Tag: brain

Posted in Science & Nature

Chalkboard

Posted on by Jinavie

The sound of fingernails scratching a chalkboard is one of the most difficult sounds to listen to. This “screech” sound gives the sensation of your soul being ripped to shreds and invokes great discomfort. Why is this?

Professor Randolph Blake of Vanderbilt Center, USA, observed that this sound is very similar to the scream chimpanzees and macaque monkeys make when they see a predator. According to other researches on this phenomenon, many species of monkeys also hate this sound greatly. Blake used these facts to hypothesise that as our primitive ancestors used this sound to alert an enemy approaching, it has been programmed into our primitive brain to trigger a negative response. Also, physically this sound amplifies in our ears at a certain frequency to cause intense pain. The pain and our basic instincts combine to generate such an unpleasant feeling.

Posted in Psychology & Medicine

Time Perception

Posted on by Jinavie

What exactly is the present? The present is the middle point between the past and future, the world that we experience and perceive on a real-time basis. But would you believe it if the world you perceive is not the true “present”? To experience the world, we use our five senses. The brain collates all these sensory information and processes it to construct “the present”. This process takes about 80 milliseconds. Ergo, the world we experience is actually the world as it was 80 milliseconds ago. For a similar phenomenon, consider the stars. The stars we observe are not what they look like now, but what the stars looked liked when they emitted the light that we see. Thus, the star you are looking at may not even exist anymore.

But 80 milliseconds is a very short time; surely it has no impact on our everyday life? To prove that this delay has a critical impact on our understanding of cause and effect, neuroscientists designed the following experiment. The researchers would ask the participant to press a button that caused a light to blink after a short delay. After about ten tries, the participants reported that the delay had disappeared and the light flashed immediately after they pressed the button. This was due to their brain editing out the time delay and directly connecting the cause (button) and the effect (flash). But a much more peculiar phenomenon was seen when the researches removed the delay between the button press and the flash. Participants reported that they saw the light flash before they even pressed the button. The participant’s brain had become so used to the editing process that it was confusing the order of the cause and the effect.

The brain’s time-editing ability can be seen in the following simple experiment. If you touch your nose and toe at the same time, logic dictates that as the toe is further from your brain, the signal will have to travel further and it will be felt later. But in reality, you feel both at the exact same time. This is because your brain uses a map of the body to edit the relative time the signal takes to reach the brain to better construct a “real-time present”.

Posted in Psychology & Medicine

Pica

Posted on by Jinavie

Occasionally, there are news stories about a man who eats steel or a girl who likes to eat plastic. Such a condition where the person develops an appetite for a non-food substance is called pica. Pica is more common than one would think. The most common cases are those of dirt, clay and chalk, with the disorder being much more prevalent in children or pregnant women. Although pica is officially a mental disorder (possibly related to OCD), it is possible that it is a neurological mechanism to cure a certain mineral deficiency. For example, patients with coeliac diseases or hookworm infections tend to be iron-deficient and the substances they eat tend to contain iron. It is unclear how the brain knows what “food” to eat to cure a disease, but there are many cases where people subconsciously consume foods that would improve their health. According to a study, between 8% and 65% of people have had a sudden urge for a very strange appetite. However, as substances commonly involved in pica (such as dirt and ice) are solids, they can damage the oesophagus and the digestive tract. Also, they may contain toxic chemicals which can cause poisonings, making pica a potentially dangerous condition.

Posted in Psychology & Medicine

Pleasure Centre

Posted on by Jinavie

During the 1950’s when the field of neuroscience was making many research breakthroughs, a fascinating fact was discovered. Scientists had located the specific part of the brain responsible for feeling pleasure. In 1954, two Canadian neuroscientists named James Olds and Peter Milner were undertaking research to find the association between electrical stimulation of the brain and sensation in rodents. During their research, they found that if they stimulated a certain part of the brain, the rats would interpret the signal as pleasure. Based on this, they inserted electrodes into the rats’ limbic system (the part responsible for emotions) and connected it to a lever in the cage. Thus, they had devised a device that allowed the rat to feel pleasure by stimulating its own brain with the press of a lever. The results were astounding. The rat furiously pumped at the lever, forgetting to eat or sleep, until it ultimately died of exhaustion (over 26 hours, the rat pressed the lever 50,000 times).

Pleasure is not the same as happiness. Happiness awards us with satisfaction and contentment, but pleasure only brings greed, obsession and addiction. Pleasure was originally a mechanism devised to reward behaviour that aided survival (such as mating and eating), but addictive things like alcohol, smoking and drugs ruin your life and any chance at happiness instead of helping you survive.

The foolish run around to seek temporary pleasure while the wise seek permanent happiness.

Posted in Psychology & Medicine

Trepanation

Posted on by Jinavie

When and what was the first surgery performed by mankind? Many would believe it to be a simple procedure such as suturing a wound. But would you believe that the earliest surgical procedure was brain surgery in 6500BC? Surprisingly, this is true.

Archaeologists have found a large amount of skulls with a large, round hole in them. Some of the oldest skulls with holes were found in France, where 40 skulls from the Neolithic era were excavated. Archaeologists believed these holes to be from a battle leading to a dent in the skull. However, these holes were actually the results of a surgery (signs of bone recovery can be seen around the edges of the hole, suggesting the patients were alive for some time even after the operation). These skulls all belonged to trepanation patients.

Trepanation is the surgical opening of the skull by drilling a hole in it. This is an ancient surgery that can be found throughout history. Hippocrates and Galen from ancient Greece both recorded detailed instructions on trepanation, ancient Incans performed the surgery and it was also common during the Middle Ages and the Renaissance in Europe. These surgeries were most likely indicated for skull fractures where fragments were embedded in the brain. During the Middle Ages when it was better known that the brain was the seat of the soul, trepanation was used for psychiatric treatments too. For example, in 15th century Netherlands, trepanation was used to excise a so-called stone of madness that was supposedly the cause of insanity. Like this, it was believed that trepanation could release the demons and insanity trapped in the skull.

Although this operation sounds hilariously misled, it is still used in modern medicine. Of course, it is not known to treat insanity, but rather to treat brain bleeds. Extradural and subdural haemorrhages occur when a rupture of an artery in the brain causes a collection of blood in the skull, compressing the brain. This is a dangerous situation which can lead to a stroke or even death. One treatment of this condition is trepanation, or a burr hole, where a small hole is drilled in the skull to relieve the pressure, lowering intracranial pressure and stabilising the patient. Trepanation is an excellent example of how we can learn from the past and how medical knowledge from ancient times is sometimes still valid.

Posted in Psychology & Medicine

Lazarus

Posted on by Jinavie

In the New Testament of the Bible, there is a scene where Jesus resurrects a man by the name of Lazarus back four days after his death. This “miracle” is of course a fictitious event, but nonetheless, the name Lazarus has come to symbolise resurrection after death. For example, there are two actual medical conditions named after Lazarus, both related to death.

The first is called Lazarus phenomenon, where a person who is declared to be clinically dead spontaneously returns to life. This is an extremely rare event that has only been recorded in about 30 cases. In most of these cases, the patients had suffered a cardiac arrest, with all attempts at resuscitation (e.g. CPR, adrenaline) had failed. Sometime after the person was declared clinically dead (usually around 5~10 minutes), the person’s circulatory system would suddenly start on its own and the person would be “resurrected” (quite literally). In one case, a 61 year-old woman was declared officially dead after her heart stopped and her vitals did not return after continuous resuscitation. At the morgue, however, she was found to have a pulse and breathing on her own. She later sued the hospital for the neurological and physical injury caused by oxygen deprivation during her death. There is even a case report of a patient who returned to life two and a half hours after dying (although he died again 3 weeks later).

Of course, the Lazarus phenomenon is not a miracle. In most cases, it is hypothesised that when resuscitation is attempted then stopped, there is a rare chance of the relieving of pressure causing blood to fill the heart, causing a sudden expansion and kickstarting the electrical circuit. Other factors that may influence this is hyperkalaemia resulting from ischaemia and high doses of adrenaline given to the patient during resuscitation having a delayed effect.
Because of this rare “complication” of death, doctors are advised to observe the patient for about 10 minutes after declaring them dead. Just in case.

The second is called Lazarus sign and it occurs not in dead patients, but brain-dead patients. Brain-dead patients are immobile as their higher functions such as cognition and motor functions are destroyed. However, there are rare cases where the brainstem is somehow stimulated, triggering a reflex arc from the spinal cord. This reflex is seen as the patient suddenly raising their arms and dropping them on their chest in a crossed position, much like Egyptian mummies. As the spinal cord is not usually damaged in brain-dead patients, this reflex arc is possible, similar to a knee jerk reflex. The Lazarus sign should not be misinterpreted as a sign that a brain-dead patient is conscious, as it is an involuntary movement. However, it has been mistaken for the resuscitation of a patient, or in some cases, as a miracle.

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Posted in Psychology & Medicine

Doorway Amnesia

Posted on by Jinavie

Have you ever experienced the curious phenomenon where you walk into the kitchen and completely forget why you came there? Or why you stepped out of the house? Almost everyone is struck with this bizarre amnesia at some point in their lives. But why does it happen? Do Men in Black come in and wipe your memory because there was an alien in the room or something? The answer lies in the doors.

It has been scientifically proven that doorways have a magical property of causing memory loss. To be exact, doors do not cause amnesia, but the physical act of passing through a doorway causes the brain to lose memories. The reason for the phenomenon is this. The human brain stores information in a very unique way where it compartmentalises information by physical location. Because of this “filing system”, the thought “I really want cake from the kitchen” that you had in the living room is difficult to access when you are in the kitchen. By crossing a doorway, the brain recognises that the physical location has changed and opens a different “folder”, metaphorically speaking. This system allows for smooth mental functioning usually as it lessens the load on the brain, but also creates confusing situations where you just stand in front of the door, questioning whether you are losing your memory.

In an experiment in France, it was found that when students were told to memorise certain objects and then walk into another room, they had much worse recollection of the objects compared to the control group (students who walked the same distance but not through a door). It was even found that a person did not even have to physically walk through a door to lose their memory. When students were made to repeat the experiment in a virtual setting (i.e. moving a computer character through a door in a game), the same thing happened. The effect was so powerful that the researchers dubbed doorways event erasers.

Although it seems like an inconvenient system, the brain’s special way of compartmentalising information according to physical location can be used to harness the power of complete memory. This is done by using the method of loci, also called the memory palace. This is a mnemonic device first devised by ancient Romans to help memorise a large amount of information. To use the memory palace, you must first visualise a certain location – one that you are familiar enough with to recall with great detail. This may be your room, house, the street you live on, or even a fictional palace. The object of the memory palace is to convert a piece of information into an item which you can place in a certain location in the palace. For example, if you have to memorise a shopping list, you can conjure a mental shelf in your mental palace and put all the items in the shelf. To enhance this effect, make the image as bizarre and fancy as possible, as the mind is prone to remembering weird things more (e.g. a massive apple with eyes and a mouth is more memorable than a normal apple). Once your memory palace is complete, you can take a “mental walk” through the palace, go to the room where the memory you need is stored, and just browse the contents to recall the information. With practice and a vivid imagination, this is an infallible method of remembering anything you want, for as long as you want.

Posted in Psychology & Medicine

Hanging

Posted on by Jinavie

Hanging is one of the most popular methods of execution and suicide throughout the ages. It is typically performed by fashioning a noose (most commonly with the eponymous hangman’s knot), placing it around the victim’s (or own) neck. The person then falls from a short height (e.g. dropped from a stand or stepping off a stool), upon which the force of the body pulling down causes the noose to tighten. This can kill a person via two ways. Firstly, if the force of the drop and the knot is strong enough, the sheer force of the noose tightening and the person being suspended by their neck will cause their neck to break. This causes spinal cord injury at the cervical level, where the brainstem lies. When the brainstem is damaged, the person loses control of autonomic processes such as breathing, causing instant death. Secondly, if the neck does not break, the person will be strangulated by the noose. This will kill the person through either choking (from airway obstruction) or brain ischaemia (as the carotid arteries are cut off). Pressure on the carotid artery may also cause something called a carotid reflex, where powerful nervous signals cause the heart to beat so slowly that it stops.

It is said that whether a person dies a quick, clean death via neck fracture or a slow, painful death via strangulation depends on how good the knot is. A hangman’s knot is made up of a loop with a series of coils above it. The more coils there are, the more friction it adds to the knot, making the noose harder to pull closed. A true hangman’s knot is defined as thirteen coils, which provides enough resistance to cause a neck fracture when a person falls. If there are fewer knots than that, the knot will tighten too quickly around the neck and not provide enough resistance to cause a neck fracture. This leads to strangulation, which is far more excruciating and a very inhumane way to die. If there are too many knots, there will be too much resistance and there is a risk of decapitation, leading to a very messy situation.

In forensic medicine, there are certain signs that reveal a victim was hung. For example, the C2 spine (second vertebrae in the neck) will exhibit a hangman’s fracture, where there is fractures on both sides. Fracture of the hyoid bone (a small bone below the chin) is also a classic sign of hanging. There will also be bruises along where the noose was and every sphincter would be open (which leads to immediate voiding of the bowels and bladder at the time of death). If the person died of strangulation rather than neck fracture, they will show signs of asphyxiation, such as blue lips (cyanosis). Another interesting result of hanging is something called a death erection. As the name suggests, it is when a corpse is found with an erection, most likely due to hanging. This is probably caused by the noose crushing the cerebellum, causing a reflex erection. The same phenomenon has been observed in women as well.

Posted in Life & Happiness

Yellow Ball

Posted on by Jinavie

If I was to put a yellow ball in front of you and ask what colour the ball is, you would confidently say “yellow”. As you say, the ball appears yellow, but the answer is technically wrong. Strictly speaking, the ball itself is not yellow – it is merely reflecting the colour yellow. The ball only appears yellow because we see the yellow part of the natural light spectrum bouncing off the ball. We cannot say that the essence of the ball is “yellow”. For example, if you were to look at the ball through a red lens, the yellow light would be filtered and you would see a black ball. A person with a certain kind of colour blindness would say the ball has a bluish hue. A butterfly, which sees the ultraviolet spectrum as well, would see a colour we cannot even name.

Human beings judge objects using the vision. We describe an object as we see it and store that information in our brain to define the object. For this purpose, the fact that a colour blind person or a butterfly sees the ball a different colour is irrelevant to us. All we need to know is that object appears yellow to us. But this is only the case for objects. Let us imagine the ball is a person. If everyone in the world sees you as a yellow ball, would that make you a yellow ball? Of course not. However, people worry too much about how others see them. Although other people’s perception does not change our true nature in the slightest, we even go as far as erasing or abandoning our nature to look good in front of another person. Thus, whether our essence is white, black, red, blue or technicolour, when others see us as yellow, we have a tendency to try desperately to become yellow. 

If the world says you are a yellow ball, act crazy and be a red ball. There is not a single reason you should have to hide your true nature. Have confidence in your essence. There is nothing wrong with that.

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Posted in Psychology & Medicine

Reaction

Posted on by Jinavie

If you were walking along the street and found a bird lying on the ground, how would you react? You would probably poke the bird to see if it is alive. We have a peculiar habit since we are children of poking living things that we see for the first time. Through poking, we discover whether it is alive or dead, soft or hard, slimy or furry, docile or aggressive.

Prompting a reaction and observing the reaction is a surprisingly useful way of learning. In chemistry, we react an unknown substance with other chemicals to discover its identity. In medicine, we stimulate parts of the brain with electricity to discover what each part does. In physics, we build giant accelerator to crash particles together to find out their constituents and properties. If you fell into a cave so dark you cannot see even one foot ahead of you, the best way to find out if there is a wall or a hole or water ahead of you is throwing a rock in that direction.

This principle can be applied to psychology. To learn how people around you behave, provoke them. Human beings are extremely sensitive to stimuli and even when they consciously try to hide it, they will subconsciously react. If you keep (subtly) poking the person, you will soon be able to predict how they will react to something, what actions they will take, and you may even discover what is on their mind.

We cannot see the wind, but we can infer that it exists because the leaves blow. The best way to prove something that you cannot see inducing and looking for reactions.