<prompt> Narcolepsy is due to abnormality inHypothalamusNeocoexCerebellumMedulla oblongata  <response>: 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, 955, 227-30. 