Adulthood was supposed to be a long period of mental decline, as brain cells slowly died off and no new ones were born. Neurobiologist Fred Gage at the Salk Institute in La Jolla, California, overturned conventional wisdom by proving that fresh cells keep growing in the human hippocampus, a brain region critical to learning and memory.
Why does it matter that some brain cells can regenerate? If we can understand the cellular and molecular mechanisms that create new neurons in a normal brain, we may be able to recruit these cells to repair damage in injured brains.
You've found that exercising mice grow twice as many new brain cells as inactive mice. Does this mean that if we exercise regularly we'll improve our brainpower? There's evidence that exercise is associated with improved learning and memory, and also decreases depression. We can speculate these changes may result from the creation of new neurons. Courtesy: Gary Payne/Liaison Agency Inc.
What's left to discover about the human brain? We're not even sure what the most important questions are. We're seeing old dogmas challenged because of the merger of brain science with related disciplines--molecular biology, engineering, chemistry, philosophy. I don't believe we will ever understand the brain completely.
Should we view the brain as an advanced computer? There are many differences between the brain and a computer. At a more fundamental level, we know how computers process information, but we don't really know how brains do it. Some advanced computers are designed to process information analogously to how we think the brain processes information, but this is theoretical at best.
Scientists recently found that one part of Einstein's brain--the parietal cortex--was unusually large. Could this be the source of his genius? The parietal cortex is where different kinds of sensory and motor information converge, and it's likely that higher cognitive processes are going on here. Einstein had a great ability to combine and create new concepts, so the area of his brain that's different is one associated with his uniqueness. But until you study the brains of a whole range of folks, it's hard to extrapolate.