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Photo: Pixabay Don't be afraid: some scientists are studying how to make people forget fear, while others are studying how to get pleasure out of fear.

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Considering that I was going to write an article about fear and horror movies, I looked up several horror movies that looked good, and then spent some effort to find resources and put them on the online disk. But at night, when I want to open one of them to see it, I really can't help it-"chainsaw" or "Shining"? Why do I have to scare myself on purpose?

If Matthias Klaassen, an associate professor at Aarhus University in Denmark, knew about my mental activity, I might be confused. He specializes in horror and recreational fear (recreational fear) and is a horror movie enthusiast. The reason why he calls the fear associated with horror movies, horror novels and haunted houses as entertainment fear is that he thinks it is essentially an act of play. I can't help frowning at this: at least for me, what scares me is not funny or funny.

Just as Klaassen published an article in Psychology Today (PsychologyToday) entitled "Why some people don't like horror movies" (Why Some People Don'tLike Horror Movies), I am also very interested in "why some people like to watch horror movies, even though they know they may be deeply disturbed in the next few days or weeks."

But in fact, these questions are too complex to answer. However, in the process of looking for answers, we can learn about the old and strong emotion of "fear" and how to turn off the fear response if necessary.

Where do emotions come from? At a time when psychology was still dominated by Freudian theory, psychologists often believed that behavioral and emotional responses came from within. In the 1920s, behaviorism represented by Pavlov and Watson emerged and put forward the view that behavior and emotional responses are conditioned responses to specific external stimuli, which is completely opposite to the psychoanalytic school. Among them, in addition to the familiar Pavlov dogs, who are trained to salivate whenever they hear the bell, there is also Albert B.

About 100 years ago, subjects Albert was forced to learn to be afraid of guinea pigs, rabbits and even Santa Claus with a white beard when he was 11 months old.

The Albert experiment. Photo Source: wikipedia Albert was originally interested in many animals and was willing to approach and touch them without showing obvious fear. But American psychologist John Watson and his assistant Rosalie Rayner have changed that.

Watson and Leonard showed Albert a guinea pig. At first Albert tried to touch it before the meeting, but when he was about to reach out, they would hit an iron bar behind him with a hammer. Even adults react in fear to sudden loud sounds, not to mention babies as young as a few months old. Albert was frightened and cried by the sudden loud sound behind him.

The pairing of the mouse with the loud sound was repeated a total of seven times. After a week, even if only the mouse was presented to Albert without a sound, he had begun to show extreme fear of the mouse-he would wail, turn around and crawl away from the mouse.

Although Watson and his colleagues planned to reconstruct conditioned reflexes against Albert to dispel these learned fear responses, Albert soon left the hospital and failed to conduct corrective experiments.

Where is the fear memory? To see if this acquired emotional response lasted for a while, Watson and his colleagues interrupted the tests for 31 days, and the results showed that a month later Albert was still very afraid of these things (such as rats, rabbits, dogs). Where are these fear memories stored during this time?

You might think of the amygdala, a cluster of amygdaloid neurons located in the temporal lobe of the brain. But many of the experiments that have shown that the amygdala is associated with fear management have been done on animals with damaged amygdala. Fortunately, the scientist later met a special patient.

Scientists call the patient SM for short. SM was diagnosed with a rare genetic disease: lipoid proteinosis (lipoid proteinosis, also known as Urbach-Wiethe disease). The disease gradually hardens and shrinks the amygdala on both sides of her brain. The amygdala plays an important role in emotion processing, especially fear. SM, whose amygdala is damaged, has never experienced fear since childhood, which fascinates scientists who are keen to study the brain.

Some researchers from the University of Iowa did everything they could to scare SM, show her the scariest horror movies, take her to a scary haunted house-she even poked monsters in the head and told her to deal with poisonous snakes and big spiders-she even asked to touch poisonous snakes, she was interested and not afraid, as if she didn't know what fear was like. The study was published in 2011 in the journal current Biology.

Haunted house. Photo Source: Dystopia Haunted House / Henriette Klausen "this shows us that the amygdala may play a role at a very instinctive and unconscious level." Justin Feinstein, lead author of the study, said, "without this area, you will become bold and not show the slightest fear in almost any situation." Although this does not always bring benefits, such as in the face of threats.

The study is based only on the findings of individual patients, so this particular case may not extend to others, because there are many other factors that affect the way the brain works. Moreover, we cannot simply correspond complex emotional states to a single brain structure. After all, the amygdala cannot act alone. It depends on other brain regions, brain circuits and their connections. The study highlights the key role of the amygdala in fear control, but where else will fear memory appear?

Researchers from the University of Puerto Rico School of Medicine and the Cold Spring Harbor Laboratory published their studies in the journal Nature in January 2015. they reported on a previously unknown set of brain connections that play an important role in how fear memories are stored and extracted.

One of the studies has shown for the first time that memory can be temporarily retained in one area of the brain and then transferred to another completely independent location. Memory storage and retrieval is achieved through communication between neurons, which mainly depends on chemical substances and electrical signal transmission.

Similar to previous experiments on conditioned reflexes, the researchers asked mice to associate a sound with a mild electric shock, causing them to react in fear to the sound. Later, even if the shock was removed, they were afraid of the sound, giving researchers an opportunity to track the changes of neurons in the brain of mice during fear. in order to reveal which neurons will be used to extract previously learned fear memories.

They found that initially, fear memories in mice were evoked through a neural connection between the prefrontal cortex (PL) and the basolateral amygdala (BLA). A week later, the circuit used to extract the same memory changed into a neuronal connection between the paraventricular nucleus of the thalamus (PVT) and the central amygdala (CeA). Later, using photogenetic techniques, they confirmed that the circuit between PVT and the amygdala, an area very close to the brainstem, helps preserve and consolidate fear memories.

Another study also found that when mice store and retrieve fear memories, neurons in the PVT become active and communicate with neurons in the central amygdala.

The new "fear" loop discovered by the two studies may provide new ideas for the treatment of fear-related diseases.

Photo Source: Pixabay turns off fear response if you talk to a so-called "fear expert" about how we can better watch horror movies, he or she will most likely say that one of the major prerequisites for us to enjoy adventure and fear is to be in a safe situation.

But the question is, each of us has more or less fear memories, so how can we get a safe signal in the face of fear, including harmless fears such as horror movies or haunted houses?

For Albert, he didn't wait for a chance to retrain. In contrast, some of the animals in the experiment used corrective training to quell that traumatic memory, that is, they were repeatedly exposed to certain conditions (such as a sound) without electric shocks or other stimuli. During this training, the brain rebuilds new memories that are "safe" and can suppress previous fear memories.

The same team of researchers from the University of Puerto Rico School of Medicine has shown that the medial prefrontal cortex (mPFC) is the home of these safe memories. In other words, this area of the brain has neural connections that turn off the fear response. To be precise, however, these safe memories, which are used to erase fear memories, are first formed in the amygdala and then transferred to mPFC for storage. If the mouse's mPFC is damaged, the initial safety signal will still be generated, but not for long.

More importantly, "the medial prefrontal cortex does inhibit the activity of the amygdala," said Gregory Quirk, head of the research team at the University of Puerto Rico School of Medicine. In other words, terrible memories still exist, but these fear memories are blocked by mPFC without making people feel dangerous or anxious. The study was published in the journal Nature in 2002.

Enjoy fear safely? This is also the experience that people experience in exposure therapy or systematic desensitization.

In addition, many people may have had a similar feeling when watching horror movies: although they are scared, they know it is safe, so they will continue to watch it-at least in some cases. Fear experts like Klaassen also saw subjects run out in panic in the haunted house experiment, and then realized it was just a haunted house and jumped happily.

It is worth mentioning that Klaassen and colleagues found that the relationship between fear and pleasure is inverted U-shaped, that is, there is a maximum, if the fear exceeds the maximum value that the individual can bear, the pleasure will decrease. Of course, according to Klaassen, the fear experience in a safe environment can not only bring pleasure, but also serve as a form of catharsis to help us deal with anxiety and other challenges in real life.

Klaassen and his colleagues have been working on fear-related research, painstakingly publicizing their findings and trying to break the prejudice that people who like to watch bloody and violent horror movies lack empathy. But as for "why some people like horror movies" or "what are the benefits of watching horror movies", their current research is still in its infancy and more experimental evidence is needed to support their view.

If you want to say that one of the benefits of horror movies with a certain theme is that after watching a lot of movies about vampires, I am no longer so afraid of blood.

References:

Https://www.sciencenews.org/article/fear-not

Https://www.sciencenews.org/article/newly-identified-brain-circuit-hints-how-fear-memories-are-made

Https://www.sciencenews.org/article/no-fear

Https://www.psychologytoday.com/intl/blog/why-we-love-horror/202301/why-some-people-dont-like-horror-movies

Https://www.sciencedirect.com/science/article/pii/S0960982210015083

Https://www.nature.com/articles/nature14030

Https://www.nature.com/articles/nature13978

Https://www.nature.com/articles/nature01138

Https://www.smithsonianmag.com/science-nature/can-experiencing-horror-help-your-brain-180980984/

This article comes from the official account of Wechat: global Science (ID:huanqiukexue)

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