HCRT and narcolepsy: Some research results suggest that gray matter reduction in the bilateral hypothalamus, thalamus, NAc, anterior cingulate cortex, left mid-orbital and rectal gyri, right inferior frontal, and superior temporal gyri may be related to the orexin pathway in narcolepsy.[42] However, there are few reports of the correlation of orexin levels with the functional brain network in HUD patients undergoing harm reduction treatment (HRD).