Innholdsfortegnelse for Understanding The Brain i Understanding The Brain

There’s a catchy quote about the brain that goes something like, “If the human brain were so simple that we could understand it, we would be so simple that we couldn’t.” Though the quote’s origin has been attributed to a variety of clever people over the years, it still rings true today: our brains are vastly complicated organs that even the brainiest experts in their feld struggle to comprehend. In this book, we look at everything from the brain’s physical structure and biochemical functions, to human and animal psychology, our emotions, dreams, and more. Enjoy!…

1 Frontal lobe Primarily controls senses such as taste, hearing, and smell. Association areas might help us determine language and the tone of someone’s voice. 2 Parietal lobe Where the brain senses touch and anything that interacts with the surface of the skin, makes us aware of the feelings of our body and where we are in space. 3 Temporal lobe What distinguishes the human brain – the ability to process and interpret what other parts of the brain are hearing, sensing, or tasting and determine a response. 4 Prefrontal cortex Executive functions such as complex planning, memorising, social and verbal skills, and anything that requires advanced thinking and interactions. In adults, helps us determine whether an action makes sense or is dangerous.…

TrackVis is a free program used by neurologists to see a map of the brain that shows the fibre connections. On every brain, these neural pathways help connect one part of the brain to another so that a feeling you experience in one part of the brain can be transmitted and processed by another part of the brain (one that may decide the touch is harmful or pleasant). TrackVis uses fMRI readings on actual patients to generate the colourful and eye-catching images. To construct the maps, the program can take several hours to determine exactly how the fibres are positioning in the brain.…

1 Prioritise practice Practise your new sport or skill in regular and short training sessions. The more your brain is exposed to muscle patterns, the quicker it will remember and master them. 2 Avoid bad habits Muscle memory can arise in any movement. Make sure you don’t pick up bad habits or your brain will hold onto these and you will naturally use these techniques. 3 Skill breakdown Different skills can involve a series of complex movements. Focus on each element of the movement first to make them easier to combine correctly. 4 Switch up the environment When training in the same place or environment, you can limit your muscle memory. To make sure your muscles are firing correctly in different scenarios, don’t make every practice session identical. 5 Take…

While several degenerative disorders primarily or exclusively impact the central nervous system, there are a collection of diseases that impact the peripheral nervous system, called peripheral neuropathies. As the impacted region is the peripheral nervous system, it leads to a loss of sensation and regulatory control of extremities. These include a loss of coordination, feeling in fingers and toes and a lack of balance. The causes are yet to be fully made clear, but scientists have determined diabetes, which causes protracted periods of high blood sugar, as one of the primary causes.…

Damage to our tissues causes mechanical and chemical changes that activate pain-sensing neurons. The neurons send signals to the spinal cord, which relays them to the brain. Painkillers try to block this process by interfering with it at different stages. The most common over-the-counter painkillers attack the very start of the pain-sensing chain. Non-steroidal anti-inflammatory drugs (NSAIDs) – like ibuprofen – try to remove some of the chemical signals that activate pain-sensing neurons. They do this by interfering with an enzyme called cyclooxygenase (COX). COX makes chemical messengers called prostaglandins, which promote inflammation. Blocking COX dampens the inflammatory response, relieving the pain. The next step in the pathway is the transmission of pain signals towards the spinal cord. Local anaesthetics work here. For nerve cells to fire they need to…

1 C-fibre When the skin senses touch, pressure and vibration, signals travel along large, slow, insulated nerve fibres. 2 A-beta fibre When the skin detects damage, signals travel along thin, fast, uninsulated nerve fibres. 3 Pain reduction When the touch-sensitive nerve fibres are active, fewer pain signals get through the gate. 4 Inhibitory interneuron A nerve cell sits between the two fibres, listening for signals and deciding which can pass through. 5 Pain gate The two types of signal compete to pass through the ‘gate’ into the spinal cord. 6 Sensory overload The gate gives preference to the larger A-beta fibres, allowing non-painful touch signals through.…

There are over 7,000 languages used across the world, and within each of these languages there are many different dialects and accents. But how did people develop such different ways of speaking, and how do our bodies learn to produce and maintain the same sounds? An accent is a specific way a person enunciates and pronounces words in a language. While different dialects range in their unique vocabulary and grammar rules, accents are the different sounds that can be made when using the same vocabulary and grammar. New accents emerge when groups of people develop their own identities and are based on two main factors: human nature and isolation. Human nature involves people’s tendency, especially historically, to form groups and remain within those groups for long periods of time. The…

For some people, moving to another country or region can cause their accent to change, but most of the sounds from your original accent are likely to remain permanent from around the age of 12. This is due to changes in brain plasticity. This is your brain’s ability to adapt, modifying connections in the brain in response to the environment. When you’re born, your brain has the ability to develop any accent it’s exposed to. But as you age, your brain becomes less flexible. You will keep your primary accent and won’t pick up another language as easily – even when learning a second language and spending significant time using a new accent, you won’t completely lose your original one. The purpose of brain plasticity is to stabilise new information…

In 2015, a team of neurologists and radiologists from Jinan Hospital in Shandong Province, China, wrote to the journal Brain reporting a rare and unusual finding. A 24-year-old female patient had been admitted with symptoms of nausea and vomiting. These were new symptoms, but she’d also suffered from dizziness and walking difficulties for most of her life. Despite these challenges, she was married and had enjoyed a successful pregnancy. The doctors referred her for computer tomography (CT) and magnetic resonance imaging (MRI) scans to search her brain for a cause of these symptoms. What they observed was a disorder so rare that less than ten people throughout the world were known to be living with it. The patient was completely missing her cerebellum. Known as the ‘little brain’, the cerebellum…

LETHOLOGICA In the middle of a conversation, our sentence stalls. We stop talking and search our brain for a word that isn’t there. This is lethologica, when a word is at the tip of your tongue. We know what we want to say and know there’s a word that fits, but we can’t recall it because our memory has faltered. This is thought to happen more often with words that we don’t use, because we haven’t built strong recall connections with these words. Adults are believed to have an average of 50,000 words in their vocabulary, so lethologica could happen with many of them. MISOPHONIA Sufferers of misophonia are sensitive to certain sound patterns that others pay no heed to, causing symptoms such as anxiety or anger. The sound of…

1 non-rapid eye movement (NREM) The initial transition from consciousness to unconsciousness. During this light sleep stage, muscles relax and heart rate slows down along with breathing and brain waves. This stage can last for up to five minutes. 2 Second NREM Over the next hour or so, sleepers enter a deeper stage in the sleep cycle. Heart rate and breathing patterns are reduced, along with the body’s temperature. During this stage, eye movements also cease. 3 Third NREM The deepest sleep stage, all vital signs reach their lowest levels and the muscles are fully relaxed. This stage typically lasts for up to 40 minutes. It’s believed that this is the most restorative stage in the sleep cycle. 4 Rapid eye movement (REM) Brain activity picks up during this stage,…

Our thoughts are our most private and personal belongings, and the idea that someone could go snooping around inside our heads is terrifying. However, the technology to do so is being developed. Besides the moral and ethical hurdles of mind-reading, the brain is an extremely complex organ. Taking it one step at a time, researchers have been analysing the electrical patterns we produce in the brain when we think of something, such as an object, number or even a sentence. The researchers can then identify and decipher distinct patterns associated with those thoughts in the hope of building a neural dictionary of patterns. The technology is still in its relative infancy, with years of development needed before complex thoughts can be interpreted. Currently this is being developed to offer insights…

Fewer people have seen the deepest parts of our oceans than have walked on the Moon, so our knowledge of what swims in the deep blue is relatively small. The deepest region of the ocean is called the hadal zone, which begins around six kilometres below the surface. This largely unexplored region consists of trenches formed by Earth’s tectonic plates and is inhabited by marine life that can withstand its extreme pressures and lack of sunlight. Some crustaceans and even species of fish, such as the hadal snailfish, have been observed in the zone as deep as eight kilometres below the surface.…

1 Nostril Unlike humans, a snake’s nostrils are only present to allow them to breathe, lacking any ability to smell. 2 Tongue Tiny odour particles from the atmosphere are collected by the snake’s forked tongue while it flicks it in the air. 3 Vomeronasal organ This chemoreceptive organ is connected to the olfactory bulb in the snake’s brain, which then intercepts the odour particles collected by the tongue. 4 Retraction Odour particles are mixed with the fluids inside the snake’s mouth as the tongue retracts.…

We feel our emotions, and not just in our head and heart – our bodily state changes to react to the chemical storm in our system. We might feel a tight knot in our stomach as we dread walking onto a stage to give a speech, or we might feel our cheeks flush red when we answer a question wrong. Researchers from Aalto University in Finland explored how humans physically feel their emotions by mapping the sensations topographically. Their findings were consistent across Western European and East Asian cultures, which suggests the way people feel during an emotional experience stems from a biological source rather than a cultural interpretation. The study also highlighted that emotions adjust our bodily state to either prepare ourselves physically to fight or flee or to encourage us…

Your dog really did eat your homework, and you have no idea who took the last biscuit from the sweet jar. Lying is in your nature, but don’t worry – it’s in the nature of most humans. It’s a technique that has evolved over billions of years, so it turns out you might not actually have that much to feel bad about. Humans are social creatures, and we have our giant brains to thank for this. They evolved to be so large because we needed the extra space to be successful at communicating with others and keeping our social group happy. This has a lot of advantages. If you can build bonds with other humans you can access more resources because your friends and family will share food and shelter,…

Pathological lying is a term that refers to the act of lying so naturally and instinctively that the individual finds it easier than telling the truth. Sometimes they can even believe their own lies. It is a condition that can be damaging to the lives of the sufferer as it destroys careers and relationships. Neurologists have discovered that there are physiological differences in the brains of pathological liars, who have 22 to 26 per cent more prefrontal white matter and approximately 14 per cent less grey matter. It’s thought that this difference means pathological liars are more able to make connections between different memories and ideas. However, it is unknown if the increased white matter is the cause of pathological lying or if the practice of frequently lying can cause…

Although it’s safe to say we’re unlikely to see open-heart surgeries carried out solely with hypnotic pain alleviation, there are plenty of examples of hypnosis managing pain during less invasive procedures. In 2014, a Guinean singer based in Paris underwent surgery to remove a parathyroid gland tumour from her throat. Although this wasn’t a life-threatening condition, without treatment the singer’s career may have come to an end. A world first at the time, Kante underwent the surgery without anaesthesia and entered a hypnotic trance-like state. This would allow her to sing during the critical moments of the surgery so that the surgeons could make sure that they did not damage her vocal cords. The surgery was a success, while Kante was blissfully unaware as she envisioned far-away Senegal.…

1 Prefrontal cortex The very front of the brain is responsible for working memory. It provides short-term storage while we’re learning. 2 Basal ganglia This cluster of brain cells manages motor learning – or ‘muscle memory’ – and the formation of habits. 3 Amygdala This small structure is responsible for the emotional content of memories. We learn better when experiences are emotionally charged 4 Hippocampus Found in part of the brain called the temporal lobe, this structure records past events, allowing us to learn from experience. 5 Neocortex This is the brain’s main storage bank. The hippocampus transfers learning to the neocortex while we’re sleeping. “The theory of human learning is founded on the idea one brain cell can’t learn on its own”…

Neurons are a kind of cell in the brain (we have many types of cell, including fat cells, kidney cells, and gland cells). A neuron is essentially like a hub that works with nearby neurons to generate an electrical and chemical charge. Dr Likosky of the Swedish Medical Institute says another way of thinking about neurons is that they are like a basketball and the connections (called axons) are like electrical wires that connect to other neurons. This creates a kind of circuit in the human body. Tallal explained that input from the five senses in the body cause neurons to fire. “The more often a collection of neurons are stimulated together in time, the more likely they are to bind together and the easier and easier it becomes for…

Nerves are the transmission cables that carry brain waves in the human body, says Sol Diamond, an assistant professor at the Thayer School of Engineering at Dartmouth. According to Diamond, nerves communicate these signals from one point to another, whether from your toenail up to your brain or from the side of your head.…

If you observe a professional athlete in the middle of a football match or launching themselves over a high jump bar, the ease of their movements can seem incredible. These are not superpowers, but the work of perfected muscle memory. Due to their relentless training schedules, the muscles that they need to control the dribble of a ball or expertly arch themselves over obstacles in athletics are almost preprogrammed. The strong neural connections that they have made to connect their mind and the rest of their body mean that while the brain focuses on the tactics of the competition, the body can perform complex moves without much conscious thought. An additional benefit to muscle memory in professional sportspeople is that it allows them to take breaks from the sport. Even though…

1 Detection When your cells are at risk, such as when you accidentally touch a hot stove, receptors in your skin initiate a nerve impulse. 2 Sensor neuron The nerve impulse travels from the dendrites of the sensory neuron towards the spinal cord. 3 Interneuron Located in the spinal cord, the interneuron acts as a relay between the sensor and motor neurons, passing the impulse onto the latter. 4 Motor neuron The nerve impulse travels away from the spinal cord and towards the target muscle receptors via the motor neuron. 5 Motor function The signal forces muscles to contract, pulling your hand away from the heat source automatically without any conscious thought needed. 6 Close neighbours The nerve impulse reaches connected neurons by ‘jumping’ across the synapse, a small gap…

The basal ganglia are found deep within the brain, in an area responsible for controlling movement. These nerves produce a compound known as dopamine, which is important in coordinating numerous functions, including executive functions and motor control. Although the cause is not yet clear, the basal ganglia can become impaired and begin to die. The result of this is Parkinson’s disease, as the loss of dopamine gradually hampers key functions such as walking, talking and memory recall. These effects are compounded by the loss of nerves responsible for producing norepinephrine, a key compound in the sympathetic nervous system needed to regulate heart rate and blood pressure.…

Given the potential impacts our gut bacteria can have on our overall health, the old adage that states ‘you are what you eat’ is becoming increasingly appropriate. We can promote the growth of good bacteria through our diets by incorporating probiotics (foods containing live good bacteria) and prebiotics (foods containing beneficial plant fibres). Probiotics can be found in certain yoghurts, cheeses and fermented foods. Prebiotics, on the other hand, are used as a food source for beneficial bacteria to grow and survive in the gut. When they digest the fibre we eat from vegetables, nuts and fruits they excrete short-chain fatty acids as waste products, which are great for nourishing our intestines and reducing inflammation. Research suggests we need a diverse range of bacteria to have a really healthy gut, but…

How do you convert the subjective experience of pain into cold hard numbers? One of the first attempts was to use a dolorimeter, a device that would push or burn the skin until the patient said ‘ouch’. This would reveal their pain threshold; the amount of pressure or heat they could tolerate. Today, the most common measure of pain is simply to ask someone how they’re feeling and how much it hurts on a scale of one to ten. However, scientists at the University of Colorado have been using brain scans to make this a more scientific test. Using a dolorimeter-like approach, they applied heat to the skin, but instead of waiting for people to say ‘ouch’, they watched their brains. In total, 114 people took part in the study, which…

Very rarely, people are born without the ability to feel pain. A defect in a gene called SCN9A makes it impossible for their pain-sensing nerve cells to transmit signals. This makes it impossible for them to tell when hot becomes burning, when cold becomes freezing or when pressure becomes crushing. The SCN9A gene codes for a protein that makes a part of a structure called a sodium channel. Sodium ions carry the electrical signals along nerves, and these channels control their movement. With the mutation in the gene, the channels don’t fit together and the pain-sensing neurons can’t fire. While this might sound like a superpower, but being unable to sense pain makes people with these genetic faults much more likely to do themselves harm.…

Sometimes we encounter people who have a high opinion of their own intelligence, and we might call them ‘big-headed’. This is because we naturally associate a big brain with high intelligence – that more brain means more thinking power. But it would be more accurate to call them ‘wrinkly brained’. The exterior of the human brain isn’t a shiny, smooth surface, but instead is a wrinkled mass of folds that form as a result of ‘gyrification’. As we develop, our brains expand into a limited space defined by the available room in the cranium. To maximise the amount of brain within this limited space, the brain expands and then folds in on itself, forming layers of gyri (bumps) and sulci (grooves). The result of gyrification is to increase the surface…

In 1996, a skeleton was unearthed from a Neolithic burial site in Alsace, France. The skeleton belonged to a man around 50 years of age who was believed to have died around 5000 BCE. Despite living 7,000 years ago, the man underwent surgery on his skull and survived for some time afterwards. The researchers who recovered his skull noticed that roughly circular pieces of it had been surgically removed in two places, which is known as trepanation. One segment was around 6.5 centimetres long, and the other around 9.5 centimetres long. While the reason for him undergoing these surgeries is unknown, other ancient cultures used trepanation as a treatment for ailments such as headaches, epilepsy and mental illnesses. The surgery carried numerous risks, including haemorrhage, brain damage and infection, yet…

Humans spend about a third of their entire lives asleep, but scientists still aren’t entirely sure why. The human body is governed by a 24-hour sleep-wake cycle known as circadian rhythm. This internal clock coordinates the body’s physical and mental systems as the body transitions from alertness to sleep. It does this by responding to the changes in natural light in your environment. As natural light dims and night falls, the circadian rhythm kicks the body’s melatonin production into gear. Melatonin is a hormone that helps the body enter the sleep portion of the sleep-wake cycle. And humans aren’t alone in having an internal body clock – countless species, including plants, fish and insects, all experience their own circadian rhythm. Once we’re asleep, our body goes through four to six…

Sitting at home, alone and in the dark, a sudden sense of fear and a swift chill may wash over your body. Sure enough, your hairs stand to attention and goosebumps cover your skin. It’s a sensation we’ve all felt at one time or another, but why does our body react in this way when we’re scared? It harkens back to a time when ancient humans faced the daily fear of life-threatening predators. As a result our bodies evolved what we now call a fight-or-flight response. This is a stress response which triggers a release of adrenaline, causing our heart race to rush, our palms to sweat and goosebumps to appear. During this state of fight or flight, the tiny muscles adjacent to each hair contract, making hairs stand on…

Typically people dream for around two hours a night. During this portion of rest, called rapid eye movement (REM) sleep, is when nightmares can creep in. Sometimes referred to as ‘threat rehearsal’, it’s believed that nightmares occur to prepare us for the possible dangers we might face in real life, although many nightmares are stress-related. At some point during human evolution nightmares may have served a purpose in bringing real-world dangers to our attention and keeping us alert to potential threats. However, in a world where we’re no longer chased by prehistoric predators or battling the elements, do nightmares still have a role to play? Although the dangers that may have birthed this neurological function are long forgotten, modern threats such as house fires, car crashes and murder keep nightmares…

Every year or so our lunar neighbour rises in the sky with an eerie crimson glow, known as a blood Moon. It’s a phenomenon that typically happens around May, and occurs during a lunar eclipse. This is similar to a solar eclipse, whereby the Moon and Sun perfectly align, blocking our view of the Sun. During a lunar eclipse, however, it is Earth that is blocking most sunlight from the Moon. Any light that does make it to the surface of the Moon passes through Earth’s atmosphere. As the visible spectrum of light travels through our atmosphere, blue wavelengths are scattered, leaving red wavelengths to journey to the Moon and giving it a reddish hue. Throughout the year there are other occasions when the Moon appears ruddy, and they’re often…

It’s all to do with the way these reptiles observe the world around them. The flicking of a serpent’s forked tongue might seem intimidating at times, but they are simply tasting the air. While we use our noses to smell and our tongues to taste, snakes gather chemicals that pertain to smell and taste from the atmosphere and interpret them. Unlike the human tongue, snakes lack the many taste buds we’ve come to rely on. They have instead evolved a sensory organ called the vomeronasal, or Jacobson’s organ, to detect moisture-borne odour particles. This has two holes – corresponding perfectly with the forked ends of the tongue – which collect the particles and deliver them to the vomeronasal organ as the snake flicks its tongue. The reason snakes do this…

As fierce hunters, cats and other nocturnal predators have evolved vertically slit pupils as a way to better ambush their prey at night. To successfully seek out their prey, cats need to be excellent at gauging the depth and distance of their next meal. This is where having a vertical pupil comes in handy. Researchers have found that predators such as snakes, cats and crocodiles are better at depth perception and can easily focus on their targets.…

The idea of spontaneously erupting into flames without any prior warning is a harrowing concept, but it’s unsubstantiated by science. As a prevalent theme in fiction during the 1800s, novels such as Charles Dickens’ Bleak House brought forth the terrifying idea that at any time one of us might suddenly ignite and perish. Following this idea were claims of real-life occurrences. However, only a handful have ever been formally investigated. Each incident involved elderly victims whose remains were found near open flames such as candles or smoking cigarettes. The fatal flaw in the idea of spontaneous human combustion is in our biology. The human body is made up of 60 to 70 per cent water, a natural enemy of fire. If an internal fire should ignite, our bodies would extinguish…

With over 7 billion people on the planet, there is surely going to be someone that shares enough of our facial features to be deemed our doppelganger. We seem to have an odd fascination with finding them and alerting others to their existence: “I saw your double in the supermarket the other day.” However, the chances of actually finding one are relatively slim. A 2015 study found that there is a one in 135 chance that someone shares enough facial features to be deemed a doppelgänger. The figure was calculated by comparing eight distinct facial features of 4,000 different people. Researchers found that finding a doppelganger with all eight matching features was a one in a trillion chance.…

How are you feeling right now? Are you relaxed laying on your sofa and listening to the gentle sounds of the dawn chorus outside your window? Or maybe you are tense with your shoulders hunched up around yourself as you try to get five minutes peace in a busy office? You would think that it is easy to work out if we are happy or sad, angry or calm, but humans cycle through such a vast array of emotions throughout their lives it can be difficult to distinguish them from one another. Emotions are not a simple experience. Every time you feel something your body initiates a physiological change, a chemical release and a behavioural response. This process involves multiple processes working together, including your major organs, neurotransmitters and limbic…

It’s thought that we learn how to lie much younger than we probably think, with some research suggesting it may have begun as early as six months old. Over the years we perfect the art, and some estimates suggest by the time we are in college we may be lying to our mothers once every five interactions. The developmental model of lying was first proposed by researchers Victoria Talwar and Kang Lee. Their work shows that children between the ages of two and three start telling primary lies – basic deceptions to cover up mistakes or bad behaviour – but without considering whether the listener will actually believe the lie. Around the age of four children start to tell secondary lies, more crafted and complex lies that are more believable. By…

In pictures, the human brain looks pink and spongy. According to Dr William Likosky, a neurologist at the Swedish Medical Institute (www.swedish.org), the brain is actually quite different from what most people think. Likosky described the brain as being not unlike feta cheese in appearance, a fragile organ that weighs about 1,500 grams and sags like a bag filled with water. In the skull, the brain is highly protected and has hard tissue, but most of the fatty tissue in the brain, which helps pass chemicals and other substances through membranes, is more delicate.…

Scientists have known for the past 100 years or so that the spinal cord is actually part of the brain. According to Melillo, while the brain has grey matter on the outside (protected by the skull) and protected white matter on the inside, the spinal cord is the reverse: the grey matter is inside the spinal cord and the white matter is outside.…

1 Long-term memory The brain stores repeated movements in long-term memory. This means muscle movements can be performed with little thought. 2 Skeletal muscles These muscles, which move the body’s skeleton, are responsible for performing the motor tasks to be stored as muscle memory. 3 Fasciculus Bundles of nerve fibre strands in the muscles connect to the central nervous system and relay signals from the brain to muscles. 4 Sarcoplasm This is the water-based cytoplasm of the muscle, which is responsible for storing and releasing calcium ions. Calcium is needed for muscle contraction to be initiated. 5 Perimysium This connective tissue sheath surrounds a muscle’s fibre bundles and protects them from forceful muscle contractions. 6 Muscle fibre The higher the number of nuclei in muscle fibres, the greater the muscle…

Neurons are the agents of signalling in our bodies, but they don’t work alone. Axons, which carry signals away from the neuron’s cell body, are coated in a sheaf of myelin. Myelin sheaves are produced in the central nervous system by cells called oligodendrocytes, enabling myelin’s function of protecting and facilitating nerve conductivity. In multiple sclerosis, an abnormal immune response strips away the protective myelin and causes lots of nerve scarring, or sclerosis, which gives the disease its name. Research efforts are underway to treat the disease by encouraging myelin regeneration. 1 Damaged myelin In multiple sclerosis, the immune system causes inflammation that destroys myelin and the cells that produce it. 2 Exposed nerve fibre Without myelin, nerves are vulnerable to inflammation damage, which causes scarring, and are less able to…

We all know that our mood and behaviour is controlled by the brain, but are we overlooking another important aspect of our neurobiology? There is an increasing amount of evidence to suggest that the activity of bacteria in your gut can significantly affect your brain. This relationship is called the gut-brain axis, and while its exact mechanisms and significance haven’t been fully figured out, it is thought that the microbes colonising your digestive tract are responsible for complex interactions between your digestive system and the nervous, endocrine and immune systems. Your intestines are filled with bacteria. When you think of bacteria you probably think of the germs that make you sick, but we actually have a lot to thank these tiny microorganisms for. We rely on ‘good’ bacteria to help…

Millions of sensitive nerves guard our tissues, listening for physical danger. These pain sensors, or nociceptors, detect temperature, pressure and chemical signals. They all have a high threshold for activation and only send messages when the body is at risk of harm. If skin temperature rises above 40 degrees Celsius or dips below 15 degrees Celsius, thermal nociceptors start to fire. If pressure exceeds three kilograms per centimetre squared, or if the skin stretches or tears, mechano-nociceptors kick into action. And if cells become damaged and start leaking their contents, chemical nociceptors switch on. A rapid response to nociceptor activation is crucial. If you put your hand in a flame, your body needs to react in fractions of a second. Nociceptors send their signals to the spinal cord, which manages…

Have you ever stubbed your toe and immediately reached down to grab your foot? Or burnt your finger and instinctively put it into your mouth? This is gate control theory at work. Pain signals travel from the site of an injury towards your brain along thin nerve fibres. As they enter the spinal cord they compete for bandwidth with the other nerves that are also trying to send messages to your brain. This includes larger fibres that carry non-painful signals, like pressure and touch. Both the painful and non-painful signals are trying to reach the projection cells of the spinal cord, but there’s a gatekeeper in the way. The gatekeeper is an inhibitory neuron. It listens for signals from both the pain fibres and the sensory fibres and decides which…

Accents are most often analysed during in-depth conversational speech. But did you know that your accent began developing before you could speak? Studies have shown that even in the first weeks of your life you already pick up some of the intonation of your native language and accent, mimicking these melodies when crying. Scientists believe that the first learnings of an accent take place while babies are still in the womb. What they hear during the months prior to being born impact their first sounds. During an experiment with 60 babies – 30 from French-speaking families and 30 German-speaking – researchers discovered that the rising and falling pitches in their cries matched the patterns of their native languages.…

1 British English Language family: Germanic Celtic A single ‘British accent’ doesn’t exist, as pronunciation patterns have evolved differently by area. ‘Received pronunciation’, also known as Queen’s English, is largely regarded as the UK’s standard, despite only accounting for three per cent of the country. 2 Australian English Language family: Australian aborigina Germanic Australian accents don’t have a strong ‘r’ sound at the end of words such as ‘teacher’. “When she woke up and spoke, she was of their own language. surprised to hear a British accent in place of her usual American one” 3 Canadian English Language family: Germanic Amerindian Inuit-Aleut The vowel sounds made in Canadian accents are more nasal than other English accents, such as American English, which produce vowels at the back of the throat. 4…

Our brain reaches nearly full volume inside the cranium within the first few years of life, but the regions of the brain still require considerable development. These major regions are each associated with controlling certain behaviours and emotions, and throughout childhood and adolescence they develop at different rates, reaching maturity at different times. By the time we’re 25, it’s widely considered that all regions of the brain have reached maturity, but prior to this time we go through periods where the development is unbalanced, leading to different behavioural traits. As the brain’s grey matter develops from back to front, the prefrontal cortex at the top-front of the brain is one of the last regions to reach maturity. Unfortunately for parents wishing to reason with their teenage children, the prefrontal cortex…

Neural development begins very early in the growth of an embryo. The central nervous system begins its existence from one structure, starting as a sheet of cells known as the neural plate. A few weeks following conception, the neural plate begins to form ridges and folds in on itself, becoming a tube structure. From here the neural progenitor cells of the tube, which can differentiate and specialise into numerous brain cell types, begin to proliferate in a highly structured manner to mature the neural tube into the developed brain. The cavity inside the hollow tube remains, becoming a ventricular space that holds the cerebrospinal fluid that protects and nourishes the cells of the brain. The expansive network of connections between neurons continues to develop throughout gestation as the brain grows,…

Words are the product of when our brains connect a particular sound to a specific meaning. Our brains are incredibly adept at maintaining this connection, providing us the power of language and the means to readily communicate complex ideas with another human that shares this knowledge. However, we can temporarily but rapidly sever the connection between sound and meaning, and we can do this simply by repeating a word. This effect is known as semantic satiation, where repetition strips a word of its meaning and renders it just a sound. You may have encountered this effect when vocalising a word over and over, perhaps when practising saying it or demonstrating its phonetics. Semantic satiation is believed to be caused by saturation of the brain with the same input, lessening the…

Do you ever get a nagging feeling that someone is staring at you? Is it really possible for us to have a six sense of when we’re being watched? Studies have found that a single brain cell fires signals when someone looks at us, stopping when their gaze moves away. This was put to the test in 2013 on a patient with cortical blindness. The patient’s visual cortex in the brain was damaged, but the brain still received information from the eyes. What was interesting was that the region of the brain that responds to potential threats, called the amygdala, became active when someone stared at the patient. This innate six sense most likely evolved in ancestral humans as a way to detect when a predator was nearby, giving them the…

Activated Several regions of the brain active during REM sleep that have different roles when considering their functions while dreaming. Regions like the cerebellum, basal ganglia and premotor cortex are linked with the motor content of our dreams. They are responsible for creating the sensation of movement, like running from an intruder during a nightmare. Others, such as the thalamus and basal forebrain are linked to emotion-processing aspects of our dreams. Deactivated While many regions are activated to produce dreams and nightmares, some are deactivated to allow them to occur. Regions of the prefrontal cortex and inferior parietal cortex are typically involved in cognitive control, perception of time and space, and self awareness. This allows us to drift off into a dream unaware of our physical bodies. The deactivation of…

Striking fear into the hearts of those that spot the tiny red markings on an otherwise ordinary-looking spider, black widows are some of the most venomous creatures on Earth. This accolade has led to many people believing this spider to be an aggressive insect. In reality these spiders are shy and they only attack humans when their bodies have been pinched or they’re accidentally squashed. However, when they do strike it wreaks havoc on the human nervous system. What makes their bite so agonising is the presence of a neurotoxin called alpha-latrotoxin. This neural hijacker causes rampant pain throughout the victim’s nervous system. However, it’s a common misconception that a single bite from a black widow spider is always a death sentence. Fatality is rare in healthy humans, with most…

Standing over a stone altar at a temple summit, an Aztec priest raises his obsidian blade before plunging it into the chest of the body before him, allowing the blood of the human sacrifice to cascade down the temple steps. It’s a scene well documented throughout history when you delve into the traditions and rituals of the Aztecs, who lived between the 14th and 16th century. Many Spanish conquistadors recorded seeing such bloodthirsty rituals, and even detailed a rack of 130,000 skulls of the victims called a tzompantli. It wasn’t until 2015 that this enormous and terrifying edifice was excavated by archaeologists, revealing the secrets of human sacrifice. People were offered as nourishment to the Aztec gods to ensure that the Sun would rise and to allow prosperity for the…

1 Cornea The dome at the front surface of the eye that offers protection and lets light pass into the eye. 2 Lens The lens changes shape to focus light into the retina. 3 Retina Within the retina are cells that can detect light, called photoreceptors, which are split into two groups called cones and rods for binocular vision and collecting dim light. 4 Optic nerve Light and image information is sent to the brain via a bundle of nerve fibres, collectively called the optic nerve. 5 Vitreous chamber A gel-like-fluid-filled chamber maintains the shape of the eye.…

Looking out into the abyss of space might leave you wondering why the universe is dominated by darkness. It’s believed that the universe is made up of roughly 80 per cent dark matter, a mysterious material which does not emit energy or light. Although we aren’t sure what it is made of, leading the pack as a potential candidate are weakly interacting massive particles (WIMPs), which have a hundred times the mass of a proton but are extremely difficult to detect.…

Where two neurons meet, a very small gap (synapse) exists between them. The electrical impulse travelling along the axon of the neuron must convert into a chemical signal to bridge this gap. The chemicals that do this are called neurotransmitters. These so-called chemical messengers are involved in our different responses to situations. Your emotions depend on fluctuating levels of neurotransmitters, which cause the activation of different parts of the brain responsible for different moods, or activate parts of the brain that trigger the stimulation of the autonomic nervous system. Adrenaline Released by the adrenal glands that sit on top of each kidney, adrenaline increases the flow of blood to our muscles, raises our heart rate and dilates our pupils. It is crucial in our fight-or-flight survival response. Oxytocin Also known as…

1 Intense eye contact Eye contact usually suggests honesty, and it is tempting for someone telling a lie to break eye contact. So they will start making more eye contact than usual, overcompensating. 2 Contrary confirmation Informal language and phrases that express they are being honest (such as ‘believe me’ or ‘to be totally honest’) hints that someone might not be telling the truth. 3 Frozen upper body People tend to move less when they are being deceptive, gesturing with their hands less frequently and sometimes completely freezing their entire upper body. 4 Prolonged eye closing Usually, people will blink for between 0.10 to 0.40 of a second, but when someone lies they often have their eyes closed for even longer than a second. 5 Head shaking If someone says…

In the late-18th century, Mesmer believed that the body was surrounded by a magnetic ‘fluid’, and with the aid of a magnet or an individual thought to have a ‘higher natural magnetic force’, such as himself, he could alter the fluid and thus relieve the patients of their issues, all while putting them into a suggestive mental state. Word spread about Mesmer’s technique – now known as ‘mesmerism’ – throughout Vienna, where he lived. However, so did rumours that the treatment was ineffective and had been disproved by his peers. As more and more people heard of the Mesmer scandal, he fled to Paris to continue his work of fraudulent mesmerism once again. Having built a new reputation, Mesmer secured high-profile clients, including royalty when Queen Marie Antoinette called upon his…