Effect of viewing distance and location of the axis of head rotation on the monkey's vestibuloocular reflex. I. Eye movement responses

Abstract

1. The vestibuloocular reflex (VOR) stabilizes images on the retina against movements of the head in space. Viewing distance, target eccentricity, and location of the axis of rotation may influence VOR responses because rotation of the head about most axes in space rotates and translates the eyes relative to visual targets. To study the VOR response to combined rotation and translation, monkeys were placed on a rate table and rotated briefly in the dark about a vertical axis that was located in front of or behind the eyes. The monkeys fixated a near or far visual target that was extinguished before the rotation. Eye movements were recorded from both eyes by the use of the search coil technique. 2. Peak eye velocity evoked by the VOR was linearly related to vergence angle for any axis of rotation. The percent change in the VOR with near target viewing relative to far target viewing at a vergence angle of 20 degrees was linearly related to the location of the axis of rotation. Axes located behind the eyes produced positive changes in VOR amplitude, and axes located in front of the eyes produced negative changes in VOR amplitude. An axis of rotation located in the coronal plane containing the centers of rotation of the eyes produced no modification of VOR amplitude. For any axis, the VOR compensated for approximately 90% of the translation of the eye relative to near targets. 3. The initial VOR response was not correct in magnitude but was refined by a series of three temporally delayed corrections of increasing complexity. The earliest VOR-evoked eye movement (10-20 ms after rotation onset) was independent of viewing distance and rotational axis location. In the next 100 ms, eye speed appeared to be sequentially modified three times: within 20 ms by viewing distance; within 30 ms by otolith translation; and within 100 ms by eye translation relative to the visual target. 4. These data suggest a formal model of the VOR consisting of four channels. Channel 1 conveys an unmodified head rotation signal with a pure delay of 10 ms. Channel 2 conveys an angular head velocity signal, modified by viewing distance with a pure delay of 20 ms, but invariant with respect to the location of the axis of rotation. Channel 3 conveys a linear head velocity signal, dependent on the location of the axis of rotation, that is modified by viewing distance with a pure delay of 30 ms.(ABSTRACT TRUNCATED AT 400 WORDS)

Vestibulo-Ocular Reflex Suppression during Head-Fixed Saccades Reveals Gaze Feedback Control

“…Thus, motion of the chair induced both a rotation and a translation of the orbits, causing both a rotational VOR (rVOR) and a translational VOR (tVOR). The tVOR, however, is a function of the reciprocal of the distance to the target, which was quite far in our experiment (Schwarz et al, 1989;Snyder and King, 1992;Crane et al, 1997). Thus, we treat the eye movements as if they were due only to the rVOR.…”

Temporal dynamics of semicircular canal and otolith function following acute unilateral vestibular deafferentation in humans

“…Transient rotation at high acceleration has been employed in combination with eccentric rotation axes and different target distances in monkey (Snyder and King 1992) and in younger (Anastasopoulos et al 1996;Crane et al 1997;Crane and Demer 1998) and older humans (Tian et al 2001a). Rotation about eccentric axes can deliver significant otolith stimulation that is either synergistic or antagonistic with canal stimulation, and produces an effect on the VOR that varies systematically with target distance (Viirre et al 1986;Snyder and King 1992;Crane et al 1997;Crane and Demer 1998;Tian et al 2001a).…”

“…Transient rotation at high acceleration has been employed in combination with eccentric rotation axes and different target distances in monkey (Snyder and King 1992) and in younger (Anastasopoulos et al 1996;Crane et al 1997;Crane and Demer 1998) and older humans (Tian et al 2001a). Rotation about eccentric axes can deliver significant otolith stimulation that is either synergistic or antagonistic with canal stimulation, and produces an effect on the VOR that varies systematically with target distance (Viirre et al 1986;Snyder and King 1992;Crane et al 1997;Crane and Demer 1998;Tian et al 2001a). As geometrically appropriate to gaze stabilization, VOR gain for rotation about an axis posterior to head is greater for near than for distant targets (Viirre et al 1986;Crane and Demer 1998;Tian et al 2001a), but is reduced for a near target for rotation about an axis anterior to head (Sargent and Paige 1991;Crane and Demer 1998;Tian et al 2001a).…”

The effect of alcohol on cervical and ocular vestibular evoked myogenic potentials in healthy volunteers

“…VOR gain is known to be affected by factors such as visual context, cognitive set and alertness (e.g. Ramat et al, 2005;Snyder and King, 1992). Animal studies show that alcohol can inhibit spike generation in the vestibular nucleus without causing conduction delay (e.g.…”