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Over the last decade Elon Musk has become
one of the most famous men on the planet.
Revolutionising the banking, automotive, rocket,
and energy industries in a relatively short
period of time. His reputation for disrupting
established industries has elevated his status
to some sort of tech jesus for many, and with
his latest venture, Neurolink, Musk appears
to trying to take that status to the next
level. Neurolink is, to me, Musk’s most
fascinating venture yet. With the goal of
developing technologies to unearth the mysteries
of our most vital organ, the brain.
We have decoded our DNA and even discovered
methods to selectively edit it. We have invented
tiny devices that can be implanted into the
body to correct our heartbeat. We can take
organs from donors and transfer them to those
in need. We can perform total joint replacements
and artificially grow skin from stem cells.
But the brain remains a mystery in many ways,
with little to no options for intervention
when malfunctions occur. We have only scratched
the surface of this organs operation, and
to me, it’s one of the final great frontiers
of science.
If you pay attention to just the headlines
of mainstream science publications, this technology
will seem like Musk is trying to create cyborg
humans.
Where healthy people will voluntarily get
biomedical implants to augment their brain
function, but that’s just Musk using his
tech jesus status to generate hype for his
latest business venture. In reality Neurolink
is so much more than something much more meaningful,
but perhaps less exciting for the average
person. This technology could help accelerate
our exploration of the brain, and help people
with severe brain malfunctions and injuries
to live happier and longer lives.
To understand what Neurolink is trying to
do. We must first look technologies Neuralink
is looking to improve on and get a basic understanding
of how the nervous system works. For that
I will pass you over to Stephanie from our
new channel Real Science:
We have many different kinds of receptors
in our body to gather information about the
world around us. Take the hair cells of your
inner ear. They are activated when vibrated
by sound and the cochlea, the snail shaped
organ in your inner ear, is shaped in a way
to allow different portions of it to be activated
by different frequencies, thanks to the differing
stiffness of the basilar membrane along the
length of the cochlea. [1]
This means the base of the cochlea, closest
to the oval window connected to the outer
ear is sensitive to high frequencies up to
20,000 hertz. And as we descend deeper into
the snail shaped sensory organ, lower frequencies
begin to vibrate the hair cells until we reach
the apex of the cochlea where frequencies
as low as 20 hertz can be detected.
When activated, these hair cells send electrical
impulses through the auditory nerve to your
brain for interpretation. The exact process
of interpretation is insanely complicated
and beyond the knowledge of man, as there
are thousands of neurons involved that gradually
branch out as they travel to their final destination.
But thanks to our understanding of the signal
input stage we can actually just bypass the
ear as a sensory organ altogether and artificially
stimulate the nervous system to allow the
deaf to hear. This is exactly what cochlear
implants do Seeing videos like this is quite
possibly the most heart-warming thing on the
internet. Children who have never heard the
sound of their mother’s voice suddenly able
to hear for the first time. Their smiles would
make anyone see the value in this technology.
So how does this work? The device consists
of a microphone and a sound processor, which
in turn generates electrical signals to send
to an electrode array which is actually inserted
directly into the cochlea where it can directly
stimulate the nerves of the inner ear with
electrical impulses. [2]
This bypasses both the hair cells of the inner
ear and the sound transmitting structures
of the outer ear, and so it can help people
who have malfunctions in these parts to ear.
An astounding technology, but it does not
require any implantation of medical devices
into the brain, as Neurolink plans to do.
It simply activates the nervous system at
its input stage. Creating a technology which
could say, activate the auditory cortex directly
to allow us to hear is a whole other ball
game.
Current technology on this side of things
is highly invasive. Take braingate. This implantable
device consists of about 256 electrodes which
can both read and stimulate neural activity.
This is exactly the function Neuralink is
working to improve on. This lady is doing
something amazing. This medical implant was
placed on the surface of her brain at the
motor cortex, where it records the activity
of the neurons in that area. [3] The data
from those records were then used to effect
a mouse cursor which has allowed her to type
and use a computer, despite having no movement
in her limbs. The researchers took this a
step further and began using the neural records
to allow another woman to control the movement
of a robotic arm. [4]
This is the exact technology Neuralink is
seeking to improve upon, and there is a lot
to be improved upon.
The first issue with Utah Array is the material
properties of the electrodes. These electrodes
are like stiff and sharp needles, which allows
them to penetrate into the brain and record
the internal activity, but this causes problems
with the bodies immune response. [5]
This is the first part of Neurolinks plans
to improve this technology by making these
electrodes much smaller.
The Utah Array’s electrodes vary from about
0.03 millimeters at their tip to about 0.1
at their base [5].Neurolink threads are much
much smaller at about 0.004 to 0.006 millimetres.[6]
Side by side that looks something like this.
Making the threads thinner allows them to
affect a smaller portion of the brain, making
them less likely to affect nerve function
or to puncture blood vessels, but perhaps
more critically makes the threads more flexible.
Allowing them to move with the brain as it
jiggles around in the skull.
This is actually a huge problem. The tissue
in the brain is very soft and elastic. If
you have stiff needle like electrodes fixed
in place, the brain will simply deform around
them. This causes scar tissue to form around
the needle which over time will block the
needles ability to read brain activity through
the scar tissue
Matching the electrodes’s material properties
to the brains as close as possible will allow
the electrode to move and deform with the
brain, and thus decrease this scar tissue
formation and extend the life of electrodes.
A vital design parameter from medical implants.
So neurolink has moved away from these stiff
silicon electrodes [7] and created thinner
flexible gold electrodes coated in a conductive
biocompatible thin film polymer. [6]
But electrodes like this come with their own
issues. Their small size and flexibility makes
them very difficult for even the skilled hand
of a surgeon to insert, so Neuralink has also
developed a robotic electrode inserter to
lend a helping hand.
The robot comes with a suite of camera and
light modules to allow the robot to accurately
insert the threads.. The robot uses a needle
to advance the electrode thread to the desired
depth in the brain before retracting and leaving
the thread behind. This robot on average could
insert an electrode thread in a little over
a minute even when the surgeon performed manual
adjustments to avoid blood vessels.
Neuralink’s white paper put particular emphasis
on this ability as the breaking of the blood
brain barrier is suspected to be a key driver
in the brain inflammatory response, which
again can cause scarring and reduce the electrodes
function.
It’s important to note that Neuralink isn’t
the first company to create thin film polymer
electrodes [8], but with this robot and their
work on streamlining the manufacturing process
for mass production has put Neuralink in a
strong position to create a viable medical
device for sale. They have also increased
the channel count significantly.
The Utah Array electrode array can reach a
max channel count of 256 channels. Whereas
this prototype system, which Neuralink surgically
implanted in a rat and successfully recorded
from has 96 electrode threads, each containing
32 electrodes, for a total of 3072 channels
to read from.
This is a very important design parameter
as more data equals more control.
This journal paper titled “Learning to control
a brain-machine interface for reaching and
grasping by primates” details an experiment
where researchers implanted a brain-machine
interface into the brain of macaque monkeys.[9]
They trained the monkeys to complete a task
on a screen using a small hand held controller.
They recorded the monkeys motor cortex neural
activity during this training and mapped a
robot arm to match his hand movements. They
confirmed that the more neurons they could
record from the higher the probability of
the robotic arm matching the monkeys actual
arm movements. Note this footage is from a
later 2008 study where the researchers actually
trained the monkeys to feed themselves. [10]
So if we can record from more channels, we
can expect to achieve higher accuracy and
later as the technology progress we can perform
more complicated tasks. Perhaps instead of
controlling a cursor or robot arm, we can
fit exo-skelatons to paralysed patients to
allow them to walk. However we have one last
and significant technology challenge before
that can ever be considered.
We somehow need to get this data out of the
brain. The electrodes record analog data from
the brain which first needs to be amplified
as neural signals are very faint with voltages
as low as 10 microvolts, noise then needs
to be filtered out and finally the analogy
signal is converted to binary data. This reduction
to simple bits is vital, as we somehow need
to transfer this data to a computer outside
of the head. Installing a processing board
inside the brain is simply not an option.
Looking at the utah array we can see there
is a lot left to be desired. The electrodes
themselves require a connector which bears
an uncanny resemblance to the headjack from
the matrix. When the researchers wanted to
use the brain machine interface they had to
plug these massive neuroport blocks to the
connector which feed the data to a huge amplifiers
and signal processing.
Neurolink is trying to fit the amplification
and data filtering step inside the onboard
processors.
This is their prototype board which they fitted
into the rat. Here the electrode threads fed
into 12 custom built microchips each capable
of processing 256 channels of data, equalling
the 3072 channels coming from the threads.
However this prototype system simply used
a USB C port for both power and data transfer.
Which again is going to require an ugly port
breaking the skin.
This isn’t just a cosmetic issue. It’s
a massive open wound in the bodies first line
of defense for infection and it leads straight
to the bodies most valuable organ. It’s
simply not an option for a commercial product.
So Neuralinks next technological challenge
is to develop a method to both power and transfer
data to these implantable devices. Elon made
some off handed comments about this during
his presentation about this:
“And the interface to the chip is wireless
so you have no wires poking out of your head.
Very, very important. So you it's basically
bluetooth to your phone. We'll have to watch
the App Store updates for that one make sure
we don't have a driver issue. Uhhhm updating
…..”
Good one Elon.
Okay, so beyond joking about people’s brain
implants potentially having driver issues.
This comment, in typical Elon fashion, is
a little misleading. Bluetooth doesn’t actually
have the bandwidth needed to transfer this
much data, so an alternative method will be
needed to transfer it from the device to outside
the skin.
The neuralink whitepaper does not shed much
light on this specific part of their plans
here, but they did present very briefly in
their presentation that their first planned
product consists of four of their N1 chips.
3 will be implanted in the motor cortex for
control and 1 will be implanted in the somatosensory
cortex for sensor feedback. These will feed
data to an inductive charging and data transfer
coil under the skin behind the ear, which
will then transfer the data to a wearable
computer and charger worn behind the ear.
This device will probably perform some further
data processing before transferring the simplified
data through bluetooth to a phone where it
will allow the user to control a cursor on
the phone or a computer.
Neuralink stated ambitious goal of beginning
human trials this year in order to begin the
long and difficult task of receiving FDA approval.
If they managed to get the food and drug association
approval for a commercial product, this would
be a major leap forward for the treatment
of injuries resulting in paralysis. Potentially
transforming the life of the hundreds of thousands
of people living with paralysis, allowing
them to complete simple tasks like controlling
their computers without the help of a carer.
While I don’t see healthy people using these
kinds of devices anytime soon, as the implanting
any device into the body never mind the brain
will always be a massive risk. It’s certainly
a plausible scenario that future humans could
elect to have a device like this implanted.
There is a legitimate worry that machine learning
and artificial intelligence is going to pose
an existential threat to human society in
the near future and you can learn more about
it by watching The A.I. Race on curiosity
stream.
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