The brainstem lies beneath the cerebrum and consists of the midbrain, pons and medulla. The brainstem consists of the midbrain, the pons, and the medulla oblongata. The brainstem consists of the medulla, the pons and the midbrain. The pons lies between the medulla oblongata and the midbrain. The superior pontine sulcus separates the pons from the midbrain. The MHB controls midbrain and cerebellum development. Methamphetamine is neurotoxic to human midbrain dopaminergic neurons at high doses. The brain consists of equal parts, cerebrum, midbrain and cerebellum. It is divided into the midbrain, pons, and medulla oblongata. Blood from the cerebellum and midbrain drains into the great cerebral vein. Lesions are usually symmetrical in the periventricular region, diencephalon, the midbrain, hypothalamus, and cerebellar vermis. The tegmentum forms distinguished divisions in the midbrain, pons, and medulla. The oculomotor nerve is derived from the basal plate of the embryonic midbrain. The midbrain, or mesencephalon, is situated above and rostral to the pons. The tegmentum which forms the floor of the midbrain, is ventral to the cerebral aqueduct.