The human brain is without equal in the animal world. The high state of development of the brain is considered to be the most essential difference between humans and animals. The brain is linked with consciousness, which is the awareness of existence. Stones, for example, also exist, but we believe that they do not experience anything. According to current theories animals are conscious, but certainly their consciousness is on a lower plane than in humans. When comparing the structure and the development of a human brain to an animal brain, the similarity in structure is striking. The brain develops as an outgrowth of the spinal cord. We can differentiate four parts of the fully developed brain: the medulla oblongata, the hindbrain, the midbrain and the fore-brain. In apes and humans the forebrain has become the large cerebrum, consisting of two symmetrical hemispheres. It lies over and above the other parts of the brain.
From the forebrain the midbrain branches out, and contains the very important regulation and relay centres the thalamus and the hypothalamus. The hindbrain has developed into the cerebellum, which also has two hemispheres. It is concerned with movement control and co-ordination. The brainstem contains the medulla oblongata and is continuous with the spinal cord. The medulla oblongata contains structures that are essential to vital functions.
Grey and white matter
Forming the outer layers of the brain we can discern the grey matter of the cortex, consisting of nerve cell bodies. The inside of the brain consists of white matter – nerve fibres with their insulation that connect the various parts.
There are milliards of nervein the brain. They are all already present at the time of birth, hence the relatively large skull of a baby. Their number never increases, although in the first two years of life the cell bodies can grow larger and further insulation of nerve fibres takes place. At puberty, the official onset of the aging process, the brain start to die, at a rate of approximately 50,000 a day. This is about 20 million a year. Up to the age of thirty however, the interconnections between brain cells can increase, by growing more of the connecting branches known as dendritic synapses.
It is not surprising that our brain functions gradually degenerate as we age. But we must also remember that the brain’s total capacity is much larger than the part of it that is actually used.