Biology 202
2004 Second Web Paper
On Serendip

"Dreaming permits each and everyone of us to be quietly and safely insane every night of our lives."
William Dement, MD

For centuries people have been fascinated with altered states of consciousness. Through sleep, illness, or chemicals, people are awed by the actions of a person who appears to be not himself. Most sleep occurs separate from the waking world, safely and quietly in one's bed, with the I-function appearing to be turned off. But some sleepers are able to perform complex activities while in the non-rapid eye movement (NREM) stages of sleep and have no recollection of this activity the following day. It appears that the body moves without the I-function, and the I-function therefore has not recall of the previous night's events. (1) This phenomenon is called somnambulism or more commonly, sleepwalking. Another parasomnia that occurs less frequently is rapid eye movement behavioral disorder. During the REM sleep cycle, a person has vivid, life like dreams. In people with REM behavioral disorder, the body is not paralyzed during the dream and they act out their dreams which are often violent. Unlike true sleep walkers, those with REM behavioral disorder will remember their dreams clearly the next day, and think they were doing some logical task in their dream while they were actually doing something quite different. For example, one man ran head on into his dresser while dreaming he was tackling an opponent in a football game. (2)

To understand the anomalies in sleep among those who sleepwalk or have REM behavioral disorder, it is useful to examine the five stages of sleep The first four stages of sleep constitute non REM sleep, which is markedly separate in terms of the level of consciousness from the fifth stage of sleep, REM sleep. During the first stage of sleep, brain scans have shown rapid small brain waves and people have reported fragmented visual images often mixed with visual and auditory input from their surroundings. Between the first and second stages of sleep, people may experience hypnic myoclonia, the rapid contraction of muscles often preceded by the feeling of falling. Sleep paralysis also occurs in the early stages of sleep. (3) This occurs when the I-function appears to wake up, but the body hasn't released the chemicals to counteract the paralysis that is normal while asleep. In stage two, eye movement stops and brain waves become sporadic. Stages three and four are considered to be deep sleep, and people are often hard to wake up while in these stages of sleep. During stage three, longer delta waves begin to predominate over the shorter, sporadic waves. Stage four sleeping is characterized by the presence of only delta waves and no eye movement. Somnambulism and night terrors occur during the third and fourth stages of sleep. The person in these stages of sleep will have no memory of the events during this time period. About 75% of the night is spent in NREM sleep. The brain wave patterns display such a dramatic difference between REM sleep and NREM sleep that they are thought to be entirely different levels of consciousness, as different from each other as they are from the fully awake conscious state. (4)

In NREM sleep, the I-function appears to be turned off. People have no memories or explanations for events that occur during these sleep stages. The night terrors and somnambulism that occur during the NREM stages are not recalled by the patient. The only way to know that these events are occurring is through the observation of family members or injuries that occur while sleep walking (5).

During REM sleep, the I-function seems to be at a different level of consciousness, but not entirely absent. While the person in the REM stage of sleep is normally paralyzed and appears to be lying silently, their mind is quite active. This is evident from brain scans, and also from the patients' subjective experiences. It appears to be an alternate world for the I-function; a world that is not affected by external stimuli. Yet the I-function is alert, as evidenced by a person's recollection of "events" that seem to be occurring to them in their dreams. It's this sense of consciousness that allows a person in the REM stage of sleep to make more concerted movements. Frequently, the activity of those who experience RBD is much more violent and directed than the behavior of those with somnambulism.

During REM sleep, which is thought to be the most restorative stage of sleep, there are several key physiological changes. (6) The eyes move rapidly, the heart rate, breathing rate, and blood pressure become elevated, and breathing becomes shallow. The body is also unable to adequately regulate temperature while in the REM stage of sleep. REM sleep allows the I-function to temporarily exist in a world without corollary discharge, and in most individuals, without motor pattern generation. It is not well understood why the body seems to let its homeostatic settings shift during REM sleep, nor is it clear why this change appears to be restorative.

When people acquire a sleep debt, they do not cycle through the five stages of sleep normally. In severe sleep debt, they will advance directly to REM sleep from fully awake. This causes several problems. The sleep stages allow a person to transition from awake and conscious to dreaming. Without the gradual change, a person may experience dreams that appear as hallucinatory images while still partially awake. Or the person may not fully be paralyzed before entering REM sleep, which can result in REM behavior disorder. (4)

The sleep disorders mentioned have been extremely useful in understanding the workings of the brain during sleep. By noting the difference between true sleepwalking and REM behavioral disorder, it can be inferred that a person is aware of his brain activity during REM sleep, but not during NREM sleep.

The psychological explanations for sleepwalking and RBD vary. RBD patients almost universally have mild mannered, amiable personalities during their waking hours. These patients report vivid, violent dreams of being chased or attacked, and often injure themselves or their bed partner while acting out such dreams. Previously, psychologists and physicians had suggested that repressed anger caused these nighttime outbursts, but as more has been discovered about the neurochemistry, this idea has faded. Patients who exhibit classic somnambulism frequently lead stressful lives. Depression and anxiety both disrupt a person's natural sleep cycle. Stress management, cognitive behavioral therapy, and other psychotherapeutic treatments for these underlying disorders have proven moderately effective in eliminating somnambulism. (6)

New research has identified a gene that may be partially responsible for somnambulism. Some neurochemicals, such as dopamine and acetylcholine, are present in lower amounts in individuals exhibiting ambulatory parasomnias, but not enough data is present to show a causal relationship. (7)Researchers have postulated that those who are ambulatory during REM or NREM sleep lack a certain neurochemical necessary to inducing paralysis during sleep. This chemical imbalance has not been pinpointed and it seems unlikely that there is one direct cause of sleepwalking.

Much of the literature attempts to make a distinction between sleep disorders caused by problems of the brain and behavioral problems. This distinction does not seem to be helpful in understanding the nature of disease, as the separation of brain and behavior are really only indicative of our current perception and knowledge of the human nervous system. What is classified today as a biological disorder is classified as such because we can demonstrate clear biological causes of it. Unless the brain is able to be fully understood, the distinctions made to organize it will remain biased towards our perception and current knowledge. The biologically based problems seem to be more socially acceptable. For example, parents are told not to worry about their sleepwalking children, as this is a normal biological process. (8) However, only 15% of children exhibit any sleepwalking, so it is not by simple majority that a behavior is perceived as normal. Rather, a biologically based reason seems to justify the sleepwalking. The 6% of adults who sleepwalk are often advised to seek professional help. Adults with RBD or sleepwalking have benefited from cognitive behavioral therapy and the use of medication. (3) Clearly, what we think of as brain and behavior aren't separate, but intertwined in a complex relationship. Both neurochemical approach and the behavioral approach result in a change in behavior. Administering small doses of tranquilizers, such as clonazepam, frequently relieves all RBD symptoms. (9) Learning stress management techniques and other psychodynamic therapies also affect the frequency and severity of the parasomnias. (4) Studies demonstrating the effects of psychological approaches to parasomnias on the neurochemistry could help explain the relationship between brain and behavior in this case.

Sleepwalking, though fascinating, is a benign problem in the most of the 15% of children it affects. RBD is more serious, though less common, because of the violent outbursts often seen in these patients. Treatment for RBD using medication has been effective, which has given patients hope and led to more patients seeking treatment. It is also worth noting that many patients with RBD will later develop Parkinson's disease, although this relationship is not well understood, it is being studied in depth. (9)

Research considering the chemical changes during puberty of adolescents who stop sleepwalking might help explain the chemical differences responsible for creating ambulation during sleep. Studies analyzing brain activity during REM sleep of those with RBD could be analyzed, comparing the data from nights with ambulation and nights without ambulation to observe the differences in brain activity for still nights versus nights with activity.

The sleeping and waking mind continue to raise interesting questions about our perceptions of life, reality and free will. The law has wavered on the consideration of the free will of a sleeping person, sometimes acquitting those who commit crimes while asleep. (10). Science is yet to define that point of the brain, if such a place exists, where what we think of as the free will, or I-function, is physically housed, but the sleep disorders have demonstrated that consciousness is more variable than it was once believed to be. A vast continuum exists, encompassing the fully brain, the deeply sleeping and apparently unaware brain, and many unknown levels in between.

References

1) Sleepwalking Disorder Article

2) Sleep Disorders May be Linked to Faulty Brain Chemistry

3) Sleep Paralysis and Associated Hypnopompic Experiences Article

4) Yahoo Stress Health Center

5) Parasomnias: Sleepwalking, Night Terrors, and Sleep Related Eating Article

6) REM Behavioral Disorder Website

7) ABC Science Website, Article on the genetics of sleepwalking.

8)A to Z Answers for Parents, article on sleepwalking in children.

9)New York Times Article, informative website with a reprinted New York Times article on RBD.

10) Sleepwalking- Insanity or Automatism , an interesting compilation of legal cases involving sleepwalking and RBD.


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