This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Sleep disorders and eating disorders, Subject name: Psychiatry
Narcolepsy is due to abnormality in 
Select and explain. 
A. Hypothalamus, B. Neocoex, C. Cerebellum, D. Medulla oblongata
A: Hypothalamus
Answer: A: Hypothalamus 
Explanation: Narcolepsy is the prototypical example of sleepiness produced by a basic CNS dysfunction of sleep mechanisms. The etiology stems from a genetically triggered Hypocretin dysfunction and deficit. It is apparent that the hypocretin system plays a critical role in narcolepsy. The Hypocretin producing cell bodies are specific to Hypothalamus and have widespread anatomical projections. Ref: Synopsis of Psychiatry, 11e, pg 548. Ebrahim IO, Howard RS et al. The Hypocretin/ Orexin system. J R Soc Med, 2002 May, 95(5), 227-30.