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 cyclical alternation of NREM-REM sleep in newborns is present from birth but at 50 to 60 minutes is much shorter than the 90-minute cycles that occur in adults. Consolidated nocturnal sleep and fully developed EEG patterns of the NREM sleep stages emerge only after two to six months. Slow-wave sleep is greatest in young children and it decreases steadily with age, even if sleep duration does not change. This may be related to changes in the structure and function of the brain.