The Idiot Brain – A Neuroscientist Explains What Your Head Is Really Up To

by Dean Burnett, Guardian books, and Faber and Faber Ltd – 2016

“Dedicated to every human being with a brain. It’s not an easy thing to put up with, so well done.”

**************************************************************** 

Chapter 1 Mind Controls – How the brain regulates the body, and usually makes a mess of things.

 Millions of years ago the first reptiles on earth had a primitive brain with the clear and simple purpose of keeping the body alive by any means necessary. Humans, with much more complicated cognitive abilities, have retained the original primitive brain functions.

 The fundamental primitive aspects are controlled in the brainstem and cerebellum – sometimes referred to as the ‘reptile’ brain. The more advanced abilities of modern humans – consciousness, attention, perception, reasoning – are found in the neocortex (Neo equals ‘new’)

 It might be hoped that the reptile brain and the neocortex would work together harmoniously, but this doesn’t always follow – the reptile brain can dominate and cause all sorts of problems – An example of the micro-manager is given in the book.

 There is a long discussion in the book about how brains function can cause motion sickness.

 Room for pudding? The author outlines how there may be conflict between what the signals from a full stomach is saying and the message from the brain saying ‘you must eat some more because the pudding looks very tasty’.

Sleep. The reason that we need to sleep is not fully understood. We know that all animals sleep and it has been shown in rats that lack of sleep can slow recovery from wounds and also reduce life. It has been shown that sleep facilitates reduction of negative emotions. The timing and duration of sleep is determined by our body’s circadian rhythms, set by specific internal mechanisms. There is the Pineal gland in the brain that regulates our sleep patterns via secretion of a hormone known as melatonin, which makes us relaxed and sleepy. The pineal gland responds to light levels.

 Flight or fight - has depended of course on biological requirements – sleeping, eating, moving and also adopting measures to defend against external threat. The emotion of fear alerts us to threat. The fear is felt in the primitive ‘reptile’ midbrain and the brainstem is set for flight or fight. This sensory information is related to the amygdala. The amygdala doesn’t do subtlety; it sends an urgent signal to the hypothalamus (directly under the thalamus).

 The hypothalamus sends a signal to the sympathetic nervous system which communicates with the central nervous system – the brain and the spinal cord - causing considerable automatic reactions in the body – flight or fight! The sympathetic nervous system dilates our pupils to ensure we have more light in our eyes, increases the heart rate while shunting blood away from peripheral areas and nonessential organs and systems (hence the dry mouth) and pushing blood towards muscles to ensure we have the energy for running or fighting.

The fight or flight response triggers the adrenaline medulla producing typical responses: tension, butterflies in the stomach, rapid breathing and even relaxing of the bowels.

 If it turns out that the threat is not real, it takes time for all the alerted body functions to return to normal so that a person can remain in a state of extreme tension for quite some time. It also needs to be noted that in modern civilisation, real dangers are fairly rare, but some small event can trigger a memory of the past danger or horror and the whole process of alerting the central nervous system can occur spontaneously with considerable adverse consequences to the person (Post traumatic stress syndrome).

 Chapter 2 the Gift of Memory or the human memory system and its strange features.

 Computers store memory in a logical way, unlike the human brain which makes its own decisions about what’s important and where and how information is to be stored.

 Short-term memory exists for a minute or less. It can be triggered by some sight or smell that distracts us from what we had previously been thinking. In some ways, short-term memory involves thinking and some neuroscientists call it ‘working’ memory. Long-term memory provides the data for our cognitive thinking. Long-term memory appears to have a huge capacity (it stores memories for your whole lifetime); whereas short-term memory is only capable of holding about four items.

Short-term memory is based on neuronal activity in the dedicated regions in the pre-frontal cortex (in the frontal lobe).

 Long-term memory is stored by new connections of neurones supported by synapses. Thus when we want to remember something, we repeat it several times, causing neurotransmitters (chain squirts of chemicals) to interact with the membrane of other neurones establishing synopses that hold the information. This stored memory can be recovered in the long-term. The hippocampus is the place where the actual encoding happens. People with damaged hippocampus can’t encode new memories, while people, such as London taxi drivers, have been shown to develop a physically large hippocampus.

 New long-term memory is encoded in the hippocampus and then slowly moves into the cortex as additional memory forms behind them. It seems that everything that is processed by the hippocampus and stored in the cortex is retained for the rest of our lives, but we forget things because we cannot retrieve the memory. Some memories are easily retrieved because they are stored with a great degree of emotional attachment; such as a memory of your wedding day; while others are not.

 Memory is often associated with some particular emotion or sense of place. For example we may have trouble remembering somebody until we recollect where we have seen them before. Similarly something that we learn when we have been drinking alcohol we may not be able to remember when we have not been drinking, but it will all come flooding back the next time we do have some alcohol!

 Memory can be distorted by the brain. This is known as memory bias and it is often driven by ego. The brain is not just a simple mechanical organ. It is you! For years thinkers have grappled with questions such as does the mind arise from the brain? Or is it a separate entity, intrinsically linked to but not exactly the same as the brain? What does this mean for free will and our ability to strive for higher goals? It is now clearly established that our consciousness resides in the brain. Our sense of self and all that goes with it – memory, language, emotion, perception and so on – are established by processes in our brain

Everything you are, is a feature of your brain and as such, much of what your brain does is dedicated to making you look and feel as good as possible. Amongst other things the brain can modify your memories to make you feel better about yourself. Thus we get distorted memories. It might be minor things; you believed you perform better at sport than you actually did, you believe you caught a large trout when in fact you caught a minnow.

 False memories. The brain can itself, put together recollections of things that didn’t happen at all; in addition to this people can implant false memories in our head merely by telling us that these things happened. People tend to be very suggestive to those they consider to be authoritative figures and, in a court situation, depending how the questions are put to a witness, they may have a different recollection of what actually happened.

The brain mechanism can go wrong and memories can be lost or distorted. Alzheimer’s disease for example can cause brain damage and neurofibrillary tangles may be formed. These tangles can develop throughout the brain affecting eventually almost all areas involved in memory.

 Stroke, a disturbance in the blood supply to the brain can be particularly bad for memory. The hippocampus, which requires an uninterrupted supply of nutrients, can have this cut-off. Even a brief loss of supply can cause serious memory problems.

 Herpes simplex, the virus responsible for cold sores, can occasionally turn very aggressive and attacked the hippocampus. This will prevent memories being laid down during the period of the attack.

Chapter 3 Fear: Nothing to be scared of - The many ways in which the brain makes us constantly afraid

In our dim evolutionary past there were many physical threats. The world has changed, but our brains haven’t caught up yet and can find many things to fret about. We get sucked into conspiracy theories, paranoid about things that are technically possible but incredibly unlikely and our brains can dream up horrible things in an imaginary future. The office of National statistics in the United Kingdom reported that one in 10 adults will experience anxiety related disorder at some point in their lives.

 The arrival of the Internet has been a boon to people who want to press conspiracy theories and to press fear onto brains ready and willing to swallow up paranoid imaginings. In a way it is going back to superstitions held before the ‘Age of Enlightenment’.

 Many of those who believe in superstitions and conspiracy theories are insecure, immature individuals, subconsciously yearning for parental approval that was not forthcoming as they grew up. However the author very firmly points out that this is not always the case. The brain is always struggling to establish patterns and reasons for things to happen and hence having observed one or two occurrences it will establish its own beliefs that may well fly in the face of observed facts. The brain may reject random events and assume that everything happens for a ‘reason’, often referred to as ‘fate’.

 The brain is capable of developing phobias to almost anything; spiders, open spaces, confined spaces and many many other things. One form of phobia is social anxiety – the need to have the approval of strangers. This can lead to difficulty in talking to a public audience, meeting and mingling in a group such as at a cocktail party and even talking on a telephone where one does not get the visual cues of a normal face-to-face conversation.

 There are people who enjoy fear. They take part in risky activities such as bungee jumping and they watch horrifyingly violent movies. It seems that this enjoyment is triggered by a very dense collection of circuits and neural relays deep in the brain with numerous links to the more sophisticated regions including the hippocampus and the frontal lobes. So it’s a very influential part of the brain. When the flight or fight response is triggered by some risky or violent experience the body is left in a state where the sensors are alert and poised for danger but if the danger doesn’t appear you are left in a pleasant situation of an adrenaline rush that gives the brain a feeling of reward. People say they feel on a ‘high’ and feel very much ‘alive’.

 Criticism is something that the brain recognises much more graphically than praise. At the fundamental neurological level, the potency of criticism may be due to the action of the hormone cortisol. Cortisol is released by the brain in response to stressful events; it is one of the chemical triggers of the fight or flight response and is widely regarded as the cause of all the issues brought about by constant stress.

 Chapter 4 think you’re clever do you? – The baffling science of intelligence

Intelligence is a complex concept. Many living creatures have brains controlling their basic functions, but so far as we know the human brain is the only one to have created its own philosophy and all sorts of technologies. Activity of this type has been defined as intelligence and so we have considered ourselves to be an intelligent species. However there are varying degrees of intelligence between people. Many measures have been developed to try and establish the intelligence quota (IQ). It becomes messy and complicated because intelligence can be considered to have many different branches and IQ tests are many and varied.

 In the 1940s to 1960s two types of intelligence were categorised – fluid intelligence and crystallised intelligence. These appear to be useful categorisations.

Fluid intelligence is the ability to use recent information, work with it, and apply it to achieve a useful outcome. Fluid intelligence involves working memory; the manipulation and processing of information. It operates very much in the prefrontal cortex.

Crystallised intelligence is the information stored in long-term memory. It is the information stored over your lifetime. This information is distributed widely throughout the brain and tends to be resilient enough to withstand the ravages of time. On the other hand the prefrontal cortex is a demanding energetic region that needs to engage in constant active processing to support fluid intelligence. The intense activity tends to give off a lot of waste products such as free radicals, energetic particles that are harmful to cells and so, as life goes on, the pre-frontal cortex becomes less effective. A person in their 80s will perform worse in a fluid intelligence test than they would in their 30s, but they may perform equally well in their 80s or 30s for a crystallised test. As a rather simplistic example; they will know that a tomato is a fruit, but they might not remember that it shouldn’t be added to fruit salad! Many neuroanatomical studies and autopsies have shown more age-related decline in the prefrontal cortex than other regions of the brain.

 It is clear that people have different degrees of intelligence depending on their interests, upbringing, environment or some underlying bias imparted by subtle neurological properties. That is why we get supposedly very smart people doing things we would consider stupid if it is outside their field of interest; they are clever enough to know better, but they are too focused elsewhere to care.

 It has been observed that high achievers in many fields persistently underestimate their abilities and achievements, despite having actual evidence of these abilities. For example Albert Einstein, towards the end of his life, remarked that the esteem with which his work was held made him feel very uneasy. On the other hand, people who are frequently in the public eye, such as politicians, may be uninformed about some topics, but they are quite happy to firmly state their opinions rather than the calmer explanations of trained experts. It has also been shown that if an opinion is very firmly and confidently put forward, it is more likely to be believed then a hesitant or unsure message delivered by the trained expert. Thus we tend to be led by pompous incompetents!

 Chapter 5 Did You See This Chapter Coming? – The haphazard properties of the brain’s observational systems.

 One feature of our mighty brain is the ability to look ‘inwards’. We are self aware, we can sense our internal state and our own minds and even assess and study them. Introspection and philosophising are prized by many people

We perceive the rest of the world by a range of sensors – vision, hearing, taste, smell and touch. Signals sent to the brain which constructs detailed representation of the environment, but this is not always accurate.

 The olfactory system, takes signals from small particles that lodge in the nose directly to the olfactory bulb to enable the experience of a smell. Certain smells or odours can trigger powerful memories of childhood and/or bring about emotional moods associated with smells. Taste is one of our weaker smells and most of the signals that we get from something on a pallet is significantly affected by the sense of smell of that object.

 Hearing in touch are both classified as mechanical sensors, meaning they are activated by pressure or physical force. The hair cells in the cochlear are activated by specific soundwave frequencies. Touch various in different parts of the body and can have different responses in the brain depending on the nature of the touch from a gentle stroke by somebody you love, to a rough push by somebody you don’t like.

 The human brain prioritises vision over all of the sensors, but the visual system boasts an impressive array of oddities.. The idea that our eyes capture everything from the outside world and faithfully relay this to the brain is a far cry from how things really work. The retina is a complex layer of photoreceptors - specialised neurones for detecting light. It has a varied number of detectors; only the central part can recognise fine detail (this is named the fovea) the rest of the retina gives us only blurry outlines, vague shapes and colours. The brain then does a fantastic job in processing this information to give us sharp image. The brain does this by rapid eye movement over the field of view and by filling in the blurry areas by intelligent guesses. The optical signal is sent back to the primary visual cortex; colour information is established by the secondary visual cortex which does an impressive job of working out colour consistency. For example a red object in bright light would look on the retina very different from a red object in dark light, but the secondary visual cortex takes the amount of light into account and works out what the colour ought to be.

 The brain is also very effective at working out the world as three-dimensional. Two eyes of course gives us parallax processing, but even with one eye closed the brain can still establish a 3-D image. Not as good as with two eyes, but still definitely 3-D.

 Paying attention: The brain is constantly bombarded with sensory information. How does it prioritise certain stimuli? Multi-tasking is difficult. A typical human has one single active ‘stream’. Attention is mostly directed by the visual field, but some sudden input – the sound of a cracking branch above you or an attacker noticed at the periphery of your eye – can override your current task and divert your attention to the new stimulus.

 Chapter 6 Personality: a testing concept –The complex and confusing properties of personality.

 Everybody has a personality. Roughly it’s a combination of an individual’s interests, beliefs, loves, hates, ways of thinking and behaving. Historically (and even today in some religious groups) there was a belief that the mind and body were separate. Personality was considered, not to be held in the brain, but held in some mysterious thing called the mind, ‘spirit’ or some other immaterial element.

 It has been suggested that there are five big personality traits:

1.       Openness – willingness to accept a new idea or challenge.
2.       Conscientiousness – a person who is prone to planning, organising and undertaking tasks properly.
3.       Extrovert – outgoing, engaging and attention seeking. The inverse is the introvert – quiet, private and solitary.
4.       Agreeableness – the extent to which behaviour and thinking is affected by the desire for social harmony. They agree to do things but they don’t want to be a bother.
5.       Neuroticism – not anxious to do anything much, but want to explain their reasons in exquisite detail.

 Recent studies have shown some physical difference in regions of the brain associated with these five personality traits. However this work is fragmented and incomplete.

 Chapter 7 Group Hug! – How the brain is influenced by other people.

 There is the classic argument about what makes a person – nature or nurture? Genes or environment? Of course both play a part and the nurture is very much driven by interaction of a brain with all the other brains that it meets. As the brain of a person develops from a baby it is continually deriving information from how others think and behave towards them.

 Facial expressions are a major part of the transmission between people. It is sometimes claimed that face and body language represents 90% of communication, but this will vary with different people – both the transmitter and receiver! The visual cortex has subsections dedicated to processing faces, hence we are very efficient at interpreting expressions. The amygdala is highly active when rereading facial expressions. Since this region is responsible for processing our own emotions it seems that it may well be very effective in processing the emotions of another person.

 Much of human culture is dedicated to forming long-term relationships. It is well known that when these breakup, through death or one partner walking away, there is considerable grief and physical unhappiness.

 Because of its need to link with other brains, it is easy for other people to develop new ideas in your brain that you strongly accept. The technique often described as ‘brainwashing’, can be relatively benign, as in the case of social groups, or it may be malicious, as in the formation of terrorist groups that can induce people to become murderers or suicide bombers. Once in a group there are some people who want to control the group and establish themselves as absolute leaders, in some cases, forming the group into an angry mob creating riots and other disturbances. This can sometimes be observed in sporting crowds.

 Chapter 8 When the brain breaks down… – Mental health problems and how they come about

 The book so far has described how the normal brain can lead us to all sorts of things – it can mess our memories, make us terrified of harmless things, mess up our diet, our sleeping, our movement and convince us that we are brilliant, when we not. A worrying list!

 It is still more worrying when the brain is not working properly. When we have a neurological or mental disorder.

A neurological disorder arises from some physical cause such as disruption of the central nervous system like damage to the hippocampus causing amnesia. These things are awful, but usually have identifiable physical causes (although we generally can’t do much about them). Parkinson’s disease is one well-known neurological disorder.

 Mental disorders are abnormalities of thinking, behaviour or feeling and they do not seem to have clear ‘physical’ causes.

 The author suggests that by computer analogy: neurological disorders are like hardware problems, while mental disorders are software problems.

 Depression – Depression is much more than simply feeling dismal or sad. It may be brought on by a series of distressing events – loss of a loved one, loss of job, failure of some enterprise or other sad occurrence in one’s life. On the other hand, some people develop depression without any obvious cause. A widely held theory is that decreased serotonin and other neurotransmitters is the primary cause of depression. However there have been recent criticisms. It has been suggested that changes in the hypothalamus may reduce neuroplasticity (the mechanism by which the brain changes itself!) And this means that the brain is less adapt at responding to adverse stimuli and stress. Antidepressants which increase neurotransmission often increase neuro plasticity and this may be why they work.

Depression is not logical. Those affected by it will not think clearly or rationally and may consider suicide as the way out, without considering any of the side effects caused on those loved-ones around them.

 Nervous break-down. The situation when a person under extreme stress finds that the brain cannot deal with all the tasks thrown at it and it just ‘shuts down’. The results experienced very between individuals – some experience bleak depression; others crippling anxiety; some even have hallucinations and psychosis.

 Drug addiction – there is a reward pathway in the brain that is stimulated by particular pleasures we may enjoy. This is a useful area since by eating food that we enjoy we get a reward and so eat more of it for the benefit of our body. However as mentioned earlier the brain can overdo this and we eat too much. It is worse if we get our reward by taking some drug which directly targets the reward system. Having had this reward our brain encourages us to have more of it and hence we become addicted. Opiates are powerful analgesics that suppress normal levels of pain by stimulating the brain’s endorphin (that is the natural painkilling, pleasure inducing neurotransmitters) so the brain responds by increasing the potency of our pain detection system and gives us a blissful cloud of opium induced pleasure. Unfortunately the opiates altar the brain functions, so that higher doses are required to achieve the same pleasure. Thus an addicted person takes higher and higher doses and is in considerable pain if they try and get off drugs by going ‘cold turkey’.

 In all cases of addiction the prefrontal cortex area has reduced activity and so logical control is reduced.

 Psychosis – an individual’s ability to tell what is real or not is compromised. They may have hallucinations (perceiving something that isn’t actually there) and delusions (unquestionably believing something that is demonstrably not true). There are many conditions described as psychosis, the most common is schizophrenia. The person may hear voices or see things that are not real, they may quite illogically believe that they are some other person (usually a high-level or distinguished person). In a normally functioning brain the connections between the sensory cortex (observing the real world) and the prefrontal cortex (decisions and thinking) keep us from mistaking events or entities in the real world for our unconscious thoughts or hallucinations. If the connections between the two cortex regions becomes broken or degraded, the brain can’t distinguish between the real and the imaginary.

 Given every possible thing that can affect how the brain does things, it’s easy to see how such processes might go a bit awry, especially considering how what’s ‘normal’ is more general-consensus than fundamental fact. It’s amazing how humans get anything done, really.

 *******************************************************************

The topics in the book are elucidated by stories from real life, including stories from the author’s own life. The work demonstrates thorough research of the literature, and every chapter concludes with a long list of scientific publications and notes.

  R H Brown
3 September 2016