This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
Spontaneous vertical nystagmus is seen in the lesion of 
Select and explain. 
A. Midbrain, B. Labyrinth, C. Vestibule, D. Cochlea
A: Midbrain
Answer: A: Midbrain 
Explanation: “Vertical nystagmus means vertical displacement of the eye, not side to side nystagmus when attempting upward or down ward gaze. As defined vertical nystagmus always indicates brainstem dysfunction”