LXIII A Comparison of Ocular Counter-Rolling Movements between Normal Persons and Deaf Subjects with Bilateral Labyrinthine Defects

Head roll dependent variability of subjective visual vertical and ocular counterroll

“…OCR is generated by brainstem circuits (Crawford et al 2003) mainly relying on vestibular input. In case of bilateral vestibular loss, OCR is reduced ) and the contribution of extra-vestibular sensors to the residual OCR is greater (Miller and Graybiel 1963;Krejcova et al 1971;De Graaf et al 1992). In paradigms investigating the contribution of otolith signals to verticality perception, proprioceptive input is usually also available.…”

Visual orientation during and after lateral head, body, and trunk tilt

“…Ocular countertorsion may be involved in both the effect and aftereffect. Although countertorsion has been considered as a specific indicator of otolith function (Miller &;Graybiel, 1963) it has been found to occur with TT (Fischer, 1927). Little is known about the recovery of ocular posture fol lowing prolonged lateral tilt, and therefore its involvement in the aftereffect is speculative.…”

“…When the body is tilted 30 0 right then, allowing for about 50 of ocular countertorsion (Miller, 1962;Miller & Graybiel, 1963;Schone, 1962), the retinal image of a GV object is tilted about 25 0 counterclockwise (CCW) relative to the normal retinal meridian of the eye. Despite this CCW displacement of the image, the GV object is judged to be tilted about 4 0 clockwise (CW).…”

Stability of apparent vertical and ocular countertorsion as a function of lateral tilt

“…Therefore more precise measurements were performed of the stability of two responses, both dependent on the statolith organs, but involving different levels of neural organization: the AV and the ocular countertorsion reflex; the former involving complex perception processes, the latter being a more direct reflection of statolith organ activity (WoeRner & Graybiel, 1959;Schone, 1962;Miller & Graybiel, 1963b;Colenbrander, 1964;Kellogg, 1965).…”