Contribution of the maculo-ocular reflex to gaze stability in the rabbit

Pettorossi, Vito Enrico; Errico, P.; Santarelli, Rosamaria

doi:10.1007/bf00231160

Cited by 4 publications

(2 citation statements)

References 17 publications

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“…This otolithic signal combines with a signal generated by head angular acceleration, detected by semicircular canals. These combined signals induce both vertical and torsional vestibulo-ocular reflexes (Barmack 1981; Van der Steen and Collewijn 1984; Pettorossi et al 1991, 1997; Angelaki and Hess 1994; Maruta et al 2006, 2008; Yakushin et al 2009). …”

Section: Introductionmentioning

confidence: 99%

Head position modulates optokinetic nystagmus

Pettorossi¹,

Ferraresi²,

Botti³

et al. 2011

Exp Brain Res

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Orientation and movement relies on both visual and vestibular information mapped in separate coordinate systems. Here, we examine how coordinate systems interact to guide eye movements of rabbits. We exposed rabbits to continuous horizontal optokinetic stimulation (HOKS) at 5°/s to evoke horizontal eye movements, while they were statically or dynamically roll-tilted about the longitudinal axis. During monocular or binocular HOKS, when the rabbit was roll-tilted 30° onto the side of the eye stimulated in the posterior → anterior (P → A) direction, slow phase eye velocity (SPEV) increased by 3.5–5°/s. When the rabbit was roll-tilted 30° onto the side of the eye stimulated in the A → P direction, SPEV decreased to ~2.5°/s. We also tested the effect of roll-tilt after prolonged optokinetic stimulation had induced a negative optokinetic afternystagmus (OKAN II). In this condition, the SPEV occurred in the dark, “open loop.” Modulation of SPEV of OKAN II depended on the direction of the nystagmus and was consistent with that observed during “closed loop” HOKS. Dynamic roll-tilt influenced SPEV evoked by HOKS in a similar way. The amplitude and the phase of SPEV depended on the frequency of vestibular oscillation and on HOKS velocity. We conclude that the change in the linear acceleration of the gravity vector with respect to the head during roll-tilt modulates the gain of SPEV depending on its direction. This modulation improves gaze stability at different image retinal slip velocities caused by head roll-tilt during centric or eccentric head movement.

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Section: Introductionmentioning

confidence: 99%

Head position modulates optokinetic nystagmus

Pettorossi¹,

Ferraresi²,

Botti³

et al. 2011

Exp Brain Res

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“…Since the otolith organs respond well to low frequency stimulation, we would expect them to contribute to the low frequency aVOR when possible. Evidence for otolith contribution to the aVOR in nonhumans exists [cat: (Rude and Baker 1988;Blanks et al 1978;Tomko et al 1988); rabbit: (Barmack and Pettorossi 1988;Pettorossi et al 1991); monkey: (Angelaki and Hess 1996;Angelaki et al 2002)]. In humans, similar evidence for a contribution of dynamic otolith signals to the aVOR mainly comes from experiments with stimuli that do not occur in everyday life, for example, long-duration offvertical axis rotation (Haslwanter et al 2000;Harris and Barnes 1987;Furman et al 1992;Darlot et al 1988), peror post-rotatory tilt (Bockisch et al 2003;Fetter et al 1996;Zupan et al 2000), or eccentric rotation about the earth-vertical axis (Merfeld et al 2001;Lansberg et al 1965).…”

Section: Introductionmentioning

confidence: 99%

Human 3-D aVOR with and without otolith stimulation

2004

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We describe in detail the frequency response of the human three-dimensional angular vestibulo-ocular response (3-D aVOR) over a frequency range of 0.05-1 Hz. Gain and phase of the human aVOR were determined for passive head rotations in the dark, with the rotation axis either aligned with or perpendicular to the direction of gravity (earth-vertical or earth-horizontal). In the latter case, the oscillations dynamically stimulated both the otolith organs and the semi-circular canals. We conducted experiments in pitch and yaw, and compared the results with previously-published roll data. Regardless of the axis of rotation and the orientation of the subject, the gain in aVOR increased with frequency to about 0.3 Hz, and was approximately constant from 0.3 to 1 Hz. The aVOR gain during pitch and yaw rotations was larger than during roll rotations. Otolith and canal cues combined differently depending upon the axis of rotation: for torsional and pitch rotations, aVOR gain was higher with otolith input; for yaw rotations the aVOR was not affected by otolith stimulation. There was a phase lead in all three dimensions for frequencies below 0.3 Hz when only the canals were stimulated. For roll and pitch rotations this phase lead vanished with dynamic otolith stimulation. In contrast, the horizontal phase showed no improvement with additional otolith input during yaw rotations. The lack of a significant otolith contribution to the yaw aVOR was observed when subjects were supine, prone or lying on their sides. Our results confirm studies with less-natural stimuli (off-vertical axis rotation) that the otoliths contribute a head-rotation signal to the aVOR. However, the magnitude of the contribution depends on the axis of rotation, with the gain in otolith-canal crosscoupling being smallest for yaw axis rotations. This could be because, in humans, typical yaw head movements will stimulate the otoliths to a much lesser extent then typical pitch and roll head movements.

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