If you were in medical school just 20 years ago you might have
been taught that the human brain was incapable of producing new
brain cells. Doctors and brain scientists believed this because
the nervous system did not seem capable of repairing itself and
no new brain cells had ever been demonstrated. New technologies
that let us study the brain in more detail are changing many old
beliefs about how the brain works, maintaining brain fitness and
memory and what the brain is capable of. The brain is estimated
to have 100 billion neurons and 100 trillion connections between
neurons. However, what we still don't know about the brain is
considerable. Think of the brain as an entire universe that we
are just beginning to journey into. When brain scientists use
the word plasticity they don't mean plastic—they are talking
about the brain’s ability to reorganize itself and adapt to new
knowledge and experience. Research over the past 20 years shows
that this ability to change and adapt is not lost with age.
Neurogenes