Sleep on the Brain
By Renee Cohen
We close our eyes, relax and ease into unconsciousness, conjuring bizarre situations and illogical tales. This is the state of being we commonly refer to as sleep. Sleeping is a period of rest during which our heart and breathing rates slow, our muscles relax and we lose awareness of our surroundings, but brain activity remains dynamic. Approximately one-third of the human existence is spent sleeping, yet researchers are just beginning to understand this necessary function of our lives. Brain studies and new technology have provided inroads into the phenomenon of sleep, and that has only led to many more questions and speculations.
But what scientific facts do we know about sleeping and dreaming? Using electroencephalographs and other tools, sleep researchers have measured biological activity, especially brain waves. Whether you are awake or asleep, the brain emits electrical signals that can be used to study various conditions. Stages of sleep are defined by the variance in brain waves. An awake person gives off approximately 10 short waves per second. As the slumber begins, waves become less frequent, though they grow larger and larger. Intermittent periods of short, faster waves occur several times during sleep. This is when dreaming occurs, the stage of sleep called REM, or rapid eye movement.
Laboratory studies have shown that sleep is a restorative function. Neurotransmitters, such as serotonin and norepinephrine, keep parts of the brain active while awake. Another chemical, adenosine, causes drowsiness after building up in the blood in the wakeful hours. During sleep, adenosine slowly breaks down and the body gradually recovers from fatigue.
Dreaming is a "safety valve," as described by Freud, keeping us from acting out some of our subconscious desires. Sleep researchers have suggested that everyone dreams, and the dreams occur in regular intervals and last longer during the night. Most memories of dreams disappear from consciousness upon awakening. Vivid recollections may suddenly be brought to mind during wakeful hours, suggesting that the dream is not really lost, but stored in a portion of the brain that is not easily reached.
Sleep study has progressed in the area of treating disorders. Insomnia, sleep apnea, narcolepsy, restless leg syndrome, snoring and sleeping sickness are just a few of the problems associated with sleep. Contrary to popular belief, a "nightcap," or any type of alcohol, is not an effective sleep inducer. Alcohol and caffeine both inhibit the ability to sleep in certain stages, causing fatigue upon awakening. And, of course, sleep deprivation can lead to numerous other difficulties.
Sleep disorders have even been the subject of court cases. Some questions that legal authorities have dealt with range from defining the state of consciousness of a sleeping person to distinguishing a true murderer from a parasomnia patient. There are over 300 cases of sleep violence in the literature. Reasonable clinical certainty is the general standard used to judge these cases, as there is very little definitive evidence on the consciousness of a sleeping person.
We probably cannot even dream of the true dynamics of a human body during sleep. What we do know from experience, though, is that getting a good night's rest is conducive to renewed vigor and enthusiasm upon awakening.
Test for Sleep on the Brain
1. Most adults sleep ________ hours per night.
2. People deprived of sleep:
a) lose energy
b) become quick-tempered
c) make mistakes during routine tasks
d) all of the above.
3. REM refers to:
a) rapid eye movement
b) renewed energy mechanism
c) resonance eye matrix
d) none of the above.
4. As people grow older, their need for sleep:
c) remains the same
d) is replaced with daytime naps.
5. Which condition is NOT present during sleep?
a) reduced heartbeat
b) relaxed muscles
c) increased responsiveness
d) repositioning of body
6. Obstructive sleep apnea can be life-threatening if:
a) parasites exist
b) a coma is induced
c) blood oxygen levels are too low
d) the nervous system is infected.
7. The condition during which a partly awakened sleeper performs various physical activities is called:
b) sleeping sickness
d) sleep apnea.
8. What is the most frequent treatment for early stages of sleeping sickness?
a) losing weight
c) increased oxygen
d) prolonged sleep
9. REM sleep is also referred to as:
a) paradoxical sleep
b) slow wave sleep
c) stage 4 sleep
d) circadian sleep.
10. Which chemical builds up in human blood and causes drowsiness?
11. During which stage of sleep does dreaming occur?
a) Stage 1
b) Stage 2
c) Stage 3
12. Why does temporary limb paralysis occur during sleep?
a) as a protection from acting out dreams
b) to prevent spasms in muscle tissues
c) to stimulate learning
d) due to fragmented brain activity
13. Why does jet lag occur?
a) fatigue from the logistics of travel
b) decrease of melatonin produced at altitude
c) disrupted circadian rhythms
14. Without external cues, such as sunlight, most people's biological clocks operate on a cycle of ___hours.
15. Major industrial accidents that were partially attributed to errors made by fatigued night-shift workers include all EXCEPT:
a) Three Mile Island
b) New York City blackout during the Summer of Sam
c) Chernobyl meltdown
d) Exxon Valdez oil spill.
16. While fighting an infection our immune system produces powerful sleep-inducing chemicals called:
c) sleep spindles
d) nocturnal neurons.
17. Infants spend proportionately more time than adults in which stage of sleep?
c) deep sleep
d) quiet sleep
18. Scientists use which instrument to monitor sleep?
c) magnetic resonance imaging
19. Most humans spend approximately how much of their lives sleeping?
20. The brain can be characterized during sleep as: