NICI > Publications > 1999 > Perturbation of combined saccade-vergence movements by microstimulation in monkey superior colliculus
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Reference
Chaturvedi, V., & Van Gisbergen, J.A.M. (1999). Perturbation of combined saccade-vergence movements by microstimulation in monkey superior colliculus. Journal of Neurophysiology, 81 (5), 2279-2296.
Abstract
This study has investigated the role of the monkey superior colliculus (SC) in the control of combined -vergence movements by assessing the perturbing effects of microstimulation. We elicited an electrical saccade (E) by stimulation while the monkey was preparing a visually-guided movement (V) to a near visual target. Electrical control trials, where stimulation was applied during fixation of a visual target, yielded no vergence. By contrast, early perturbation trials, where the E-stimulus was applied soon after the onset of the visual target, caused an E-triggered response with a clear vergence component toward the V-target. This study shows that artificial intervention in the SC, while a 3D refixation is prepared or is ongoing, can effect the timing (WHEN) and the metric-specification (WHERE) of both saccades and vergence. This effect would be expected if the population of movement cells at each SC site is tuned in 3D, combining the well-known topographical code for direction and amplitude with a nontopographical depth representation.