What is brain swelling? What causes brain swelling? What are the symptoms of brain swelling? How is brain swelling diagnosed? What is the treatment for brain swelling? What are the long-term effects of brain swelling? How can I protect my head?

Understanding Brain Swelling

Cerebral edema, also known as brain swelling, is a serious medical condition where excess fluid accumulates within the brain, leading to increased intracranial pressure (ICP). This can occur due to a variety of reasons, including traumatic brain injury, strokes, infections, tumors, or even high-altitude exposure. The brain is enclosed within the rigid skull, and any increase in volume can have devastating consequences, potentially cutting off blood flow and depriving the brain of vital oxygen and nutrients.

Causes of Brain Swelling

There are several potential causes of brain swelling, including:

• Traumatic Brain Injury (TBI): Sudden impacts or rapid acceleration/deceleration of the head can directly damage brain tissue, leading to swelling.
• Ischemic Strokes: Blood clots or blockages that cut off blood supply to the brain can cause brain cells to die and swell.
• Hemorrhagic Strokes: Ruptures of blood vessels in the brain can cause bleeding and swelling.
• Infections: Illnesses like meningitis, encephalitis, and toxoplasmosis can all trigger inflammatory brain swelling.
• Tumors: Growths within the brain can press on surrounding tissues and block the drainage of cerebrospinal fluid, leading to edema.
• High Altitudes: Rapid ascent to high elevations can cause a condition called high-altitude cerebral edema (HACE).

Symptoms of Brain Swelling

The symptoms of brain swelling can vary depending on the severity and underlying cause, but often appear suddenly. Common signs include:

• Severe headache
• Nausea and vomiting
• Confusion or disorientation
• Drowsiness or lethargy
• Seizures
• Pupil dilation
• Difficulty speaking or understanding speech
• Loss of coordination or balance

Diagnosing Brain Swelling

Diagnosing brain swelling typically involves a combination of physical examination, medical history, and imaging tests. Healthcare providers may order the following:

• Neurological exam to assess cognitive, motor, and sensory function
• CT scan or MRI to visualize the brain and detect any abnormalities
• Lumbar puncture (spinal tap) to measure intracranial pressure
• Blood tests to look for signs of infection or other underlying conditions

Treating Brain Swelling

The treatment for brain swelling depends on the underlying cause, but the primary goal is to reduce intracranial pressure and restore normal blood flow to the brain. Potential treatments include:

• Medications like corticosteroids, diuretics, or anti-seizure drugs
• Mechanical ventilation to control breathing and oxygenation
• Surgical procedures to remove excess fluid or relieve pressure
• Hypothermia therapy to lower metabolic demands on the brain

Long-Term Effects of Brain Swelling

The long-term effects of brain swelling can be severe and may include permanent brain damage, cognitive impairment, motor dysfunction, and even death. The specific outcomes depend on the underlying cause, severity, and duration of the swelling. Early recognition and prompt treatment are crucial to minimizing the risk of these devastating consequences.

Protecting Your Head

Given the potentially serious nature of brain swelling, it’s important to take steps to protect your head and prevent traumatic brain injuries. This includes wearing appropriate safety gear during activities like sports, using seatbelts and helmets when driving, and being cautious in environments with fall or collision risks. Seeking prompt medical attention for any head injuries or sudden neurological symptoms is also crucial.

In summary, brain swelling is a serious medical condition that can have a wide range of underlying causes, from traumatic injuries to infections and high-altitude exposure. Recognizing the symptoms, seeking prompt medical care, and taking preventive measures to protect the head are all essential for minimizing the risks and long-term consequences of this potentially life-threatening condition.

Cerebral Edema (Brain Swelling): Symptoms, Causes, & Treatment

Written by Beth Roybal

• What Is Brain Swelling?
• What Causes Brain Swelling?
• What Are the Symptoms of Brain Swelling?
• How Is Brain Swelling Diagnosed?
• What Is the Treatment for Brain Swelling?
• What Are the Long-Term Effects of Brain Swelling?
• How Can I Protect my Head?
• More

If you bump your knee, it’s likely to swell. But what if you injure your brain?

Swelling — also called edema — is the body’s response to many types of injury. It can result from overuse or infection. Usually, swelling happens quickly and is simple to treat with some combination of rest, ice, elevation, medication, or removal of excess fluid.

Your brain can also swell as a result of injury, illness, or other reasons. Brain swelling, though, can quickly cause serious problems — including death. It’s also usually more difficult to treat. As your body’s master control system, the brain is critical to overall function. Yet, the thick, bony skull that snugly protects this vital organ provides little room for the brain to swell.

Brain swelling goes by many names:

• Brain edema
• Elevated intracranial pressure
• Cerebral edema

Swelling can occur in specific locations or throughout the brain. It depends on the cause. Wherever it occurs, brain swelling increases pressure inside the skull. That’s known as intracranial pressure, or ICP. This pressure can prevent blood from flowing to your brain, which deprives it of the oxygen it needs to function. Swelling can also block other fluids from leaving your brain, making the swelling even worse. Damage or death of brain cells may result.

Injury, other health problems, infections, tumors, and even high altitudes — any of these problems can cause brain swelling to occur. The following list explains different ways the brain can swell:

• Traumatic brain injury (TBI): A TBI is also called a head injury, brain injury, or acquired brain injury. In TBI, a sudden event damages the brain. Both the physical contact itself and the quick acceleration and deceleration of the head can cause the injury. The most common causes of TBI include falls, vehicle crashes, being hit with or crashing into an object, and assaults. The initial injury can cause brain tissue to swell. In addition, broken pieces of bone can rupture blood vessels in any part of the head. The body’s response to the injury may also increase swelling. Too much swelling may prevent fluids from leaving the brain.
• Ischemic strokes: Ischemic stroke is the most common type of stroke and is caused by a blood clot or blockage in or near the brain. The brain is unable to receive the blood — and oxygen — it needs to function. As a result, brain cells start to die and swelling occurs.
• Hemorrhagic strokes: Hemorrhage refers to blood leaking from a blood vessel in the brain (intracerebral). Hemorrhagic strokes are the most common type of stroke. They occur when blood vessels anywhere in the brain rupture. As blood leaks and the body responds, pressure builds inside the brain. High blood pressure is thought to be the most frequent cause of this kind of stroke. Hemorrhages in the brain can also be due to certain medications and unknown malformations present from birth.
• Infections: Illness caused by an infectious organism such as a virus or bacterium can lead to brain swelling. Examples of these illnesses include:
  • Meningitis: This is an infection in which the covering of the brain becomes inflamed. It can be caused by bacteria, viruses, other organisms, and some medications.
  • Encephalitis: This is an infection in which the brain itself becomes inflamed. It is most often caused by a group of viruses and is sometimes spread through insect bites. 
  • Toxoplasmosis: This infection is caused by a parasite. Toxoplasmosis most often affects fetuses, young infants, and people with damaged immune systems.
  • Subdural abscess: Subdural abscess (empyema) refers to an area of the brain becoming abscessed or filled with pus, usually after another illness such as meningitis or a sinus infection. The infection can spread quickly, causing swelling and blocking other fluid from leaving the brain.
• Tumors: Growths in the brain can cause swelling in several ways. As a tumor develops, it can press against other areas of the brain. Tumors in some parts of the brain may block cerebrospinal fluid from flowing out of the brain. New blood vessels growing in and near the tumor can leak and also lead to swelling.
• High altitudes: Although researchers don’t know the exact causes, brain swelling is more likely to occur at altitudes above 4,900 feet. This type of brain edema is usually associated with severe acute mountain sickness (AMS) or high-altitude cerebral edema (HACE).

Symptoms of brain swelling vary, depending on the severity and the cause. Usually they begin suddenly. You may notice any of these symptoms:

• Headache
• Neck pain or stiffness
• Nausea or vomiting
• Dizziness
• Irregular breathing
• Vision loss or changes
• Memory loss
• Inability to walk
• Difficulty speaking
• Stupor
• Seizures
• Loss of consciousness

The steps used by your doctor to diagnose brain swelling depend on the symptoms and the suspected cause. Common exams and tests used in the diagnosis include:

• Head and neck exam
• Neurologic exam
• CT scan of the head to identify the extent and location of the swelling
• MRI of the head to identify the extent and location of the swelling
• Blood tests to check for causes of the swelling
• Lumbar puncture

Minor cases of brain swelling due to causes such as moderate altitude sickness or a slight concussion often resolve within a few days. In most cases, however, more treatment is needed quickly.

The goal is to assure that the brain receives enough blood and oxygen to remain healthy while the swelling is relieved and any underlying causes are treated. This may require a combination of medical and surgical treatments. Prompt treatment usually results in quicker and more complete recovery. Without it, some damage may remain.

Supportive care for brain edema may include any combination of the following:

• Hyperbaric oxygen therapy: Providing oxygen through a respirator or in a chamber helps make sure that the blood has enough oxygen in it.  
• IV fluids: Giving fluids and medicine through an IV can keep blood pressure from dropping too low. This helps to make sure that the body — including the brain — is receiving enough blood. However, some fluids can make swelling worse. Doctors attempt to use the right amounts of the right fluids in someone with brain swelling.
• Lowering body temperature (hypothermia): Lowering the temperature of the body and brain helps relieve swelling and allows the brain to heal. Hypothermia as a treatment for brain swelling is not widely used, however.
• Medication: In some cases of brain edema, your doctor may start a drug to help relieve the swelling. Medication may also be given for other reasons, such as to slow your body’s response to the swelling or to dissolve any clots. The drugs your doctor gives you depend on the cause and symptoms of brain swelling.
• Ventriculostomy: In this procedure, a surgeon cuts a small hole in the skull and inserts a plastic drain tube. Cerebrospinal fluid is drained from inside the brain, helping to relieve the pressure.
• Surgery: Surgery may have one or more of these goals:
  • Removing part of the skull to relieve intracranial pressure; this procedure is called decompressive craniectomy.
  • Removing or repairing the source of the swelling, such as repairing a damaged artery or vein or removing a growth

It’s common to have lingering effects from brain swelling. The problems you notice depend on the severity as well as the location of the injury. Symptoms may be noticed with any of the following:

• Sleeping
• Thinking and attention skills
• Headaches
• Depression
• Communication skills
• Movement
• Urinary incontinence 

Your health care team is available to help you deal with these challenges. While some problems may continue to diminish over time, others may require ongoing treatment.

To protect the brain, keep these tips in mind as you go about your daily activities:

• Use a helmet when biking, skating, playing contact sports, or performing other activities in which you might fall and hit your head.
• Wear seat belts properly when driving or riding in vehicles.
• Make sure you are doing all you can to control high blood pressure and heart disease.
• Avoid smoking.
• When traveling to high elevations, take your time — allow your body to adjust to the altitude.

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Cerebral Edema (Brain Swelling): Symptoms, Causes, & Treatment

Written by Beth Roybal

• What Is Brain Swelling?
• What Causes Brain Swelling?
• What Are the Symptoms of Brain Swelling?
• How Is Brain Swelling Diagnosed?
• What Is the Treatment for Brain Swelling?
• What Are the Long-Term Effects of Brain Swelling?
• How Can I Protect my Head?
• More

If you bump your knee, it’s likely to swell. But what if you injure your brain?

Swelling — also called edema — is the body’s response to many types of injury. It can result from overuse or infection. Usually, swelling happens quickly and is simple to treat with some combination of rest, ice, elevation, medication, or removal of excess fluid.

Your brain can also swell as a result of injury, illness, or other reasons. Brain swelling, though, can quickly cause serious problems — including death. It’s also usually more difficult to treat. As your body’s master control system, the brain is critical to overall function. Yet, the thick, bony skull that snugly protects this vital organ provides little room for the brain to swell.

Brain swelling goes by many names:

• Brain edema
• Elevated intracranial pressure
• Cerebral edema

Swelling can occur in specific locations or throughout the brain. It depends on the cause. Wherever it occurs, brain swelling increases pressure inside the skull. That’s known as intracranial pressure, or ICP. This pressure can prevent blood from flowing to your brain, which deprives it of the oxygen it needs to function. Swelling can also block other fluids from leaving your brain, making the swelling even worse. Damage or death of brain cells may result.

Injury, other health problems, infections, tumors, and even high altitudes — any of these problems can cause brain swelling to occur. The following list explains different ways the brain can swell:

• Traumatic brain injury (TBI): A TBI is also called a head injury, brain injury, or acquired brain injury. In TBI, a sudden event damages the brain. Both the physical contact itself and the quick acceleration and deceleration of the head can cause the injury. The most common causes of TBI include falls, vehicle crashes, being hit with or crashing into an object, and assaults. The initial injury can cause brain tissue to swell. In addition, broken pieces of bone can rupture blood vessels in any part of the head. The body’s response to the injury may also increase swelling. Too much swelling may prevent fluids from leaving the brain.
• Ischemic strokes: Ischemic stroke is the most common type of stroke and is caused by a blood clot or blockage in or near the brain. The brain is unable to receive the blood — and oxygen — it needs to function. As a result, brain cells start to die and swelling occurs.
• Hemorrhagic strokes: Hemorrhage refers to blood leaking from a blood vessel in the brain (intracerebral). Hemorrhagic strokes are the most common type of stroke. They occur when blood vessels anywhere in the brain rupture. As blood leaks and the body responds, pressure builds inside the brain. High blood pressure is thought to be the most frequent cause of this kind of stroke. Hemorrhages in the brain can also be due to certain medications and unknown malformations present from birth.
• Infections: Illness caused by an infectious organism such as a virus or bacterium can lead to brain swelling. Examples of these illnesses include:
  • Meningitis: This is an infection in which the covering of the brain becomes inflamed. It can be caused by bacteria, viruses, other organisms, and some medications.
  • Encephalitis: This is an infection in which the brain itself becomes inflamed. It is most often caused by a group of viruses and is sometimes spread through insect bites. 
  • Toxoplasmosis: This infection is caused by a parasite. Toxoplasmosis most often affects fetuses, young infants, and people with damaged immune systems.
  • Subdural abscess: Subdural abscess (empyema) refers to an area of the brain becoming abscessed or filled with pus, usually after another illness such as meningitis or a sinus infection. The infection can spread quickly, causing swelling and blocking other fluid from leaving the brain.
• Tumors: Growths in the brain can cause swelling in several ways. As a tumor develops, it can press against other areas of the brain. Tumors in some parts of the brain may block cerebrospinal fluid from flowing out of the brain. New blood vessels growing in and near the tumor can leak and also lead to swelling.
• High altitudes: Although researchers don’t know the exact causes, brain swelling is more likely to occur at altitudes above 4,900 feet. This type of brain edema is usually associated with severe acute mountain sickness (AMS) or high-altitude cerebral edema (HACE).

Symptoms of brain swelling vary, depending on the severity and the cause. Usually they begin suddenly. You may notice any of these symptoms:

• Headache
• Neck pain or stiffness
• Nausea or vomiting
• Dizziness
• Irregular breathing
• Vision loss or changes
• Memory loss
• Inability to walk
• Difficulty speaking
• Stupor
• Seizures
• Loss of consciousness

The steps used by your doctor to diagnose brain swelling depend on the symptoms and the suspected cause. Common exams and tests used in the diagnosis include:

• Head and neck exam
• Neurologic exam
• CT scan of the head to identify the extent and location of the swelling
• MRI of the head to identify the extent and location of the swelling
• Blood tests to check for causes of the swelling
• Lumbar puncture

Minor cases of brain swelling due to causes such as moderate altitude sickness or a slight concussion often resolve within a few days. In most cases, however, more treatment is needed quickly.

The goal is to assure that the brain receives enough blood and oxygen to remain healthy while the swelling is relieved and any underlying causes are treated. This may require a combination of medical and surgical treatments. Prompt treatment usually results in quicker and more complete recovery. Without it, some damage may remain.

Supportive care for brain edema may include any combination of the following:

• Hyperbaric oxygen therapy: Providing oxygen through a respirator or in a chamber helps make sure that the blood has enough oxygen in it.  
• IV fluids: Giving fluids and medicine through an IV can keep blood pressure from dropping too low. This helps to make sure that the body — including the brain — is receiving enough blood. However, some fluids can make swelling worse. Doctors attempt to use the right amounts of the right fluids in someone with brain swelling.
• Lowering body temperature (hypothermia): Lowering the temperature of the body and brain helps relieve swelling and allows the brain to heal. Hypothermia as a treatment for brain swelling is not widely used, however.
• Medication: In some cases of brain edema, your doctor may start a drug to help relieve the swelling. Medication may also be given for other reasons, such as to slow your body’s response to the swelling or to dissolve any clots. The drugs your doctor gives you depend on the cause and symptoms of brain swelling.
• Ventriculostomy: In this procedure, a surgeon cuts a small hole in the skull and inserts a plastic drain tube. Cerebrospinal fluid is drained from inside the brain, helping to relieve the pressure.
• Surgery: Surgery may have one or more of these goals:
  • Removing part of the skull to relieve intracranial pressure; this procedure is called decompressive craniectomy.
  • Removing or repairing the source of the swelling, such as repairing a damaged artery or vein or removing a growth

It’s common to have lingering effects from brain swelling. The problems you notice depend on the severity as well as the location of the injury. Symptoms may be noticed with any of the following:

• Sleeping
• Thinking and attention skills
• Headaches
• Depression
• Communication skills
• Movement
• Urinary incontinence 

Your health care team is available to help you deal with these challenges. While some problems may continue to diminish over time, others may require ongoing treatment.

To protect the brain, keep these tips in mind as you go about your daily activities:

• Use a helmet when biking, skating, playing contact sports, or performing other activities in which you might fall and hit your head.
• Wear seat belts properly when driving or riding in vehicles.
• Make sure you are doing all you can to control high blood pressure and heart disease.
• Avoid smoking.
• When traveling to high elevations, take your time — allow your body to adjust to the altitude.

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Every seventh person wakes up after sleep with a heavy head

Why do many people wake up with a heavy head, why do we experience drowsiness and how much sleep does a healthy person need? Scientists were able to better understand these issues, finding out along the way that at least one in seven people wakes up with a heavy head.

Summer seems to be over, endless rain has charged outside the window, the body wants to sleep terribly. Someone overcomes this state relatively easily, but

one in seven people, according to researchers from the Stanford University School of Medicine, suffers from pathological sleepiness.

Electric dreams on order

Scientists figured out how lucid dreams arise and were able to induce them artificially, with electric…

May 12 12:56

And on days like this it gets even stronger.

It is interesting that in English the expression sleep drunkenness is used to denote it. A person wakes up in the morning as if with a hangover: he has poor coordination of movements, with orientation in space, his thoughts are confused, and it is often impossible to remember what happened the day before.

In medical parlance, this is called “awakening confused.”

In general, the state of “heavy head” in the morning is familiar to many, but usually it passes quickly. For most people, “sleepy intoxication” lasts no more than five minutes, but for about a third of people it can last up to 15 minutes, write the authors of an article in the journal Neurology .

In a published study, scientists are trying to figure out whether this condition is a pathology, whether it is associated with some kind of mental disorders. They studied data from nearly 20,000 Americans, analyzing their lifestyle, sleep patterns, and physical and mental health.

Winter time in the spring session

The science department of Gazeta.Ru figured out how Russia will switch to winter time in the fall, and…

02 April 11:43

15.2% of the respondents, or one in seven, said that they experience “sleepy intoxication”. Almost 9% noted that they had a partial memory loss in the morning – amnesia. 70% of those suffering from “sleepy intoxication” said that they do not sleep well at all. This condition is more common in people who spend a lot of time in bed (nine hours or more).

In 37.4% of cases, in those experiencing “sleep intoxication”, doctors noted some kind of mental impairment.

And most often this condition affects people suffering from depression , bipolar disorder or experiencing panic attacks .

Experts admit that they were surprised by such a high frequency of “sleep intoxication”: every seventh is quite a lot. It is worth taking care, because a person in this state cannot fully control himself, be responsible for his actions and do his job. “Imagine a pilot or designer waking up in such a state of intoxication a few minutes before starting their work,” says Maurits Ohayon, the first author of the article. Without self-control, a person is also capable of spontaneous aggression. There is a known case when a man, awake, killed a friend who woke him up.

Increased drowsiness can have different manifestations. The condition of excessive sleep duration is called hypersomnia .

It can also occur in apparently healthy people as a reaction to a long lack of sleep or to stress, trauma.

Sleep for the whole world

On March 14, humanity celebrates the International Day of Sleep. Instead of getting enough sleep that day…

March 14 14:53

There is a hypothesis developed by the Russian neurophysiologist Vadim Rotenberg . According to this hypothesis, sleep in a state of stress plays a protective role (especially REM or REM sleep ), because at this time the brain solves a problem that it cannot solve in reality. This protects the body from the severe effects of stress.

Drowsiness depends on the season, on the light, and on the weather. In summer, with long daylight hours, at early sunrise, it is much easier for us to wake up than in winter, in the dark, or when it is cloudy and raining outside.

Light mode adjusts our biological clock, we need light to wake up.

“The human body is designed in such a way that it must wake up every morning after sunrise, not before. And when we pull back the curtain, our biological clock mechanism is restarted,” Vladimir Kovalzon, president of the Russian Society of Somnologists, explained to Gazeta. ru .

But there is also pathological hypersomnia, including narcolepsy , in which a person can fall asleep quite suddenly during the day, but usually sleeps poorly and does not get enough sleep at night. In severe cases, he may experience hallucinations. Since such a person can fall asleep even on the go, even while driving a car, narcolepsy is life-threatening, and it must be treated.

“Let’s live normally from autumn onwards”

“Gazeta.Ru” became aware of the details of the bill, according to which the eternal…

17 January 11:50

How much sleep does a person need? On this score, sleep medicine doctors do not have a definite answer, but most believe that a healthy adult needs seven to eight hours of sleep.

“Seven to eight hours of sleep is considered normal for an adult,” told a Gazeta.Ru correspondent somnologist, associate professor of the Moscow Medical Academy. Sechenov Mikhail Poluektov. – The most obvious consequences of lack of sleep are a decrease in attention, memory, and performance. Labor productivity is reduced by about half, the number of errors increases. It is estimated that the risk of getting into an accident in a sleepy person increases five times.

Although much depends on the individual characteristics of the organism: on genetics, temperament and psycho-physiological type of personality. Some people get five or six hours of sleep, although they are few. For others, eight hours is not enough. Chronic lack of sleep is a direct link to diabetes and cardiovascular disease, although scientists have shown that sleeping too much (more than nine hours a night) is also unhealthy as if sleeping too little (more than five hours).

why we only notice what we want – T&P

Everyone believes in their own objectivity. It seems to us that we are observant enough to find all the evidence against the theory we hold – and since this evidence is not enough, then the theory is correct. But what if the brain filters any – even visual – information in accordance with our beliefs? Can we remain impartial, or even our neuroscience contradicts this? Journalist Tom Vanderbilt discusses the paradoxes of perception in an article on the Nautil.

us website, while Theories and Practices translated the main points.

Palmer Field, Princeton, 1951. A traditional fall American football match: the undefeated Princeton Tigers, with their famous tailback Dick Kazmaier, against the Dartmouth team. In a shoot-out game, Princeton managed to defeat Big Green, but at a high cost: about a dozen players were injured, and Kazmaier himself ended the match with a broken nose and a concussion. As The New York Times put it mildly, it was “a rough game that led to recriminations from the two teams.” Each claimed that the opponents played dirty.

This story appeared not only in the pages of sports publications, but also in the Journal of Abnormal and Social Psychology. Shortly after this incident, psychologists Albert Hastorf and Hadley Cantril conducted a survey among students, showing them a video of the match. They had to decide which of the rivals started the dirty game. But the subjects’ opinions about the game of this or that team turned out to be incredibly biased, and the researchers came to an unexpected conclusion: “the data indicate that there is no separate phenomenon of” game “that exists outside the minds of specific people. ” Everyone saw the game they wanted to see. But how? Perhaps they were an example of what the father of cognitive dissonance, Leon Festinger, said: “People perceive and interpret information in such a way that it satisfies their own beliefs.”

When the students watched and analyzed the footage of the match, they behaved like children who saw the famous duck-rabbit illusion. If the picture was shown on Easter Sunday, children were more likely to see a rabbit, while on any other Sunday, most children saw a duck. The picture itself can be interpreted in two ways, and “switching” from one image to another requires effort.

In the experiment of Alison Gopnik and her colleagues, not a single child in the group of 3 to 5 years old could independently switch from one image to another (they were shown the “vase-face” illusion). In the group of older but still “naive” children, a third made the switch. Almost everyone else succeeded when they were hinted at the duality of the image. Interestingly, children who were able to recognize both images also did better on the “theory of mind” task, the ability to recognize the subjectivity of their perception in relation to the outside world (for example, children were shown a box of crayons, which actually contained candles, and then were asked to guess what another child would think of the contents of the box when they saw it).

Even if you yourself can’t see both the duck and the rabbit at first, don’t be discouraged: in any such study, adults “probably have more complex representational abilities” who are unable to “switch” are found. There is also no single correct interpretation of the image: although there is some tendency to see rabbits, duck people are also full.

Everyone can see a duck-rabbit at some point, but there is one thing no one can do: no matter how hard you try, you cannot see both the duck and the rabbit at the same time.

I asked Lisa Feldman Barrett, head of the Interdisciplinary Affective Science Laboratory at Northeastern University in Boston, if we live in some sort of metaphorical duck-rabbit world. Her answer was short: “Not even metaphorically, I think.” Our brain is designed in such a way that there are much more internal connections between neurons than those through which sensory information comes from outside. “The brain itself provides the necessary details to an incomplete picture,” she says, “in order to give concrete meaning to ambiguous sensory data.”

Lisa Feldman Barrett calls the brain a “jammer”. According to the increasingly popular “predictive coding” hypothesis, perceptions are generated by our own brains and only corrected by external information. Otherwise, it would have to process too much data. “It’s not rational,” she says, “the brain needs workarounds.” Therefore, he constantly predicts. When “incoming sensory information does not match the prediction, either the prediction or the information itself has to be changed.”

Scientists have long been interested in this relationship between external sensory information and internal beliefs and predictions. In a study published in Neuropsychologia, subjects were asked to decide whether a statement about the relationship between a color and an object (for example, “banana is yellow”) is true. At the same time, the same areas were activated in their brains as during normal color discrimination. For the brain, it made no difference whether its owner saw a real yellow color or thought of a yellow banana. Such “repeated perception” is similar to the mechanism of recollection (however, the researchers note “the different nature of the perception and reproduction of knowledge”).

Information from the outside world comes to us through a narrow window of perception and forms our beliefs. But then those beliefs act like a lens, focusing on what they need to see. Last year, at the New York University Psychology Lab, a group of people were shown a 45-second recording of a violent fight between a police officer and an unarmed person. It was not obvious whether the policeman behaved correctly in relation to the person he was trying to tie up. Before the screening, study participants were asked how much they identified with police officers in general. After watching, during which the movements of the subjects’ eyes were tracked, they had to decide which of the fighters was wrong. Naturally, the actions of the policeman were more severely condemned by those who were less disposed towards him initially. But this was only the case if they looked at him longer. The decision of those who looked at him less did not depend in any way on their initial attitude towards the policemen.

According to Emily Balsetis, head of the New York University Social Perception, Action, and Motivation Laboratory and co-author of the study, we tend to think that our preferences are shaped by conscious decisions. “But what thought processes precede these decisions?” Balsetis asks. “Mindfulness is simply what you allow your eyes to see.” In the case of the video of the policeman, “the movements of your eyes give rise to an entirely new understanding of the facts. ” Those who most severely condemned the policeman’s actions looked at him more often (and, as in the case of the duck-rabbit, probably could not see both him and the detainee at the same time). “If you don’t like someone,” Balsetis says. “You look at him more. You will always be on the lookout for someone who poses a potential threat.”

But what influences such an assessment of the situation? It’s hard to say for sure. In many studies, subjects have a characteristic neural response when they see a picture of a person of the same race as them. But what happens if we say that the people in the photographs are a kind of “team” to which the subject belongs? “In about the first 100 milliseconds, we solve the rabbit-duck problem,” says Jay Van Bayvel, professor of psychology at New York University. Who do you see – a member of your team or a person of a different race? Van Bavel’s study found positive neural activity in response to images of “team members” while racial characteristics become completely irrelevant (as in the case of the duck-rabbit, we are only capable of one interpretation at a particular point in time).

© Tim O’Brien

However, once we make a decision, we will stubbornly insist on it. Paying tribute to the duck-rabbit, Balsetis and colleagues conducted an experiment in which a group of people were shown images of “sea animals” and “livestock”. The subjects had to choose which of the two is shown in the picture: for each answer they either gained points or lost (note: some received points for “sea animals” and lost for “livestock”, others – vice versa). After finishing the game with a positive score, they received a package of marmalade as a reward. If the score was negative, they got “a can of liquid canned beans.” The decisive moment came at the end, when the subjects saw a vague image of either a horse or a seal (the seal was a little harder to see). In order not to choke on the ill-fated beans, they needed to recognize the image for which they would score points. And most succeeded. But what if they saw both images and reported only the one that should have brought them a win? The experiment was repeated with new participants, but this time their eye movements were tracked. Those who needed to find more “livestock” looked at the “livestock” button more often (after pressing it, the answer would be counted and they would move on to the next question), and vice versa. A glance at the “correct” (in their opinion) answer button betrayed their intentions without any calculations of brain activity. First of all, the choice was made by their vision.

Even if the experiment simulated a computer error and told the subjects, “I’m sorry, these ‘sea animals’ would actually save you from liquid beans,” the majority still insisted on their original interpretation of the image, even in light of the new motivation. “They are unable to look differently at an image already ingrained in their minds,” says Balsetis. – “because if you endow an ambiguous phenomenon with a specific meaning, it ceases to be ambiguous.”

A recent study by Kara Federmyer shows that something similar happens in the formation of memories. It dealt with the misconception about the political candidate agenda, as when most people believed that Michael Dukakis, not George W. Bush, was going to be an “educational president.” Studies of the brain activity of the subjects using EEG found that the signals of false and correct memories are almost the same. The personal version of what happened was so fixed in the minds of the subjects that it became true.

Such “fixation” can also occur unconsciously. In a study published in Pediatrics, more than 1,700 parents in the United States received brochures from one of four campaigns designed to demystify the dangers of the liquid measles vaccine. According to the results of the study, none of the campaigns had any effect on parents’ decision to get vaccinated. Yes, the original opponents of the vaccine were a little skeptical that it causes autism. But together they became even more convinced that it was impossible to do GI. Images of swollen and rash-covered children only reinforced parents’ belief in its dangerous side effects.

It is not yet clear how exactly this fixation occurs, and why a person can suddenly change his mind and switch from a duck to a rabbit. The debate about how switching occurs has been going on for a long time and continues to this day. One argument argues that this is a “bottom-up” process: the neurons that tell you that there is a duck in front of you get tired or “satiated”, giving way to new information about a rabbit.

Another possible mechanism – “top down” – suggests that the switch occurs in the higher parts of the brain: if we already know something, then we will expect and look for it in every possible way. If you tell a person not to try to switch, then he most likely will not do it – unlike a person who is asked to switch as quickly as possible.

Juergen Kormeier and colleagues at the Institute for Advanced Psychology and Mental Health Research in Freiburg, Germany, proposed a hybrid model that combines both mechanisms. As Kornmeier told me, even at a very early age, eye activity and visual systems influence “downward” processes, so information cannot be said to be one-sided. He suggests that even if we didn’t notice a duck or a rabbit, our brain subconsciously recognized both images, but considered one unreliable and did not tell us about it.