The future is now.
We’ve got the entire world wide web in our pockets,
chefs have created veggie burgers that bleed like real meat,
and scientists can control minds.
Wait...what?
Yeah, that’s not a joke!
Hey there!
I’m Alie Astrocyte, and on this episode of Neuro Transmissions,
we’re gonna talk about optogenetics.
Controlling the brain using light.
When I say mind control, it might sound
like something out of Star Wars.
But in the last decade,
advances in technology have let scientists
figure out how to directly control
the signaling between neurons.
See, neurons use electricity to send signals.
All along both sides of the cell membrane are
electrically charged ions, which create
an electrical gradient.
To send a signal, called an action potential,
ion channels have to open to allow ions
to flow across the plasma membrane,
shifting the balance of the electrical charge.
This change in the charge sends
the action potential shooting down
the axon of the neuron,
passing the signal along to the length of the cell.
Since that action potential is the key to
how neurons communicate,
neuroscientists have been
trying to figure out how to control it.
Control action potential and you
control the brain!
Kinda.
But it wasn’t until the early 2000’s
that they found the right tools for the job.
In 2003, some scientists discovered a protein
called channelrhodopsin.
A light-sensitive ion channel
produced by an algae.
This channel opens in response to light,
allowing the algae to sense the direction
of a light source. Like the sun.
Scientists immediately realized that this
new protein could be the answer to
their conundrum.
In 2004, two separate groups of neuroscientists
were able to use viruses to insert
the channelrhodopsin gene into neurons.
Since channelrhodopsin can be
activated by shining a light on it,
when it’s expressed in neurons,
shining a light on those neurons
opens up the channels,
generating an action potential.
Scientists have been able to create mice that
naturally express the protein in their neurons.
And, researchers can surgically insert
tiny LED lights or optic fibers into
different brain regions, to focus their
light beam on specific structures or cell types.
When they turn on the light, they essentially
turn on the neurons exposed to the light.
This lets scientists examine how turning
those cells on and off affect
a lot of different things.
Including controlling the behavior of
an awake animal.
And because light is so easy
to turn on and off,
optogenetics allow very precise control
of neuronal activation.
Like, in the realm of milliseconds.
Because optogenetics only requires a
single gene to create the protein,
scientists can target specific types of neurons
to make them express channelrhodopsin,
letting them pick apart the roles of
different cells in the brain.
Even more recently, researchers have started
using new light-sensitive proteins to influence
neuronal signaling.
Some of them open and close at different rates,
affecting the speed of the neuron’s signal.
And some of them can actually suppress action potentials,
letting scientists effectively turn off
particular neurons within a circuit.
Using optogenetics, neuroscientists have been
able to discover some
pretty fascinating new stuff.
Some researchers have identified a circuit
in the amygdala, sometimes thought of
as being the “fear center” of the brain,
that’s involved in how we learn to fear something.
And, they’ve also been able to tease apart
some of the circuits that are affected in
movement disorders like Parkinson’s disease.
Other researchers, including some of my
friends here at UCSD,
are using optogenetics to understand things
like how the brain processes time,
and how different brain cells are connected to
aggressive behaviors.
Some scientists are even trying to use
optogenetics to help human patients
by developing new kinds of pacemakers
that use light to regulate the heartbeat.
That’s the beauty of a technology like optogenetics.
It can be used for so many different things.
The possibilities are really endless!
I guess we’d better be careful and
make sure we keep this technology away from
the mad scientists, huh?
Thanks for watching this episode of Neuro Transmissions!
If you liked it, give us a thumbs up, and
hit subscribe to learn more about the
new kinds of technologies scientists are using
to study the brain.
Until our next transmission, I’m Alie Astrocyte.
Over and out.