The Human Brain—Three Pounds of Mystery
Who would argue that a building could build itself, or a television set manufacture itself, or a computer design and program itself? It takes brains to do these things. Yet some argue that brains just happened. Is the human brain simpler than buildings, television sets and computers?
DAVID gazed at the starry vault above and saw the message reflected there: “The heavens are declaring the glory of God; and of the work of his hands the expanse is telling.” He was awed by their immensity and wondered why God would be mindful of insignificant man: “When I see your heavens, the works of your fingers, the moon and the stars that you have prepared, what is mortal man that you keep him in mind, and the son of earthling man that you take care of him?” Yet when David contemplated his own body he again marveled: “I shall laud you because in a fear-inspiring way I am wonderfully made. Your works are wonderful, as my soul is very well aware.”—Pss. 19:1; 8:3, 4; 139:14.
What a contrast with men today! David was overwhelmed by God’s majestic power when he saw some 2,000 stars. Today men discern some hundred billion stars in our Milky Way galaxy, estimate a hundred billion other galaxies in the universe (each with billions of stars), yet deny the existence of a Creator. David marveled at the intricate design of his own body and lauded Jehovah. Today men know far more about the body’s wonders, but attribute it all to blind evolution. They are ever learning but seem unable to come to the knowledge of the truth declared by their discoveries, namely, that it takes a wise and powerful Creator to bring into existence such marvels of design.
The Scientific American magazine noted this design and said: “It almost seems as if the universe must in some sense have known that we were coming.” The magazine attributed this preparation for us to “the many accidents of physics and astronomy that have worked together to our benefit.” However, it was not the universe but Jehovah God who knew that we were coming, and through no accidents he prepared the earth and its immediate heavens for us. No doubt we feel as David did when we view the grandeur of the earth and the vast expanse of the heavens—small and insignificant. But when Jehovah tells us that the earth was made for man, that he expects man to be its caretaker, and that he has equipped man with the ability to meet this responsibility, then we need not feel that our smallness disqualifies us from being worthy of his attention.—Gen. 1:14-18, 26-28; 2:15; Isa. 45:18.
THREE POUNDS OF MYSTERY
The greatest of God’s gifts to equip us to care for the earth is a gray, mushy substance slightly larger than a grapefruit. Its preciousness is emphasized by its protected location. It is enveloped by three membranes and practically floats in a cushioning fluid, and all of this is encased in solid bone—the skull. It is what sets us apart from unreasoning animals and imparts to us the possibility of being in the image and likeness of God. We think, learn, feel, dream and remember with it—but we cannot understand it. In spite of all the intensive scientific research to fathom its workings, it remains a mystery. British physiologist Sir Charles Sherrington wrote: “The brain is a mystery; it has been and still will be. How does the brain produce thoughts? That is the central question and we have still no answer to it.” The noted anthropologist Dr. Henry Fairfield Osborn wrote: “To my mind, the human brain is the most marvelous and mysterious object in the whole universe.”
The nervous system is of awesome complexity. Its cells are called neurons and extend throughout the body. Some are only a fraction of an inch in length; others are several feet long. The longest connects the brain with the big toe. The electrochemical impulses carrying messages to and from the brain travel from 2 to 200 miles (3.2 to 320 kilometers) an hour. The larger nerves are composed of thousands of fibers, the optic nerve having some million fibers, each carrying a separate message. The autonomic nervous system directs, without one’s conscious thought, the workings of organs, circulatory system, membranes and many muscles, such as those having to do with breathing, swallowing and the peristaltic movements in the intestines.
The brain itself has 10 billion neurons and 100 billion glia cells that form supportive structures and probably have nutritional functions. The neurons of the brain are active day and night, even during sleep, and use up energy at a high rate. In each cell the energy is derived from the oxidation of glucose. The brain is motionless, neither contracts nor grows, and is only 2 percent of the body’s weight. And yet, to keep functioning, it must receive 20 percent of the blood pumped from the heart; it requires 25 percent of the blood’s oxygen supply. If it is deprived of blood for 15 seconds, consciousness is lost; if for four minutes, irreversible brain damage may occur. Its electrical activity can be measured and recorded on paper as wavy lines, called brain waves, and this recording is called an electroencephalogram, or EEG.
The higher thought processes of the brain are centered in the cerebrum, with its various lobes, and is divided into a right and a left side. The left brain controls the right side of the body, is generally the dominant one, and is the center of logic, verbal abilities and the data processing of the millions of bits of information pouring into the brain every second. The right brain controls the left side of the body, and it is devoted to the creative and intuitive activities of the mind. But if one side of the cerebrum fails at a young age, the other side takes over most of its functions. The brain is considered to be underutilized; it has a potential for making geniuses out of plain, ordinary folk.
MESSAGES, THOUGHTS, EMOTIONS
“The hearing ear and the seeing eye—Jehovah himself has made even both of them.” (Prov. 20:12) The ear receives sound waves and turns them into electrical triggers that touch off impulses in the auditory nerve. When they reach the hearing area of the brain, they are interpreted as sounds, and thoughts are created. Light enters the eye, and rods and cones turn this light into electrical triggers that set impulses moving along the optic nerve to the brain, where they become scenes that stimulate thinking. Similarly, Jehovah has provided sensory nerve receptors in the nose and mouth and skin that turn smells and tastes and touches and heat into electrical triggers. These send impulses to the brain, which, in turn, analyzes the messages thus received, and decides on the appropriate responses to make.
The neurons or nerve cells have on one end dendrites that spread out like the branches on a tree; the other end is a long thread called an axon. The dendrites pick up the impulses and send them along the axon, which passes them on to the dendrites of the next neuron. But axon and dendrites never touch. There is a tiny gap 1/500th as narrow as a human hair that must be bridged as the impulses race on from neuron to neuron until they reach the brain. These gaps, or synapses as they are called, are bridged usually by chemical messengers known as neurotransmitters. The messages do not travel to and from the brain like electricity in a wire. They are electrochemical in nature, travel in impulses that vary in frequencies depending on the intensity of the stimulus, and do not need to be pushed along by an outside source of power as electricity in a wire does. Each neuron is like a small battery, is its own power source, and the intensity or power of the impulse is constant all the way to or from the brain. There are no losses along the way.
The data-processing abilities of the brain defy understanding. Imagine what must be going on in the brain of the conductor of a great symphony orchestra! There are conductors who have memorized the scores for 50 or 100 instruments. As the orchestra plays, and hundreds of notes a second with their various frequencies are pouring into the conductor’s brain, he is comparing them with his memory patterns. If one of the many instruments plays a wrong note, he detects it! Or consider a concert pianist playing a difficult score with all fingers flying! What an amazing kinematic sense his brain must have, to order the exact spacial relationship of the fingers, so that they strike the right keys to match the notes in his memory!
The networks of interconnections among the 10 billion neurons in the brain reach such astronomical numbers as to be incomprehensible, meaningless. The latest research shows not only connections between axons and dendrites but also connections between axon and axon, and microcircuits between the dendrites themselves. The following quotations provide further information.
“Of the many billions of nerve cells in the cerebral cortex, by far the great majority are utilized in associative memory. These cells are linked together in chains by billions of association fibers. These cells and fibers may be reused indefinitely; each time they are used, impulses cross their synapses with greater ease. Memories stored in some cells can thus associate with those stored in others, and new impressions can be compared with memories of previous impressions. Thus logical conclusions can be reached and these can further result in creative thinking.”—Encyclopedia Americana, Vol. 4, p. 423, 1977 edition.
“The brain weighs less than three pounds, yet a computer capable of handling a single brain’s output would cover the entire earth. The brain sorts one hundred million bits of data from the eyes, ears, nose and other sensory outposts each second, yet uses far less electricity than an average light bulb. . . . Since each neuron contains some two hundred thousand synapses along its numerous leaf points, and there are billions of neurons, the synapses provide the brain with an almost limitless flexibility.”—Mainliner Magazine, March 1978, pp. 43, 44.
A thought, if strong enough, produces a feeling. The feeling, if strong enough, causes an action. You think of Jehovah’s creations, you feel gratitude, you serve him. You think of a loved one in danger, you feel fear, you take action to save him. Evil thoughts work the same way. When someone looks at a woman with adulterous thoughts, desire grows; adultery may be committed. Both Jesus and the disciple James confirm this: “Each one is tried by being drawn out and enticed by his own desire. Then the desire, when it has become fertile, gives birth to sin.” (Jas. 1:14, 15; Matt. 5:27, 28) Sensory nerves to the brain produce feelings. For example, there are pleasure centers in the brain that, when stimulated with electrodes, produce pleasure. When stimulated by electrodes other emotional centers produce rage, fear or peace. Cats thus stimulated can be made to cringe in fear at the sight of a mouse. Rats with electrodes in one spot feel rage; in another spot, feel pleasure. Pedals have been wired up so that rats, on pressing them, stimulate their pleasure centers. They pressed these pedals up to 5,000 times an hour, ignoring food and sex and sleep until they dropped from sheer exhaustion!
MANY MYSTERIES REMAIN
Much has been learned about the brain, but far more remains a mystery. By the use of electrodes, areas of the cerebral cortex have been mapped out, showing what functions are performed and where. Some false beliefs have been removed, such as phrenology—the study of “character traits” by feeling bumps on the head. The shape of the skull is not determined by the shape of the cerebrum, nor is it possible to assign “character traits” to specific areas of the brain.
However, it is not known how the tips of nerves at sensory receptors turn the stimuli they receive into electrical triggers. It is not known how memory works. It is not known how thought arises from electrochemical impulses, or how decisions are reached, or how responses sent out on the motor nerves are initiated. Even the transmissions of impulses along the neurons are not completely understood. Beyond our understanding is how these electrical impulses cause dreams, the writing of poems, the composing of music—or, for that matter, cause consciousness itself to exist!
Have you considered the magnitude of brainwork required for acts that we take for granted—walking, talking, eating, swimming, riding a bicycle, or catching a baseball? A beginner weaves around under a high fly ball, and it usually lands several feet from him. In contrast, the professional takes off at the crack of the bat. The sound of the bat on the ball tells him how hard it has been hit, his eye notes its trajectory and speed, and his brain computes the general area where it will land. He races in that direction, but, as he runs, his computer brain is making continuous calculations to pinpoint the spot where he must be to catch it. Is there a wind? How strong is it? Is it pushing the ball to the right or the left? Is it slowing the ball down, or carrying it farther? Must he change direction, run faster or slower? Is the ground uneven, is there a hole to be avoided, is another fielder coming up to catch it, and should he let him have it or wave him off?
All these things he must note, yet never take his eye off the ball! To do so would “unplug his computer,” and he would miss the catch. There is no time consciously to make these many calculations and decisions. The player’s mind and muscles, trained by experiences recorded in his memory, perform automatically because his brain has been programmed by practice to do it all. How he came to have the ability to catch a baseball is in itself a mystery!
Can the intelligence of the brain be attributed to chance, as so many scientists now do? They are very inconsistent when they consider chance. They talk of beaming radio signals to stars to establish communication with a distant civilization on a hypothetical planet. How would those distant receivers recognize the signals as coming from an intelligent source and not being just chance? They might carry simple arithmetic equations, such as two times three equals six. This can be done easily. Or, the signals could be far more complicated, but having an order that would convey information, perhaps even make a picture of a man. Certainly if one of our big radio telescopes probing deep space picked up such a pictorial message scientists would never doubt that it originated from an intelligent source. Yet this is so simple compared to the brain, and far more simple than the single cell in the womb that can make not only a brain but a complete human creature! Is it consistent to say that the brain can just happen, that the cell in the womb can just happen, but that patterned radio signals prove beyond doubt that an intelligent source is behind them? Such a question needs no answer.
While conversing on the nature of God, the universe and man, Albert Einstein suddenly looked up at the sky and said: “We know nothing about it at all. Our knowledge is but the knowledge of schoolchildren.” He was asked: “Do you think that we shall ever probe the secret?” He replied: “Possibly we shall know a little more than we do now. But the real nature of things—that we shall never know, never.”
Both Einstein and David were awed by the mysteries of the night sky and man. And we continue to be awed by that three pounds of mystery encased inside our skulls—the human brain.