(ethereal music)
- [Instructor] The sounds you're listening to
were generated from data.
Data that came from a recording of a teeny tiny pocket of
space between two brain cells.
This music represents findings about how brains work that
have wide ranging implications
for the field of neuroscience.
From understanding neuropsychiatric conditions like autism,
to building human-computer interfaces.
So how do you get a song out of a neuron?
And what's it telling us.
- Oh, these neurons really excited.
- Simone Sun studies neuroscience
in the Chen Lab at NYU Langone.
We paid a visit to the lab,
a kind of synaptic recording studio
to gather the data that will eventually
end up in that song we just played.
Simone studies, neuroplasticity,
the brain's ability to change and adapt.
She does this by taking recordings of synapses,
which are the electrochemical connections
between neurons or brain cells.
- So like if two neurons are connected
to each other by a synapse,
the one that is sending the signal will spike and then
release some neurotransmitters or like chemicals that get
received by the other neuron.
- These cells in the brain can be plastic
or change in a number of ways.
- One of the ways that we classically
think about neurons is that
they can exhibit something that we call Hebbian plasticity
where, neurons that fire together wire together.
And so if two neurons are talking to each other,
quite a bit, the connection between them
get stronger and stronger.
- In other words,
Hebbian plasticity is like plugging a microphone into an
amplifier and turning it up,
strengthening a signal so that it takes less time for
information to travel from point A to point B.
It's why things that you do frequently become almost
automatic with practice.
But an unchecked amplifier will just turn up every signal
until the speaker blows, (beeps)
which is why we have something called homeostatic
plasticity, which stabilizes information in the brain
by keeping signals from being amplified too much.
- We typically think of these things
as two separate processes, that Hebbian plasticity
does its thing and homeostatic plasticity comes in to say,
hey, keep it down, tone it down a little bit
and keep everything in check.
- But Simone's finding, it's not that simple.
- This idea that they're in opposition to each other
is not as clean cut as we previously thought.
- Simone's experiments are changing
the theoretical frameworks used
to understand plasticity in the brain.
And they could have broad implications for the
field of neuroscience.
To understand these processes,
Simone takes recordings of synaptic activity.
- To sort of listen to the synapses
that our neuron possesses,
I take neurons from up the cortex of mice,
and I grind them up is a little intense of a word,
but essentially dissociate them so
they're not connected to each other
and then I take some of them and
I put them on a little glass surface and then
they just naturally regrow and form their networks again.
- Once they're ready, the dish of neurons
goes under a microscope and a machine
keeps warm artificial, cerebralspinal fluid flowing,
so they don't die.
- And then after I do that,
I take a little electrode and I go right up to one of the
neurons, that one looks good.
And then I sort of poke it a little bit
and I essentially get inside the neuron.
- Simone then applies a little negative pressure
by sucking in some air to attach the pipette to the cell.
- Let's see if we can break in.
- And then she gives it a little kiss to break in.
- Now we're inside and let's get a recording.
Let's see what it's doing.
It's almost, I've essentially like built a forest, right?
I've taken a bunch of little seedlings,
I've let the forest grow,
and then I go up to one of the trees and try and figure out
how it interacts with all of the other trees around it.
And from that, I can see all of the different
the electrical responses, the synaptic responses
and do use that to answer questions about how
homeostatic plasticity works?
- Simone's last step is to actually listen
to the different electrical responses.
- The first time I encounter the data,
it kind of gives me that same feeling, right?
When you're done with the experiment and you have the data
in front of you, you don't know what it's going to say.
When I, plug it into the music software
and hit play for the first time,
it's like a fresh new experience of,
what's the result, what am I seeing?
- What is she seeing?
A recording, any recording is just a
continuous measurement of how something changes over time.
When a microphone picks up a sound wave,
that's being translated into a voltage,
which creates that squiggle you see on a screen.
Brain signals are recorded on the computer in the same way.
The electrochemical changes are translated into a voltage
and you see a squiggle like you
would in a piece of audio software.
- If you remember, we were recording from inside a neuron
and so what we're doing here is we're listening
to the different synapses that it all has
so it's receiving thousands of synapses from,
all of the neurons around it.
- The height of each of these responses
represents the strength of the synaptic signal.
Simone wrote a computer program that takes the strength or
the height of each response and assigns it a specific note.
Put all those spikes in sequence and you get this.
(ethereal music)
- It's essentially, you're kind of
hearing all of the synapses pinging.
- What's more, neurons that behave differently
can sound different.
To induce a homeostatic response,
Simone treats neurons with drugs that prevent them from
transmitting producing a unique song.
- So this neuron was treated with a drug that turns off the
spiking, so it can't spike and transmit anymore.
And so after a long period of time,
there's the homeostatic response where it increases the
strength of the synapses.
And so the range of the notes in the musical version of this
is much wider and there are more of them.
- What's Simone's finding doesn't just make for a new hit
single, among other things, it could change
how we understand neuropsychiatric conditions.
- There's ideas that in autism that the
homeostatic plasticity or the mechanisms of homeostatic
plasticity are altered in a particular way.
Understanding exactly how a mutation that is associated with
this kind of thing changes the way that a neuron acts and is
connected with another one could potentially give us some
understanding into exactly how autism can come from
particular changes to these kinds of proteins in the brain.
- There's also evidence that brain recordings can be used to
engineer audio that can have clinical applications and even
therapeutic effects on people.
Research shows that music based on recorded brain signals
from EEG can influence people's breathing rates and make
them more relaxed by creating a personalized tempo.
Scientists are using this same technology to construct a
brain computer interfaces that convert brain signals of
people who have loss of motor control into music.
But for Simone music is just another context for data.
A way to differently communicate
the ongoing chatter of the brain.
- So this is another way of giving the data
a voice and having it, allowing it to speak to us
in the same way that when we're analyzing it
and trying to find different kinds of patterns in it.
No, (laughs) no let's not go with that one.
(instrumental music)