The vertebrobasilar arteries are the blood vessels in the back of the neck, next to the spinal cord, that supply the brainstem -- the portion of the brain that, among other things, is responsible for maintaining consciousness. A blockage of blood flow in the vertebrobasilar arteries can cause syncope.
1. NREM-a recurring sleep state during which rapid eye movements do not occur and dreaming does not occur; accounts for about 75% of normal sleep time. nonrapid eye movement, nonrapid eye movement sleep, NREM sleep, orthodox sleep. sleep, slumber-a natural and periodic state of rest during which consciousness of the world is suspended; he didn't get enough sleep last night; calm as a child in dreamless slumber. 1  Facebook.
The REM Sleep Stage. REM sleep is the second type of sleep, often kicking in only after a full cycle of NREM sleep. This is the stage where most dreaming occurs. REM is sometimes called paradoxical sleep because brain scans of people who are in REM show that their brains are very active, despite the fact theyâre fast asleep. However, while your brain is active, only your eyes can move. There are exceptions though.