Thursday, 20 March 2008

The Pain is All in Your Head (no brain=no pain?)

I’ve been reading several interesting articles lately about the brain, and the strange way it seems to work (and NOT work at times). Some of it ties in with the incredible effect of placebos that I have mentioned in recent posts.

Jack Tsao, A US Navy officer/neurologist at Bethesda Maryland has found some interesting treatments for the phantom pain that often tortures folks with amputated limbs. He recruited twenty-two amputees with one missing leg and randomly assigned three treatments. One group were instructed to sit in front of a mirror and move the non-amputated leg as they watched the movement in the mirror and imagined moving the missing leg. A second group did the same, but with the mirror covered, and a third group was told just to imagine moving the missing leg. And the results? After four weeks of the therapy the second group had over half the patients report increased pain over the four weeks of treatment. For the third group, who only imagined moving the missing limb, two-thirds reported increased pain. For the mirror group, 100% (that’s not a typo).. All of them reported a reduction in pain.

A suggested explanation is that after the amputation the mind notices the lack of sensation from the missing leg, and sort of turns up the sensory volume in the nerve chain for that region of the body, producing increased pain sensation. The therapy seems to fool the mind in regions of so-called “mirror neurons” in the brain which respond when we move or watch someone else move.

As a teacher I get to watch kids behavior during tests, and one of the things you notice is the “looking for the answer on the ceiling” gazes that have nothing to do with cheating. Students will gaze to the left or right or at the ceiling as they ponder the solution to a math question. In the 1970’s there was lots of research about this tendency to gaze off to one side or the other when we are trying to think of the answer to a question. For a while it seemed that there might be an association between the direction of the gaze, left or right, and the type of question but that explanation seems to be too simplistic. There is still definitely an effect, and it appears that if you are prevented from this “lateral eye movement” which actually has an acronym, LEM, that you are less able to answer the question. (See Glenberg, Arthur M., Jennifer L. Schroeder, and David A. Robertson (1998). Averting the gaze disengages the environment and facilitates remembering. Memory & Cognition 26/4: 651-8.)

You can sort of test the idea that harder questions are more likely to induce the LEM by asking a series of questions on this link, that progressively get harder. According to the researchers, only a third of the sample of college students could answer 20 or more of the 33 questions. Ask them of a friend, and watch the eyes. Record the questions that require LEM; according to the research they should occur more on the later, harder questions. Here are a couple of them to whet your appetite, with the answers below.

Six easiest ones are
1. What’s the name of the comic strip character who eats spinach to increase his strength?
2. What’s the last name of the brothers who flew the first airplane at Kitty Hawk, North Carolina?
3. What’s the name of the crime of purposely setting a building or property on fire?
4. What’s the name of Dorothy’s dog in "The Wizard of Oz"?
5. What’s the name of the man who rode horseback in 1775 to warn that the British were coming?
6. What’s the last name of the famous magician and escape artist who died of appendicitis?

And the final six (supposedly very hard) are
28. What’s the name of the mountain range separating Asia from Europe?
29. What’s the name of the first person to run the mile in under four minutes?
30. What was the name of the Cuban leader overthrown by Castro?
31. What was the last name of the artist who painted "American Gothic"?
32. What was the name of the town through which Lady Godiva supposedly made her famous naked ride?
33. What’s the name of the highest mountain in South America?

If you need the answers, here they are for these questions, with the percentage of the college sample who answered them correctly…

1. Popeye (94%)
2. Wright (92%)
3. Arson (88%)
4. Toto (84%)
5. Paul Revere (82%)
6. Houdini (80%)

28. Ural (9%)
29. Bannister (7%)
30. (4%)
31. Wood (3%)
32. Coventry (1%)
33. Aconcagua (0%)

So how did you do… Do you notice yourself looking right or left more on the hard ones??? (HEY, over here!!!)
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