Posts Tagged ‘NIH’

Suggestible You 2

March 18, 2017

“Suggestible You” is the title of a book by Erik Vance.  The subtitle is “The Curious Science of Your Brain’s Ability to Deceive, Transform, and Heal.  This book is about the placebo response and related phenomena.   This is the second post on this book.

Vance participated in an experiment in Luana Colloca’s laboratory on the campus of the National Institutes of Health.  Dr. Colloca attached a variety of devices to Vance including two on his left hand.  One device delivered the shock, the other, on his middle finger.  She said that this device will tap into the A-B fibers in his hand that will occasionally interrupt the shocks, nearly cutting the pain altogether.  As he explained it, the difference between the weak shock and the powerful shock would be that one has a crossing guard and the other does not.  He was told that he would know which one was coming via a screen that will turn green when the A-B fibers are blocking the pain and red when they are not.

Vance said that the small shock feels like a pinprick or a pinch, but the bigger shock doesn’t feel like a bigger pinprick. He said that it’s more like a dull squeeze wrapped in fire, localized in his hand but seemingly all over his body as well.  Colloca slowly increased the strength of the shock, working Vance up a scale of 1 to 10 (10 being the worst tolerable pain), testing his pain threshold.  He agreed to a shock level of 6, although he said that this was very uncomfortable.  He went through two rounds of 12 shocks each.

On the third round he noticed that the green (weak) shock) had gotten slightly worse—maybe from a 1 to a 2.   He thinks there might be a problem with the shock blocker.  They ran through 11 more trials and the torture session was over.  When Colloca returned she told him his pain threshold was smack in the middle of the bell curve for pain, which is 100 hertz of electricity.  She remarked that pain thresholds vary tremendously among individuals.

Then Colloca pointed to a sheet of paper showing Vance’s third round and dropped a surprise telling him, “In Block 3 we used green and red both at 100 hertz.  You felt the green as less painful, compared to the red, when actually you received the same, and that is the placebo effect.”  There never was any magic pain-lessening wire.

The question regarding why the placebo effect works was addressed by a team in Scotland in 1975.  We do have a form of homemade opioids called endorphins.  These endorphins play a number of tiles in our brain, such as regulating circadian rhythms,  appetite and body temperature.  They are the primary chemicals that make sex feel so good.  Two neurologists, Jon Levine and Howard Fields conducted a simple experiment with people in pain after dental surgery.

The plan was to give a group of patients who had recently had a dental procedure either a placebo or naloxone.  Naloxone blocks the endorphins.  They told all of the patients that they were receiving a painkiller.  As expected, many of those  who got the placebo felt less pain, whereas the naloxone group felt miserable, as their own natural opioid (endorphin) generator was being blocked.  When naloxone was given to the genuine placebo group, they also felt miserable.  So this study does show that pain placebos work because the brain self-medicates with the opioid like drug endorphins.


The Risks of Acetaminophen

May 27, 2016

Acetaminophen is the most common drug ingredient in the United States.  It is an ingredient in more then 600 medicines.  About a quarter of all Americans take acetaminophen every week.  However, there are risks to acetaminophen according to an article by Amy Ellis Nutt  in the Health Section of the May 17 2016 edition of the Washington Post, titled, “You don’t feel my pain? Blame acetaminophen.”

The article report research published online  in the journal Social  Cognitive and Affective Neuroscience conducted  by scientists from the National Institutes of Health and Ohio State University.  The results come from two experiments involving more than 200 college students.

In one experiment 80 participants were asked to drink a liquid.  Half the participants received something containing 1,000 milligrams of acetaminopheh.  The other half constituted the control group that drank something without the drug.  An hour later all were asked  to rate the pain experienced by characteristics in eight different fictional scenarios.  In some of the stories, the characters went through a physical trauma, whereas in others an emotional trauma.  In general, those who had taken the acetaminophen rated the pain of the characters as less severe than those who had taken the placebo.

The second experiment exposed participants to brief blasts of white noise.  As one who has experienced brief blasts of white noise, these are extremely discomforting.  They were then asked to rate the pain of another (anonymous) study participant who had also been subjected to the blasts of white noise.  Research participants who had received acetaminophen rated the pain of this anonymous individual as being less severe than those who had taken the placebo.

In another test in which participants had to judge online skits involving social rejection, they showed the same effects as in the noise experiments.  “In this case, the participants had the chance to empathize with the suffering of someone who they thought was going through a socially painful experience.  Still those who took the acetaminophen  showed a reduction in empathy.  They weren’t as concerned about the rejected person’s hurt feelings.

This research built on previous studies identifying a brain region that appears to be key to a person’s empathic response.  The anterior insula, located deep in the folds between the front and side of the brain, is a place where mind and body are integrated.  It also plays a key role in awareness, including emotional awareness.  The less pain a person feels, the less able he or she is to empathize with someone else’s pain.

The researchers note, “Because empathy regulates prosocial and antisocial behavior, this drug-induced reduction in empathy raise concerns about the broader social side effects of acetaminophen.”