Unless you’ve been living in complete oblivion or in Antarctica, I bet you watched Stranger Things on Netflix.
Yeah, the T.V. show where a guy gets sucked into a lightbulb and his best friends find him through secret government experiments and unnatural forces.
But the coolest part of the show was a girl, named Eleven, who showed up out of nowhere and barely talked, but controlled things with her mind and had constant nosebleeds instead.
It was quite the roller coaster.
Undeniably, the most exhilarating part of the show was Eleven’s superpowers.
Namely, her telekinetic abilities.
Being hyperactive middle schoolers when the show first aired, my friends and I talked about the show constantly. I, for one, took it upon myself to practice my telekinetic abilities day and night to no avail.
While many of us dreamt of waking up one day and controlling things with our mind, it seemed to be an impractical idea; only to be contained within a fictional realm.
But while telekinesis might not be a reality just yet, we’re getting pretty close to it.
When I think of mind control, one company pops into my head immediately.
And unless you’ve been living under a rock, you’ve probably heard of it too.
From Neuron to Computer.
What’s so wild about Neuralink?
Well, Neuralink is currently designing a neural implant, called the “Link,” which will allow users to control a computer or a mobile device anywhere they go.
Neuralink’s initial goal is to use the Link to allow quadriplegic patients, or completely paralyzed individuals, to control a computer or smartphone using just their thoughts.
But they don’t plan on stopping there.
Neuralink plans to do something that many of us thought was only contained within science fiction. Merging humans with AI to give people superhuman intelligence, and allow all individuals to have the opportunity to communicate in such a manner.
Due to this unforeseen goal, the ethical questions that surround Neuralink continue to remain prevalent.
Is it right for us to surgically implant a mechanical interface in a human? Why does it need to be implanted in such a manner in the first place?
Many argue that neural activity can be monitored through non-invasive methods techniques, such as an EEG, or electroencephalogram, which records the electrical activity of the brain through electrodes placed along the scalp.
But the potential of EEG headsets is far behind the potential of invasive Brain-Machine Interfaces, such as the one Neuralink proposes.
Electroencephalogram (EEG): a test or device that detects and records electrical activity in the brain using electrodes attached to the scalp. EEG’s determine changes in brain activity that might be useful in diagnosing brain disorders, such as brain tumors, brain damage, brain dysfunction, inflammation, stroke, and sleep disorders. EEG headsets can also be used for the augmentation of neural function, such as those being developed by companies such as OpenBCI, Muse, and Neurable which are developing headsets for focus, meditation, and more.
The neural signals picked up by EEG’s are heavily infiltrated by external noise, muscle, eye, and body movement, and post-synaptic extracellular currents.
The electrical fields produced by the neurons decay exponentially the farther the receiver is from it. Therefore, a signal can only be detected when a significantly larger group of neurons are isolated and grouped together. The local field potential, or the electric potential in the extracellular space around neurons, cannot be detected. EEG’s function at a macro-scale, only detecting activity in certain parts of the brain and the presence or absence of certain brainwaves.
In addition, the signals that EEG’s can pick up on are largely confined to pyramidal neurons, which have long, parallel dendrites; branches that reach out from the body of the neuron to the surface of the brain. The high numbers of pyramidal neurons in the cortex result in their signals being detected by the EEG, whereas local field potentials tend to reflect a larger variety of electrophysiological processes, such as action potentials.
The signal-to-noise ratio, or SNR, is high within EEG’s, as brain tissue acts as an adjunct filter on top of the other elements mentioned above. With the exception of action-potential bursts contained within large groups of neurons, EEGs can only pick up on activity usually lower than 90 Hz. In comparison, invasive devices can detect and convey signals up to several kHz.
EEG’s also do not account for the spatial distortion due to the extracellular space within the neurons, which is composed of varying media, including polysaccharides and various proteins, containing vastly different electrophysiological properties.
In turn, these properties influence how electrical fields spread and are detected. Often, they spread in the cerebrospinal fluid, skull, and scalp, which causes further spatial distortion between reaching the electrodes on the EEG.
While invasive Brain-Machine Interfaces lead to many ethical scrutinies, the recordings provided by these interfaces are much more accurate, even potentially allowing us to pick up on the intracellular states of neurons, despite surgical intervention being required for their use.
But invasive interfaces are inherently characterized by one trait. They can actually interact with the surrounding environment, influencing and affecting neurological function. And we have to power to control the efficiency with which they do so.
Invasive interfaces have to be small. Obviously. It just wouldn’t make sense nor would it be at all safe to have ping-pong ball-sized computational globs situated inside our heads.
But how small do we really mean?
Invasive electrodes come in many forms; single-electrodes, electrodes with multiple contact points along the shaft, and multi-electrode arrays (containing tens to thousands of microelectrodes). The size of these electrodes is variant on the interface; ranging from a single millimeter to a few dozen.
While these are considerably more accurate, more functional, and have much more potential to transform neural function than large, non-invasive interfaces, they are still significantly large.
Imagine two pennies, side by side. Now, imagine them inside your brain.
That’s only about 40mm, the average size of our current Brain-Machine Interfaces.
Here’s where nanotechnology comes in.
Using Nanotechnology, we can scale this number down drastically. Using nanoscale probes and interfaces, we can turn 40mm into just a few tens of nanometers.
In the case of Neuralink, 1,024 tiny electrodes protrude out from the base of the surgically-implanted interface in the form of nanoscale threads, also known as nanowires. These threads penetrate the outer surface of the brain and detect electrical impulses from nerve cells, showing that the brain is at work.
Nanowire-based bioelectronics might be the key to developing a new generation of cell electrophysiology tools.
While there isn’t a precise definition for what constitutes a nanomaterial, they are characterized by their extremely tiny dimensions, measured in nanometers. Most scientists agree that at least of if its dimensions must be smaller than 100 nanometers for a material to be classified as so.
A nanometer is one-millionth of a millimeter. For context, this is approximately 100,000 smaller than the diameter of a human hair.
Nano-sized particles are not all manmade. They exist in nature through forms including metal oxides, clay minerals, viruses, and sulfides. Yet they can also be engineered from a variety of products including carbon or silver. The nanomaterials we engineer can take on very special optical, magnetic, and electrical properties, greatly influencing fields such as neural nanotechnology.
Nanomaterials are strong and conductive materials and are often great catalysts, inturn inducing chemical reactions (such as neurobiological ones). Solid nanoparticles can even act like fluids by changing their composition, and easily change their materialistic properties, such as their color and elasticity.
Since the biological processes within the brain work at such a nanoscale level, it only makes sense for the devices we use to aid these processes to work at a nanoscale level as well.
Nanoscale structures are the most integral tools in the intersection of nanotechnology with a variety of fields, including drug delivery, solar cells, batteries, photonics, and electronics. Nanomaterials resemble biomolecules in their relative structure and size; therefore, they can be manipulated to be taken advantage of in neurobiological systems.
In particular, nanowires and nanotubes can be arranged in microelectrode arrays and can be deployed as a multitude of applications, such as sensors or probes to aid or augment neurological function.
Carbon nanotubes (CNTs), discovered in 1991, have shown astonished researchers with their mechanical, thermal, and conductive properties. Although CNTs are about a sixth of the weight of steel, their strength is significantly higher.
CNTs are cylindrical molecules, consisting of rolled-up sheets of single-layer carbon atoms, known as graphene. They can either be single-walled (SWCNT), which means they contain a diameter of less than 1 nm, or can consist of several interlinked nanotubes, which are multi-walled (MWCNT).
Carbon nanotubes receive their immense strength from a form of molecular glue, none other than extremely strong covalent bonds, meaning that the carbon atoms share electrons to complete their valence shells and stabilize the atoms.
Along with the covalent bonds, carbon atoms are naturally inclined to rope together due to van der Waals forces, which define many intermolecular forces, carbon nanotubes can develop into extremely high-strength, low weight materials with high conductive, electrical, and thermal properties.
Van der Waals Forces: forces that form the backbone of molecular physics. They include attraction and repulsions between atoms, molecules, and surfaces, as well as other intermolecular forces. The three main types include Dispersion, Dipole-Dipole, and Hydrogen Bonding.
Carbon nanotubes can be very useful for studying the organization of neural networks. Simultaneously, their electrical conductivity can be taken advantage of as a mechanism to monitor or stimulate neurons through ion channels, which mediate many aspects of neuronal signaling from neuronal communication to the generation of action potentials, an explosion of electrical activity that occurs when a neuron sends information down the axon.
The metal-based electrodes that are frequently used for brain implants have high electrical impedance, the measure of resistance to the electrical flow. The higher the impedance of the electrode, the smaller the amplitude of the signal that is picked up. Metal-based electrodes also have poor charge deliveries.
Carbon nanotubes can be employed to improve the performance of these microelectrodes, using their high mechanical strength to penetrate tissue, act as conductors, lower electrical impedance, and increase charge transfer.
Template synthesis is by far the most simple and easiest mechanism for the growth of complex nanostructures. Certain membranes, porous alumina (metal with 0.1–10nm-sized pores), and other nanoporous structures are used as templates. These structures are used to prepare nanoscale rods, wires, and tubes made of carbon, conductive polymers, and metals.
In order to complete the process of creating nanowires or nanotubes inside a template, various deposition techniques are used. In particular, electroless and electrochemical deposition allow for the synthesis of nanostructures which allows us to control the architecture and design of the device.
Electroless deposition can be used to create nanoelectrodes in templates that are generally non-conductive. It can be used to coat the nanoporous membrane or metal by filling up the pore with the material of interest, such as carbon. The metal deposition occurs uniformly at the pore walls and creates hollow, metallic nanotubes inside of the pores.
Electrochemical deposition is used mainly to create arrays of nanoelectrodes, called multi-electrode arrays. The density of the nanoelectrode arrays allows for a high signal to noise ratio as there is a high ratio of surface area to volume. Electrochemical deposition uses an electrical current, resulting in the accumulation of a substrate (in this case the material of interest), onto the surface of another material (nanoporous surface).
Multi-Electrode Arrays (MEAs)
Microelectrode arrays have proven to be the most effective approach to study brain circuitry, connectivity, neurophysiology, or pathology, or build brain-machine interfaces. They allow for real-time, long-term recordings of chemical fluctuations in the extracellular environment and other neurophysiological activity. Due to their size, they are minimally invasive and reduce many of the risks associated with the surgical implantation of invasive brain-machine interfaces.
Anything from the organization of the neural network to neuron excitability, to synaptic plasticity, can be monitored and influenced by MEAs.
Carbon nanotubes, CNT’s, can be used with MEA chips to detect extremely small neurochemical and neurophysical fluctuations; from changes in dopamine concentration at a nanomolar level to achieving an extremely high signal-to-noise ratio of electrical signals.
MEA chips can be used for various applications, such as drug screening and concentration, monitoring and influencing synaptic plasticity and pathogenic processes associated with conditions such as stroke, epilepsy, or other neurodegenerative disorders, such as Alzheimer’s or Parkinson’s Disease.
Nanostructures are platforms that can be used in countless mechanisms for both brain repair and augmentation.
Due to the unique electrical and physiological properties of nanowires and nanotubes, assembled on sensing platforms to create multi-electrode arrays, they hold immense potential for the augmentation of brain function.
The future of neural nanotechnology holds the potential to treat neurological conditions such as stroke and epilepsy, and eradicate neurodegenerative disorders such as Alzheimer’s or Parkinson’s Disease.
Beyond treating existing issues, neural nanotechnology might be the answer to augmenting human function. While researchers have only made substantial progress with such developments in mice and monkeys, with devices such as the Link, it’s our turn is next.
Looks like our middle school dreams aren’t dead just yet. Telekinesis might not be so far in the future after all.
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