Part One

I have found a study of the structure and function of the brain to be a very fascinating subject. Information about the human brain found in this chapter has been largely gleaned from "Psychology a Dynamic Science", by Kurt Schlesinger and Philip M. Groves; "The Origin of Consciousness in the Breakdown of the Bicameral Mind", by Julian Jaynes; "Evolution of the Brain and Intelligence", by Harry J. Jerison; "Divided Consciousness", by Ernest R. Hilgard, and from lectures on the brain, given at Auckland University by Dr. G. Tunnell.

You may have wondered about the claims we hear of messages being received from deceased relatives; or of people who have visions and hear the voice of god. What about spiritual healing and many other apparent demonstrations of the supernatural? Hearing voices and seeing visions are supposed by many to be signs of insanity. There have been very many perfectly normal people who have heard voices.

It is certain that people of many cultures and religions hear voices which appear to come from an exact location outside their own body. Creators of new religions and prophets down through the centuries have recorded hearing voices which were thought to be the voice of a god. There is no doubt that these were sincere people of good standing. Dreams were also often thought to carry a divine message. The Bible is full of occasions when dreams, voices and visions were interpreted as divine instructions. Shamans or medicine men, or specialists in the sacred, from many countries go into trance in public. They believe that a trance is associated with a spirit or spirits. These people could not rightly be called followers of god in a Christian sense. Nor could they be regarded as mentally ill.

Is it true or merely wishful thinking that messages come from a god or some other supernatural source? Or is there a rational psychological or physical reason why so many people from many cultures, religions and various other backgrounds have these experiences?

Dr. Julian Jaynes of Princeton University, in his interesting book "The Origin of Consciousness in the Breakdown of the Bicameral Mind", tells us:

"Hallucinations must have some innate structure in the nervous system underlying them. We can see this clearly by studying the matter in those who have been profoundly deaf since birth or very early childhood. For even they can - somehow - experience auditory hallucinations."

Until comparatively recent times, science knew very little about the function of the human brain, and there is still much to learn. Gradually knowledge has increased until we now know the main functions of each hemisphere of the brain. Mapping of the brain commenced in 1861 when Dr. Paul Bro-ca located an area where speech is centred. Since then a great deal of information has been acquired from the study of the effects of the surgical removal of parts of the brain due to accident or disease. We know, for instance, that what we see with our eyes is processed in the occipital brain, which is located at the back of the head. If this area receives a heavy blow, or is removed by surgery, the patient may suffer partial or complete blindness.

In the late thirties Dr. Egaz Moniz established an operation procedure for which he received the Nobel Prize in 1949. The operation was called prefrontal lobotomy and involves the cutting of certain nerve connections deep within the brain. The result is that patients become relieved of anxiety, delusions, phobias or epileptic fits, among other ills. There have been many thousands of people whose suffering has been relieved in this way. But there is a heavy price to pay. The personality of the patient is changed. Drs. W. Freeman and J. Watts had this to say: "It is becoming more and more plain that patients who undergo lobotomy must sacrifice some of the virtues, some of the driving force, some of the uplift, altruism, creative spirit, soul or whatever else one would like to call it." This operation has gone out of favour, drugs have taken its place.

In the late 1920s, Dr. W. Penfield discovered that when he applied a very weak electrical current through a wire to various parts of the brain, his patients heard voices, saw shapes and colours, involuntarily moved arms and legs, and could tell him what they saw. He also confirmed that most of the brain centres were duplicated, one on each side of the brain. Dr. Penfield confirmed that in right-handed people speech was located in the left temporal brain and usually not in the right. Because there are no pain receptors in the brain, local anesthetic is all the surgeon needs to use during the operation. Doctors can therefore ask questions and fully conscious patients can state exactly what they hear, see or feel. It is interesting that electrical stimulation of the appropriate region, near the posterior temporal lobe, often produces awareness of singing and music.

For the sake of clarity and for the purposes of this study, unless otherwise stated, we will refer to the speech or dominant hemisphere as being on the left side of the brain.

In describing how the brain physically transmits information received from our five senses, Sch-lesinger and Groves tell us that synapses are the functional contacts between separate neurons (nerve cells). The cells do not actually touch one another;they simply come very close to some part of another cell. When sufficient excitation has been produced, a transmission of information is achieved by means of small chemical packets. These are discharged and move across the small space between the cells to act on the next nerve cell. This is called an 'excitatory synaptic transmission'. They say,

"Each nerve cell in the nervous system is constantly receiving excitatory, inhibitory, or, more commonly, some combination of these synaptic effects. Thus each cell acts as an individual computer, combining and weighing excitatory and inhibitory action and determining when, and when not to fire an action potential. Given the complexity of individual nerve cells, and given that there are many billions of cells in our nervous systems, it would be impossible to build a computer that would do all the myriad operations that our brains are not only capable of carrying out but actually do carry out every minute".

There are three speech areas on the left side of the brain. In ascending order of importance they are: Supplementary motor area, Broca's area and Wernicke's area. The first has to do with articulation. The second, with articulation, vocabulary, inflection and grammar. The third area has to do with vocabulary, syntax, meaning and understanding speech. The removal of any one of these areas may results in a temporary or permament loss of meaningful speech.

Julian Jaynes tells us that

"The neurological structure for language exists in the right hemisphere as well as the left. In a young child, a major lesion of Wernicke's area on the left hemisphere, or of the underlying thalamus which connects it to the brainstem, produces transfer of the whole speech mechanism to the right hemisphere. A very few ambidextrous people actually do have speech in both hemispheres. Thus the usually speechless right hemisphere can under certain conditions become a language hemisphere, just like the left."

Jaynes further tells us that both hemispheres understand language. If the speech areas on the left are anaesthetised, leaving only the right hemisphere working, the patient can still follow directions. He or she cannot speak but sometimes a person can sing. When the injection is on the right side, he or she can speak but cannot sing. A stroke patient who has had a haemorrhage on the left side of the cortex and cannot speak can still understand, and sometimes a person can sing.