Tag Archives: amygdala

Meet the people who literally feel no fear

Courage comes in all shapes and sizes. Running into a burning building to save a person, exposing corruption in a country whose leadership has a history of making journalists disappear, and confronting a bully are all acts that require conquering one’s fear, even when the potential consequences are life-threatening. But that doesn’t mean that these people don’t feel fear — they actually do just as much as you or me. It’s how they handle the fear they feel that sets them apart.

Oddly enough, though, there are people who literally feel no fear at all. For them, looking death in the eye is no more exciting than an oatmeal breakfast. This rare abnormal condition is either owed to disease or some brain damage following an accident that affected the brain circuitry associated with the fear response.

Jordy Cernik abseiled down a 418ft (128 m) tower. Credit: Jordy Cernik.

Take, for instance, the extraordinary case of Jordy Cernik. The British man first knew something was wrong with him when he went skydiving in 2013 and didn’t feel a rush. Since then, Cernik went through all sorts of stunts that would have most people scared beyond belief, including scaling down the edge of the 128-meter National Lift Tower in Northampton, but he found all of them uneventful.

It all started when Cernik was diagnosed with Cushing’s Syndrome in 2005, a medical condition that occurs when the body produces too much cortisol, the main hormone related to the body’s stress response. The excess steroids in the man’s blood made his body feel like it was under a relentless onslaught of imaginary threats. Cernik suffered from excessive weight gain, despite exercising daily and dieting, as well as excessive sweating.

The rare disease, which affects 10 to 15 people per million each year, is caused by a pituitary tumor secreting adrenocorticotropic hormone (ACTH), a hormone that is usually produced by the pituitary gland.

“It’s not a nice one to have,” Cernik told SBS. “Sometimes it can be cured by scraping out the pituitary gland— so that was the brain surgery I had.”

“But mine was persistent and then they ended up having to take my adrenals out just to stop the connection altogether, but then that causes other problems along the way.”

These other problems are those that arise from living life with no fear — quite literally. When Cernik descended one of the tallest towers in the UK on a rope, he was fitted with bands by cognitive scientists that measured his body’s response. These instruments showed that the British man’s body did not react at all as it should have in a normal person.

Scientists believe Cernik’s condition is due to the removal of his adrenal glands during the brain surgery, for which the consequences go beyond just a fearless life. Without any adrenaline in his body, which acts as a sort of painkiller, even a slight injury can be really painful. Also, Cernik doesn’t just feel fear, he’s also devoid of just about any exciting emotion, which makes it incredibly challenging to keep himself motivated.

“It’s just like a switch in my brain that’s gone off and it’s not telling my body to react and its a strange feeling,” he says. 

Fear can be your worst enemy, but also your greatest ally

The amygdala in the brain. Credit: Life Science Databases/Wikimedia Commons.

Humans and just about every sentient creature on Earth feel fear for a good reason, playing a crucial role in our survival and, hence, our evolution. Fear is a primordial emotion that is involved in the brain’s “fight or flight” response. It’s the stimulus that keeps us away from predators or emboldens us to fight back when necessary. It’s such an ancient and instinctual emotion, shared with ancestors that lived hundreds of millions of years ago, that it partly explains why humans are still afraid of heights or insects.

Fear first starts in a part of the brain called the amygdala, which activates other brain areas involved in the fight or flight response and releases stress hormones. In response, the heart and breathing rates rise, blood vessels constrict, and adrenaline kicks in. In some cases, if the fear is extreme, the effects on the body can be so extreme that it is actually possible to be scared to death.

Besides the amygdala, another important region of the brain known as the hippocampus is also involved in the fear response. Closely connected to the almond-shaped amygdala, the hippocampus and prefrontal cortex — both heavily involved in higher-order thinking — help us to interpret whether the initially perceived threat is real or not. For instance, seeing a captive lion at the zoo is much less threatening than seeing the same animal untethered in the African savanna at a leaping distance. The hippocampus provides the explicit memory permitting one to define the context of the fear stimulus while the prefrontal cortex processes and tidies up all this information to establish whether or not you should flee, fight, or just chill since there’s an impenetrable barrier between you and the captive zoo creature.

Most people usually experience it in three stages: freeze (a reaction that is rooted in our evolutionary history to keep us hidden from predators), run (the instinct to move away from danger), and fight (when there’s no way to get away from the fear-triggering object, the ultimate response is to fight).

Fear is automatic, meaning you can’t help feeling it. The degree to which people experience fear and find the power to overcome, of course, varies among people. But not feeling any fear at all is extremely rare and it goes without saying that it is unnatural.

This woman visited the world’s scariest ‘haunted house’ and was held at knife-point. She never flinched

Clinical observations suggest that humans who’ve suffered amygdala damage have abnormal fear reactions and reduced experience of fear to the point that it is nonexistent. A 2011 study led by researchers at the University of Iowa describes the case of a patient, going by the initials S.M. to preserve her identity, who has focal bilateral amygdala lesions. Her brain damage is the result of a very rare inheritable disease known as Urbach-Wiethe disease, which is characterized by infiltration of hyaline-like material in the mucous membranes, internal organs, and the brain. In this particular case, calcium deposits on the amygdala caused lesions in the brain region, resulting in an inhibited sense of fear.

The scientists subjected SM to a battery of what were supposed to be nerve-wracking tests, such as exposing her to live snakes and spiders, a haunted house tour, and film clips of scary movies. However, the 44-year-old woman “repeatedly demonstrated an absence of overt fear manifestations and an overall impoverished experience of fear,” according to the researchers.

Although SM told the researchers she ‘hates’ snakes and ‘tries to avoid them’, when she was taken to an exotic pet store, she held one of the snakes for over three minutes during which she rubbed the reptile’s leathery scales, touched its flicking tongue, and closely watched its movements as it slithered through her hands. She also asked 15 different times if she could touch one of the larger snakes, despite the store clerk declining each time, repeatedly cautioning her that the snake in question was dangerous and could bite her.  When asked why she would want to touch something that she knows is dangerous and claims to hate, SM replied that she was overcome with “curiosity.”

During Halloween, the researchers took SM to the Waverly Hills Sanatorium, which regularly ranks as one of the “most haunted” places in the world. The haunted house at the sanatorium is specially designed to elicit fear with eerie scenes, scary music, loud music, and people dressed as monsters, ghosts, or murderers. SM was joined by a group of five women, all of whom were strangers. SM voluntarily led the group through the haunted house, showing no signs of hesitation. “This way guys, follow me!” she beckoned as other members lagged behind her. When monsters leaped out, she always laughed, approached and talked to them. On one occasion, SM frightened one of the supposed monsters by poking them in the head.

The scary movie clips also had the opposite effect. SM exhibited no fear response but she nonetheless found the films exciting and entertaining, inquiring during one particular case about the name of the movie so she could rent it back home. Interestingly, the 10 different fear-inducing films that the researchers selected aimed at inducing a variety of types of emotions, including disgust, anger, sadness, happiness, and surprise. SM exhibited behaviors compatible with all of these emotions — except fear.

Lastly, SM also shared her general experience of fear by completing a self-reported questionnaire and openly talking about events that would have induced trauma in most other people. For instance, she has been held up at knife-point and at gun-point, she was once physically accosted by a woman twice her size, she was nearly killed in an act of domestic violence, and on more than one occasion she has been explicitly threatened with death. However, on no occasion did SM act with desperation or urgency.

During one notably impressive feat, SM was walking alone through a small park in her town when a man beckoned her over a bench. As she approached, the stranger pulled her down and struck a knife to her throat, threatening her “I’m going to cut you, bitch!”. Hearing a church choir sing in the distance, she confidently said, “If you’re going to kill me, you’re gonna have to go through my God’s angels first.” The man let her go and SM confidently walked (not ran) away. The next day, she went back to the same park.

“When asked to recollect how she felt during the aforementioned situations, SM denied feeling fear, but did report feeling upset and angry about what had happened,” the researchers wrote.

Similar to SM, then 28-year-old Jody Smith received a complex brain surgery meant to cure his severe epilepsy which resulted in the removal of not only parts of the amygdala, but also the temporal lobe and hippocampus.

“Surgery was the only option to prevent the chance of the seizures getting worse, continuing to damage my brain, or potentially killing me,” he told VICE.

Smith underwent brain surgery to treat his severe epileptic seizures. In the process, part of his amygdala was removed which greatly diminished his fear response. Credit: Jody Smith/VICE.

Before his surgery, Smith regularly experienced bouts of panic and anxiety, which he attributed to past traumatic experiences from both his father and brother dying when he was very young. Two weeks after his operation, however, Smith no longer had panic attacks. He soon found out that he had an almost superhuman ability to be fearless.

According to Smith, however, his fearlessness can be described as nuanced. He claims he still intellectualizes the potential consequences of a threat and is aware of things that could harm him. It’s just that he doesn’t seem to get the fight or flight response.

“As an avid hiker, I frequently find myself near cliffs,” he said.

“The experience of fear near cliffs was clearly different. I still didn’t want to fall, and would still feel tense if I started to slip when scrambling, but I didn’t feel the fear part of that. That’s when I started to experiment a bit with my fear: by intentionally walking towards cliffs to see what my instincts would say.”

While out and about in Newark, New Jersey, Smith walked close to a group of men who, by all means, looked like they were about to mug him. But instead of panicking or even experiencing a seizure, as his former self would have, Smith simply and calmly passed through them, much to the men’s surprise who left him alone. “Apparently, my lack of fear struck them,” he said.

What acquired fearlessness may teach us about curing our own anxieties

Although a minimal to non-existent fear response may sound dangerous, we luckily live in a modern society where most of the threats and dangers humans have evolved to face are no longer part of the environment. In fact, one could argue that our natural fear response that could have saved our lives during our caveman days is actually a handicap in today’s society. Such irrational fears fuel anxiety, phobias, obsessive compulsive disorder, and depression.

Nearly one in four people experience a form of anxiety disorder during their lives, and nearly 8 percent experience post-traumatic stress disorder (PTSD).

But superhuman-like cases such as SM, Smith, and Cernik could help scientists better understand mental health disorders that are due to an exaggerated fear response, such as generalized anxiety disorder.

Frank Herbert’s Dune teaches us that fear is the mind-killer. In the real world, though, fear can also be the life-saver. Like all things in life, a balance must be struck.

Your brain might have a specific circuit for political arguments

Most people have deeply rooted political beliefs. As anyone who’s gotten in a heated political debate knows, most people are also very resistant to different opinions, becoming wildly defensive when their beliefs are threatened. Now, a new study might have pinpointed just how that happens.

Almost all political arguments are futile, because usually all parties refuse to consider that their beliefs are wrong. Image credits: Chiltepinster.

Researchers have found that when people’s political beliefs are challenged, their brains light up in areas that govern personal identity and emotional responses to threats. When people become defensive about their political opinions, parts of the amygdala light up, parts associated with decision-making and emotional reactions. So in a way, people don’t view politics rationally, but emotionally. In this way, politics is similar to religion.

“Political beliefs are like religious beliefs in the respect that both are part of who you are and important for the social circle to which you belong,” said lead author Jonas Kaplan, an assistant research professor of psychology at the Brain and Creativity Institute at USC Dornsife College of Letters, Arts and Sciences. “To consider an alternative view, you would have to consider an alternative version of yourself.”

In order to reach this conclusion, researchers recruited 40 people who were self-declared liberals. They were presented with eight political statements and eight non-political statements, which they said to believe equally strong. They were then showed five counter-claims to each one of the 16 statements.

The amygdala — the two almond-shaped areas hugging the center of the brain near the front — tends to become active when people dig in their heels about a political belief. Credit: Photo/Courtesy of Brain and Creativity Institute at USC

The non-political statements were simple facts, such as “Thomas Edison invented the lightbulb” and “Albert Einstein was a great physicist.” But when presented with counter arguments, the participants’ belief in them waned. Yes, people started to doubt whether Einstein was a great physicist.

“I was surprised that people would doubt that Einstein was a great physicist, but this study showed that there are certain realms where we retain flexibility in our beliefs,” Kaplan said.

However, when it came to political beliefs, participants wouldn’t budge. They didn’t change their beliefs much, or at all, and the people who were the most resistant had the strongest activity in the amygdala. Most interestingly, a circuit of the brain called the Default Mode Network surged in activity when the political beliefs were challenged. The default mode network is most commonly shown to be active when a person is not focused on the outside world and the brain is at wakeful rest, such as during daydreaming and mind-wandering. But it is also active when the individual is thinking about others, thinking about themselves, remembering the past, and planning for the future. The importance of emotions should not be underestimated, even in complex, rational decisions.

“We should acknowledge that emotion plays a role in cognition and in how we decide what is true and what is not true,” Kaplan said. “We should not expect to be dispassionate computers. We are biological organisms.”

Sarah Gimbel of the Brain and Creativity Institute was a co-author of the study. She says that understanding why and how this happens could be key for our progress as a society.

“Understanding when and why people are likely to change their minds is an urgent objective,” said Gimbel, a research scientist at the Brain and Creativity Institute. “Knowing how and which statements may persuade people to change their political beliefs could be key for society’s progress,” she said.

Journal Reference: Jonas T. Kaplan, Sarah I. Gimbel & Sam Harris. Neural correlates of maintaining one’s political beliefs in the face of counterevidence. Scientific Reports, December 2016 DOI: 10.1038/srep39589

The brain judges face trustworthiness even when we can’t consciously see it

A new study adds to a body of evidence that suggests the brain is involved in a unconscious process of screening human faces for patterns that suggest trustworthiness or otherwise. Namely, our brains are busy judging other people based on their physical features even when we aren’t even get the chance to properly see those features.

Hardcoded prejudice

“Our findings suggest that the brain automatically responds to a face’s trustworthiness before it is even consciously perceived,” explains Jonathan Freeman, an assistant professor in New York University’s Department of Psychology and the study’s senior author.

“The results are consistent with an extensive body of research suggesting that we form spontaneous judgments of other people that can be largely outside awareness,” adds Freeman, who conducted the study as a faculty member at Dartmouth College.

The researchers directed their efforts on the amygdala  – the part of the brain known to be heavily involved in human social and emotional behavior. Previously, the amydala was shown to become active when judging the trustworthiness of faces, but it wasn’t clear if the structure was active when the signal (visual face cues) didn’t reach perceptual awareness.

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To study how the amygdala responded to such stimuli, the researchers presented a series of photographs to study participants in order to gauge their activity levels. The photographs featured both real human faces  and computer generated ones with various degrees of trustworthiness, like low, neutral or high. The computer general images were based on proven metrics for trustworthiness:  higher inner eyebrows and pronounced cheekbones are seen as trustworthy and lower inner eyebrows and shallower cheekbones are seen as untrustworthy.


The researchers quickly showed the study’s subjects images of real faces as well as artificially generated faces whose trustworthiness cues could be manipulated. Image: Journal of Neuroscience

Before the actual experiments, the researchers tested how accurate their images were at soliciting trust, so they asked a separate group to rate them. Indeed, subjects strongly agreed on the level of trustworthiness conveyed by each given face. Onto the actual experiment, the researchers presented yet another group with the same images, with some key distinctions. This time, the volunteers viewed the faces while inside a brain scanner and, most importantly, they were only briefly exposed to the faces. Each image was shown as a flash, appearing on the screen for only a millisecond – definitely not enough to consciously recognize any features – and was followed by a ‘backward max’. Backward masking works by presenting subjects with an irrelevant “mask” image that immediately follows an extremely brief exposure to a face, which is thought to terminate the brain’s ability to further process the face and prevent it from reaching awareness.

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In total, two experiments were performed: one where the subjects were screened for amygdala activity under flash exposure to faces, and another in response to a fully continuous spectrum of trustworthiness. The findings suggest that even though the subjects never become aware of the faces they were exposed to, their amygdalas were hard at work both tracking and assessing face trustworthiness signals. Apparently, first impressions are made in the millionth of a second.

“These findings provide evidence that the amygdala’s processing of social cues in the absence of awareness may be more extensive than previously understood,” observes Freeman. “The amygdala is able to assess how trustworthy another person’s face appears without it being consciously perceived.”

Findings were reported in the Journal of Neuroscience.

Mothers teach babies fear through smell

Babies can learn what to fear from the first days of life simply by smelling their distressed mothers, a new study has shown. This doesn’t only work after the pregnancy, but also during it and even before – if a mother experiences something specific which makes her fearful.

It’s the first direct observation of this kind – University of Michigan and New York University researchers studied mother rats who had learned to fear the smell of peppermint – theyalso showed that the mothers passed this fear on to their offspring and also pinpointed the exact area of the brain where the learning of fear takes places in the first days of life.

This may help explain something which has puzzled biologists for decades – how is it that a mother’s traumatic experiences are passed on to her offspring?

“During the early days of an infant rat’s life, they are immune to learning information about environmental dangers. But if their mother is the source of threat information, we have shown they can learn from her and produce lasting memories,” says Jacek Debiec, M.D., Ph.D., the U-M psychiatrist and neuroscientist who led the research.

So in a way, even before they can actually accumulate knowledge of their own, they get a taste (or rather, a smell) of their mothers’ experience.

“Our research demonstrates that infants can learn from maternal expression of fear, very early in life,” he adds. “Before they can even make their own experiences, they basically acquire their mothers’ experiences. Most importantly, these maternally-transmitted memories are long-lived, whereas other types of infant learning, if not repeated, rapidly perish.”

In order to figure this out, they devised an experiment which involved making mother rats fear the smell of peppermint by exposing them to non harmful, but unpleasant electric shocks while they smelled the scent, before they were pregnant. Then after they gave birth, the team exposed the mothers to just the minty smell, but didn’t deliver the shocks. They found that newborns quickly picked up on the fear – even though they had no direct reason to fear it. They could learn their mothers’ fears even when the mothers weren’t present.

Using special brain imaging, and studies of genetic activity in individual brain cells and cortisol in the blood, they found that this learning takes place in the lateral amygdala. The amygdala is present in virtually all evolved mammals, playing a complex role in the in the processing of memory, decision-making, and emotional reactions.

Researchers now hope to conduct the same kind of study for mothers and their babies, but they have every reason to believe they will get similar results.


Part of the brain subjectively encodes information related to human emotions

Primates are among a couple of mammals that have a dedicated system for processing faces, something that involves a lot of neuropower and energy expenditure. While there are people that resemble each other, no two humans have the same exact faces (not even identical twins). Some people see, and thus analyze, thousands of faces each day, depending on how much they go outside. Recognizing emotions is an even more complicated process, one that gives even the brain some problems.


Photo: Ralph Adolphs / Caltech. Arrows indicate responses from single neurons.

Researchers at Caltech, Cedars-Sinai Medical Center, and Huntington Memorial Hospital in Pasadena targeted brain activity in the amygdala, the region of the brain responsible for encoding information related to emotional reactions. Their findings suggest that some brain cells recognize emotional face patterns based on a subjective approach (i.e. the viewer’s preconception), and not through an entirely objective process that should have revealed the true emotional pattern. This is the first time neurons in the amygdala were shown to encode the subjective judgment of emotions shown in face stimuli, rather than simply their stimulus features.

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Participants in the study were shown images of partially obscured faces and asked to decide which emotion they were showing. They did not see the red circles shown here to outline the areas where the faces appeared. - See more at: http://www.caltech.edu/content/sorting-out-emotions#sthash.hOjJsi1h.dpuf

Participants in the study were shown images of partially obscured faces and asked to decide which emotion they were showing. They did not see the red circles shown here to outline the areas where the faces appeared. Photo: Ralph Adolphs / Caltech

For their purpose, the researchers investigated over 200 single neurons in the amygdalae of 7 patients treated for epilepsy who had surgically implanted depth electrodes. MRI image of the patients’ brain activity were taken while the participants were shown images of partially obscured faces showing either happiness or fear. Each participants was asked to judge which of the two emotions was shown. Here’s what the authors report:

“During trials where subjects responded correctly, we found neurons that distinguished fear vs. happy emotions as expressed by the displayed faces. During incorrect trials, these neurons indicated the patients’ subjective judgment. Additional analysis revealed that, on average, all neuronal responses were modulated most by increases or decreases in response to happy faces, and driven predominantly by judgments about the eye region of the face stimuli,” from the abstract of the paper published in the Proceedings of the National Academy of Science.

What this means is that the amygdala doesn’t necessarily respond to what’s actually there in the world, but to what SEEMS to be there, after it passes an internal filter. Things become more interesting when you take into account the fact that the amygdala is linked with a number of psychiatric diseases like depression or autism. Many of these afflictions might be due to a skewed perception of the patient’s surroundings.  That doesn’t mean the amygdala alone is responsible for all of this.

“Of course, the amygdala doesn’t accomplish anything by itself.  What we need to know next is what happens elsewhere in the brain,  so we need to record not only from the amygdala, but also from other brain regions with which the amygdala is connected,” says Shuo Wang, a postdoctoral fellow at Caltech and first author of the paper. 

MRI shows a decrease in volume in certain brain regions of professional fighters

For decades, there’s been significant discussions on how professional fighting affects the brain, but not much scientific progress has been made on the matter. Now, a new (not yet peer reviewed) MRI study has shown that important regions and connections of the brain have decreased in volume in both amateur and professional fighters with the most experience.


104 boxers and 135 mixed-martial arts (MMA) competitors — many of them “cage fighters” — were studied, and the results showed a correlation between the number of years fighting and reduced volume in the caudate and amygdala, while strong trends were seen toward smaller volumes in the thalamus and putamen. The caudate nucleus is an important part of the brain’s learning and memory system, while the amygdala is crucial to the processing of memory and emotional reactions.

Cognitive and other functional deficits in professional fighters have been noted for decades, if not centuries, and are caused by hits to the head. The average career length at enrollment was 4 years and the mean number of self-reported fights was 11; at this time, the differences weren’t all that big. However, as researchers report, after the 5th year, the volumes start to shrink significantly, most sharply for the caudate. In that region, volumes were 10% lower in participants with 15 years of experience compared with those fighting for 5 years or less.

Also, the biggest correlations were observed in subjects who started fighting in their adolescence. While as I mentioned, this hasn’t been peer reviewed, I believe it points a pretty good picture, showing an intuitive, but not really researched result.