Teaching Methods wernickles areas

BRAIN: STRUCTURE AND FUNCTION If you are left-handed, you have probably felt discriminated against at one time or another: most school desks are built to be written on by right-handers, scissors work much better if you are right-handed, and in some cultures you are not permitted to eat or even touch food with your left hand. The Devil, too, is said to be left-handed, and many words such as 'sinister' and 'gauche' come from words meaning 'left'. 'Dexterity' comes from the Latin word for 'right'. Being 'right' in the moral sense of the word also derives from the use of the right hand.
As if all this were not enough, it seems that Nature, too, discriminates against left-handers, for they are more likely to suffer from a variety of language disorders and learning disabilities, ranging from higher incidences of stammering to a complete loss of language. They seem to die younger, too. (Perhaps they get more involved in automobile or industrial accidents due to errors in the operation of equipment, equipment which is designed for right-handers.) Consequently, while almost 13% of the population worldwide is naturally left-handed, with a higher percentage among males (about 10% male and about 4% female), by age 80, only 1% of left-handers in the total population are still alive. Why the rate of left-handedness should be so much higher for males is not known although one factor might be related to the effect of sexual hormones in the brain development of the fetus.
Left-handers need not throw up their hands in despair, however, because among them there is a greater proportion of artists, musicians and writers than is found among right-handers. And if you use both hands equally well,i.e., are ambidextrous, you can take heart, for you are in the company of the likes of Leonardo da Vinci. You might not like the word 'ambidextrous', though, since it means, from Latin, 'to have two right hands'!
Handedness is directly related to the structure and development of the brain. The brain and the spinal cord, together, make up the central nervous system. From the top of the spine upwards are the medulla oblongata, the pons Varolii, the cerebellum and the cerebral cortex (cerebrum) in that order. These four major parts of the brain form an integrated whole by means of connective tissue. The first three are concerned with essentially physical functions, including breathing, heartbeat, transmission and coordination of movement, involuntary reflexes, digestion, emotional arousal, etc. In comparing the brains of lower vertebrates with those of higher vertebrates and primates, such as man and the apes, the most noticeable difference is in the part of the brain which developed last in the course of evolution, the cerebral cortex. While in fish, for example, the cerebral cortex is barely visible and is one of the smallest parts of the brain, in humans it has increased in size and complexity to become the largest part of the brain. The cerebral cortex, itself, is a layer of grooved, wrinkled and winding tissue. In time, due to growth in the number and complexity of brain cells, the cerebral cortex takes on a pink-gray appearance, giving us the common term "gray matter" for referring to this part of the brain or our intelligence.
The cerebral cortex is characterized by its division into two halves, termed hemispheres which are connected by tissue called the corpus callosum. The corpus callosum, it should be noted, is not only a connector for the hemispheres, but it is the principle integrator of the mental processes which are carried out in the two hemispheres. The general appearance of the cerebral hemispheres as a whole is that of a walnut with the two adjoined parts mirror images of one another. Each cerebral hemisphere is divided into four sections: the frontal, parietal, temporal and occipital lobes. They are a convenient dividing of the brain into parts, loosely based on physical features. Functions such as cognition (to some degree) occur in the frontal lobe, general sensing (in the arms, legs, face, etc.) in the parietal lobe, hearing in the temporal lobe and vision in the occipital lobe. As we shall see later, some of these areas are also involved in the structure and function of language.
As far as our linguistic abilities are concerned, however, it is not evident exactly how important the actual size and weight of the brain are. Whales and elephants have bigger brains, but they also have bigger bodies, so it might be the ratio of brain to body size and weight which is important. However, the brain of the average 13 year old human weighs 1.35 kg and the proportion to body weight (45 kg) is 1:34. This is the same ratio as in a 3-year old chimp. Thus, while brain size is almost certainly related to general intelligence in a very broad sense as one moves up the evolutionary ladder from species to species, there is no indication that size and size alone is the crucial factor which would explain human language and non-human lack of language. Structural differences must exist which account for intelligence, language and other highly cognitive functioning. back to top