The otolith organs and their influence on oculomotor movements

Fluur, E.; Mellström, A.

doi:10.1016/0014-4886(71)90228-7

Cited by 73 publications

(10 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Existing evidence suggests that responses to activation of a single focal region on a single macula (or any small bundle of axons within the utricular or saccular nerve) are relatively small compared to ampullary nerve responses and often disconjugate, with direction and speed that depend not only on which afferents are activated but also on the temporal dynamics of the stimulus, visual target distance and eccentricity, and the pattern of simultaneous activity in ampullary nerves (Fluur and Mellström 1970a, 1970b, 1971; Goto et al 2003, 2004; Curthoys 1987; Meng and Angelaki 2006). Absent clear guidance from the literature regarding the relationship between macular stimulation patterns and the 3D axis of aVOR/tVOR responses, we assumed that macula-mediated responses were negligible.…”

Section: Discussionmentioning

confidence: 99%

“…Dense packing of hair cells and afferents with widely varying directional sensitivities in the utricular and saccular maculae and their nerves makes the relationship between electrically-evoked macular nerve stimulation and aVOR/tVOR-mediated eye movements less predictable (Suzuki et al 1969a, 1969b; Fluur and Mellström 1970a, 1970b, 1971; Goto et al 2003, 2004; Curthoys 1987). Existing evidence suggests that eye movement responses to natural stimulation of macular nerves are modest compared to aVOR responses to SCC input during natural head rotation (Baarsma and Collewijn 1975); therefore, we neglected the effects of macular nerve activity when predicting 3D eye movement axes from the pattern of vestibular nerve activity reported by the model.…”

Section: Model Descriptionmentioning

confidence: 99%

See 1 more Smart Citation

Virtual labyrinth model of vestibular afferent excitation via implanted electrodes: validation and application to design of a multichannel vestibular prosthesis

et al. 2011

View full text Add to dashboard Cite

To facilitate design of a multichannel vestibular prosthesis that can restore sensation to individuals with bilateral loss of vestibular hair cell function, we created a virtual labyrinth model. Model geometry was generated through 3-dimensional (3D) reconstruction of microMRI and microCT scans of normal chinchillas (Chinchilla lanigera) acquired with 30–48 μm and 12 μm voxels, respectively. Virtual electrodes were positioned based on anatomic landmarks, and the extracellular potential field during a current pulse was computed using finite element methods. Potential fields then served as inputs to stochastic, nonlinear dynamic models for each of 2415 vestibular afferent axons with spiking dynamics based on a modified Smith and Goldberg model incorporating parameters that varied with fiber location in the neuroepithelium. Action potential propagation was implemented by a well validated model of myelinated fibers. We tested the model by comparing predicted and actual 3D angular vestibulo-ocular reflex (aVOR) axes of eye rotation elicited by prosthetic stimuli. Actual responses were measured using 3D video-oculography. The model was individualized for each animal by placing virtual electrodes based on microCT localization of real electrodes. 3D eye rotation axes were predicted from the relative proportion of model axons excited within each of the three ampullary nerves. Multiple features observed empirically were observed as emergent properties of the model, including effects of active and return electrode position, stimulus amplitude and pulse waveform shape on target fiber recruitment and stimulation selectivity. The modeling procedure is partially automated and can be readily adapted to other species, including humans.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Model Descriptionmentioning

confidence: 99%

Virtual labyrinth model of vestibular afferent excitation via implanted electrodes: validation and application to design of a multichannel vestibular prosthesis

et al. 2011

View full text Add to dashboard Cite

show abstract

“…Focal mechanical stimulation of one or more ampullary nerves causes binocular eye movements with little or no disconjugacy (e.g., during nystagmus due to benign paroxysmal positional vertigo or superior semicircular canal dehiscence in otherwise normal subjects [Cremer et al 2002]), so we would expect inadvertent electrical stimulation of non-target ampullary nerves to elicit aVOR responses that are conjugate regardless of how well they align with the head rotation axis. In contrast, existing evidence suggests that the eye movement responses to activation of a single region on a single macula (or other combinations of axons within the utricular and saccular nerves) are disconjugate (Suzuki et al 1969a, 1969b; Fluur and Mellström 1970a, 1970b, 1971; Goto et al 2003, 2004; Curthoys 1987). It seems reasonable to assume that the disconjugacy we observed between 3D rotation axes of the two eyes in each animal upon initial MVP activation represents an electrically-evoked translational VOR (tVOR) and/or ocular tilt reaction driven by inadvertent macular nerve stimulation.…”

Section: Discussionmentioning

confidence: 97%

Cross-axis adaptation improves 3D vestibulo-ocular reflex alignment during chronic stimulation via a head-mounted multichannel vestibular prosthesis

et al. 2011

View full text Add to dashboard Cite

By sensing three-dimensional (3D) head rotation and electrically stimulating the three ampullary branches of a vestibular nerve to encode head angular velocity, a multichannel vestibular prosthesis (MVP) can restore vestibular sensation to individuals disabled by loss of vestibular hair cell function. However, current spread to afferent fibers innervating non-targeted canals and otolith endorgans can distort the vestibular nerve activation pattern, causing misalignment between the perceived and actual axis of head rotation. We hypothesized that over time, central neural mechanisms can adapt to correct this misalignment. To test this, we rendered five chinchillas vestibular-deficient via bilateral gentamicin treatment and unilaterally implanted them with a head mounted MVP. Comparison of 3D angular vestibulo-ocular reflex (aVOR) responses during 2 Hz, 50°/s peak horizontal sinusoidal head rotations in darkness on the first, third and seventh days of continual MVP use revealed that eye responses about the intended axis remained stable (at about 70% of the normal gain) while misalignment improved significantly by the end of one week of prosthetic stimulation. A comparable time course of improvement was also observed for head rotations about the other two semicircular canal axes and at every stimulus frequency examined (0.2–5 Hz). In addition, the extent of disconjugacy between the two eyes progressively improved during the same time window. These results indicate that the central nervous system rapidly adapts to multichannel prosthetic vestibular stimulation to markedly improve 3D aVOR alignment within the first week after activation. Similar adaptive improvements are likely to occur in other species, including humans.

show abstract

“…The contribution of sacculus versus utriculus to torsional eye movements recorded in human subjects on centrifuges was estimated roughly at a 1:3 ratio (De Graaf et al 1996). Although fewer in the number of relay neurons and not as strong in their synaptic drive, torsional eye movements could be elicited via polysynaptic pathways from both utriculus and sacculus (Curthoys 1987;Fluur and Mellstrom 1971;Isu et al 2000;Sasaki et al 1991;Uchino et al 1996).…”

Section: Compensatory Lvor Versus Orienting Ocular Responsesmentioning

confidence: 99%

Frequency-Dependent Spatiotemporal Tuning Properties of Non–Eye Movement Related Vestibular Neurons to Three-Dimensional Translations in Squirrel Monkeys

Chen-Huang

Peterson

2010

Journal of Neurophysiology

View full text Add to dashboard Cite

Chen-Huang C, Peterson BW. Frequency-dependent spatiotemporal tuning properties of non-eye movement related vestibular neurons to threedimensional translations in squirrel monkeys. J Neurophysiol 103: 3219-3237, 2010. First published April 7, 2010 doi:10.1152/jn.00904.2009. Responses of vestibular-only translation sensitive (VOTS) neurons in vestibular nuclei of two squirrel monkeys were studied at multiple frequencies to three-dimensional translations and rotations. A novel frequency-dependent spatiotemporal analysis examined in each neuron whether complex models, with unrestricted response dynamics in three-dimensional (3D) space, provided significantly better fits than restricted models following simple, cosine rule. Subsequently, the statistically selected optimal model was used to predict the maximum translation direction, expressed as a unitary vector, Vt max , and its associated sensitivity and phase across frequencies. Simple models were sufficient to quantify the 3D translational responses of 66% of neurons. Most VOTS neurons, complex or simple, exhibited flat-gain or low-pass response dynamics. The Vt max of simple neurons was fixed, whereas that of complex neurons changed with frequency. The spatial distribution of Vt max in simple neurons, which fell within 30°o f either the horizontal plane or/and the sagittal plane, was closely aligned with Vt max of vestibular afferents. In contrast, the frequencydependent Vt max of most complex neurons migrated from the dorsoventral axis at higher frequency toward the horizontal plane, especially the interaural axis, at lower frequency. When the maximum rotation direction was estimated from responses of the same VOTS neurons to 1.2 Hz yaw, pitch, and roll rotations, complex neurons were more likely to respond to rotations activating vertical canals. Responses to 0.15-0.3 Hz linear accelerations produced by inertial or gravitational forces were indistinguishable in most complex neurons but significantly different in most simple neurons. These observations suggest that simple and complex VOTS neurons constitute distinctive vestibular pathways where complex neurons, exhibiting a novel spatiotemporal filtering mechanism in processing otolith-related signals, are well suited to drive tilt-related responses, whereas simple neurons probably mediate pure translation related responses.

show abstract

The otolith organs and their influence on oculomotor movements

Cited by 73 publications

References 20 publications

Virtual labyrinth model of vestibular afferent excitation via implanted electrodes: validation and application to design of a multichannel vestibular prosthesis

Virtual labyrinth model of vestibular afferent excitation via implanted electrodes: validation and application to design of a multichannel vestibular prosthesis

Cross-axis adaptation improves 3D vestibulo-ocular reflex alignment during chronic stimulation via a head-mounted multichannel vestibular prosthesis

Frequency-Dependent Spatiotemporal Tuning Properties of Non–Eye Movement Related Vestibular Neurons to Three-Dimensional Translations in Squirrel Monkeys

Contact Info

Product

Resources

About