Why Do Some People Sleepwalk?
—Carlos Navarro, via e-mail
Neurologist Antonio Oliviero of the National Hospital for Paraplegics in Toledo, Spain, explains:
Sleep disorders such as sleepwalking arise when normal physiological systems are active at inappropriate times. We do not yet understand why the brain issues commands to the muscles during certain phases of sleep, but we do know that these commands are usually suppressed by other neurological mechanisms. At times this suppression can be incomplete—because of genetic or environmental factors or physical immaturity—and actions that normally occur during wakefulness emerge in sleep.
People can perform a variety of activities while asleep, from simply sitting up in bed to more complex behavior such as housecleaning or driving a car. Individuals in this trancelike state are difficult to rouse, and if awoken they are often confused and unaware of the events that have taken place. Sleepwalking most often occurs during childhood, perhaps because children spend more time in the “deep sleep” phase of slumber. Physical activity only happens during the non–rapid eye movement (NREM) cycle of deep sleep, which precedes the dreaming state of REM sleep.
Recently my team proposed a possible physiological mechanism underlying sleepwalking. During normal sleep the chemical messenger gamma-aminobutyric acid (GABA) acts as an inhibitor that stifles the activity of the brain’s motor system. In children the neurons that release this neurotransmitter are still developing and have not yet fully established a network of connections to keep motor activity under control. As a result, many kids have insufficient amounts of GABA, leaving their motor neurons capable of commanding the body to move even during sleep. In some, this inhibitory system may remain underdeveloped—or be rendered less effective by environmental factors—and sleepwalking can persist into adulthood.
Sleepwalking runs in families, indicating that there is a genetic component. The identical twin of a person who sleepwalks often, for example, typically shares this nocturnal habit. Studies have also shown that frequent sleepwalking is associated with sleep deprivation, fever, stress and intake of drugs, especially sedatives, hypnotics, antipsychotics, stimulants and antihistamines.
To clarify the many mysteries of sleepwalking, we need to find out more about the brain mechanisms that control sleep and arousal states. Future research will have to focus not only on what is happening while sleepwalkers are sleeping but also on the characteristics of their waking brains.
Why do we get “brain freeze” when we eat something cold?
-Christina Zuniga, via e-mail
Mark A. W. Andrews, professor of physiology and director of the Independent Study Pathway at the Lake Erie College of Osteopathic Medicine, replies:
This commonly experienced pain, also known as an ice cream headache, results from quickly eating or drinking very cold substances. Officially termed sphenopalatine ganglioneuralgia (talk about a painful mouthful!), it is the direct result of the rapid cooling and rewarming of the blood vessels in the palate, or the roof of the mouth. A similar but painless blood vessel response causes the face to appear “flushed” after being outside on a cold day. In both instances, the cold temperature causes blood vessels to constrict and then experience extreme rebound dilation as they warm up again.
In the palate, this dilation is sensed by nearby pain receptors, which then send signals back to the brain via the trigeminal nerve, one of the major nerves of the facial area. This nerve also senses facial pain, so as the signals are conducted the brain interprets the pain as coming from the forehead—the same “referred pain” phenomenon seen in heart attacks. Brain-freeze pain may last from a few seconds to a few minutes, which is blissfully short as compared with the duration of its cousin, the migraine headache. Research suggests that the same vascular mechanism and nerve implicated in brain freeze cause the aura (sensory disturbance) and pulsatile (throbbing pain) phases of migraines. Interestingly, it is impossible to give yourself an ice cream headache in cold weather—only in a warm ambient temperature will it hurt to wolf down a banana split.
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7 Comments
Add CommentI am a sleepwalker myself and I do sleepwalk frequently; I am 35 years old now. It started when I was ten years old and until now I still do sleepwalk. There were so many sleepwalks that I've done that were alarming like hurting myself. There was a time when we had a training and we were housed on a pad which has a veranda overlooking a lake. On the first night, I sleepwalked towards the door leading the veranda and My roommate was awakened when he heard some noise from me trying to open the locked door and he suddenly shouted at me to keep me to keep me awake and I realized what happened to me I was able to get out and alone in the veranda which is 50 feet high. He told me that my eyes was so glaring. There was also a time when I slept in the second deck and I've broken my knees 'coz I sleepwalked and fell. These are only two of my the many sleepwalk experiences of mine and I'm so worried about it. I want to offer myself for observation subject if you have studies about sleepwalking. You can reach me at +63918382118. I live in the Philippines. Thank you
Reply | Report Abuse | Link to thisI was just told about my neighbors daughter who sleepwalks. she just got out of bed and went to the kitchen, opened the refrigerator and opened the crisper and urinated in the crisper drawer. This just happened tonight
Reply | Report Abuse | Link to thisMy neighbor's 7 yr. old daughter just got out of bed-sleepwalking tonight. She went down to the refrigerator, opened the crisper drawer and urinated in the drawer. She woke up crying and apologizing.
Reply | Report Abuse | Link to thisI'm worried that I am a sleepwalker! I noticed a few days ago that things like jewelry, pens, bobbypins, and other random objects that were on my desk were thrown all over my floor! I've never had a problem with sleepwalking before....
Reply | Report Abuse | Link to thisI believe sleep walking is a state where another spirit takes control of the mind. This spirit, which perhaps knows everything about the person and their weakness(es) takes control and makes the body do whatever it wants. These spirits may cause the person to commit harmless or extremely evil acts. While on tour in Iraq as a soldier in the U S Army, I saw two cases in which two of my comrades were controlled in their sleep; one of them was my room mate. To make these stories short, my room mate woke up and started talking, I looked at him and saw in his eyes that he was not the person I knew. The other case, the soldier got up, in the middle of the night, suited up, with his rounds unloaded(thank God) and went a few feet from his sleeping area to fall asleep on a Humvee. Both these soldiers had no recollection of the events.
Reply | Report Abuse | Link to thisSleepwalking is the state of mind that is similar to drunkenness, rage,hypnotism etc. Sometimes these spirits are Vienna control of the body and sometimes they can just take control. Either way is dangerous. That's how harmless people commit random acts of violence.
There is so much to say on this topic but I might discourage you with all this writing when all the other posts are so much shorter.
I am 28 yrs old, a mother of two, I have been sleep walking. I do this about 3-5 times a yr that I can actually remember. The latest episodes have been with me taking medications in my sleep, I remember the dream and then counted the medication and realized it happened. Then the next night I dreamt I slept between mine and the neighbors garden...I didn't think anything of it, but when I realized I had taken the pills I thought i would check and yes the grass is matted down between the two gardens and some of their plants are pulled up...Before I had never left the house, that I remember, now I am worried! I could have over dosed and I could have really been hurt outside. what can I do to stop this? I need help. please if anyone has any information respond.
Reply | Report Abuse | Link to thisI did sleep walk when I was a child and then stopped till about 4 years ago when I started up again (36 yrs. old). I have recently started to take PharmaGaba and magnesium at night and have not had a sleep walking episode since. It has been three weeks. I usually would sleep walk a couple times a week. I hope this helps others get the sleep they need!
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