Direct projection of cat midbrain tegmentum neurons to the medial rectus subdivision of the oculomotor complex.

This study explores neurons in the medial midbrain tegmentum of cats projecting directly to the medial rectus subdivision of the oculomotor complex, using antidromic microstimulation techniques. Many of these neurons were located in areas just lateral and dorsal to the oculomotor complex, e.g. in the medial part of the midbrain reticular formation and ventralmost part of the periaqueductal gray. These results suggest that at least some neurons in the midbrain tegmentum presumed to be the site of origin of vergence eye movements directly project to the medial rectus subdivision to control medial rectus motoneurons.