Brain-to-Brain Interface

Brain-to-brain interface (BBI) refers to interface technology that allows for communication between biological brains. These interfaces typically employ the use of a brain-machine interface (BMI; also called brain-computer interface or BCI) to establish a connection from one brain to a machine, which then transmits the received neural information to another brain. Brain-to-brain interfaces have been utilized among non-human animals, and recent developments have also allowed for successful implementation between humans and non-human animal as well as across human brains.

Research in BBIs

Recent work in brain-to-brain interfaces include demonstrations of brain-to-brain communication in animals (such as between rats), cross-species communication (such as between a rat and a human), and communication between two or more humans. Some of this research is discussed below.

Duke University

A brain-to-brain interface between rats was established in 2013 by scientists at Duke University. Two rats learned to press either a right or left lever, and then a brain-machine interface was used to record cortical and sensorimotor signals containing information on which lever one rat pressed. The information was passed through and decoded by a computer, and was then transmitted to the brain of the other rat, with the goal of having the other rat correctly receive the brain signals of its counterpart, and then press the same lever. The receiving rat learned to press the correct lever seven out of ten times.

The study received mixed reviews. Neuroscientist Ron D. Frostig at the University of California, Irvine, described it as “an amazing paper” that demonstrated information could be transferred from one brain to another in real time, while Andrew B. Schwartz, neuroscientist at the University of Pittsburgh, stated the study was “very simplistic”.

Harvard Medical School

Harvard Medical School interspecies BBI. https://www.extremetech.com/extreme/162678-harvard-creates-brain-to-brain-interface-allows-humans-to-control-other-animals-with-thoughts-alone#:~:text=Researchers%20at%20Harvard%20University%20have,to%20control%20the%20rat's%20tail.&text=To%20put%20it%20bluntly%2C%20we,by%20neurons%20in%20the%20brain.

In 2013, associate professor of radiology Seung-Schik Yoo led a team of researchers in developing the first interspecies BBI, between a human and a rat. Using a non-invasive method of BBI, this technology used a flashing light to generate a signal from the human brain, which was then transmitted to the brain of an anesthetized rat, causing it to move its tail. This was done by attaching a "focused ultrasound machine," or a FUS machine, which was designed to stimulate a specific part of the rat's brain which was associated with tail movement, to the rat. They then used BCI technology to read the neural signals of a human using an electroencephalogram (EEG). By connecting these two systems, the flashing light that the human participant was asked to look at triggered a burst of ultrasound waves connected to the rat’s brain, causing it to move it's tail. Dr.Yoo seeks to improve this study by being able to send more sophisticated messages through BBI, as well as exploring the idea of 'neural coupling.'

University of Washington

In 2013, researchers at the University of Washington established brain-to-brain communication in six participants, described in the study as the “first direct brain-to-brain interface in humans.” Participants had to play a cooperative computer game and were paired up, with one person playing the role of the “sender” and the other as the “receiver.” They had to play the game while in two separate buildings on campus, located one mile apart. The “sender” was able to see the game on a computer screen but had no device to control the firing of a cannon in the game, while the receiver could not see the game but had a touchpad to control the cannon. Using electroencephalography (EEG), electrical brain activity containing the motor information to operate the cannon was recorded from the “sender” and sent to a brain-computer interface server. Transcranial magnetic stimulation (TMS) was then utilized; the information was transmitted to a TMS server and created stimulation of specified brain regions in the “receiver,” causing motor movement of the hand in the receiving participant to click or move the mouse in the game.

Description of BrainNet. https://www.nature.com/articles/s41598-019-41895-7/figures/1

Carnegie Mellon University

Scientific journal Nature published a study in 2019 from a joint collaboration between researchers at the University of Washington & Carnegie Mellon University in which they introduced BrainNet, described as the “first multi-person non-invasive direct brain-to-brain interface for collaborative problem solving” and “a next-generation BBI that addresses many of the limitations of past BBIs.” It is designed to allow for brain-to-brain communication on a collaborative task between more than two participants. The study specifically involved three human subjects playing a game similar to Tetris together, in which information from the brains of two “senders” was recorded through use of EEG and transmitted to the brain of the “receiver” over the internet through a brain-computer interface based on TMS.

The authors of the paper identified three ways BrainNet improved upon prior human brain-to-brain interfaces:

• “BrainNet expands the scale of BBIs to multiple human subjects working collaboratively to solve a task.”
• “BrainNet is the first BBI to combine brain recording (EEG) and brain stimulation (TMS) in a single human subject, eliminating the need to use any physical movements to convey information”
• “Using only the information delivered by BrainNet, Receivers are able to learn the reliability of information conveyed to their brains by other subjects and choose the more reliable sender. This makes the information exchange mediated by BrainNet similar to real-life social communication, bringing us a step closer to a ‘social network of brains’.”

Possible Use Cases

First Dry EEG with VR Headset Integration that uses Neurable's API.

While there are certainly ethical concerns around brain-to-brain interface technology and potentially negative use cases, there are also many positives to the development of this research.

Medicine

BBI technology has already been used in many medical devices. Neural implants, such as cochlear implants, bypass the auditory apparatus and allow a person to hear sounds from outside by converting them into electrical signals that directly reach the brain. Furthermore, some prosthetics, like artificial arms and legs, have already been made to move in response to a patient's thoughts.

Automotive

Car accidents are one of the biggest causes of death worldwide, but a BCI-enabled car could help prevent these accidents by recognizing thoughts in a driver's mind and taking a decision faster than the driver could. Nissan, an automobile manufacturer, is already conducting research on a system that would allow the vehicle to slow down or turn the steering wheel 0.2 to 0.5 seconds faster than the driver could.

Office

BCI technology could also be used in the office place in multiple ways. For example, BCI could detect when attention levels are too low and could trigger an alert to focus, or even adapt the lighting in the room to affect a person. A startup named "Muse" is already developing tools that could do this. Their sensing startup can give real-time information on brain activity and give insight on engagement levels, which could help individuals complete their tasks.

Gaming

Several gaming companies have also started to utilize this technology to make their games more immersive. Game developers Valve and Neurable have already made devices. Valve is in development for a passive interface, rather than implanted, that controls a game using a wearer's mind. Neurable, on the other hand, currently already has a device that can control an escape game using sensors in a cap, but has since moved on to military applications.

Ethical Considerations

While brain-to-brain interface technology is still in relatively early stages of research, several concerns have been identified in discussion of the ethics of brain-to-brain interfaces.

Autonomy and Privacy

Elisabeth Hildt from the Center for the Study of Ethics in the Professions at the Illinois Institute of Technology in Chicago has discussed various issues with multi-person BBIs related to autonomy, privacy, agency, accountability, and identity. Concerning autonomy in brain-to-brain interfaces, there is a risk of information taken from individual brains being transmitted and shared within the network without the consent of the individuals involved. Privacy issues may arise if brain information is recorded and used from a person unaware or against the information being recorded and distributed. In addition, those receiving brain information in a network may also have things they do not wish to receive. It is also unclear whether receivers in BBI networks could be harmed through their use of these technologies, as their brains are affected by the signals being transmitted and there could exist some risk of overstimulation.

Enhancement

Other scientists have discussed the ethical concern of enhancement. Advanced brain-to-brain interface technology could be used to modify human cognition through potential enhancement of speed of knowledge or skill acquisition. Such enhancement could be useful for learning, yet these technologies would likely be expensive and only available to certain groups of people, highlighting problems of social inequities in education and other areas.

Cross-Species Neural Interfacing

It is also important to consider the ethical implications of cross-species neural interfacing. The UK Academy of Medical Sciences has speculated on this topic, in the report, "Animals Containing Human Material," where they identify a category of research as, "Substantial modification of an animal’s brain that may make the brain function potentially more ‘human-like’, particularly in large animals." The possibility of conducting this research is well within the scope of brain-to-brain interface technology. Scientists at Harvard Medical School have already conducted the first interspecies brain interfacing study, by using EEG to take recorded signals from a human scalp, and use them to stimulate movement in the tail of an anesthetized rat. They have also suggested the possibility of using this technology to transmit neural stimulation from non-human animals to humans, with the possibility of enhancing human sensory systems. Modifying the human brain to have animal-like functions and instincts presents a need for further consideration of ethical concerns before moving forward.

Military Use

There are also concerns with brain-to-brain interfaces, combined with brain-machine interfaces, being utilized in a military setting. The Defense Advanced Research Projects Agency (DARPA) is one of several military-affiliated groups with an interest in BBIs; researchers at Rice University exploring applications of BBIs and BMIs received $8 million in funding from DARPA in 2021, an addition to $18 million received in 2018. Use of these technologies in the military has raised concerns pertaining to agency and identity.