Sleepers drift in and out of light sleep and can be

  • No School
  • AA 1
  • 42

This preview shows page 14 - 16 out of 42 pages.

Sleepers drift in and out of light sleep and can be awakened easily. During this stage, the person may begin to breathe more slowly and evenly, the brain produces theta waves, which are smaller and lower in frequency than alpha waves. Muscle activity, measured by the EMG, shows a slowing down of movement and the sleeper may begin to twitch. These twitches are called hypnic jerks and sometimes wake the sleeper, particularly if the jerk is accompanied by the sensation of falling, which many people experience from time to time. Since individuals may have some knowledge of the world around them, it is in this stage of sleep that some people report out-of-body experiences. Non-REM stage two Within a few minutes, the sleeper may pass into another form of light sleep known as stage two of non- REM sleep. The sleeper’s breathing pattern and heart rate slow down and they become less aware of the outside world. Eye movement stops and sleepers’ theta waves become even slower with the occasional bursts of brain activity every minute or so; these bursts of activity are sometimes known as sleep spindles. Stage two non-REM sleep is also characterized by a type of brain wave activity known as a K-complex. A K-complex is a high voltage of EEG activity with a sharp downward spike followed by a slower upward component; it sometimes resembles a mountain. This stage accounts for the largest part of human sleep (45–50% of sleep in adults 19 ) and is sometimes referred to as true sleep. Like stage one sleep, stage two is also considered relatively ‘light’ sleep and if sleepers were to be woken up during either of these stages they may deny that they had been asleep at all. The stages of sleep In humans, sleep can be broadly divided into non-rapid eye movement (non-REM) sleep and rapid eye movement (REM) sleep. The first of the five sleep stages is a form of light sleep, or non-REM stage one sleep. This stage is essentially the bridge between being awake and sleep.
Image of page 14
25 24 Dreaming Dreams have been a subject of awe and inspiration for thousands of years, appearing in the oldest works of literature, such as Epic of Gilgamesh (c.2200 B.C.), as well as in recent Hollywood blockbusters such as Inception and Shutter Island (2010). Some people are better at remembering dreams than others, but most would agree that their dreams are meaningful to them. Many people believe that dreams are a gateway for understanding our feelings, thoughts, behaviours, motives and values. The theoretical link between dreaming and eye movements during sleep was made as far back as in 1868 24 , and the explicit connection between REM sleep and dreaming was made almost a century later 25 . It is possible that our eyes move because we are following the images of the dream in our sleep. Since we all experience REM sleep, we all have the potential to experience dreams.
Image of page 15
Image of page 16

You've reached the end of your free preview.

Want to read all 42 pages?

  • Fall '19
  • Sleep Matters

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern

Stuck? We have tutors online 24/7 who can help you get unstuck.
A+ icon
Ask Expert Tutors You can ask You can ask You can ask (will expire )
Answers in as fast as 15 minutes
A+ icon
Ask Expert Tutors