T.S. of Midbrain

   The midbrain is the most cranial part of the brainstem.  It is divided into 2 parts - tectum and cerebral peduncle.
   The tectum is made up of the superior and inferior colliculi. The superior colliculi are involved in visual reflexes whole the inferior colliculi are involved in auditory reflexes.
   The cerebral peduncles are divided into the following, going from anterior to posterior - CST (mnemonic), i.e., crus cerebri, substantia nigra and tegmentum. The decrease in dopamine in the substantia nigra is known to cause Parkinson's Disease.
   The diagram shows a section of the midbrain at the level of the superior colliculus. I am again really sorry for my abbreviations.... here is their full form -
RF=Reticular Formation
M,T,S=Medial, Trigeminal,  Spinal lemniscus
MLB=Medial Longitudinal Bundle
TD=Tegmental Decussation