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by Gerald Epling

If you lost a few brain cells, would you miss them?  How would you know?  These questions get at the nature of memory and the importance of memory to our sense of wellbeing.

The brain is intimately linked to all of our expressions, emotions, thoughts, experiences, and self-knowledge.  The closeness of the physiological to the psychological makes it difficult to know, if the brain is the cause of a particular state of mind or merely the responder to psychological activity.  The placebo effect demonstrates how well the body can respond to the mind.  In contrast, there are many examples of a healthy body having a positive impact on the mind.  It is exhilarating to wake up rested and alert whatever adventures a new day may bring.

The effect of the mind on the body is complemented by the effect of the body on the mind.  The dance between the psychological and the physiological is one of tension, mood, and memory.

How sensitive is the mind to the health of the body?  Could there be an emotional expression of essential knowledge that comes with a decline in brain cells?  The short answer to the second question is, yes.  The question of just how sensitive the mind is to the health of the body.  The renewal of the brain is a bit more complicated.

In order to look for an effect of reduced brain cell regeneration, we have to find an existing practice that temporarily interrupts the brain’s renewal system.  This sort of temporary impairment is found in a treatment for cancer that is known as chemotherapy.

Chemotherapy destroys primitive cells and other newly forming cells in the body.  This medical intervention may be used to fight cancer, when there is a fear that some of the cancer may be left behind after surgery.  It is not unusual for people on chemotherapy to experience increased feelings of melancholy, sadness, or depression.  This melancholy is linked to the loss of brain cells that would normally be replaced by new brain cells.  The importance of memory to our sense of wellbeing is profound.

Each day about 700 new cells are added to the brain’s hippocampus.  The hippocampus is an area of the brain that is activated when we form or recall many types of memories.  Chemotherapy would tend to reduce the number of new cells that arrive in the hippocampus each day to replace older brain cells.  This sort of loss is linked to a sense of melancholy receiving chemotherapy.

Could the effect work in reverse?  That is to say, could people experience an increase in sense of wellbeing with an increase in new brain cells showing up to supply our thoughtful needs?  The question might appear to be open.  However, there are good indications that increasing the natural renewal process of the brain supports a sense of overall wellbeing.  We know that learning and education increase the number of brain cells.

It is interesting to note that as recently as 1998, medical dogma maintained that there is no replacement of brain cells in the mature adult brain.  Then in 1998, Gage and colleagues found clear evidence that the brain does experience neurogenesis.  Other studies built upon the discovery techniques and expanded our understanding to include the recent indication that about 700 new neurons appear in the hippocampus every day.



Relevant Reading

Eriksson, P.S., Perfilieva, E., Björk-Eriksson, T., Alborn, A., Nordborg, C., Peterson, D.A., & Gage, F.H. (1998). Neurogenesis in the adult human hippocampus. Nature Medicine, 4, 1313-1317.

Gibbs, W.W. (1998, November). DOGMA OVERTURNED: Upending a long-held theory, a study finds that humans can grow new brain neurons throughout life–even into old age. Scientific American, 19-20.

Insel, T.R. (1995). The Development of Brain and Behavior. In F.E. Bloom, & D.J. Kupfer (Eds.), Psychopharmacology, The Fourth Generation of Progress (pp. 683-694). New York: Raven Press.

Kaplan, M.S., & Hinds, J.W. (1977). Neurogenesis in the adult rat: electromicrographic analysis of light radioautographs. Science, 197, 1092-1094.