# Show Reference: "Eye movements evoked by collicular stimulation in the alert monkey"

Eye movements evoked by collicular stimulation in the alert monkey Vision Research, Vol. 12, No. 11. (November 1972), pp. 1795-1808, doi:10.1016/0042-6989(72)90070-3 by David A. Robinson
@article{robinson-1972,
abstract = {Electrical stimulation of the superior colliculi of alert, behaving monkeys evoked allor-nothing saccades whose amplitude and direction were independent of stimulus parameters and depth within the colliculus. They were also independent of initial eye position and were thus not goal-directed. Across the colliculus, the saccades were small (1°) rostrally, large (50°) caudally with up components medially, down components laterally. A map of amplitude and direction was constructed which agrees with the retinotectal projection and reveals a simple spatial coding in the tectum for ocular orienting reflexes. Temporal interaction with double stimulation was also investigated.},
author = {Robinson, David A.},
citeulike-article-id = {9972432},
doi = {10.1016/0042-6989(72)90070-3},
issn = {00426989},
journal = {Vision Research},
keywords = {biology, motor, sc},
month = nov,
number = {11},
pages = {1795--1808},
posted-at = {2015-01-05 11:15:17},
priority = {2},
title = {Eye movements evoked by collicular stimulation in the alert monkey},
url = {http://dx.doi.org/10.1016/0042-6989(72)90070-3},
volume = {12},
year = {1972}
}



Electrical stimulation of the cat SC can evoke saccades.

Typically, these saccades go into that general direction in which natural stimuli would lead to activation in the area that was electrically stimulated.

The `foveation hypothesis' states that the SC elicits saccades which foveate the stimuli activating it for further examination.

Certain neurons in the deep SC emit bursts of activity before making a saccade.

It has long been known that stimulating the SC can elicit eye movements.

The size and direction of a saccade before which deep SC neurons show the greatest activity depends on where they are in the SC: Neurons in medial regions of the SC tend to prefer saccades going up, neurons in lateral regions of the SC tend to prefer saccades going down.

Long saccades are preceded by strong activity of rostral neurons, short saccades by activity of caudal neurons.

Deep SC neurons which have preferred saccades have these preferred saccades also in total darkness. They thus do not simply respond to the specific location of a visual stimulus.

Robinson reports two types of motor neurons in the deep SC: One type has strong activity just (~20 milliseconds) before the onset of a saccade. The other type has gradually increasing activity whose peak is, again, around 12-20 milliseconds before onset.

Neurons in the deep SC whose activity spikes before a saccade have preferred amplitudes and directions: Each of these neurons spikes strongest before a saccade with these properties and less strongly before different saccades.