by Marian Diamond
It was only when I was in my 50's did I learn that my English heritage provided me with a family crest stating "love conquers all," Virgil's simple and powerful phrase. Why did it take so long to learn about this family crest? Because my father was the only one of his large family to leave England and settle in the sunny, clean air of southern California in the 1920's. Though I had visited England many times, I never knew about this crest and its message until twenty years ago. How appropriate I felt it was and how pleased I was to learn that my ancestor had succinctly coveted my basic belief which I had derived for myself seven thousand miles away. For without human love what is the purpose of our existence?
I often use the phrase, "love conquers all", at the end of examinations in my class at the university -- a class of almost 600 students who are learning about the house in which they will spend their lives, namely the human body. I often think if everyone understood what we know today about his or her body and worked to keep fit, and everyone practiced the golden rule, how much we could all enjoy, study, and maintain our beautiful earth to its fullest extent.
But for all of this to come about, what is it that is responsible for understanding our bodies, practicing the golden rule and enjoying the beauties of this earth? None other than our brains -- this three pound mass of tissue, about 2% of our total body weight, which we carry at the top of our heads. Do you ever introspect behind your eyes to allow your brain to contemplate itself?
As a teenager in southern California, I had seen my first human brain while accompanying my father on his rounds in Los Angeles County Hospital. There in front of me was a mass that was responsible for all human behavior, and it could think. At about the same time, I had written in the front of one of my books: two basic human desires are: Love and Knowledge. Wisdom was not yet a high priority because I had not yet accumulated enough knowledge upon which to base wisdom. But I did know the importance of love and that love was not created in the heart.
The ancients placed love in the heart because of its strong responses to emotional input, such as speeding up and causing the whole body to have glorious sensations of exhilaration, warmth and beauty. The increase of the heart beat is due to stimulation of the autonomic nervous system whose center is in the forebrain, specifically in the hypothalamus. But the feelings associated with love are not specifically localized in the brain because love is a many splendored thing. There are endless kinds of love with diverse parameters, and to mention all is nearly impossible. For love between two human beings allows them to express their deepest feelings of passion, intimacy, trust, pleasure, kindness, truth, joy, tenderness, sharing future plans and dreams, contentment, magnificence, adoration, desire for companionship, understanding, sharing one's hopes and fears, comfort and beauty, just to mention a few.
One component of love that I mentioned was pleasure. One kind of pleasure center has been established in the brain; it is called the septal area. If an electrode is placed in the septal area in a rat, he will cross a hot grid to voluntarily press a lever to stimulate this area. He will do it repetitively. A pathway leading from the septal area goes into the hypothalamus. Once again we can bring in the hypothalamus as a brain region associated with a component of love.
Most of the conscious components of human love appear to be associated with the frontal lobe of the cerebral hemispheres, the most highly evolved part of our brains. I mentioned trust, appreciation, respect, tenderness, acceptance, desire for companionship, understanding, sharing one's hopes and fears, planning the future, etc. These can be categorized as the higher mental functions associated with human love.
I cannot mention love and the brain without including more of the limbic system which to some is considered to be the emotional center of the brain. I will specifically refer to the amygdala, because a certain amount of aggression is necessary when seeking love. Once a possible lovable partner is identified, one shifts gears and develops a higher level of considerate aggression, a function associated with the amygdala, an area at the tip of the temporal lobe. We are presently working on the amygdala to understand its degree of plasticity, i.e. its ability to change with a changing environment. We are asking whether we can educate the amygdala through the cerebral cortex and perhaps, have some hope for curbing the abnormal violence and aggression we witness with human behavior.
When people are in love, there is undoubtedly heightened sensitivity in the reticular formation, a system which forms a core of nerve cells throughout the nervous system and decides what sensory input can enter the central nervous system. It can also regulate the input to the cerebral cortex. One in love is often more creative, has more endurance, more energy, and is more focused and less interested in the broad problems of society. (Love is blind is a common phrase. Is this the reason there are more endorphins, chemicals which reduce pain, in the female visual cortex?)
Other aspects of love can include the esthetic constituent, the physical attractiveness of your love. Seeing him or her at any time will stimulate the primary visual cortex and in turn the visual association area which can bring back the enjoyable memories of times together running on the beach at North Beach in Point Reyes at the end of a warm summer day with the brilliant sunset in the background. The auditory cortex can be stimulated by hearing the sound of one's love's voice, just speaking normally across the room or whispering soft messages close to one's ear.
Of course, the sense of touch is a magnificent element of love, holding hands or just the warmth of one's love's body will stimulate the primary sensory cortex. The sensory cortex registers touch, pressure, and temperature. If we go even a step further, we can consider writing love letters or in today's world, love by electronic mail. Such actions will bring in the whole motor system, including the motor cortex, basal ganglia, cerebellum, etc. I think by now, my message is clear. As we think of the many aspects of human love and try to associate brain areas with them, one way or another we can bring in most brain regions. If love is going to conquer all, it must have as many facets or synapses (the junctions between nerve cells) as possible.
Now let us turn to an equally esoteric subject, wisdom, and see if we can find areas of focus in the brain; or will wisdom, like love, also be more universally determined? Since no two brains are alike, no two people will define wisdom identically. If we go to the literature, we find that one definition might begin by stating that an individual who possesses wisdom denotes mental qualities that have to do with the ability to understand situations, anticipate consequences, and make sound decisions. Wisdom is a broad term, embracing the meanings of all its synonyms in addition to outranking them all in suggesting a rare combination of discretion, maturity, keenness of intellect, broad experience, extensive learning, profound thought and compassionate understanding. In its full applications, wisdom implies the highest and noblest exercise of all the faculties of the moral nature as well as noblest exercise of all the faculties of the moral nature as well as of the intellect: a great scientist would base her or his decisions on a wisdom gained from far more than the study of science.
There is no doubt in my opinion that the ultimate source of wisdom represents a product of the experiential input into the cerebral cortex. This information is followed by integrative processes in the association cortices. Here the primary input is mixed with previously stored information. The cortex, however, does not work alone. The thalamus below it is gating everything coming into the cortex. If the thalamus is injured or damaged, information to the cortex can be incomplete or inaccurate. Several steps take place before the thalamus processes the sensory information. Input to the thalamus depends upon the condition of the receptors which gather sensations from the external and internal environment.
To gain some idea on how the environment influences the cortex, we can turn briefly to our own long term studies here at Berkeley to indicate how we can measure morphological changes in the cerebral cortex as a consequence of stimulating or deprived environments. Learning must take place before wisdom.
We have been able to demonstrate cerebral cortical changes in response to the environment at any age. With greater exposure to new input, more regions of the cortex respond. Long term memories are thought to be stored throughout the cortex. As stated earlier, wisdom entails extensive learning and broad experiences. However, some people can make broad, sweeping, wise decisions when they are young; others display their specific type of wisdom when they are old. Perhaps, intuition in the young is playing a powerful role or perhaps, the young have different combinations of the neurotransmitters in the synapses of their cerebral cortices to provide a more profound use of the incoming stimuli. There are many factors to be considered in determining what makes intelligence in the first place and then the greater combination of available factors which provide wisdom have to be considered.
Once while I was speaking to a group of 13-14 year old teenagers in Shanghai, China in 1985, a young girl stood up and asked, "Why is it that we are the most creative before 40 and yet wisdom does not come until after 60?" I gathered my thoughts for a moment and then asked if I could base my answer on experiments with rats. Yes, of course, was her answer. Many years ago I had this drawing of a nerve cell and its potential. With our young rats living in enriched environments, it was the 3rd or 4th order dendrites that showed growth with enrichment; with our 600 day old rats it was the 6th order dendrites that showed the greatest effects of enrichment. Does creativity come from the more focused dendrites as seen with the 3rd and 4th orders and wisdom with broad spread of sampling? A possible idea.
Finally, I would like to add one more variable. When choosing terms to define wisdom, I think courage should be strongly stressed. Often one makes wise decision but does not have the courage to follow them through and make useful societal changes based on their own brand of wisdom. It is often easy to exhibit wisdom, but very difficult to demonstrate the courage to put it into action.
In conclusion, like love, wisdom depends on many brain regions feeding information into the cerebral cortex where the highest association areas, the last to develop embryologically and phylogenetically, can integrate the input. The frontal lobe is undoubtedly the most important area to culminate the neural processes leading to what we call wisdom and the most refined sense of love. The limbic system obviously plays a role in the emotional component of love. It is almost as if everything comes to a pinnacle in the frontal cortex right behind your forehead. As far as we know there is no limit to the power of the human mind in designing its unique patterns of wisdom and love. Let me end with Michelangelo's painting on the ceiling of the Sistine Chapel. Here is God and here is Man. Notice that the body of God is surrounded by a shroud in the outline of the human brain, the ultimate source of wisdom and love.
About the Author
Marian Diamond is a Professor of Integrative Biology at the University of California, Berkeley and is a member of the AHIMSA Advisory Board. She is co-author of Magic Trees of the Mind.
Copyright © January 2000
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