This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Stroke and TIA, Subject name: Medicine
Diencephalic pupils are due to damage to? 
Select and explain. 
A. Superior colliculus, B. Lateral geniculate body, C. Optic pathway, D. Hypothalamus
D: Hypothalamus
Answer: D: Hypothalamus 
Explanation: Diencephalic pupils are a result of bilateral hemispheric dysfunction and are small. Damage occurs at the hypothalamus and will lead to damage to the origin of sympathetic fibers which will lead to small but reactive pupils. -Mid-position (4-7mm) non-reactive pupils are a result from direct midbrain (tectal region) damage.