Following are a brief overview on wakefulness and sleep mechanisms. There are many books on this subject. Principles and practice of sleep medicine 3 and Sleep disorders medicine: Basic science, technical considerations and clinical aspects ⁶ are recommended.

It has been known for more than half a century that wakefulness and consciousness depend on the activity of neurons within the brainstem reticular formation. These neurons form the ascending reticular activating system (RAS) (Fig 3). ¹ They receive collateral input from visceral, somatic, and special sensory system and project via dorsal pathway to the thalamus and via ventral pathway to the basal ...