BCI(Brain Computer Interface) / BMI (Brain Machine Interface)
BCI refers to Brain Computer Interface and some people likes to call it as Brain Machine Interface. Since computer can get connected to so many other machines and control them easily, once your brain get connected to a computer it can get the control over almost everything outside of your body.
The concept itself is simple. It is connecting brain to computer or machine as illustrated below. The question is 'HOW'.
Image Source : Bringing Brain Computer Interfaces Home
What I want to talk about BCI in this note are as follows :
Is BCI real ? or Science Fiction ?
It depends on how you define Science Fiction... but I think I know what you mean. There is no clear answer to this for now. Even among those players in the industry or academia of this field, some people sound like 'it is real' but some other people say 'it is far, far away from reality' (even though they would not say 'science fiction' explicitely).
My personal opinion about this question are as follows (as of writing this. Dec 2022)
Why BCI ? Why do we want to create this kind of interface ? There are wide range of motivation for BCI and some of most frequently motivations are as follows :
Two main approaches : Invasive and NonInvasive
There are roughly two different types of connecting the brain to computer. One is called Invasive method and the other one is called Noninvasive method.
Invasive Method : This is the method / technology that requires physical break-open to look into a system. In terms of BCI, it is the method that requires physical operation to connect the brain to computer. Most of BCI technology except EEG belongs to this category.
NonInvasive Method : This is the method / technology that does not requires physical break-open to look into a system. In terms of BCI, it is the method that does not requires physical operation to connect the brain to computer. EEG is the most typical example of Noninvasive technology.
It would sound fancy to make connection between brain and computer/machine and control everything with your brain, but you know the reality never goes like textbook. It is not easy to realize the connection. With all sort of challenges, there has still been various attempts and prototypes. In this section, I am going to list well known (at least well known to me) examples of physical interface between brain and computer/machine.
EEG stands for ElectroEncephaloGram. This would be the most widely used and safest interface. This is non-invasive technology. Just sticking bunch of electrode on top of the brain as shown below and reads electrical signals from each of the electrodes. This technology has been used for long time in diagnosis or other brain researches not associated with BCI.
Once you got these electrode connected and you need to have proper software algorithm to analyze those signals to associate with specific activities (e.g, moving a mouse pointer, pressing a specific key on virtual keyboard etc). Usually various AI algorithms are used for this purpose.
The Utah Electrode Array(UEA) is an arry of electrode that is designed to inserted into a specific brain region and recorde the activity of multiple layers of the cortex area simultenously (For the details of electrode itself, check out this note) . As the name implies it was developed at the University of Utah, and it has been used in a variety of research and clinical applications. It was aimed at developing a brain-machine interface that could be used to control prosthetic devices, such as a robotic arm or a computer cursor, using the activity of neurons in the brain. The UEA has since been widely used in research and clinical settings, and has been instrumental in advancing our understanding of the brain and the development of treatments for neurological disorders.
Image Source : Electrode Technology with Dr. Rio Vetter | Webinar
Stentrode is a term coined by combining two words : Stents and Electrode. Stents is a small mesh of metals that has been develop to treat narrow or weak blood vessels. Since it was developed in 1970s, it has widely used in the field. The idea behind the strentrode is to attach electrodes in the stents and place it within a blood vessel which are closes to the brain part that we want to interact (i.e, reading the electric activity of the brain part). The other end of the stentrode located outside of the body and wirelessly connected to computer.
Image Source : A Brain Implant That Turns Your Thoughts Into Text | Tom Oxley | TED
Understadably this would record better the electrical activity of a brain part comparing to EEG beause the electrode is placed closer to the brain region comparing EEG, but may not record at the same level of sensitivity / accuracy as Utha electrode or Neuralink since the stentrode cannot get as close to the brain region as Utha electrode or Neuralink thread.
I think the biggest advantage of the stentroid is that it may achieve great tradeoff between signal accuracy and safety. In terms of signal accuracy, it may not be as accurate / sensitive as Utha electrode or Neuralink thread but it is based on the technology (stents) that has been proved safe for long time.
Image Source : Neuralink Show and Tell, Fall 2022
There are many BCI technologies as shown above (there would be even more that are not introduced in this note), but at least as of now (as of writing this note : Jan 2023) it doesn't seem that there is any best solutions. Each of the technologies appears to have its own challenges. I am trying to list some of challenges that are mentioned most commonly.
Challenges with Noninvasive technology
In terms of safety, Noninvasive technology like EEG would be almost ideal (seemily no known harms), but there would be some challenges listed below. The first 5 items are what I got from chatting with chatGPT and I agree with the reply from it. It is an amazing that I can chat with an AI about this kind of topics and at this kind kind of level (human like response).
Challenges with Invasive technology
Invasive technology such as Utah Electrode Array, Nuralink, Stentrode etc surpass better than non-invasive technology (e.g, EEG) in terms of signal strength, spatial / temporal resolution etc. But these technology have their own challenges as well. Some of these challenges are listed below. The first 5 items are what I got from chatting with chatGPT and I agree with the reply from it.
Challenges with Wireless Communication
Regardless of whether they use Invasive technology or non Invasive technology, it is highly likely that the interfacing between the electrode and computer/machine would be based on wireless communication when it is commercialized for public. When the connection become wireless, they would come across some additional challenges. Some of the widely mentioned challenges with wireless communication are listed as below.
Prosthetics are devices that are used to replace or enhance a missing or impaired body part. The field of prosthetics is focused on designing, developing, and fitting these devices to help people with physical limitations to improve their mobility, function, and quality of life.
Prosthetics can be classified into two main categories: external prosthetics, which are worn on the outside of the body, and internal prosthetics, which are implanted inside the body.