Walsh & Hoyt: Vergence

Summary. Vergence eye movements permit stereopsis and prevent diplopia by moving the eyes in opposite horizontal directions. The vergence system maintains the image of an object on the fovea of each eye whether the object is located far away or nearby, and whether it is moving toward or away from the viewer. Posterior temporal, prestriate, and dorsal prefrontal cortex of monkeys are involved in vergence. Neurons in the parietal lobe of monkeys are activated during visual tracking of objects moving in the sagittal plane. Three types of vergence cells (vergence burst, vergence tonic, and vergence burst-tonic cells) are intermixed in the midbrain reticular formation dorsal to the oculomotor nucleus. These neurons process supranuclear convergence and divergence commands that are delivered to medial rectus and lateral rectus motoneurons.