Tag: brain

Posted in Psychology & Medicine

Hypnagogia

Posted on by Jinavie

Every person has had the experience of having a few seconds of brilliance just before their consciousness slips into sleep. During this short moment, we have some of the most creative and innovative ideas. Unfortunately, this is all lost by the time we wake up. This state is known as the hypnagogic state and has been well known since ancient Greece. Many philosophers and writers such as Aristotle and Edgar Allan Poe have written on the subject and how they received some of their greatest ideas in this state. 

Recent researches show that during hypnagogia, thought processes and cognition vastly differs to normal wakefulness. It appears that hypnagogic cognition is more based on the subconscious mind, with people in this state being more open to suggestion (e.g. hypnosis). Ideas seem to flow in a fluid yet illogical way and they are based on external stimuli, thus explaining the heightened suggestibility as the brain incorporates the surrounding into its thought process. The thought process is also less restricted, leading to openness and sensitivity. A process called autosymbolism occurs where abstract ideas that we are thinking are converted into concrete images. This explains the artistic inspiration seen in hypnagogia.

One of the more pronounced phenomena of hypnagogia is insight. It has been noted by many people throughout history that the moment before sleep is when we have the best ideas. For example, a chemist called August Kekulé realised that benzene was a ring structure after seeing an image of snakes biting each other’s tails to form a ring. Because of this, many famous artists and inventors tried to harness the power of hypnagogia through techniques such as the Dalí nap. Thomas Edison, Isaac Newton, Beethoven and Richard Wagner also practised similar techniques to gain insight into a problem that they were trying to solve or bring fresh ideas.

Another fascinating side of hypnagogia is the strange sensory phenomena associated with it. As in the case of sleep paralysis (which usually occurs in hypnapomp – the state between sleep and waking up), people often report strong hallucinations in the form of bright colours, geometric shapes, or even nightmarish visions (such as a ghost sitting on your chest). Other senses are affected as well, such as hearing whispering (commonly associated with the nightmarish hallucinations mentioned above) or out-of-body experiences. Hypnic jerks are also common, where the person jerks awake just before drifting off to sleep. This is thought to be caused by the brain misinterpreting sleep as “death” or the body shutting down, leading it to jolt the system back to life. 

Finally, an interesting psychological phenomenon is the Tetris effect, where people who have spent a prolonged time on one activity cannot stop seeing images and thinking about that activity in the hypnagogic state. This was seen in people who had played too much Tetris seeing coloured bricks before they went to sleep. Other common versions of the Tetris effect include chess boards and pieces, feeling waves after being at sea and seeing words and numbers after working on documents for a long time.

The combination of insight, creativity and sensory illusions leads to hypnagogia causing strange “experiences”. Ergo, hypnagogia is now thought to explain many supernatural experiences such as ghost sightings, UFO abductions, premonitions and visions.

Posted in Psychology & Medicine

Phantom Limb Pain

Posted on by Jinavie

In up to 80% cases of amputations, a strange phenomenon occurs where the amputee reports sensation or even severe pain where the limb has been amputated. It was noticed in field hospitals during wars when a soldier would wake up and ask someone to scratch his leg – which was no longer attached to his body. The sensation can be so powerful that victims actively believe that their phantom limb can interact with real objects. For example, there have been case reports of patients trying to pick up a cup with an amputated arm and becoming frustrated with their inability to.

Phantom limb pain may persist even after the amputee realises the limb is no longer there. The basis for phantom limb pain is a neurological system called the cortical homunculus. The cortical homunculus is a concept that the part of the brain responsible for sensation and movement is mapped out so that each part corresponds to a part of the body (see picture). For example, the top of the primary somatosensory and motor cortices (said parts of the brain) is responsible for foot sensation and movement while the side receives information from and sends signals to the face. It lets the brain construct an image of what the body looks like from sensory information it collates from various body parts. It is suggested that phantom limb pain is caused by a remapping of the cortical homunculus, fooling the brain to think that the limb is there even if it has been physically cut off. This also explains a similar condition called supernumerary phantom limb, where the brain believes there is an extra limb (e.g. a third arm).

As the homunculus concept is a recent idea, treatment options had not advanced much until the late 1990s. In 1998, a neuroscientist called Dr. Vilayanur S. Ramachandran devised a method called the mirror box treatment. He noticed that victims of phantom limb pain (PLP) had paralysis or pain in the limb just before the amputation (such as tightly gripping something before the arm got blown up by a mine), suggesting that PLP may be a form of learned paralysis. This means that the brain believes that the arm is still paralysed and any movement causes an uncomfortable sensation as the brain thinks the limb is contorted into a painful position. To fix this problem, Dr. Ramachandran invented a box with two holes, each going into a separate compartment. One compartment is for the good arm while the other has a mirror positioned on an angle to reflect the other arm (instead of seeing the stub they put in the hole). He would then instruct the patient to perform symmetric movements with both hands while looking at the reflected arm. For example, he would tell the patient to squeeze their “fists” tightly as possible and then let go. Through this procedure, the brain is retrained to let go of the perceived paralysis and pain as it is tricked in to thinking that the arm is healthy again. The mirror box therapy drastically improved the outcome and quality of life of PLP patients through the power of illusions.

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Posted in Psychology & Medicine

Alien Hand Syndrome

Posted on by Jinavie

There is a very rare, disturbing and interesting medical condition called alien hand syndrome (AHS). An individual with this neurological disorder has full sensation in the rogue hand, but is unable to control its movements and does not feel that it is a part of their body. The hand becomes personified, as if it has a will of its own, and its owner will usually deny ownership of the limb.

Though AHS was first identified in 1908, it was not clearly defined until 1972. Depending on the cause of the injury, the movements may be random or purposeful, and may affect the dominant or non-dominant hand. The symptoms are brought on by an injury to the brain, such as head trauma, stroke, tumour, or infection. It can also be a side effect of a certain kind of brain surgery where the patient has the two hemispheres of the brain separated to relieve severe epilepsy.

If the AHS is caused by separation of the corpus callosum (the area of the brain that connects the two halves of the brain) by surgery or injury, the movements are usually complex purposeful behaviour, such as compulsive manipulation of tools, undoing buttons, or tearing clothes. For example, a right-handed person is left-hemisphere-dominant, thus their left hand (controlled by the right hemisphere) will become “alien”. Sometimes the sufferer is completely unaware of what the hand is doing until it is brought to his or her attention, or until they happen to see it themselves. 

Strangely, many of the alien hand’s actions are the complete opposite of what the person is doing with the other hand. For example, if they start packing a suitcase, the alien hand will unpack it. It is believed that one half of the brain (usually the right brain) is unaware of why the other hand is doing something (due to the lack of connection between the two hemispheres) and so proceeds to “correct” it. There are also reports of the alien hand attacking the patient by hitting them or even trying to strangle them in their sleep. 

There is currently no treatment for alien hand syndrome, but the symptoms can often be relieved by giving the rogue hand an object to manipulate, to keep it occupied. One patient whose alien hand had a compulsion of holding on to door handles or other objects to stop the man from walking was given a cane. The alien hand would grab on to the cane and not interfere with the patient’s walking.

There is currently no treatment for alien hand syndrome, but the symptoms can often be relieved by giving the rogue hand an object to manipulate to keep it occupied. One patient whose alien hand had a compulsion of holding on to door handles or other objects to stop the man from walking was given a cane. The alien hand would grab on to the cane and not interfere with the patient’s walking.

Although it is a distressing condition, some patients learn to live with the disease. For instance, when one patient’s alien hand kept throwing away the cigarette her dominant hand put in her mouth, she shrugged and said: “I guess ‘he’ doesn’t want me to smoke that”. Perhaps the alien hand is simply a way for the subconscious mind to physically act on the conscious mind.

Posted in Psychology & Medicine

Kuru

Posted on by Jinavie

European explorers who visited the island of Papua New Guinea in the 1950’s noticed that the Fore tribe suffered from a strange disease. The patient would initially have headaches, joint pains and tremors. They then show signs of weakness and are unable to stand.  The shaking of limbs, a classic symptom of the disease, becomes progressively worse as the disease progresses (“kuru” is a Fore word for “to shake”). In the late stages, the patient shows other neurological symptoms such as uncontrollable laughter and emotional instability. By this point, their tremors and ataxia (lack of coordination) is so severe that they cannot sit without support. They may also suffer from inability to speak or swallow, become unresponsive to their surroundings, develop ulcers on the skin and become incontinent (cannot hold urine/faeces). Within 3 months to 2 years after the symptoms develop, the patient dies.

Kuru is exclusive to the Fore tribe and medical researchers were puzzled by the nature of this disease. It is incurable and takes more than 10 years to develop (from the time of infection). In 1961, Dr Michael Alpers discovered that kuru was spread due to a certain cultural behaviour within the tribe – cannibalism. The Fore tribe had a tradition of eating the corpse of a deceased tribe member at the funeral as to return their life force back in to the tribe. Of course, this involved the consumption of the brain as well.

It was discovered that kuru is caused by a strange pathogen known as a prion. Prions are misfolded pieces of proteins that cause disease by converting the body’s proteins into “wrong” proteins. These new prions then convert more proteins until the body is filled with deposits of such proteins. Prions mainly affect the brain and cause spongiform encephalopathy – meaning that the brain becomes sponge-like and full of holes. The most famous example of prion disease is mad cow disease.

After colonists took over Papua New Guinea, cannibalism was banned and kuru faded away. This was proof that cannibalism was what spread the prion from one victim to another. It was also discovered that women and children had a higher incidence as men would have priority in choosing what part of the body to eat first. As with lions, the men always chose muscles first and women and children would often finish the organs such as the brain. As prions are indestructible, it cannot be treated, cured or prevented (other than not eating brains). It also means that it transmits perfectly from a dead patient to an unsuspecting victim who is feasting on the infected brain.

A disease that causes the brain to disintegrate, causing limb shaking and inability to walk, spread by the ingestion of brains. Is it possible that zombies are caused by eating brains and not the other way around?

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Posted in Psychology & Medicine

Egg Of Columbus

Posted on by Jinavie

After returning to Spain after his discovery of the New World, Christopher Columbus was dining with some nobles. One noble approached him and said:

“Even if you had not discovered the West Indies, another fine Spaniard would have gone to discover it anyway.”

Columbus did not respond and merely smiled. He then asked for an egg, which he placed on the table and asked:

“I bet that no one can make this egg stand by itself.”

All the nobles tried but were unsuccessful and the egg would continue to fall down. Columbus stepped forward and grabbed the egg, which he tapped on the table so that one end would be cracked and flattened. The egg would now stand on its flattened base.
Although the nobles initially complained that they knew that was the solution, the message was loud and clear: once the feat is done, everyone knows how to do it.

This is known in psychology as the historian’s fallacy – a logical fallacy that can be summarised in the words: “I told you so”. Essentially, people assume that people had the same information in the past or that they would not have made the same mistake if they were placed in such a situation. It is another example of cognitive dissonance where the brain finds conflict between a problem and information that could have prevented said problem (which the other person did not have at the time). Therefore, the brain immediately convinces itself that it would have made the right decision as it already knows the answer. This means that we are almost incapable of putting ourselves in other people’s shoes. We label those people as idiots, because they apparently had the same information (they did not) and still could not make the right decision.

People never realise that given the foreknowledge we have now, the Americans would have known about Japan’s plan for attacking Pearl Harbour or that Germany would not have invaded Russia. Although they say “those who cannot remember the past are condemned to repeat it”, we have a tendency to think that people in the past were stupid and we would never make the same mistakes.

Hindsight is 20/20.

Posted in Science & Nature

Murphy’s Law

Posted on by Jinavie

In 1947, an aerospace engineer named Edward A. Murphy Jr was involved in high-speed rocket sled experiments led by the US Air Force. The aim of the experiment was to research the effect of sudden deceleration on the human body so to improve the safety of jet fighter pilots. To study this, a flight surgeon named Dr John Stapp devised a “sled” attached to a rocket that could be used on a long track. The rocket would propel the sled to a massive speed and brakes would induce as sudden deceleration. However, they found that the machines that were used to measure the G-force (force of deceleration relative to the force of gravity) were unreliable. Murphy proposed that they use electronic strain gauges attached to the harness of the test subject to measure the G-force, something he learned while working with centrifuges.

The idea was great but there was one problem: the gear kept failing, showing no reading whatsoever. Murphy soon found that the sensors were attached correctly but were wired backwards. This simple mistake frustrated Murphy, who blamed the incompetency of his assistant, stating that “if that guy has any way of making a mistake, he will.” This became the famous Murphy’s law, now simplified to “Anything that can go wrong will go wrong”.

Murphy’s law actually played a fundamental role in defensive design, where the worst-case scenario is always assumed and prepared for. Thanks to this system, the rocket sled experiment was successful and in 1954 Dr Stapp became the fastest man in the world – travelling at a speed of 1011km per hour and decelerating at a force of 46G (it was hypothesised that a human being could not survive past 18G). Not only did he survive (albeit with broken limbs, ribs, hernias, detached retina and temporary blindness), Dr Stapp went to build bigger rockets to further test the limits of the human body.

Interestingly, there’s another side to the Murphy’s law involving psychology. People suffer from a fallacy called appeal to probability, where they believe that because there is a possibility of something can happen, it will happen. The brain is surprisingly inefficient in dealing with probabilities and has a tendency to ignore that there is a relatively miniscule possibility and instead focuses on the absolute fact that there “is” a probability. This is the best explanation for why people are compelled to buy lottery tickets and why every student believes they will grow up to be rich and successful. 

Posted in Psychology & Medicine

Korsakoff’s Syndrome

Posted on by Jinavie

It is a well-known fact that excessive drinking leads to a so-called “blackout”. This form of memory loss is common in normal people and cannot be seen as a major illness. However, there is another disease that can be caused by excessive drinking called Korsakoff’s syndrome. Strictly speaking, this is not caused by alcohol but due to a thiamine (vitamin B1) deficiency and is commonly found in alcoholics and malnourished patients (it has also been reported to be caused by mercury poisoning and after centipede bites in Japan).

The six characteristic symptoms of this syndrome are: anterograde (cannot form new memories) and retrograde (cannot remember old memories) amnesia, confabulation, lack of detail in conversation, lack of insight and apathy.

Korsakoff’s syndrome patients show a very peculiar behaviour. As stated before they suffer from both anterograde and retrograde amnesia so not only can they not remember the past but they cannot make new memories either. Ergo, the brain uses information from its surroundings and attempts to recreate the lost memories, the result being confabulation. Confabulation is essentially what happens when the brain tries to fill in blanks in memories with false information. Confabulation is seen in everyday life too with healthy people but in the case of Korsakoff’s patients the effects are significantly more profound. For example, if you ask a patient what she did yesterday, she may look at your horse-print tie and claim she was horse-riding. If you ask the same question an hour later without your tie and instead holding a book with a photo of a Ferris wheel on the cover, she’ll state that she was at the amusement park. As one of the leading causes of amnesia and confabulation, Korsakoff’s should be suspected in any alcoholic or very underweight patient who keeps changing their stories around. 

As previously explained, the disease is caused by thiamine deficiency – therefore, the treatment is administering thiamine. But if the syndrome has persisted for a long time, the brain injury may be permanent. Also, treating the underlying alcoholism and malnutrition is important. 

If the thiamine deficiency is prolonged, it may lead to another disease called Wernicke’s encephalopathy. This is known as Wernicke-Korsakoff’s syndrome and in addition to the above symptoms, the patient may also experience confusion, tremors, nystagmus, paralysis of eye muscles, ataxia, coma and can eventually lead to death. All because of a deficiency of a single vitamin.

Who said nutrition is not important?

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(NB: Dory from Finding Nemo is one of the most accurate portrayals of amnesia in films)

Posted in Psychology & Medicine

Gait

Posted on by Jinavie

In medicine, a person’s way of walking is termed gait. By analysing a person’s gait, a trained professional can gain insight into what pathologies the person may be suffering from. For example, just from the way the patient limps, the doctor may discover that the patient has an incurable degenerative brain disease.

The most common gait abnormality is the antalgic gait, or limping due to pain. Most people would have experienced the difficulty of walking with a sprained or broken ankle, muscle ache or knee problems. This is easy to spot as the patient quickly switches to the other feet when leaning on the affected leg due to the pain. Therefore, the side that stays on the ground less than the other is the affected leg.

Sometimes, you can see a person “waddling” along as they swing from one side to the other. This may be a waddling gait, also known as Trendelenburg’s gait, caused by a weakness in the hip muscles that support the pelvic girdle, either due to muscle or nerve damage. As the patient cannot support their weight on the affected side, their pelvis tilts towards the opposite side. To avoid falling over, the patient lurches their body towards the other side, causing them to waddle. Looking at the tilt and lurch gives insight into what side is affected.
Another rather common gait is the steppage gait, where the person lifts one leg higher than the other, while their foot drags on the ground. This is caused by nerve damage leading to the loss of ability to lift the foot up (termed foot drop).

As the brain controls the motor system, damage to the brain also leads to motor dysfunction. A common example is a stroke.
If the stroke damages a significant part of the motor cortex, the patient suffers from hemiparesis/hemiplegia, or weakness/paralysis of one half of the body. This causes the limbs on the affected side to stiffen, as seen by an extended leg pointing inwards and retracted arm. The patient has to swing the affected leg around while they walk as they cannot flex the hip, known as a hemiplegic gait.
If the cerebellum is damaged, balancing becomes an issue. This causes the patient to suffer from ataxia, where they cannot coordinate their movements and are prone to toppling over. These patients tend to sway violently from side to side as they try to walk in a straight line.

Lastly, degenerative brain diseases can also affect gait. There are two main examples.
In Parkinson’s disease, the patient suffers from what is called hypokinesia and bradykinesia – reduced and slow movement. This leads to a shuffling gait where the patient walks slowly by shuffling their feet in small steps. They are also stooped over and are often seen with a pill-rolling tremor of their hands – a cardinal symptom of the disease.
In Huntington’s chorea, the opposite (hyperkinesia) occurs. This causes flailing as the muscles contract in an uncoordinated manner, including both the arms and legs. Ergo, their gait is quite jerky and interrupted by bouts of flailing, termed choreiform gait, but their balance is fine so walking in a straight line is still possible.

Knowledge of these disorders may help one appreciate the suffering a patient walking along the street has to undergo everyday of their life.

(Video demonstrations: http://stanford25.wordpress.com/gait-abnormalities/)

Posted in Psychology & Medicine

Locked-in Syndrome

Posted on by Jinavie

Imagine that one day, you wake up, but then no matter how hard you try, you cannot move a single part of your body. Trying to roll out of bed, lifting your arm, or even moving your fingers is impossible. You think it is merely sleep paralysis, but you soon realise that it is not as simple as that, or even a dream. No voice escapes your throat.
The only thing you can do is blink and roll your eyes around.

Welcome to the world of Locked-in Syndrome (LIS), a neurological condition where your brain has no connection to all the muscles in your body. The actual symptoms list is: quadriplegia, paralysis of most facial muscles, inability to speak, with complete preservation of cognitive function (sometimes sensation too). In simpler terms, a LIS patient’s mind is essentially trapped inside an unmoving body, with only the senses and eyes to interact with the real world.

It is caused by damage to a part of the brainstem known as the pons, which not only carries motor nerve fibres to the spinal cord (where it then carries on to supply the muscles of the body), but is also the origin of some cranial nerves. This explains the symptoms of paralysis, even the face (e.g. damage to the facial nerve, or CN VII). More specifically, the damage only affects the pons and not the brain itself, meaning that cognition (thinking), intelligence, memory and sensation (if the fibres are spared in the brainstem) are completely functional.
This can be caused by trauma, stroke, drugs, degenerative neuropathies, or anything that can selectively damage the pons.

Due to the nature of the disease, there are no treatment or cures for LIS. Prognosis is very poor and most patients are not expected to regain motor control. This can be very distressing news to LIS patients, as it essentially means that they will be trapped in a motionless, voiceless body for the rest of their natural lives, which could feel like eternity. Although over 90% of the patients die within 4 months, some continue to survive for much longer periods. To improve their quality of life, methods have been developed to allow the patients to communicate, such as Morse code (by blinking eyes) or alphabet boards. Technology is allowing even better options such as eye-tracking and brain-computer interfaces, where a machine tries to interpret a pattern in brain activity, trying to relate a certain action to a pattern. This may allow simple communication such as yes/no answers.

Because of the almost complete paralysis, even professional neurologists often miss this condition, diagnosing the patient as being in a vegetative state.
What would it be like to be trapped in your own body – or “living corpse” as described by Alexandre Dumas in The Count of Monte Cristo – and not be able to tell others that you were still in there?

Posted in Psychology & Medicine

Brain Freeze

Posted on by Jinavie

When you quickly eat or drink something cold, you experience a sudden onset of a painful headache. This is commonly known as brain freeze, or medically, a sphenopalatine ganglioneuralgia.

Although the cause is not perfectly understood, it is believed to be due to the coldness on the palate (roof of mouth) causing a sudden cooling and rewarming of the sinus capillaries, which causes them to suddenly constrict and then rapidly dilate. Dilation of blood vessels in this area causes pain due to receptors in the vessels. This phenomenon is similar to the cause of a flushed face when exposed to cold wind, and why it sometimes causes headaches.

The only way to prevent a brain freeze is to slowly let the mouth get used to the cold, warming the food or beverage in the mouth instead of quickly swallowing it. Warming the palate with your tongue is another effective way to shorten the duration of a brain freeze.