Learn More
Using galvanic vestibular stimulation (GVS), we tested whether a change in vestibular input at the onset of goal-directed arm movements induces deviations in arm trajectory. Eight head-fixed standing subjects were instructed to reach for memorized visual targets in complete darkness. In half of the trials, randomly-selected, a 3 mA bipolar binaural galvanic(More)
A number of processes have been identified that adaptively modify oculomotor control components. The adaptive process studied here can be reliably produced over a short period of time by a visual stimulus that forces postsaccadic error. This short-term adaptive process, usually termed parametric adaptation, consists of a change in response amplitude that(More)
The role of ocular muscle proprioception in the localization of visual targets has been investigated in normal humans by deviating one eye to create an experimental strabismus. The passively deviated eye was covered and the other eye viewed the target. With a hand-pointing task, targets were systematically mislocalized in the direction of the deviated(More)
Passive deviation of one eye through 18 degrees, 30 degrees and 42 degrees, achieved by force applied to a sucked-on contact lens, caused the direction of visual targets seen by the other eye to be misjudged in the direction of the passive movement by an amount roughly one-sixth of the angle of passive deviation. The result was the same when the perceived(More)
1. This study investigated whether accurate perception of body rotation after passive horizontal whole-body rotations in the dark requires the integration of both vestibular and neck-body proprioceptive signals. 2. In the first experiment, the gain of the vestibuloocular reflex (VOR) of normal subjects ("controls") and of a patient without proprioception of(More)
The present study evaluated the capacity to compare retinal and vestibular signals in a heterosensorial matching task. In the first experiment, subjects evaluated the magnitude of passive whole-body rotations in relation to the eccentricity of a visual target briefly presented before rotation. Such a task elicits multimodal sensory stimulations experienced(More)
The vestibular signal plays a significant role in sensing changes in head orientation during rotations and in determining the magnitude of the rotations, but has only minor contributions in updating the internal representation of object positions with respect to the body after body rotations. The small contribution of the vestibular signal in egocentric(More)
1. We studied the effects of midazolam (MDZ), a benzodiazepine, on spatio-temporal contrast sensitivity, choice reaction time, and mood visual analogue scales in healthy volunteers. 2. Eight extensively trained, healthy volunteers were included in a placebo-controlled cross-over double-blind trial of MDZ (0.15 mg kg-1). Treatments were injected(More)
The contribution of retinal and extraretinal signals to the coding of eye position in the head was studied in human subjects (Ss). Horizontal saccades were produced in darkness. For some trials, before returning gaze direction to the starting position, a visual signal briefly stimulated the foveal retina. Results showed that this retinal input helped Ss to(More)
The role of arm proprioception in motor learning was investigated in experiments in which, by moving the arm, subjects followed the motion of a target displayed on a monitor screen. Adaptive capabilities were tested in visuomanual tracking tasks following alterations in the relationship between the observer's actual arm movement and visual feedback of the(More)