EYE MOVEMENT-RELATED NEURONS IN THE RED NUCLEUS

Extracellular unit activity of the parvocellular red nucleus (RN) and spontaneous horizontal eye movements were recorded in adult, nitrous oxide-anesthetized and C1 transected cats. It was found that 7.5% of the neurons of each RN were related to spontaneous horizontal saccadic eye movements. Three types of neurons were observed: (1) bidirectional neurons which increased their frequency of discharge in relation to any horizontal eye movement; (2) unidirectional neurons which altered their frequency of discharge in relation to a horizontal eye movement of a precise direction; and (3) neurons which increased their frequency of discharge in relation to the rapid phase of an horizontal nystagmus. These 3 types of neurons modified their frequency of discharge before the initiation of the eye movement. One pair of oculomotor neurons recorded simultaneously in both RN showed a significant correlation coefficient. These results suggest that the RN may contribute to the preparation or execution of horizontal eye movements. © 1990.