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Imagine the brain could reboot,
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updating its withered and damaged cells
with new, improved units.
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That may sound like science fiction,
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but it's a potential reality
scientists are investigating right now.
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Will our brains one day
be able to self-repair?
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It's well known that embryonic cells
in our young developing brains
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produce new neurons,
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the microscopic units
that make up the brain's tissue.
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Those newly generated neurons migrate
to various parts of the developing brain,
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making it self-organize
into different structures.
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But until recently,
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scientists thought cell production came to
an abrupt halt soon after this initial growth,
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leading them to conclude
that neurological diseases,
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like Alzheimer's and Parkinson's,
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and damaging events, like strokes,
are irreversible.
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But a series of recent discoveries
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has revealed that adult brains
actually do continue to produce new cells
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in at least three specialized locations.
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This process, known as neurogenesis,
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involves dedicated brain cells,
called neural stem cells
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and progenitor cells,
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which manufacture new neurons
or replace the old ones.
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The three regions where neurogenesis
has been discovered
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are the dentate gyrus,
associated with learning and memory,
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the subventricular zone, which may
supply neurons to the olfactory bulb
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for communication
between the nose and brain,
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and the striatum,
which helps manage movement.
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Scientists don't yet have a good grasp
on exactly what role
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neurogenesis plays
in any of these regions,
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or why they have this ability
that's absent from the rest of the brain,
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but the mere presence of a mechanism
to grown new neurons in the adult brain
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opens up an amazing possibility.
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Could we harness that mechanism
to get the brain to heal its scars
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similar to how new skin
grows to patch up a wound,
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or a broken bone
stitches itself back together?
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So here's where we stand.
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Certain proteins and other small molecules
that mimick those proteins
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can be administered to the brain
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to make neural stem cells
and progenitor cells
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produce more neurons
in those three locations.
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This technique still needs improvement
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so that the cells
reproduce more efficiently
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and more cells survive.
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But research shows that progenitor cells
from these areas
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can actually migrate to places where
injury has occurred
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and give rise to new neurons there.
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And another promising possible approach
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is to transplant healthy
human neural stem cells,
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which are cultured in a laboratory,
to injured tissue,
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like we can do with skin.
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Scientists are currently experimenting
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to determine whether transplanted
donor cells can divide, differentiate
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and successfully give rise
to new neurons in a damaged brain.
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They've also discovered
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that we might be able to teach
other kinds of brain cells,
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such as astrocytes
or oligodendrocytes
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to behave like neural stem cells
and start generating neurons, too.
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So, a couple of decades from now
will our brains be able to self-repair?
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We can't say for sure,
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but that has become one of the major
goals of regenerative medicine.
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The human brain has 100 billion neurons
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and we're still figuring out the wiring
behind this huge biological motherboard.
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But everyday, research on neurogenesis
brings us closer to that reboot switch.