Could your brain repair itself? - Ralitsa Petrova

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Imagine the brain could reboot, updating its damaged cells with new, improved units. That may sound like science fiction — but it’s a potential reality scientists are investigating right now. Ralitsa Petrova details the science behind neurogenesis and explains how we might harness it to reverse diseases like Alzheimer’s and Parkinson’s.

Lesson by Ralitsa Petrova, animation by Artrake Studio.

Imagine the brain could reboot,

updating its withered and damaged cells
with new, improved units.

That may sound like science fiction,

but it's a potential reality
scientists are investigating right now.

Will our brains one day
be able to self-repair?

It's well known that embryonic cells
in our young developing brains

produce new neurons,

the microscopic units
that make up the brain's tissue.

Those newly generated neurons migrate
to various parts of the developing brain,

making it self-organize
into different structures.

But until recently,

scientists thought cell production came to
an abrupt halt soon after this initial growth,

leading them to conclude
that neurological diseases,

like Alzheimer's and Parkinson's,

and damaging events, like strokes,
are irreversible.

But a series of recent discoveries

has revealed that adult brains
actually do continue to produce new cells

in at least three specialized locations.

This process, known as neurogenesis,

involves dedicated brain cells,
called neural stem cells

and progenitor cells,

which manufacture new neurons
or replace the old ones.

The three regions where neurogenesis
has been discovered

are the dentate gyrus,
associated with learning and memory,

the subventricular zone, which may
supply neurons to the olfactory bulb

for communication
between the nose and brain,

and the striatum,
which helps manage movement.

Scientists don't yet have a good grasp
on exactly what role

neurogenesis plays
in any of these regions,

or why they have this ability
that's absent from the rest of the brain,

but the mere presence of a mechanism
to grown new neurons in the adult brain

opens up an amazing possibility.

Could we harness that mechanism
to get the brain to heal its scars

similar to how new skin
grows to patch up a wound,

or a broken bone
stitches itself back together?

So here's where we stand.

Certain proteins and other small molecules
that mimick those proteins

can be administered to the brain

to make neural stem cells
and progenitor cells

produce more neurons
in those three locations.

This technique still needs improvement

so that the cells
reproduce more efficiently

and more cells survive.

But research shows that progenitor cells
from these areas

can actually migrate to places where
injury has occurred

and give rise to new neurons there.

And another promising possible approach

is to transplant healthy
human neural stem cells,

which are cultured in a laboratory,
to injured tissue,

like we can do with skin.

Scientists are currently experimenting

to determine whether transplanted
donor cells can divide, differentiate

and successfully give rise
to new neurons in a damaged brain.

They've also discovered

that we might be able to teach
other kinds of brain cells,

such as astrocytes
or oligodendrocytes

to behave like neural stem cells
and start generating neurons, too.

So, a couple of decades from now
will our brains be able to self-repair?

We can't say for sure,

but that has become one of the major
goals of regenerative medicine.

The human brain has 100 billion neurons

and we're still figuring out the wiring
behind this huge biological motherboard.

But everyday, research on neurogenesis
brings us closer to that reboot switch.