The Brain That Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science

by Norman Doidge

To find out if neurogenesis can strengthen mental capacity, Gage’s team has set out to understand how to increase the production of neuronal stem cells. Gage’s colleague Gerd Kempermann raised aging mice in enriched environments, filled with mice toys such as balls, tubes, and running wheels, for only forty-five days. When Kempermann sacrificed the mice and examined their brains, he found they had a 15 percent increase in the volume of their hippocampi and forty thousand new neurons, also a 15 percent increase, compared with mice raised in standard cages. Mice live to about two years. When the team tested older mice raised in the enriched environment for ten months in the second half of their lives, there was a fivefold increase in the number of neurons in the hippocampus. These mice were better at tests of learning, exploration, movement, and other measures of mouse intelligence than those raised in unenriched conditions. They developed new neurons, though not quite as quickly as younger mice, proving that long-term enrichment had an immense effect on promoting neurogenesis in an aging brain.

neurogenesis can be accessed at an older age though not as fast as pre pruning age. continues to be more effeciant in a stimulating enviroment.