[Interactions between retino-collicular and retino-cortical pathways at the level of the lateral geniculate nucleus]

Interactions between retino-collicular and retino-cortical pathways at the level of the lateral geniculate nucleus were studied in anesthetized and paralyzed rabbits. In a first series of experiments the cortico-geniculate influence was analyzed by cortical depression. The disruption of cortical functions led to a specific abolition of the geniculate responses to right-left movement of the stimulating spot. The response to the opposite direction was unaffected. In a second series of experiments the stimulus presentation was triggered by a spontaneous collicular spike. This resulted in a significant modification of the geniculate responses recorded simultaneously suggesting that the superior colliculus is capable of modifying the transmission that occurs through the geniculate. Data are discussed in view of the visuo-motor integration.