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.
Each sleep cycle that is experienced every night lasts approximately 90 to 110 minutes on average. Earlier in the night you experience more NREM stages 3 and 4 with little REM sleep, but as the night progresses you spend less time in NREM stages 3 and 4 also known as slow wave sleep, or Belta wave sleep.eep sleep is reached about 30 to 45 minutes into your sleep cycle. If your an 8 hour sleeper you will move through about 5 sleep cycles, where a 6 hour sleeper will move through 4 and a half cycles. Best Answer. (like sisipamprsboi above) will often wake up ~ one hour as they complete each sleep cycle...DD.