Disturbances in sleep mechanism as a result of lesions of the pons and medulla oblongata, although rare, have been reported by a number of observers. Some investigators are of the opinion that somnolence in cases of such lesions is caused by involvement of the nuclei of the ocular nerves, which are situated in the mesencephalon and metencephalon. They believe that the sleep-regulating center is located in the region of these cranial nerve nuclei and that there is a connection between sleep and the ocular mechanism.
In our group of 8 cases, it was possible to demonstrate that the descending hypothalamic pathways in the brain stem were invariably implicated. Somnolence in these cases was probably due to the lesions in these pathways. Involvement of the nuclei of the ocular nerves was secondary to the specific location of the lesion in the brain stem and most likely played an insignificant role in