Vestibular Signals in Self-Orientation and Eye Movement Control

Physiology ◽  
2001 ◽  
Vol 16 (5) ◽  
pp. 234-238 ◽  
Author(s):  
Bernhard J. M. Hess
Keyword(s):  
Signal Processing ◽  
Eye Movement ◽  
Vestibular System ◽  
Retinal Image ◽  
Internal Model ◽  
Movement Control ◽  
Head Position ◽  
Head Motion ◽  
Afferent Information ◽  
The Brain

The central vestibular system receives afferent information about head position as well as rotation and translation. This information is used to prevent blurring of the retinal image but also to control self-orientation and motion in space. Vestibular signal processing in the brain stem appears to be linked to an internal model of head motion in space.

scholarly journals Vestibular implants studied in animal models: clinical and scientific implications

2016 ◽  
Vol 116 (6) ◽  
pp. 2777-2788 ◽  
Author(s):  
Richard F. Lewis
Keyword(s):  
Animal Models ◽  
Vestibular System ◽  
Animal Studies ◽  
Vestibular Function ◽  
Clinical Problem ◽  
Head Motion ◽  
The Past ◽  
New Treatment ◽  
Vestibular Damage ◽  
The Brain

Damage to the peripheral vestibular system can result in debilitating postural, perceptual, and visual symptoms. A potential new treatment for this clinical problem is to replace some aspects of peripheral vestibular function with an implant that senses head motion and provides this information to the brain by stimulating branches of the vestibular nerve. In this review I consider animal studies performed at our institution over the past 15 years, which have helped elucidate how the brain processes information provided by a vestibular (semicircular canal) implant and how this information could be used to improve the problems experienced by patients with peripheral vestibular damage.

Primate Head-Free Saccade Generator Implements a Desired (Post-VOR) Eye Position Command by Anticipating Intended Head Motion

1997 ◽  
Vol 78 (5) ◽  
pp. 2811-2816 ◽  
Author(s):  
J. Douglas Crawford ◽  
Daniel Guitton
Keyword(s):  
Head Movement ◽  
Head Position ◽  
Slow Phase ◽  
Head Motion ◽  
Eye Position ◽  
Coordination Strategies ◽  
Context Dependent ◽  
The Brain ◽  
Normal Head

Crawford, J. Douglas and Daniel Guitton. Primate head-free saccade generator implements a desired (post-VOR) eye position command by anticipating intended head motion. J. Neurophysiol. 78: 2811–2816, 1997. When we glance between objects, the brain ultimately controls gaze direction in space. However, it is currently unclear how this is allocated into separate commands for eye and head movement. To determine the role of desired final eye position commands, and their coordination with intended head movement, we trained three monkeys to make large gaze shifts while wearing opaque goggles with a monocular 8° aperture. Animals eventually developed a new set of context-dependent eye-head coordination strategies, in particular expanding the head range and compressing the eye-in-head range toward the aperture (while wearing the goggles). However, when we shifted the location of the aperture to a different subsection of the normal head-free oculomotor range (by covering the original aperture and creating a new one), eye-head saccades failed to acquire visual targets, because they continued to drive the eye ultimately toward the now occluded original aperture. Even when a head-stationary saccade acquired the new aperture, subsequent head-free saccades drove the eye eccentrically toward a point that anticipated the intended head movement, such that the subsequent vestibuloocular reflex slow phase brought the eye onto the location of the original aperture. Animals could only acquire the new aperture consistently after several days of retraining. These results suggest that 1) eye-head coordination is achieved by a plastic, context-dependent neural operator that uses information about initial eye/head position and intended movement to compute desired combinations of final eye/head position and 2) acquisition of these positions involves sophisticated anticipatory compensations for subsequent movement components, akin to those observed previously in complex oral and manual behaviors.

The Vergence System

2008 ◽  
Author(s):  
Agnes Wong
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Retinal Image ◽  
Computer Software ◽  
The Gaze ◽  
Pupillary Constriction ◽  
System P ◽  
Catch Up ◽  
Alcohol And Other Drugs ◽  
The Brain

Vergence eye movements shift the gaze point between near and far, such that the image of a target is maintained simultaneously on both foveae. Unlike other eye movement systems, vergence movements are disjunctive, meaning that the eyes move in opposite directions. To move from a far to a near target, the eyes converge (i.e., rotate toward the nose) so that the lines of sight of the two eyes intersect at the target. To aim at a target farther away, the eyes diverge (i.e., rotate toward the temples). When the target is located at optical infinity, the lines of sight are parallel. During deep sleep, deep anesthesia, and coma, the eyes diverge beyond parallel, indicating that eye alignment is normally actively maintained by the brain because the orbits, in which the eyeballs are located, are divergent. The vergence system is believed to be relatively new evolutionarily. Just as a new version of computer software tends to have bugs, perhaps it is for this reason that vergence is the last of the eye movement systems to reach full development in children, that it is often the first system to be affected by fatigue, alcohol, and other drugs, and that defective vergence is a common cause of strabismus and diplopia. Vergence eye movements are very slow, lasting 1 sec or longer. One reason for this may be that vergence, unlike saccades, is driven by visual feedback, which normally takes at least 80 msec. Another reason may be that the speed of vergence movements is limited by how fast the lenses change shape (accommodation) and how fast the pupils constrict. There may simply be no advantage for vergence to take place quickly and then wait for the lenses and pupils to catch up. The triad of convergence, accommodation, and pupillary constriction constitutes the near triad. The two most important stimuli for vergence are retinal image blur and retinal disparity. If the retinal image of an object is blurred, the target is either too near or too far away.

scholarly journals Context-independent encoding of passive and active self-motion in vestibular afferent fibers during locomotion in primates

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Isabelle Mackrous ◽  
Jérome Carriot ◽  
Kathleen E. Cullen
Keyword(s):  
Mathematical Modeling ◽  
Vestibular System ◽  
Direct Proof ◽  
Head Motion ◽  
Sensory Coding ◽  
Primate Locomotion ◽  
Afferent Fibers ◽  
Self Motion ◽  
The Brain ◽  
Efferent Vestibular System

AbstractThe vestibular system detects head motion to coordinate vital reflexes and provide our sense of balance and spatial orientation. A long-standing hypothesis has been that projections from the central vestibular system back to the vestibular sensory organs (i.e., the efferent vestibular system) mediate adaptive sensory coding during voluntary locomotion. However, direct proof for this idea has been lacking. Here we recorded from individual semicircular canal and otolith afferents during walking and running in monkeys. Using a combination of mathematical modeling and nonlinear analysis, we show that afferent encoding is actually identical across passive and active conditions, irrespective of context. Thus, taken together our results are instead consistent with the view that the vestibular periphery relays robust information to the brain during primate locomotion, suggesting that context-dependent modulation instead occurs centrally to ensure that coding is consistent with behavioral goals during locomotion.

Using ERP to examine eye movement control in reading

2001 ◽  
Author(s):  
Erik D. Reichle ◽  
Lesley A. Hart ◽  
Charles A. Perfetti
Keyword(s):  
Eye Movement ◽  
Movement Control ◽  
Eye Movement Control

Differences in the brain stem terminations of large- and small-diameter vestibular primary afferents

1995 ◽  
Vol 74 (3) ◽  
pp. 1362-1366 ◽  
Author(s):  
J. A. Huwe ◽  
E. H. Peterson
Keyword(s):  
Brain Stem ◽  
Large Diameter ◽  
Small Diameter ◽  
Movement Control ◽  
Three Dimensions ◽  
Significant Shift ◽  
Axon Diameter ◽  
Vestibular Complex ◽  
The Brain ◽  
Adjacent Brain

1. We visualized the central axons of 32 vestibular afferents from the posterior canal by extracellular application of horseradish peroxidase, reconstructed them in three dimensions, and quantified their morphology. Here we compare the descending limbs of central axons that differ in parent axon diameter. 2. The brain stem distribution of descending limb terminals (collaterals and associated varicosities) varies systematically with parent axon diameter. Large-diameter afferents concentrate their terminals in rostral regions of the medial/descending nuclei. As axon diameter decreases, there is a significant shift of terminal concentration toward the caudal vestibular complex and adjacent brain stem. 3. Rostral and caudal regions of the medial/descending nuclei have different labyrinthine, cerebellar, intrinsic, commissural, and spinal connections; they are believed to play different roles in head movement control. Our data help clarify the functions of large- and small-diameter afferents by showing that they contribute differentially to rostral and caudal vestibular complex.

scholarly journals Role of Primate Cerebellar Hemisphere in Voluntary Eye Movement Control Revealed by Lesion Effects

2009 ◽  
Vol 101 (2) ◽  
pp. 934-947 ◽  
Author(s):  
Masafumi Ohki ◽  
Hiromasa Kitazawa ◽  
Takahito Hiramatsu ◽  
Kimitake Kaga ◽  
Taiko Kitamura ◽  
...  
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Smooth Pursuit ◽  
Movement Control ◽  
Cerebellar Hemisphere ◽  
Target Velocity ◽  
Eye Movement Control ◽  
Pursuit Eye Movements ◽  
Catch Up

The anatomical connection between the frontal eye field and the cerebellar hemispheric lobule VII (H-VII) suggests a potential role of the hemisphere in voluntary eye movement control. To reveal the involvement of the hemisphere in smooth pursuit and saccade control, we made a unilateral lesion around H-VII and examined its effects in three Macaca fuscata that were trained to pursue visually a small target. To the step (3°)-ramp (5–20°/s) target motion, the monkeys usually showed an initial pursuit eye movement at a latency of 80–140 ms and a small catch-up saccade at 140–220 ms that was followed by a postsaccadic pursuit eye movement that roughly matched the ramp target velocity. After unilateral cerebellar hemispheric lesioning, the initial pursuit eye movements were impaired, and the velocities of the postsaccadic pursuit eye movements decreased. The onsets of 5° visually guided saccades to the stationary target were delayed, and their amplitudes showed a tendency of increased trial-to-trial variability but never became hypo- or hypermetric. Similar tendencies were observed in the onsets and amplitudes of catch-up saccades. The adaptation of open-loop smooth pursuit velocity, tested by a step increase in target velocity for a brief period, was impaired. These lesion effects were recognized in all directions, particularly in the ipsiversive direction. A recovery was observed at 4 wk postlesion for some of these lesion effects. These results suggest that the cerebellar hemispheric region around lobule VII is involved in the control of smooth pursuit and saccadic eye movements.

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