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The brain is organised much like a road atlas - one of those atlases you leaf through when you go on a journey by car or go on summer holiday. The multitude of provincial roads, main roads, motorways, junctions, small towns and large cities give us a rough idea of how complex our brains are. The towns and villages that we see on the map correspond to nuclei which process information, whilst the various roads represent the fascias of fibres that connect and transmit the information from one nucleus to another.
Two characteristics make the brain a very special organ: the first is called redundancy and the second is plasticity. Redundancy means overabundance. Let’s imagine our road map. There isn’t just one road that leads to one city, but several different roads. For example, the A1 motorway is not the only road that goes from Rome to Milan. It’s the same with our brains. There are several pathways that connect two nuclei in our brains and this is a considerable advantage.
In the example of the road network, if one route is blocked due to work in progress, landslide, falling rocks or whatever, an alternative route allows us to reach our destination anyway. The same thing applies in our brain; if some of the pathways are interrupted by trauma or the effects of the ageing process, there will be another route that will re-route the nervous system message.
However, the redundancy characteristic functions within certain limits. Neurosurgeons know full well that when they carry out the most delicate of operations on the brain they must be exceedingly careful not to cut the large fascias of fibre that run through it because once they are cut they never heal. Therefore, redundancy only functions if the damage is only slight.
The second characteristic that makes our brain special is its plasticity. But what exactly does this mean? The brain of the foetus, just like clay, is very malleable and easy to mould. This is why a lot of precautions need to be taken during pregnancy to avoid external agents altering the delicate mechanisms that are in the process of being formed. Plasticity diminishes with the development of the brain to guarantee a substantial stability to the individual. Otherwise, the brain would be completely at the mercy of the external environment that would continually modify it. But just like the chameleon that changes the colour of its skin, the adult brain maintains its ability to modify itself as a result of damage, the ageing process or continuous exercise.
The outermost part of our brain is called the cortex and is important as an information-processing centre. The maps of the sensory surfaces of our bodies are retained in part of the cortex. A phenomenon that can give us an idea of the plastic ability of these maps is the so-called phantom limb syndrome. If a limb is amputated, the sensory area of the cortex receiving information from it is reused to process information from other parts of the body. A patient who has suffered an amputation of the hand feels the pressure of the amputated hand if touched on the face.
Restructuring also results from brain lesions. If a trauma damages a small part of the cortex, other areas of the brain change functions and carry out the function of an area that is out of action. It is similar to how the Internet works. For whatever reason, when a server breaks down, the network does not break down because there are other servers that can carry out the functions of the faulty one. Also, exercise modifies our brain and consequently improves its capacity. For example, in the cerebral cortex of some violinists, the region that processes the movement of the left hand that presses the strings and is therefore most exercised is wider than that of most people’s cortex. Furthermore, the learning of a foreign language further develops the area of the brain that processes a language, and taxi drivers mainly develop the cerebral areas that process spatial information.
Plasticity is not only extraordinary in the young adult brain but also in old people’s brains. Although less than in young people, ample research shows that mental exercise also improves the performance of old people’s brains. This is why Brain Training and More Brain Training are genuine aids to keep your brain young to an advanced age.
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