Food for thought…
A Decade of Discovery Yields a Shock About the Brain
January 4, 2000 New York Times
By SANDRA BLAKESLEE
As scientists look back at all the discoveries made in the 1990’s, the so-called Decade of the Brain, one finding stands out as the most startling and, for many scientists, the most difficult to accept: people are not necessarily born with all the brain cells they will ever have.
In fact, from birth through late adolescence, the brain appears to add billions of new cells, literally constructing its circuits out of freshly made neurons as children and teenagers interact with their environments. In adulthood, the process of adding new cells slows down but does not stop. Mature circuits appear to be maintained by new cell growth well into old age…
Although the Congressionally mandated “Decade” produced many other discoveries, from ways to obtain images of fleeting thoughts inside a person’s head to new drugs for a wide variety of mental disorders, the finding that the brain develops and maintains itself by adding new cells is the most revolutionary. …
Some researchers have begun isolating special cells that continue to divide and produce new brain tissue, with the hope of implanting such cells into areas of the brain that are damaged by disease or accidents.
For decades, it was axiomatic that people were born with all the brain cells they would ever have. Unlike the bones, the skin, the blood vessels and other body parts, where cells divide throughout life to give rise to new cells, it was believed that the brain did not renew itself.
Though the brain did add vast amounts of new connections early in life and could compensate somewhat for many injuries, it was thought that no one could be expected to grow more brain cells with age. Quite the opposite. People were told that the only thing they could look forward to was gradual mental deterioration as cells died off and were never replenished.
These ideas were so firmly established that many scientists have a hard time believing the findings, reported in the last couple of years by a number of investigators, that the human brain makes new cells after birth, said Dr. Fred H. Gage, a neuroscientist at the Salk Institute in La Jolla, Calif.