I was only fifteen years of age when I first came across a natural phenomenon in the West of Scotland known as “The Electric Brae”. It lay some 40 miles or so away from our home in those days and whenever driving around that part of the South Ayrshire coast, I never cease to be fascinated by my car’s apparent tendency to run uphill, whilst making much ‘heavier weather’ of the descent. It is of course a classic – and in that part of the world, i.e. Scotland, a celebrated – example of an optical illusion.
Our ‘story’ – such as it is – of the human brain would be grossly deficient, were we not to take into our brief account of the means of coping, i.e. the human brain, the apparent conflict between our common and indeed universal perception of an individual or “singular mind”, yet emanating from an organ consisting of two hemispheres, which appear identical but which could hardly be more different functionally. When I write about the “left and right brains” I am in fact referring to the two halves – or hemispheres – of the cerebral cortex, i.e. the portion of the brain that is well developed only in higher mammals.
As we have witnessed earlier, the higher centres overlay the smaller mammalian and reptilian ‘brains’, the cerebellum and the spinal cord. (As we have also seen, these lower parts of the brain have only non-verbal awareness and knowledge and are involved in the management of basic movement and balance). It has long been known that each half of the brain can develop its own separate train of thought and thus appear to think in fundamentally different ways. For the most part, the left hemisphere handles language, logical sequencing and problem solving. By seeming contrast, the right hemisphere carries out functions that do not require or will not fit into words; e.g. the recognition of a face in a crowd, the completion of a jigsaw puzzle, in other words the capacity to analyze information spatially, sequentially and simultaneously.
Each half of the brain is connected only to the other half of the body, if you see what I mean. Neural connections facilitating the exchange and flow of information between the hemispheres use a kind if super neural highway stretching between them and known as the “corpus collosum”·. In normally functioning individuals, the corpus collosum* makes it possible for either hemisphere to see, feel and move the other side of the body, although any kind of conscious awareness of such input into and impact upon the body from either hemisphere, is of course completely absent. In cases where the corpus collosum has been entirely severed (as in a form of brain surgery designed to prevent epileptic seizures) the two hemispheres will be totally isolated. In such instances, each can see and feel – and indeed mobilize – the other side of the brain. However – and although everything appears to be normal to the casual onlooker in such instances – the individual concerned can talk, see and feel only with the right hemisphere. Their left hand and field of vision (controlled you will recall, by the opposite, i.e. the right hemisphere) will not respond with speech but can learn independently, solve complex problems and react emotionally. This left/right split in the brain is in reality, fluent testimony to a competitive process, which in fact begins in the pre-birth state. Each hemisphere therefore responds to and carries out those functions, which it is best equipped to carry out, whilst the other appears to hold back. Thus an entirely advantageous working relationship developed between the two. If on the other hand, the left hemisphere is (perhaps because of the presence of a tumour or whatever) surgically removed before the age of five years is attained, either side can develop a language capacity but beyond that, it seems that only the crudest language ability will stand any chance of being established. (More about this in my next posting).
Under normal circumstances, the left-brain does appear to begin life with an inbuilt advantage for verbal language. On the other hand, the right brain – being designed to dominate in non-verbal, and spatial and visual tasks – develops accordingly. Removal of the right brain would of course leave language unimpaired, although a somewhat ‘computer-like’ construction would ensue and the literal meaning of words, although remaining in tact, would lack all inflection and emotional tone. (C)SB
* Situated just above the various ventricles, i.e. fluid filled cavities or chambers, which make up the hollow of the brain, the corpus collosum (Latin for “hard Body”) is a tough bridge of white matter (nerve fibres) which keeps the cerebellum acting as one unit, although as we shall see, the hemispheres are, at least potentially, independent.
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