Posts Tagged ‘Fear’

Suggestible You 6

March 22, 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 post is about the placebo response and related phenomena.   This is the sixth post on this book.

This post is on nocebos.  Remember that placebo is Latin for “I shall please.”  Nocebo means “I shall harm.”  So nocebos can be thought of as negative placebos.

In 1886 a physician named John Mackenzie was treating a woman with a serious case of hay fever and asthma.  For a variety of reasons, he was not convinced that the patient’s condition was fully authentic.  For her next visit he place a rose in his office.  As soon as she sat it she had powerful allergic reaction that brought on an asthma attack.  The flower was artificial and served as the nocebo.

Cholecystokinin (CCK) is a key messenger in activating intestinal functions, including digestion and the release of gastric acid and bile.  It also plays a role in making you feel full after a good meal.  But if you inject CCK into someone, it causes anxiety and nausea and can induce panic attacks.  It also seems to increase pain by lessening the impact of internal opioids.  Fabrizio Benedetti set up an experiment with patients recovering from  minor surgery in which he gave them a drug and told them it would make their pain worse when it was actually just saline.  The patients did report more pain with the saltwater injection.  Then Benedetti blocked their brains’  CCK release with another drug.  Now the patients felt better when the CCK was blocked.  Vance wrote,”What opioids are for placebos is what CCK is for nocebos; a mechanism giving expectation power in the body.  And whereas blocking opioids killed the placebo response and made patients feel worse, blocking CCK actually supercharged pain relief by allow the brain’s internal pharmacy to run wild.”

Nocebo effects are much easier to create than placebo effects.  Negative expectations can be stronger than positive expectations.  Vance note that nocebos and placebos in the brain take two different routes.  They look similar, go to similar places, share some of the same highways, but still are totally different routes, and nocebos take all the best shortcuts.  This does make  sense, as the aversion to pain is fundamental not just to being human, but also to being alive.  Colloca notes that although the nocebo affects the same reward/expectation regions in the brain, it also includes one more that placebos do not:  fear.  The hippocampus plays a key role in the storage of memories and it also plays a key role in fear conditioning anxiety.  Brain imaging indicates that while the hippocampus is mostly absent from placebo effects, it lights up during the experience of nocebos.

Fear is at the heart of nocebos, and fear is a powerful emotion.  Fear headlines in the news elicit much stronger responses that do pleasant ones.  In 2014, even before anyone had died of Ebola in the United States, 25% of Americans were worried they or their families could contract it.  Thousands of people visited doctors claiming they had signs of the virus, and 650 of those people had symptoms serious enough for their cases to be passed on to federal officials.  As it turned out, only four people in the United States had the disease:  a visitor who got it in Liberia, two nurses who had treated him, and a doctor who had been working in an Ebola.

So we need to be careful to not let our fears get out of hand.  And let us hope that doctors make more use of nocebos in treating pain.

Why When Matters are Objectively Good Do We Feel So Bad? Part One

August 19, 2016

By any objective standard, matters are quite good in the United States.  Just eight years ago, the world was on the verge of an economic collapse.  That collapse did not materialize,and today unemployment is low and the economy in the United States is among the best in the world.  So why are people saying that this country is on the wrong track?  Why are some people willing to vote for an emotionally unstable individual with none of the skills for the job for President of the United States?  There are a number of reasons for this, but this current post will focus on the following article in the Insight section of the 6 August 2016 issued of the New Scientist, titled “July was bad news but I’m fine—so why do I feel so terrible?”  The author notes that July brought an unusual dump of bad headlines including the televised deaths of Philander Castile and Alton Sterling, police being killed in Dallas and Baton Rouge, terror attacks in Istanbul, Baghad, Nice and Saint-Etieene-du-Rouvray, plus other acts of violence in Germany and Japan.

Peter Ayton who studies decision-making at City University in London says that we should be wary of the idea that there’s something in the water.  “This is an attempt at induction: grouping events on the idea of some force or influence may be engineering the shape of the days.”  Even if news stories are random, statistically we should still expect to see runs of more upsetting headlines.

Elaine Fox of the University of Oxford notes that we are predisposed to focus on bad stuff.  “Threat information activates the fear system, while positive news activates the reward system.  The fear system is stronger, and works to shut down the rational part of our brain.  Once we are in a fearful state, we’re conditioned to see out more bad news.

Fox continues, “The sense of immediacy provided by 24-hour rolling news means the brain is saying, “this is a real threat to me.”  This explains why we feel so personally affected even though chances of being caught up in a shooting or terrorist attack are vanishingly small.  The vividness of images may also skew our sense of risk.  In October 2014 after several months of disturbing TV reports from West Africa, a Gallup Poll found that 22 % of people in the US were worried about contracting Ebola, despite only six people in the country being infected and none picking it up on home soil.

Ayton notes that we underestimate our ability to adapt to huge changes.  A 1978 study showed that after two years, people paralyzed in accidents and lottery winners showed little change in overall happiness, instead habituating to their new state.  This finding has been replicated many times.

The Amygdala and the Problem of Reverse Inference

January 18, 2014

This blog post is based on the book Brainwashed: The Seductive Appeal of Mindless Neuroscience by Sally Satel and Scott O. Lillenfeld. Please bear with me as this is just the third post that I’ve written based on a source viewed on my Kindle.

The amygdala is a small region on each side of the brain. So we all should have two amygdalae. They are located in the temporal lobes, one in each hemisphere. In popular reports the amygdala has become almost synonymous with the emotional state of fearfulness. This is true. When you experience fear, the amygdala lights up. I have personal experience with research on the amygdala that I conducted when I was a graduate student. This was back in the days before brain imaging. I surgically implanted electrodes in rats placed under anesthesia so that they would electrically stimulate only their amygdalae. They were deprived of water and when placed in the operant chamber, they immediately started drinking. They received a shock after drinking. When they were placed back into the operant chamber they would not drink even if they were thirsty. However, if an electric current had been sent to the amygdalae when they were shocked the memory of the shock would never have been formed, so they would drink without fear when placed back in the operant chamber.

Although the amygdala is involved in fearfulness, it also responds to things that are unexpected, novel, unfamiliar or exciting. “This probably explains its increased activation when men look at pictures of a Ferrari 360 Modena. The amygdala reacts to photos of faces with menacing expressions, but also to photos of friendly, unfamiliar faces. If fearful faces are expected and happy faces unexpected, the amygdala will respond more strongly to the happy faces. The amygdala also helps register the personal relevance of a stimulus at a given moment. For example, one study revealed that hungry subjects manifested more robust amygdala responses to pictures of food than did their nonhungry counterparts.1

This amygdala example illustrates the problem of reverse inference, which is a problem that plagues the popular media. Reverse inference is the common practice of reasoning backward from the neural activation viewed in an image to subjective experience. The problem is that brain structures rarely perform single tasks, so one-to-one mapping between a given region and a particular mental states is highly prone to error. So “When Jeffrey Goldberg views a picture of Mahmoud Ahmadinejad and his ventral striatum lights up like a menorah, some investigators might think, ‘Well we know that the mental striatum is involved with processing reward, so this subject, with his activated mental striatum is experiencing positive feelings for the dictator’”2 This would be true only if the ventral striatum exclusively processed the experience of pleasure. But novelty can also stimulate the ventral striatum.

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