Alright, here we are at part three of battling neuromythology! We’ve been looking at nine examples of facts and fiction about the brain per post, and the pattern will be continued with this entry. The format will also continue, with a statement followed by verifying whether it is true or false, and an explanation. Without further ado, let’s get started:
1. During sleep the brain is relatively inactive. Not always! EEG portraits show that sleep consists of a complex series of brain states, not just an “inactive” period. Dreams are when the brain is active and it was originally thought to only occur during REM (rapid eye movement) sleep, but we now know that dreams occur in other sleep stages as well, such as SWS (slow-wave sleep). In fact the brain cycles through SWS and REM sleep throughout the night.
2. Sleepwalkers are acting out dreams. Mostly False! Somnambulism occurs most commonly during the first half of the night and the problem is simply their inability to wake into full contact with their surroundings. To add to the picture though, there are a minority of people with REM Behavior Disorder that actually has organized behavior–fighting some imaginary foe, eating a meal, acting like an animal, etc. This disorder doesn’t usually present until after age 50, for some reason is more common in men than in women, and its onset is often followed by early symptoms of Parkinson’s Disease or dementia. Yikes.
3. Prolonged sleep deprivation will make you temporarily crazy. False! The most common behavior of those that have been deprived of sleep for 205 hours (8.5 days) are simple increases in irritability, difficulty in concentrating, and episodes of disorientation. Moderate sleep debt can accumulate as well. A study in 2003 showed that folks who got 4 or 6 hours of sleep per night for two weeks showed “ever-mounting deficits in attention tasks and in speed of reaction.” Can lack of sleep eventually lead to death? Yes. Rats consistently die after about 19 days of no sleep, and even fruit flies require sleep. People born with fatal familial insomnia, where in midlife they simply stop sleeping, die 7-24 months after the insomnia begins.
4. Some animals can have half their brain asleep and the other half awake. True! Dolphins, for example, have only half of their brain in slow-wave sleep at a time. It’s as if one whole hemisphere is asleep while the other is awake. In effect, the two hemispheres of their brain take turns sleeping. Some birds also have unilateral sleep–for example a bar-tailed godwit flew nonstop more than 10,000 miles, from Alaska to Australia, in a week!
5. The left side of the face is more emotionally expressive than the right side. True! The two hemispheres of our brain operate differently in how they recognize emotional stimuli. Results of research indicate the right hemisphere is better than the left at interpreting emotional aspects of vocal messages. In fact scientists study this by cutting a photograph of a person who is displaying an emotion down the exact middle of the face. They create two composite photos, one that combines the two left sides of the face (mirroring one side) and another that combines the two right sides and the difference is visible. This is consistent for pleasant and unpleasant emotions, for both sexes and all ages. Here is an example.
6. Prolonged stress can cause heart disease. True! In fact stress involves and affects not only the nervous and endocrine systems but also the immune system. There are fields of research called psychosomatic medicine, health psychology and psychoneuroimmunology (try saying that five times fast) dedicated to this stuff. Incidents of illness tends to be higher in people who sustain prolonged stress, but physical health and strategies to cope with stress are important. Another reason to exercise and having coping skills!
7. All cultural groups recognize the same facial expressions for various emotions. Uncertain. For example, people in preliterate New Guinea show emotional facial expressions like those of people in industrialized societies, but there are some differences: isolated nonliterate groups did not agree with Westerners about recognizing expressions of surprise and disgust. This may suggest that cultures prescribe rules for facial expression. In fact everyone agrees that culture does affect the facial display of emotions, the controversy is over the extent of the influence.
8. It is possible to determine scientifically whether someone is lying. False (for now)! The polygraph test is based on the assumption that people have emotional responses when lying because they fear detection and/or feel guilt about lying. Those who support polygraph tests say they’re 95% accurate, but more impartial researchers put the overall accuracy at 65%. Even if the 95% figure was accurate that would still mean tons of people would be falsely accused of lying. Following the terrorist attacks of September 11th the National Research Council again confirmed that “accuracy in distinguishing actual or potential security violators from innocent test takers is insufficient to justify reliance on its use in employee security screening.” However PET images reveal selective activation of prefrontal cortex in subjects engaged in lying, so who knows what the future holds.
9. Scientists are not sure why antidepressant drugs work. True! The most widely prescribed antidepressants these days are SSRI’s like Prozac, Zoloft, Cymbalta, etc. While over 50% of folks studied have a slight improvement versus a placebo (a sugar pill), only 13% responded significantly better to the drug than to a placebo. About 20% showed no improvement at all. In fact, there is no evidence that SSRI’s do better than placebos when given to children or teenagers, and evidence suggests they actually increase the risk of suicide in these populations–and that drug companies have concealed this fact. The thinking behind the drug is that reduced serotonin stimulation causes depression, so SSRI’s increase it. However, while SSRI’s achieve their intended effect within hours, it takes weeks before people feel better. This paradox suggests it’s the brain’s response to increased serotonin that relieves the symptoms, and that the response takes time–but nobody knows what that response is.
* Bonus Info: Another myth that seems to be perpetuated is that folks often get addicted to painkillers like morphine after having surgery. The danger of this addiction has been vastly overexaggerated; it is no more than 0.04% of folks! In the media, people addicted to painkillers are often reported to gotten addicted when given a prescription, but investigation reveals that in nearly all instances these folks had been drug abusers before they were given a prescription for pain. This myth results in millions of people being under-treated for pain each year.
Thanks for taking a look here, I hope this stuff is as interesting to you as it is to me! In the next and final installment I’ll be looking at (among other things) whether some folks are actually incapable of producing any new memories, if we ever really forget anything we’ve experienced, if some people are “right-brained” or “left-brained”, can people take in a whole visual scene with just a glance, and is it true a child can have half their brain removed and still develop normal intelligence?!