Explain how the discovery of neurogenesis has changed our view of the aging of the brain as well as the feasibility of using new techniques for repairing the brain

What will be an ideal response?

Answer will include that until only a few years ago, it was widely believed that we are born with all the brain cells we will ever have. This led to the depressing idea that we all slowly go downhill, as the brain loses thousands of neurons every day. However, we now know that a healthy 75-year-old brain has just as many neurons as it did when it was a 25-year-old brain. Although it is true that the brain loses cells daily, it simultaneously grows new neurons to replace them. This process is called neurogenesis. Each day, thousands of new cells originate deep within the brain, move to the surface, and link up with other neurons to become part of the brain's circuitry. The discovery of neurogenesis in adult brains has raised new hopes that some types of brain damage can be repaired. One approach is constraint-induced movement therapy, in which the arm not affected by the stroke is immobilized, forcing the impaired arm to become more active to increase the rate of neurogenesis in the damaged part of the brain and speed recover. Drugs have also been injected into the damaged area to speed up neurogenesis. Such techniques are beginning to offer hope to people suffering from strokes, blindness, and Parkinson's disease.