HCRT and hyperinsulinemic hypoglycemia, familial, 4: Potentially related to this latter finding, Feng et al. described an essential role for the orexin-sublaterodorsal tegmental nucleus neural pathway in relieving REM sleep pressure and presented evidence that disruption of this pathway accounts for the disturbance in sleep-onset REM sleep associated with the orexin deficiency state of narcolepsy [23].