translational VOR

An elegant and influential mathematical model of eye movements is the geometric compensation required for visual fixation location in the translational vestibulo-ocular reflex (VOR). Compensatory eye velocity scales with the inverse of fixation distance during head translation because larger angular eye movements are required to minimize retinal slip during head translation when targets are closer. This model has been extensively verified in experiments. Since the VOR and vestibular perception have shared anatomic pathways, we asked whether the same scaling may affect motion perception...

Patients with Wernicke's encephalopathy (WE) often have unusual patterns of vertical nystagmus. Initially there is often a spontaneous upbeating nystagmus that may change to downbeat nystagmus with a change in the direction of gaze, convergence or with vestibular stimuli. Patients also often show a profound loss of the horizontal but not the vertical vestibulo-ocular reflex (VOR). Furthermore, the acute upbeat nystagmus may change to a chronic downbeat nystagmus. We present hypotheses for these features based on (1) the location of vertical gaze-holding networks near the area postrema of the dorsomedial medulla where the blood-brain barrier is located, which we suggest becomes compromised in WE, (2) the location of the vestibular nuclei in the brainstem, medially for the horizontal VOR, and laterally for the vertical VOR, (3) neuronal circuits differ in susceptibility to and in the ability to recover from thiamine deficiency, and (4) impaired processing of otolith information in WE, normally used to modulate translational vestibulo-ocular reflexes, leads to some of the characteristics of the spontaneous vertical nystagmus including the peculiar reversal in its direction with a change in gaze or convergence...

Dynamic visual acuity (DVA) provides an overall functional measure of visual stabilization performance that depends on the vestibulo-ocular reflex (VOR), but also on other processes, including catch-up saccades and likely visual motion processing. Capturing the efficiency of gaze stabilization against head movement as a whole, it is potentially valuable in the clinical context where assessment of overall patient performance provides an important indication of factors impacting patient participation and quality of life...

The role of the otoliths in mammals in the angular vestibuloocular reflex (VOR) has been difficult to determine because there is no surgical technique that can reliably ablate them without damaging the semicircular canals. The Otopetrin1 (Otop1) mouse lacks functioning otoliths because of failure to develop otoconia but seems to have otherwise normal peripheral anatomy and neural circuitry. By using these animals we sought to determine the role of the otoliths in angular VOR baseline function and adaptation...

Locomotion involves complex combinations of translational and rotational head movements. For gaze stability, this necessitates the interplay of angular and linear vestibulo-ocular reflexes (VOR) as well as the integration of visual feedback about the desired viewing distance. Furthermore, gaze stabilizing systems must be able to cope with vast differences in head motion brought about by changing locomotor speeds and patterns (walking vs. running). The present study investigated horizontal and vertical angular VOR (aVOR) and linear gaze stabilization (lGS) as well as compensation for linear head movements by angular counter rotation of the head during treadmill walking and running at different velocities (0...

Vestibulo-ocular reflexes (VORs) rely on neuronal computations that transform vestibular sensory signals into spatio-temporally appropriate extraocular motor commands. The motoneuronal discharge for contractions of the superior oblique eye muscle during linear translation derives from a utricular epithelial sector that is spatially aligned with the pulling direction of this muscle. In Xenopus laevis , the alignment is gradually achieved during larval development and requires motion-related semicircular canal afferent activity...

BACKGROUND: The histone deacetylase (HDAC) inhibitor vorinostat (VOR) can increase HIV RNA expression in vivo within resting CD4+ T cells of aviremic HIV+ individuals. However, while studies of VOR or other HDAC inhibitors have reported reversal of latency, none has demonstrated clearance of latent infection. We sought to identify the optimal dosing of VOR for effective serial reversal of HIV latency. METHODS: In a study of 16 HIV-infected, aviremic individuals, we measured resting CD4+ T cell-associated HIV RNA ex vivo and in vivo following a single exposure to VOR, and then in vivo after a pair of doses separated by 48 or 72 hours, and finally following a series of 10 doses given at 72-hour intervals...

Neuroscientific research has made a concerted effort to determine cortical localization using various functional imaging techniques. This approach has undoubtedly yielded important novel anatomical knowledge, albeit at times contradictory, regarding the structural organization of the vestibular cortex. Unfortunately however, this knowledge has not translated to our understanding regarding how neural mechanisms control vestibular function. Based upon recent functional imaging, lesion and neuro-physiological data that have demonstrated (i) the close behavioral and neuro-anatomical relationship between cortical processing of vestibular and spatial attention signals, and (ii) that inducing interhemispheric competition can in-turn strongly modulate vestibular function akin to that observed in cortical lesion patients, I herewith propose the hypothesis that vestibular cortical processing is controlled, as per for spatial attention, via dynamic interhemispheric competition...

Vestibulo-ocular reflexes (VOR) ensure gaze stability during locomotion and passively induced head/body movements. In precocial vertebrates such as amphibians, vestibular reflexes are required very early at the onset of locomotor activity. While the formation of inner ears and the assembly of sensory-motor pathways is largely completed soon after hatching, angular and translational/tilt VOR display differential functional onsets and mature with different time courses. Otolith-derived eye movements appear immediately after hatching, whereas the appearance and progressive amelioration of semicircular canal-evoked eye movements is delayed and dependent on the acquisition of sufficiently large semicircular canal diameters...

BACKGROUND: The cerebellum plays a central role in the online, real-time control, and long-term modulation of eye movements. EVIDENCE ACQUISITION: We reviewed the latest (fifth) edition of Leigh and Zee's textbook, The Neurology of Eye Movements, and literature in PUBMED using the following terms: cerebellum, flocculus, paraflocculus, vermis, oculomotor vermis, dorsal vermis, caudal fastigial nucleus, fastigial oculomotor region, uvula, nodulus, ansiform lobule, eye movements, saccades, ipsipulsion, contrapulsion, smooth pursuit, vergence, convergence, divergence, gaze-holding, down beat nystagmus, vestibulo-ocular reflex (VOR), angular VOR, translational VOR, skew deviation, velocity storage...

Some individuals with noise-induced hearing loss (NIHL) also report balance problems. These accompanying vestibular complaints are not well understood. The present study used a rat model to examine the effects of noise exposure on the vestibular system. Rats were exposed to continuous broadband white noise (0-24 kHz) at an intensity of 116 dB sound pressure level (SPL) via insert ear phones in one ear for three hours under isoflurane anesthesia. Seven days after the exposure, a significant increase in ABR threshold (43...

The learning of motor skills is thought to occur largely through trial and error; however, the error signals and rules controlling the induction of motor learning have not been fully elucidated. We evaluated the learning rules that translate the sensory and motor cues available during training into learned changes in the gain and phase of the vestibulo-ocular reflex (VOR) of mice. Contrary to previous theories, neither the phase of retinal image motion relative to head motion nor the phase of retinal image motion relative to eye movement could consistently predict the direction of the learned change in the gain of the VOR across all training conditions tested...

The vestibular system plays a crucial role in the multisensory control of balance. When vestibular function is lost, essential tasks such as postural control, gaze stabilization, and spatial orientation are limited and the quality of life of patients is significantly impaired. Currently, there is no effective treatment for bilateral vestibular deficits. Research efforts both in animals and humans during the last decade set a solid background to the concept of using electrical stimulation to restore vestibular function...

Developmental and evolutionary data from vertebrates are beginning to elucidate the origin of the sensorimotor pathway that links gravity and motion detection to image-stabilizing eye movements--the vestibulo-ocular reflex (VOR). Conserved transcription factors coordinate the development of the vertebrate ear into three functional sensory compartments (graviception/translational linear acceleration, angular acceleration and sound perception). These sensory components connect to specific populations of vestibular and auditory projection neurons in the dorsal hindbrain through undetermined molecular mechanisms...

The vestibulo-ocular reflex (VOR) acts to maintain images stable on the retina by rotating the eyes in exactly the opposite direction, but with equal magnitude, to head velocity. When viewing a near target, this reflex has an increased response to compensate for the translation of the eyes relative to the target that acts to reduce retinal image slip. Previous studies have shown that retinal velocity error provides an important visual feedback signal to increase the low-frequency (<1 Hz) VOR response during near viewing...

Extinct animal behavior has often been inferred from qualitative assessments of relative brain region size in fossil endocranial casts. For instance, flight capability in pterosaurs and early birds has been inferred from the relative size of the cerebellar flocculus, which in life protrudes from the lateral surface of the cerebellum. A primary role of the flocculus is to integrate sensory information about head rotation and translation to stabilize visual gaze via the vestibulo-occular reflex (VOR). Because gaze stabilization is a critical aspect of flight, some authors have suggested that the flocculus is enlarged in flying species...

UNLABELLED: The vestibular organ is a sensor that measures angular and linear accelerations with six degrees of freedom (6DF). Complete or partial defects in the vestibular organ results in mild to severe equilibrium problems, such as vertigo, dizziness, oscillopsia, gait unsteadiness nausea and/or vomiting. A good and frequently used measure to quantify gaze stabilization is the gain, which is defined as the magnitude of compensatory eye movements with respect to imposed head movements...

Histone deacetylase inhibitors (HDACIs) are being investigated as novel therapies for cancer, inflammation, neurodegeneration, and heart failure. The effects of HDACIs on the functional expression of cardiac gap junctions (GJs) are essentially unknown. The purpose of this study was to determine the effects of trichostatin A (TSA) and vorinostat (VOR) on functional GJ expression in ventricular cardiomyocytes. The effects of HDAC inhibition on connexin43 (Cx43) expression and functional GJ assembly were examined in primary cultured neonatal mouse ventricular myocytes...

Compensatory counter-rotations of the eyes provoked by head turns are commonly attributed to the vestibulo-ocular reflex (VOR). A recent study in guinea pigs demonstrates, however, that this assumption is not always valid. During voluntary head turns, guinea pigs make highly accurate compensatory eye movements that occur with zero or even negative latencies with respect to the onset of the provoking head movements. Furthermore, the anticipatory eye movements occur in animals with bilateral peripheral vestibular lesions, thus confirming that they have an extra vestibular origin...

Despite antiretroviral therapy, proviral latency of human immunodeficiency virus type 1 (HIV-1) remains a principal obstacle to curing the infection. Inducing the expression of latent genomes within resting CD4(+) T cells is the primary strategy to clear this reservoir. Although histone deacetylase inhibitors such as suberoylanilide hydroxamic acid (also known as vorinostat, VOR) can disrupt HIV-1 latency in vitro, the utility of this approach has never been directly proven in a translational clinical study of HIV-infected patients...