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  • This episode of Real Engineering is brought to you by Curiosity Steam. Sign up today and

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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 titledLearning to control a brain-machine interface for reaching and

  • grasping by primatesdetails 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.