 2. Stimuli consisted of sinusoidal rotations in vertical planes. Neck tilt stretched neck muscles, whereas whole-body tilt stimulated vestibular receptors. 3. For each afferent we first determined the most effective direction of neck tilt, then used stimuli oriented close to this direction to study response dynamics, particularly gain of responses to stimuli of different amplitudes (0.5-7.5 degrees). 4. Three-quarters of the afferents failed to respond to 0.5 degrees, 0.2-Hz neck rotations. Stimuli that were effective usually elicited responses that had low gain and were linear over the whole range of amplitudes. Only a few afferents had behavior typical of spindle primary afferents: high-gain responses to small sinusoidal stimuli, gain decreasing as stimulus amplitude increases. This prevalence of static spindle responses in the unparalyzed cat is in striking contrast to results obtained on neck-muscle spindles in paralyzed, decerebrate cats, and on hindlimb extensor muscle spindles in decerebrate, unparalyzed cats. 5. Paralysis produced by injection of Flaxedil changed the behavior of 2/4 spindle afferents tested, causing the appearance of high-gain responses to 0.5 degrees stimuli and of nonlinear behavior.(ABSTRACT TRUNCATED AT 250 WORDS)

Response of vestibular neurons to head rotations in vertical planes. II. Response to neck stimulation and vestibular-neck interaction

1988 ◽  
Vol 60 (5) ◽  
pp. 1765-1778 ◽  
Author(s):  
J. Kasper ◽  
R. H. Schor ◽  
V. J. Wilson
Keyword(s):  
Head Rotation ◽  
The Body ◽  
Head Movements ◽  
Body Tilt ◽  
Whole Body ◽  
Frequency Range ◽  
Vestibular Input ◽  
Response Dynamics ◽  
Neck Input ◽  
Wide Range

1. We have studied the responses of neurons in the lateral and descending vestibular nuclei of decerebrate cats to stimulation of neck receptors, produced by rotating the body in vertical planes with the head stationary. The responses to such neck stimulation were compared with the responses to vestibular stimulation produced by whole-body tilt, described in the preceding paper. 2. After determining the optimal vertical plane of neck rotation (response vector orientation), the dynamics of the neck response were studied over a frequency range of 0.02-1 Hz. The majority of the neurons were excited by neck rotations that brought the chin toward the ipsilateral side; most neurons responded better to roll than to pitch rotations. The typical neck response showed a low-frequency phase lead of 30 degrees, increasing to 60 degrees at higher frequencies, and a gain that increased about threefold per decade. 3. Neck input was found in about one-half of the vestibular-responsive neurons tested with vertical rotations. The presence of a neck response was correlated with the predominant vestibular input to these neurons; neck input was most prevalent on neurons with vestibular vector orientations near roll and receiving convergent vestibular input, either input from both ipsilateral vertical semicircular canals, or from canals plus the otolith organs. 4. Neurons with both vestibular and neck responses tend to have the respective orientation vectors pointing in opposite directions, i.e., a head tilt that produces an excitatory vestibular response would produce an inhibitory neck response. In addition, the gain components of these responses were similar. These results suggest that during head movements on a stationary body, these opposing neck and vestibular inputs will cancel each other. 5. Cancellation was observed in 12 out of 27 neurons tested with head rotation in the mid-frequency range. For most of the remaining neurons, the response to such a combined stimulus was greatly attenuated: the vestibular and neck interaction was largely antagonistic. 6. Neck response dynamics were similar to those of the vestibular input in many neurons, permitting cancellation to take place over a wide range of stimulus frequencies. Another pattern of interaction, observed in some neurons with canal input, produced responses to head rotation that had a relatively constant gain and remained in phase with position over the entire frequency range; such neurons possibly code head position in space.

scholarly journals Galvanic Vestibular Stimulation Induces a Spatial Bias in Whole-body Position Estimates

2015 ◽  
Vol 8 (5) ◽  
pp. 981-983
Author(s):  
Mitesh Patel ◽  
R. Edward Roberts ◽  
Qadeer Arshad ◽  
Maroof Ahmed ◽  
Mohammed U. Riyaz ◽  
...  
Keyword(s):  
Body Position ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Whole Body ◽  
Spatial Bias

The effect of galvanic vestibular stimulation on path trajectory during a path integration task

2018 ◽  
Vol 72 (6) ◽  
pp. 1550-1560 ◽  
Author(s):  
Tanya Karn ◽  
Michael E Cinelli
Keyword(s):  
Path Integration ◽  
Body Position ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Whole Body ◽  
Final Position ◽  
Completion Task ◽  
Significant Difference ◽  
Main Effect ◽  
Triangle Completion

The purpose of this study was to determine the effects of galvanic vestibular stimulation (GVS) on path trajectory and body rotation during a triangle completion task. Participants ( N = 17, female, 18-30 years) completed the triangle completion task in virtual reality using two different size triangles. GVS was delivered at three times each participant’s threshold in either the left or right direction prior to the final leg of the triangle and continued until the participant reached their final position. Whole body kinematics were collected using an NDI Optotrak motion tracking system. Results revealed a significant main effect of GVS on arrival error such that no GVS (NGVS) had significantly smaller arrival errors than when GVS was administered. There was also a significant main effect of GVS on angular error such that NGVS had significantly smaller error than GVSaway and GVStowards. There was no significant difference between GVS trials in path variability during the final leg on route to the final position. These results demonstrate that vestibular perturbation reduced the accuracy of the triangle completion task, affecting path trajectory and body position during a path integration task in the absence of visual cues.

scholarly journals Responses of neurons in the rostral ventrolateral medulla to whole body rotations: comparisons in decerebrate and conscious cats

2011 ◽  
Vol 110 (6) ◽  
pp. 1699-1707 ◽  
Author(s):  
V. J. DeStefino ◽  
D. A. Reighard ◽  
Y. Sugiyama ◽  
T. Suzuki ◽  
L. A. Cotter ◽  
...  
Keyword(s):  
Brain Stem ◽  
Body Position ◽  
Rostral Ventrolateral Medulla ◽  
Whole Body ◽  
Ventrolateral Medulla ◽  
Otolith Organs ◽  
Decerebrate Cats ◽  
Conscious Animals ◽  
The Brain ◽  
Stimulation Of

The responses to vestibular stimulation of brain stem neurons that regulate sympathetic outflow and blood flow have been studied extensively in decerebrate preparations, but not in conscious animals. In the present study, we compared the responses of neurons in the rostral ventrolateral medulla (RVLM), a principal region of the brain stem involved in the regulation of blood pressure, to whole body rotations of conscious and decerebrate cats. In both preparations, RVLM neurons exhibited similar levels of spontaneous activity (median of ∼17 spikes/s). The firing of about half of the RVLM neurons recorded in decerebrate cats was modulated by rotations; these cells were activated by vertical tilts in a variety of directions, with response characteristics suggesting that their labyrinthine inputs originated in otolith organs. The activity of over one-third of RVLM neurons in decerebrate animals was altered by stimulation of baroreceptors; RVLM units with and without baroreceptor signals had similar responses to rotations. In contrast, only 6% of RVLM neurons studied in conscious cats exhibited cardiac-related activity, and the firing of just 1% of the cells was modulated by rotations. These data suggest that the brain stem circuitry mediating vestibulosympathetic reflexes is highly sensitive to changes in body position in space but that the responses to vestibular stimuli of neurons in the pathway are suppressed by higher brain centers in conscious animals. The findings also raise the possibility that autonomic responses to a variety of inputs, including those from the inner ear, could be gated according to behavioral context and attenuated when they are not necessary.

scholarly journals No Impact of Stochastic Galvanic Vestibular Stimulation on Arterial Pressure and Heart Rate Variability in the Elderly Population

2021 ◽  
Vol 15 ◽  
Author(s):  
Akiyoshi Matsugi ◽  
Koji Nagino ◽  
Tomoyuki Shiozaki ◽  
Yohei Okada ◽  
Nobuhiko Mori ◽  
...  
Keyword(s):  
Heart Rate ◽  
Arterial Pressure ◽  
Elderly Population ◽  
Nervous Activity ◽  
The Elderly ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Body Tilt ◽  
Whole Body ◽  
Healthy Elderly

ObjectiveNoisy galvanic vestibular stimulation (nGVS) is often used to improve postural stability in disorders, such as neurorehabilitation montage. For the safe use of nGVS, we investigated whether arterial pressure (AP) and heart rate vary during static supine and slow whole-body tilt with random nGVS (0.4 mA, 0.1–640 Hz, gaussian distribution) in a healthy elderly population.MethodsThis study was conducted with a double-blind, sham-controlled, cross-over design. Seventeen healthy older adults were recruited. They were asked to maintain a static supine position on a bed for 10 min, and the bed was tilted up (TU) to 70 degrees within 30 s. After maintaining this position for 3 min, the bed was passively tilted down (TD) within 30 s. Real-nGVS or sham-nGVS was applied from 4 to 15 min. The time course of mean arterial pressure (MAP) and RR interval variability (RRIV) were analyzed to estimate the autonomic nervous activity.ResultnGVS and/or time, including pre-/post-event (nGVS-start, TU, and TD), had no impact on MAP and RRIV-related parameters. Further, there was no evidence supporting the argument that nGVS induces pain, vertigo/dizziness, and uncomfortable feeling.ConclusionnGVS may not affect the AP and RRIV during static position and whole-body tilting or cause pain, vertigo/dizziness, and discomfort in the elderly.

Somatosensory Loss Increases Vestibulospinal Sensitivity

2001 ◽  
Vol 86 (2) ◽  
pp. 575-585 ◽  
Author(s):  
F. B. Horak ◽  
F. Hlavacka
Keyword(s):  
Peripheral Neuropathy ◽  
Vestibular System ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Body Tilt ◽  
Whole Body ◽  
Galvanic Current ◽  
Galvanic Stimulation ◽  
Control Subjects ◽  
Postural Orientation

To determine whether subjects with somatosensory loss show a compensatory increase in sensitivity to vestibular stimulation, we compared the amplitude of postural lean in response to four different intensities of bipolar galvanic stimulation in subjects with diabetic peripheral neuropathy (PNP) and age-matched control subjects. To determine whether healthy and neuropathic subjects show similar increases in sensitivity to galvanic vestibular stimulation when standing on unstable surfaces, both groups were exposed to galvanic stimulation while standing on a compliant foam surface. In these experiments, a 3-s pulse of galvanic current was administered to subjects standing with eyes closed and their heads turned toward one shoulder (anodal current on the forward mastoid). Anterior body tilt, as measured by center of foot pressure (CoP), increased proportionately with increasing galvanic vestibular stimulation intensity for all subjects. Subjects with peripheral neuropathy showed larger forward CoP displacement in response to galvanic stimulation than control subjects. The largest differences between neuropathy and control subjects were at the highest galvanic intensities, indicating an increased sensitivity to vestibular stimulation. Neuropathy subjects showed a larger increase in sensitivity to vestibular stimulation when standing on compliant foam than control subjects. The effect of galvanic stimulation was larger on the movement of the trunk segment in space than on the body's center of mass (CoM) angle, suggesting that the vestibular system acts to control trunk orientation rather than to control whole body posture. This study provides evidence for an increase in the sensitivity of the postural control system to vestibular stimulation when somatosensory information from the surface is disrupted either by peripheral neuropathy or by standing on an unstable surface. Simulations from a simple model of postural orientation incorporating feedback from the vestibular and somatosensory systems suggest that the increase in body lean in response to galvanic current in subjects with neuropathy could be reproduced only if central vestibular gain was increased when peripheral somatosensory gain was decreased. The larger effects of galvanic vestibular stimulation on the trunk than on the body's CoM suggest that the vestibular system may act to control postural orientation via control of the trunk in space.

Vestibular Influence on Human Auditory Space Perception

2000 ◽  
Vol 84 (2) ◽  
pp. 1107-1111 ◽  
Author(s):  
Jörg Lewald ◽  
Hans-Otto Karnath
Keyword(s):  
Cold Water ◽  
Human Subjects ◽  
Space Perception ◽  
Median Plane ◽  
Vestibular Stimulation ◽  
Whole Body ◽  
Interaural Level Difference ◽  
Auditory Periphery ◽  
Auditory Space ◽  
Sound Image

We investigated the effect of vestibular stimulation on the lateralization of dichotic sound by cold-water irrigation of the external auditory canal in human subjects. Subjects adjusted the interaural level difference of the auditory stimulus to the subjective median plane of the head. In those subjects in whom dizziness and nystagmus indicated sufficient vestibular stimulation, these adjustments were significantly shifted toward the cooled ear compared with the control condition (irrigation with water at body temperature); i.e., vestibular stimulation induced a shift of the sound image toward the nonstimulated side. The mean magnitude of the shift was 7.3 dB immediately after vestibular stimulation and decreased to 2.5 dB after 5 min. As shown by an additional control experiment, this effect cannot be attributed to a unilateral hearing loss induced by cooling of the auditory periphery. The results indicate the involvement of vestibular afferent information in the perception of sound location during movements of the head and/or the whole body. We thus hypothesize that vestibular information is used by central-nervous mechanisms generating a world-centered representation of auditory space.

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