Veterans Affairs and Case Medical Center

Cleveland, OH, United States

Veterans Affairs and Case Medical Center

Cleveland, OH, United States
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Liao K.,Veterans Affairs and Case Medical Center | Schneider R.M.,Veterans Affairs and Case Medical Center | Yaniglos S.S.,Veterans Affairs and Case Medical Center | Bertolini G.,University of Zürich | And 4 more authors.
Annals of the New York Academy of Sciences | Year: 2011

Prior studies indicate that the human translational vestibulo-ocular reflex (tVOR) generates eye rotations approximately half the magnitude required to keep the line of sight pointed at a stationary object-a compensation ratio (CR) of ∼0.5. We asked whether changes of visual or vestibular stimuli could increase the CR of tVOR. First, subjects viewed their environment through an optical device that required eye movements to increase by ∼50% to maintain fixation of a stationary visual target. During vertical translation, eye movements did increase, but tVOR CR remained at ∼0.5. Second, subjects viewed through LCD goggles providing 4 Hz strobe vision that minimized retinal image motion; this reduced tVOR CR. Finally, subjects were rotated in roll while they translated vertically; no increase in tVOR occurred. Taken with prior studies, we conclude that tVOR is optimally set to generate eye rotations that are about 50% of those required to stabilize the line of sight. © 2011 New York Academy of Sciences.


King S.A.,Veterans Affairs and Case Medical Center | Schneider R.M.,Veterans Affairs and Case Medical Center | Serra A.,Veterans Affairs and Case Medical Center | Leigh R.J.,Veterans Affairs and Case Medical Center
Annals of the New York Academy of Sciences | Year: 2011

The cerebellum plays an important role in programming accurate saccades. Cerebellar lesions affecting the ocular motor region of the fastigial nucleus (FOR) cause saccadic hypermetria; however, if a second target is presented before a saccade can be initiated (double-step paradigm), saccade hypermetria may be decreased. We tested the hypothesis that the cerebellum, especially FOR, plays a pivotal role in programming sequences of saccades. We studied patients with saccadic hypermetria because of either genetic cerebellar ataxia or surgical lesions affecting FOR and confirmed that the gain of initial saccades made to double-step stimuli was reduced compared with the gain of saccades to single target jumps. Based on measurements of the intersaccadic interval, we found that the ability to perform parallel processing of saccades was reduced or absent in all of our patients with cerebellar disease. Our results support the crucial role of the cerebellum, especially FOR, in programming sequences of saccades. © 2011 New York Academy of Sciences.


PubMed | Veterans Affairs and Case Medical Center
Type: | Journal: Annals of the New York Academy of Sciences | Year: 2011

The cerebellum plays an important role in programming accurate saccades. Cerebellar lesions affecting the ocular motor region of the fastigial nucleus (FOR) cause saccadic hypermetria; however, if a second target is presented before a saccade can be initiated (double-step paradigm), saccade hypermetria may be decreased. We tested the hypothesis that the cerebellum, especially FOR, plays a pivotal role in programming sequences of saccades. We studied patients with saccadic hypermetria because of either genetic cerebellar ataxia or surgical lesions affecting FOR and confirmed that the gain of initial saccades made to double-step stimuli was reduced compared with the gain of saccades to single target jumps. Based on measurements of the intersaccadic interval, we found that the ability to perform parallel processing of saccades was reduced or absent in all of our patients with cerebellar disease. Our results support the crucial role of the cerebellum, especially FOR, in programming sequences of saccades.


PubMed | Veterans Affairs and Case Medical Center
Type: | Journal: Annals of the New York Academy of Sciences | Year: 2011

Prior studies indicate that the human translational vestibulo-ocular reflex (tVOR) generates eye rotations approximately half the magnitude required to keep the line of sight pointed at a stationary object--a compensation ratio (CR) of 0.5. We asked whether changes of visual or vestibular stimuli could increase the CR of tVOR. First, subjects viewed their environment through an optical device that required eye movements to increase by 50% to maintain fixation of a stationary visual target. During vertical translation, eye movements did increase, but tVOR CR remained at 0.5. Second, subjects viewed through LCD goggles providing 4 Hz strobe vision that minimized retinal image motion; this reduced tVOR CR. Finally, subjects were rotated in roll while they translated vertically; no increase in tVOR occurred. Taken with prior studies, we conclude that tVOR is optimally set to generate eye rotations that are about 50% of those required to stabilize the line of sight.

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