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1. Most recording studies on the role of the monkey superior colliculus (SC) in eye movement generation have so far indicated that the code of the recruited population of cells is a fixed vector command representing the desired saccadic eye displacement vector, irrespective of the position of the eyes in the orbit. Experimental evidence from(More)
An earlier model for the collicular role in the generation of saccades (Van Gisbergen et al. 1987), based on ensemble coding and linear vector addition of movement contributions from independent movement cells, yields normometric saccades in all directions over a considerable range of amplitudes. The model, however, cannot account for two nonlinear(More)
The coordination between eye and head movements during a rapid orienting gaze shift has been investigated mainly when subjects made horizontal movements towards visual targets with the eyes starting at the centre of the orbit. Under these conditions, it is difficult to identify the signals driving the two motor systems, because their initial motor errors(More)
Because the inner ear is not organized spatially, sound localization relies on the neural processing of implicit acoustic cues. To determine a sound's position, the brain must learn and calibrate these cues, using accurate spatial feedback from other sensorimotor systems. Experimental evidence for such a system has been demonstrated in barn owls, but not in(More)
This paper describes the effect of spectro-temporal factors on human sound localization performance in two dimensions (2D). Subjects responded with saccadic eye movements to acoustic stimuli presented in the frontal hemisphere. Both the horizontal (azimuth) and vertical (elevation) stimulus location were varied randomly. Three types of stimuli were used,(More)
The superior colliculus in the monkey contains a topographically organized representation of the target in its upper layers and saccade-related activity in its deeper layers. Since collicular movement fields are quite large, a considerable region of the colliculus is active whenever a saccade is made. We have modelled the collicular role in saccade(More)
We have investigated the involvement of collicular movement cells in the monkey in the execution of averaging saccades, elicited by a visual double-step stimulus. We found that, qualitatively, most (12/14) movement cells were recruited during averaging saccades in roughly the same way as for comparable visually-elicited saccades to single targets(More)
A procedure is described to calibrate three-dimensional eye position with a dual-search coil implant in rhesus monkeys using a two-field magnetic system. The method allows one to determine the sensitivity of the search coils taking into account the presence of d.c. offset voltages. The orientation of the implant on the eye relative to a space-fixed(More)
In this paper, we report a detailed study of the dynamic properties of horizontal, vertical and oblique saccades. These eye movements were measured with an improved version of the double-magnetic induction method in two rhesus monkeys. We found that onsets of orthogonal components of oblique saccades are so well synchronized in the monkey that a common(More)
In the alert monkey we have compared the properties of saccades elicited by a visual stimulus (V-saccades) with those generated by electrical stimulation in the superior colliculus (E-saccades). We found that whereas there exists a graded relation between E-saccade amplitude and current strength, E-saccade direction is remarkably independent of electrical(More)