WE ARE OUR BRAINS - CHAPTERS 12, 13, 14
CHAPTER 12 - THE BRAIN AND SPORTS
Boxing: shows the onset of neurological damage during the sport itself: unsteady gait, impaired speech, eyes flickering left to right, epileptic fits, reduced consciousness, coma, death. Long term damage is more common than acute dam ante. 17% of professional boxers have Parkinson's. When someone is knocked out, their brain is slammed into the hole under the skull, compressing the medulla, which regulates vital functions. Blows destroy the hypothalamus and pituitary gland, causing hormonal deficiencies in 50% of boxers.
Two factors determine human lifespan: metabolism and brain size. The higher the metabolism, the shorter the lifespan. Top athletes at Harvard have shorter lifespans than their non-athletic colleagues. The more flight movements a fly makes, the faster it dies. If you confine it, it can live up to three times longer.
The larger and more active the brain is the longer you live. Brain stimulation also delays the onset of Alzheimer's. So it may be healthier to watch a sport than to partake in it.
CHAPTER 13 - MORAL BEHAVIOUR
Empathy is the capacity to recognise and share the feelings of others. It provides the basis for all moral behaviour.
Moral precepts serve to promote cooperation and support within social groups, they act as a social contract, imposing restraint on the individual to benefit the community at large.
It is hardwired in us, shown in other animals, and infants, who comfort others. There are altruistic actions done without the incentive of a short or long term reward, the roots of altruism go back a long way.
Mirror neurons come into play when we observe the actions of others. When you see someone move a hand, the same neurons fire in your brain as if you were making the movement. They help us learn by imitation.
Damage to the prefrontal cortex leads to amoral behaviour, lack of empathy.
The amygdala is involved in calculating the social significance of facial expressions.
"Man is a chimpanzee with ideas above his station."
The origins of empathy lie in a mother's caring behaviour for her offspring. They are just as important and ancient as feelings of competition.
Women empathise with cheaters when they are punished, while men don't.
If you are open and trust everyone, others will perceive your behaviour as abnormal and shut you out.
The reason humans are so good at torture is because they excel in imagining what others would feel. The more empathetic, the crueler you can be.
CHAPTER 14 - MEMORY
Mental activity stimulates the development of nerve cells and their axons in the part of the brain being used. So existing connections between groups of cells can be reinforced by an increase in the number of terminal arborisations.
Short term memory is limited in the amount of information and time it can be held.
Long term memory requires the synthesis of new proteins, because it involves forming new connections between neurons. this amounts to a structural change for which glial cells produce lactate, the essential fuel.
Highly emotional events often bypass the short term memory and immediately be stored in the long term memory.
"If memory is localised anywhere, it is everywhere."
Functional scans show whether a brain area is involved with a certain function, but brain damage only reveals whether it is crucial to that function.
Hippocampus: means seahorse because of the shape of the structure. When there is severe damage to the hippocampus, the person may be rendered completely incapable of making new memories.
It specialises in combining sensory information, and if it wants to retain this information it transfers it to the long term memory. It does this with the entorhinal cortex - here the first sings of Alzheimer's appear, this is why people with Alzheimer's may not remember what happened an hour ago. It is also involved in spatial orientation. London taxi drivers show a gradual increase in grey matter at the back of the hippocampus. It is also necessary for imagining the future.
The deciding factors for storing information in the long term memory are the importance of the information and the emotional charge of the moment.
The amygdala, just in the front of the hippocampus in the temporal lobe imprints memories that have a strong emotional charge under the influence of the stress hormone cortisol, registering them immediately in the long term memory. This is why 80% of our earliest memories have negative associations - remembering bad events is more important for survival.
Post traumatic stress disorder happens when the amygdala has done its work too well, preventing the prefrontal cortex for signalling the the threat is over. The amygdala is activated by noradrenaline so beta-blockers are used to prevent the amygdala from so strongly labelling dramatic experiences and the individual from being overwhelmed by negative emotions.
Borderline personality disorder: emotional instability and impulsiveness, negative emotions are linked to such a strong stress reaction that the person runs an increased risk of retrograde and anterograde amnesia.
During sleep the hippocampus constantly activates memories and transmits them to the cerebral cortex.
Different aspects of an event are stored in different sites of the brain. They have to be pieced together to recall the memory, and the empty bits are filled by our brains.
eg. Prospognosia - face blindness; you ca see well but not regonize the face.
eg. Capgras syndrome - being convinced that someone is an imposter of the person they are supposed to be.
The various components of vision are processed in different parts of the brain - some people can't see things while they are in motion, and then can see them normally when they stop.
The safest place for information to be stored is our remote memory: language and music are stored there, which are also the last to go in illnesses that affect the memory, such as Alzheimer's.
80% of our neurons are in the cerebellum.
- they ensure our movement and speech are flowing and coordinated.
- they contain the memory of how to do things
- they keep track of motor learning and steer performance of these tasks
- surprise the impact of your own actions on other parts of the brain - you can't tickle yourself
Damage to the cerebellum makes you very clumsy; stumble, not able to touch your own nose etc.
Alcohol and cannabis affect the cerebellum and hence your movement and coordination.