Author: Moheb Costandi
All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason.’ Immanuel Kant (1787)
The brain’s main output: According to Daniel Wolpert – a British Neuroscientist – we have a brain for one reason and one reason only; to produce adaptable and complex movements.
The brain is an ‘inference machine’: Seems that Immanuel Kant’s thinking was prophetic as he foresaw what science confirms today; every waking second, the brain is trying to make sense of bodily sensations. To do so, the brain generates predictions which it then compares to actual inputs to determine the causes of these physical sensations. This is how the brain learns a model of the self and maps the world around us to guide our behaviour appropriately.
You are your connectome: The brain consists of billions of cells organized into elaborate networks which neuroscientists are mapping into a human ‘connectome’. Personality is known to be determined by brain structure and function but scientists still have no idea how this develops. All science knows is you are your connectome.
Thoughts come from your body: Thoughts and behaviours are the result of dynamic interactions between the brain, the body and the environment. The knowledge that bodily states and actions underlie thinking will eventually lead to a new generation of artificial limbs that the brain recognizes to be part of the body.
Decision-making is emotional: Emotions give rise to unconscious physiological signals – or ‘markers’ – that modify our responses. We literally feel our way through decision making. The emerging field of Neuroeconomics draws on psychology and neuroscience to address the shortcomings of conventional Economic theory which assumes decision-making is rational.
Spotlighting consciousness: Conscious awareness is the ability to perceive ourselves and the world around us. However, it provides an inaccurate and incomplete picture because consciousness operates like a theatre spotlight shining a beam of attention only on information prioritised by the brain. Our awareness is limited to the things we actively attend to making consciousness the filter that also determines what enters working memory.
Faulty memory: Not only is the information received distorted by attention-filters but retrieval too is tricky. Memory recall is not like pushing the ‘Play’ button on a video recorder. Retrieving a memory involves stitching together small fragments of information into a meaningful narrative. Memory is reconstructive because remembering the past and imagining the future involve the same parts of the brain. Reconstruction is more useful when helping us predict, with some degree of accuracy, how an event we have not yet experienced may unfold. The important question is; if memory retrieval is known to be so prone to error what are the implications for witnesses in the legal system?
Addiction and the reward centre: The pleasure centre is the brain’s reward system producing the neurotransmitter dopamine. This brain chemical once rewarded activities necessary for wellbeing and reproduction – like food and sex – but it can be easily hijacked by unhealthy habits such as addictive drugs. Drugs like cocaine, amphetamines (speed) and nicotine enhance dopamine transmission and the experience of euphoria leads addicts to overvalue harmful activities at the expense of healthier ones. Addiction also involves learning to associate drug-taking with paraphernalia and/or certain situations. Exposure to such cues reactivates the familiar neural pathways and this is what users experience as cravings.
Risky teenagers: The ‘reward centre’ is more active in adolescents than in children or adults and this goes some way towards explaining their risky behaviour. Teenagers take risks because novelty and sensation primes them to move away from familiar ground which – in turn – is thought to prepare them to live independently of the family home.
Plasticity: Learning causes physical changes in the brain – known as ‘neuroplasticity’ – which is one of the most important discoveries of modern neuroscience. The brain makes new synaptic connections throughout life and breaks them because ‘pruning’ is crucial for learning and memory. The brain matures well into our late 20s and changes continuously throughout life. Some self-help gurus and charlatans proclaim that their programmes induce neuroplasticity and ‘rewire the brain’ but – when used this loosely – the term becomes meaningless.
Stress is toxic: Research shows that repeated exposure to stressful situations such as neglect and abuse can stunt brain growth. This leads to persistent, negative effects on mental functions later in life as well as an increased risk of mental health problems (depression, psychosis, post-traumatic stress disorder, personality disorders and substance abuse). Prolonged stress – such as being raised in poverty – is toxic to the brain but some of the harmful effects can be reversed if action is taken early on.
Offsetting old-age: A new surprising picture of the ageing brain is emerging which shows that the brain undergoes functional changes to offset age-related decline. Scientists have identified SuperAgers – people whose brains seem to be immune to the ravages of old age – suggesting that deterioration is not inevitable. Why some people are affected more than others is unclear but some scientists put it down to possible genetic variants and lifestyle choices – education, exercise, diet, sleeping patterns and even socializing.
Neural stem cells: The brain contains several areas of self-renewing cells. These stem cells maintain and repair tissue and are found in most organs of the body. This finding raises the possibility that the brain may be able to repair itself following injury but far more research is needed.
Science fiction coming to life: The gaming industry has developed brain–computer interfaces that could enable people with spinal cord injuries to control prosthetic limbs or regain control of paralysed limbs.
And who knows what advances will be next …