Characteristics of Nystagmus Evoked by Electrical Stimulation of The Uvular/Nodular Lobules of the Cerebellum in Monkey

1992 ◽  
Vol 2 (3) ◽  
pp. 235-245
Author(s):  
S.J. Heinen ◽  
D.K. Oh ◽  
E.L. Keller
Keyword(s):  
Electrical Stimulation ◽  
Velocity Storage ◽  
Large Field ◽  
Slow Phase ◽  
Stimulus Pulse ◽  
Storage Mechanism ◽  
Velocity Storage Mechanism ◽  
Stimulus Offset ◽  
Eye Velocity ◽  
Stimulation Of

Electrical stimulation in the monkey vestibulocerebellum has previously been shown to produce ocular nystagmus, but large stimulating current values were used. Using long duration (⩽10-second) stimulus pulse trains and low current values (<50 μA), we studied the nystagmus evoked by microstimulation in the uvular/nodular regions of the cerebellum. In doing this, we found quantitative differences in the nystagmus evoked from these two regions. Stimulation of the nodulus typically produced a vigorous nystagmus with a contralateral slow phase and a prolonged afternystagmus in the same direction. In contrast, stimulation of the uvula typically produced a regular ipsilateral nystagmus pattern with a very short, if any, afternystagmus in the same direction. In addition, at some stimulation sites in the uvula we observed an adaptation in the slow phase eye velocity during the time that the stimulation remained on. This effect could result in a secondary nystagmus, with a slow phase velocity direction opposite to that first evoked by the stimulation, followed by a prolonged afternystagmus in the direction of the secondary nystagmus at stimulus offset. The nystagmus evoked by these cerebellar stimulations differs from both natural nystagmus produced by large field visual motion and from the nystagmus produced by electrical stimulation of the nucleus of the optic tract. The nystagmus produced by uvular and nodular stimulation shows a shorter latency and a more rapid slow phase eye velocity buildup. The uvula stimulations also showed a much shorter afternystagmus. Also, the same nystagmus was evoked whether the animal was in a lighted or dark surround. These characteristics and recent single-unit recording studies in the uvula seem to suggest that the uvula acts not as a direct input to the velocity storage mechanism, but instead perhaps as part of an internal regulator for balance between the bilateral vestibular nuclei which are normally part of the nystagmus response. On the other hand, the nodulus, with its prolonged afternystagmus in the same direction as the evoked nystagmus, may be involved as a part of the velocity storage mechanism.

Spatial orientation of postrotatory nystagmus during static roll tilt in cats

2002 ◽  
Vol 12 (1) ◽  
pp. 15-23
Author(s):  
Keiko Yasuda ◽  
Hiroaki Fushiki ◽  
Rinnosuke Wada ◽  
Yukio Watanabe
Keyword(s):  
Spatial Orientation ◽  
Vertical Axis ◽  
Longitudinal Axis ◽  
Velocity Storage ◽  
Slow Phase ◽  
Storage Mechanism ◽  
Spatial Disorientation ◽  
Acceleration And Deceleration ◽  
Eye Velocity ◽  
Roll Tilt

While the stimulation of otolith inputs reduces the duration of postrotatory nystagmus (PRN), there is still room for dialogue about the effect of static tilt on the orientation of PRN. We studied one possible influence of static roll tilt on the spatial orientation of PRN in cats. The animal was rotated about an earth-vertical axis (EVA) at a constant velocity of 100 deg/s with an acceleration and deceleration of 120 deg / s 2 . Within two seconds after stopping EVA rotation, the animal was passively tilted at 45 deg/s about its longitudinal axis by as much as ± 90 deg in steps of 15 deg. Eye movements were measured with magnetic search coils. The angle of the PRN plane and its slow phase eye velocity were measured. The time constant of PRN decreased with an increase in roll tilt. The PRN plane remained earth horizontal within a range of ± 30 deg roll tilt. Beyond this range, the velocity of PRN decreased too rapidly to measure any change in orientation. Our results indicate a spatially limited and temporally short interaction of the semicircular canal and otolith signals in the velocity storage mechanism of cat PRN. Our data, along with previous studies, suggest that different species show different solutions to the problem of the imbalance and spatial disorientation during contradictory stimuli.

Role of irregular otolith afferents in the steady-state nystagmus during off-vertical axis rotation

1992 ◽  
Vol 68 (5) ◽  
pp. 1895-1900 ◽  
Author(s):  
D. E. Angelaki ◽  
A. A. Perachio ◽  
M. J. Mustari ◽  
C. L. Strunk
Keyword(s):  
Steady State ◽  
Vertical Axis ◽  
Dynamic Responses ◽  
Velocity Storage ◽  
Slow Phase ◽  
Otolith Organs ◽  
Galvanic Stimulation ◽  
Storage Mechanism ◽  
Velocity Storage Mechanism ◽  
Ocular Nystagmus

1. During constant velocity off-vertical axis rotations (OVAR) in the dark a compensatory ocular nystagmus is present throughout rotation despite the lack of a maintained signal from the semicircular canals. Lesion experiments and canal plugging have attributed the steady-state ocular nystagmus during OVAR to inputs from the otolith organs and have demonstrated that it depends on an intact velocity storage mechanism. 2. To test whether irregularly discharging otolith afferents play a crucial role in the generation of the steady-state eye nystagmus during OVAR, we have used anodal (inhibitory) currents bilaterally to selectively and reversibly block irregular vestibular afferent discharge. During delivery of DC anodal currents (100 microA) bilaterally to both ears, the slow phase eye velocity of the steady-state nystagmus during OVAR was reduced or completely abolished. The disruption of the steady-state nystagmus was transient and lasted only during the period of galvanic stimulation. 3. To distinguish a possible effect of ablation of the background discharge rates of irregular vestibular afferents on the velocity storage mechanism from specific contributions of the dynamic responses from irregular otolith afferents to the circuit responsible for the generation of the steady-state nystagmus, bilateral DC anodal galvanic stimulation was applied during optokinetic nystagmus (OKN) and optokinetic afternystagmus (OKAN). No change in OKN and OKAN was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Vestibular implantation and longitudinal electrical stimulation of the semicircular canal afferents in human subjects

2015 ◽  
Vol 113 (10) ◽  
pp. 3866-3892 ◽  
Author(s):  
James O. Phillips ◽  
Leo Ling ◽  
Kaibao Nie ◽  
Elyse Jameyson ◽  
Christopher M. Phillips ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Human Subjects ◽  
Vestibular Function ◽  
Slow Phase ◽  
Vestibular Loss ◽  
Stimulation Current ◽  
Eye Velocity ◽  
Over Time ◽  
Stimulation Of

Animal experiments and limited data in humans suggest that electrical stimulation of the vestibular end organs could be used to treat loss of vestibular function. In this paper we demonstrate that canal-specific two-dimensionally (2D) measured eye velocities are elicited from intermittent brief 2 s biphasic pulse electrical stimulation in four human subjects implanted with a vestibular prosthesis. The 2D measured direction of the slow phase eye movements changed with the canal stimulated. Increasing pulse current over a 0–400 μA range typically produced a monotonic increase in slow phase eye velocity. The responses decremented or in some cases fluctuated over time in most implanted canals but could be partially restored by changing the return path of the stimulation current. Implantation of the device in Meniere's patients produced hearing and vestibular loss in the implanted ear. Electrical stimulation was well tolerated, producing no sensation of pain, nausea, or auditory percept with stimulation that elicited robust eye movements. There were changes in slow phase eye velocity with current and over time, and changes in electrically evoked compound action potentials produced by stimulation and recorded with the implanted device. Perceived rotation in subjects was consistent with the slow phase eye movements in direction and scaled with stimulation current in magnitude. These results suggest that electrical stimulation of the vestibular end organ in human subjects provided controlled vestibular inputs over time, but in Meniere's patients this apparently came at the cost of hearing and vestibular function in the implanted ear.

The Velocity Storage Mechanism of the Optokinetic Nystagmus Under Apparent Stimulus Movements in Squirrel Monkeys

1997 ◽  
Vol 7 (6) ◽  
pp. 441-451
Author(s):  
J. Kröller ◽  
F. Behrens ◽  
V.V. Marlinsky
Keyword(s):  
Steady State ◽  
Brain Stem ◽  
Apparent Movement ◽  
Squirrel Monkeys ◽  
Constant Light ◽  
Velocity Storage ◽  
Slow Phase ◽  
Stripe Pattern ◽  
Storage Mechanism ◽  
The Brain

Experiments in two awake untrained squirrel monkeys were performed to study the velocity storage mechanism during fast rise of OKN slow phase velocity. This was done by testing the monkey’s capability to perform OKN in response to a stationary-appearing stroboscopically illuminated stripe pattern of a horizontally rotating drum. Nystagmus was initially elicited during constant illumination lasting between 0.6 and 25 s. The periodicity of the stripe pattern was 2.37°. When after the constant light the flash illumination was switched on again, two types of behavior could occur, depending on the length of the constant light interval (CLI): 1) when the CLI was shorter than a threshold value of 6.2 seconds, the OKN ceased under the flash stimulation. Then a “post-OKN” occurred that increased with the length of the CLIs, indicating that the intermittently illuminated pattern did not provoke fixation suppression of OKN aftereffects. 2) when the CLI was above threshold, the OKN continued under the flash light: it will he called “apparent movement OKN.” The threshold CLI between the type 1 and the type 2 response did not depend on drum velocities between 21.5°/s and 71.3°/s. The average gain of the apparent movement OKN was 0.83 ± 0.04; gain and stability of slow phase eye movement velocity did not deviate systematically from the usually elicited OKN. OKAN after apparent movement OKN did not deviate from OKAN after constantly illuminated moving patterns. In response to the OKN initiation by a constantly illuminated pattern up to pattern velocities of 100°/s, the OKN steady state gain was reached within the first 2 or 3 nystagmus beats. We ascribe the increase of the post-OKN with CLI and the existence of a threshold constant light interval to activity-accumulation in the common velocity-to-position integrator (velocity storage) of the brain stem. Loading of the velocity storage takes place after the OKN gain has already reached the steady-state value. Apparent movement OKN could also be elicited in guinea pigs that lack an effective smooth pursuit system. We suggest that apparent movement OKN is produced by mechanisms located in the brain stem.

Norepinephrine uptake as an indicator of cardiac reinnervation in dogs

1978 ◽  
Vol 235 (3) ◽  
pp. H289-H294 ◽  
Author(s):  
M. P. Kaye ◽  
G. M. Tyce
Keyword(s):  
Electrical Stimulation ◽  
Sympathetic Nerves ◽  
Progressive Increase ◽  
Canine Heart ◽  
Storage Mechanism ◽  
Specific Membrane ◽  
Heart Uptake ◽  
Membrane Mechanism ◽  
Stimulation Of

To study the possible role of uptake of [3H]norepinephrine ([3H]NE) as an indicator of sympathetic reinnervation of the surgically denervated canine heart, uptake was determined from multiple areas of hearts at various stages of reinnervation (1--6 mo), and these data were correlated with myocardial catecholamine content and functional response of the heart to electrical stimulation of the sympathetic nerves. Our experiments confirm that NE content correlates poorly with the degree of reinnervation of the previously denervated canine heart. There is, however, a progressive increase of [3H]NE uptake from 1 mo to 6 mo, at which time uptake has returned to approximately 57% of control values in the left atrium. The development of the storage mechanism lags far behind the specific-membrane mechanism for uptake in the reinnervating surgically denervated canine heart.

scholarly journals Spatial and temporal properties of eye movements produced by electrical stimulation of semicircular canal afferents

2012 ◽  
Vol 108 (5) ◽  
pp. 1511-1520 ◽  
Author(s):  
Richard F. Lewis ◽  
Csilla Haburcakova ◽  
Wangsong Gong ◽  
Faisal Karmali ◽  
Daniel M. Merfeld
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Semicircular Canal ◽  
Low Frequency ◽  
Velocity Storage ◽  
Rotational Axis ◽  
Temporal Properties ◽  
Normal Manner ◽  
Semicircular Canal Afferents ◽  
Stimulation Of

To investigate the characteristics of eye movements produced by electrical stimulation of semicircular canal afferents, we studied the spatial and temporal features of eye movements elicited by short-term lateral canal stimulation in two squirrel monkeys with plugged lateral canals, with the head upright or statically tilted in the roll plane. The electrically induced vestibuloocular reflex (eVOR) evoked with the head upright decayed more quickly than the stimulation signal provided by the electrode, demonstrating an absence of the classic velocity storage effect that improves the dynamics of the low-frequency VOR. When stimulation was provided with the head tilted in roll, however, the eVOR decayed more rapidly than when the head was upright, and a cross-coupled vertical response developed that shifted the eye's rotational axis toward alignment with gravity. These results demonstrate that rotational information provided by electrical stimulation of canal afferents interacts with otolith inputs (or other graviceptive cues) in a qualitatively normal manner, a process that is thought to be mediated by the velocity storage network. The observed interaction between the eVOR and graviceptive cues is of critical importance for the development of a functionally useful vestibular prosthesis. Furthermore, the presence of gravity-dependent effects (dumping, spatial orientation) despite an absence of low-frequency augmentation of the eVOR has not been previously described in any experimental preparation.

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