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1. The locations and connections of the smooth and saccadic eye movement subregions of the frontal eye field (FEFsem and FEFsac, respectively) were investigated in seven hemispheres of five Cebus monkeys. The supplementary eye field was also mapped in seven hemispheres and the hand/arm regions of the dorsal and ventral premotor areas were localized in five(More)
During rapid head rotations, saccades ipsiversive with compensatory vestibulo-ocular reflex (VOR) slow phases may augment the deficient VOR and assist gaze stabilization in space. The present experiments compared these vestibular catch-up saccades (VCUSs) with visually and memory-guided saccades. To characterize VCUSs and their relationship to deficiency of(More)
We compared saccadic eye movements in 21 patients with Huntington's disease (HD) and 21 normal subjects. In a predictive tracking task, HD patients were unable to anticipate normally the timing and location of a visual target that alternated its position predictably (+/- 10 degrees, 0.5 Hz; mean latency of +170 msec in HD and -78 msec in normal subjects).(More)
1. Intracortical microstimulation was used to localize and define the smooth and saccadic eye movement subregions of the frontal eye field (FEF) and the supplementary eye field (SEF) in nine hemispheres of six Cebus apella monkeys and to map the hand/arm areas in the dorsal premotor area and other adjacent areas in five hemispheres of three C. apella(More)
To look successively at sites where several spots of light have appeared in the dark, we cannot simply rely on the image left by these targets on our retina. Our brain has to update target coordinates by taking into account each gaze movement that has taken place. A particular type of brain cell--the quasi-visual (QV) neuron--is assumed to play an important(More)
To determine age-related changes, the initial horizontal vestibulo-ocular reflex (VOR) of 11 younger normal subjects (aged 20-32 years) was compared with that of 12 older subjects (aged 58-69 years) in response to random transients of whole-body acceleration of 1,000 and 2,800 degrees/s2 delivered around eccentric vertical axes ranging from 10 cm anterior(More)
The vestibulo-ocular reflexes stabilize retinal images during head movements. While there is a wealth of information about the interaction between the cerebellum and vestibulo-ocular reflexes mediated by the semicircular canals, little is known about the role of the cerebellum in the generation of the otolith-mediated linear vestibulo-ocular reflex (LVOR).(More)
1. Intracortical microstimulation was used to map the supplementary eye field (SEF) in eight hemispheres of five Cebus apella monkeys. Monkeys were immobilized during experiments with Telazol (tiletamine HCl and zolazepam HCl), a dissociative anesthetic agent that was demonstrated to have no significant effect on microstimulation-induced eye movement(More)
The vestibulo-ocular reflex (VOR) stabilizes gaze to permit clear vision during head movements. It has been supposed that VOR function might be inferred from dynamic visual acuity (DVA), the acuity during imposed head motion. We sought to determine effectiveness of DVA for detection and lateralization of unilateral vestibulopathy, using rigorous(More)
During transient, high-acceleration rotation, performance of the normal vestibulo-ocular reflex (VOR) depends on viewing distance. With near targets, gain (eye velocity/head velocity) enhancement is manifest almost immediately after ocular rotation begins. Later in the response, VOR gain depends on both head rotation and translation; gain for near targets(More)