Imagine a world where our thoughts could be instantly transmitted to machines, computers, and other people’s brains. One important application of thought transmission would be creating sophisticated neuroprosthetics for people with a variety of disorders, a goal that has sparked exciting research aiming to connect brains with machines and computers (called Brain Machine Interfaces or Brain Computer Interfaces—BMI/BCI, respectively). More recently, researchers have begun to explore connecting two brains (called brain-to-brain interfacing or BTBI). Large-scale BTBI would allow professors to broadcast lectures telepathically, doctors to communicate with patients unable to speak, and dog lovers to know how their pets really feel. While these technologies seem very exciting, we may start to wonder if this level of connectivity is always desirable. What happens to our privacy if our thoughts are instantly transmittable and available?

A prosthetic limb with fine motor skills (UPMC)

A prosthetic limb with fine motor skills (UPMC)

Gaming, no controller needed (Fusionopolis)

Gaming, no controller needed (Fusionopolis)

 

Telepathy isn’t distant science fiction anymore. The fields of BMI/BCI have succeeded greatly in using neural signals recorded from someone’s brain to operate mechanical arms or play video games. The main application of this research can be seen in cochlear implants, but advances are being made with robotic arms and exoskeletons. These advances have started to blur the line between humans and computers, which raises several ethical questions. Does the definition of the “self” change when your brain is connected to a computer? And what about accountability? Would you or your computer be responsible for any harm done to others?

BTBI is a related but younger area of research concerned with whether the neural signals recorded from one brain can be transmitted—not to a machine or computer—but to another brain. Could that second brain use, or at learn to use, the information conveyed by the neural signal it receives? Research I’ll explore in this post suggests that it can, meaning the first organism can actually change the second organism’s brain processes and associated decisions. This finding even further complicates issues of accountability and responsibility.

An example of BCI and CBI being integrated to form a BTBI (brain-to-brain interface, yay acronyms!) between human brains. (Grau et al 2014)

An example of BCI and CBI being integrated to form a BTBI (brain-to-brain interface, yay acronyms!) between human brains. (Grau et al 2014)

Recently, several groups of neuroscientists have had success transferring information from one human or rodent brain to a second human or rodent brain. In these experiments, the neural signals from one organism were first extracted and sent to a computer with a brain-to-computer interface (BCI). This computer then uses this information to stimulate the second organism’s brain through a computer-to-brain interface (CBI). In essence, computers translate, simplify, and transmit the neural “language” of the first brain to the second brain, which scientists call BTBI.

BTBI schematic from the 2013 Duke experiment. The explanatory notes in blue are mine. (Pais Vieira et al 2013)

BTBI schematic from the 2013 Duke experiment. The explanatory notes in blue are mine. (Pais Vieira et al 2013)

 

In 2013, a lab at Duke University created a BTBI where neural activity recorded from the motor cortex of the first rat, which the researchers called the “encoder”, was used to stimulate the motor cortex of the second, or “decoder”, rat. More specifically, the first rat was cued to the left or right side of a chamber (red dot in diagram), and pressed the matching lever (watch them here). Their neural activity during this decision determined the intensity with which the second rat’s motor cortex was stimulated. Importantly, the second rat only had the stimulation derived from the first rat’s brain to guide its choice. The researchers found that the second rat performed modestly better when its brain was linked to the first rat’s brain, indicating the BTBI was effective (see graph). To show the rats weren’t secretly sharing information through subtle scents or sounds, the authors put one rat in Natal, Brazil and another in Durham, USA and found the same enhanced performance.

The decoder rat showed increased performance during BTBI (Pais-Vieira et al. 2013).

The decoder rat showed increased performance during BTBI (Pais-Vieira et al. 2013).

In December 2013, a group of (DARPA funded) scientists at Wake Forest University used real-time BTBI to transfer simple short term memories between rats. The use of BTBI in a memory paradigm instead of a motor paradigm is exciting and brings up many possibilities concerning memory enhancement and prosthetics. In fact, the authors state that their study “provides the basis for utilizing extracted appropriate neural information from one brain to induce, recover, or enhance memory-related processing in the brain of another subject”. This possibility is exhilarating and chilling at the same time: while it would be an amazing advancement to treat the memory loss that can happen with diseases like Alzheimer’s, Traumatic Brain Injuries, or PTSD, if you have someone else’s memories do you become them in a way? Although memory transfer between humans has yet to be implemented, agencies like DARPA are very interested in these technologies, sparking some attention-grabbing headlines.

In Humans

While there are notable BTBI advances in humans, the field is still quite young. BTBI in rodents is an invasive procedure, as recording and stimulating devices are put directly in or on top of the brain. Although BTBI can be performed non-invasively in humans, neural information is smeared by the scalp before it’s recorded, which can introduce a degree of imprecision. However, there have been two notable noninvasive BTBI studies in humans that broadly follow these steps:

Step 1: The sender of the message thinks about moving their hand or foot

Step 2: During step 1, electrical signals are recorded from the sender’s brain using a technique called electroencephalography (EEG)

Step 3: The EEG signals were sent to a computer which translated the signals into sequences of jolts

Step 4: These jolts were delivered to the recipients brain using Transcranial Magnetic Stimulation (TMS)

At the University of Washington, participants cooperatively played a video game using this general protocol (watch the researchers do the experiment). The video game required participants to defend a city from an enemy rocket by firing a cannon on the 50% of trials in which the enemy (a pirate ship) appeared. The “sender” saw the game on a computer screen but could not control the cannon, while the “receiver” could not see the game, but could fire the cannon. To fire a rocket the “sender” imagined moving their right hand (step 1), and the amount of mu rhythm activity measured from their brain (step 2) moved the white cursor on the left toward the blue circular target. When the white cursor hit the blue circle, the receiver’s motor cortex was stimulated with TMS (steps 3 & 4). This stimulation would cause the receivers hand to click the touchpad, thus firing the cannon. Notably, the duos had to be fast – the cannon had to be fired before the rocket hit the city. A group in Barcelona used a similar set-up to transmit short words, although their experiment was not performed in real-time (meaning the “senders” activity was recorded ahead of time and then used for multiple “receivers”). Although the types of BTBI in both of these experiments are simple, they were the first to show that BTBI between humans can be achieved through non-invasive means.

The display, which only the “sender” saw. The sender could not control the defense cannon.

The display, which only the “sender” saw. The sender could not control the defense cannon.

The achievements with BMI, BCI, and BTBI indeed have important implications for neuroprosthetic development and has expanded our understanding of how the brain works. Yet, they have limits. The hardware isn’t cheap, with the (cheaper) noninvasive EEG systems ranging from $5,000 to $10,000. Furthemore, a lot of time goes into developing the many computer algorithms necessary for these systems to run. Because of these costs, few BTBI studies have all the necessary control groups to give us conclusive data. Additionally, the rate of information transmission in the human BTBI experiments was exceedingly slow; the BTBI from the Barcelona study transmitted 2 bits per minute, or more than 600 times slower than information transmission via morse code. Finally, these experiments require EEG and TMS, methods that researchers will have to refine before BTBI can be effectively used by the General population. Basically, BTBI systems need a lot of optimization before they’ll be widely adopted.

Despite these caveats, the number of groups that have implemented BTBI make it clear that the technologies are here to stay. Furthermore, with the pace of technological advancement, recording and computing should soon allow fast, wireless noninvasive BTBI, meaning telepathy through BTBI won’t seem futuristic for long.

Maybe it’s time to start thinking about how the potential uses of BTBI, and other technologies on the horizon, will change our concepts of ownership and personal agency. What if instead of launching cannons in a video game, BTBI was used by the military to relay information from agents on the ground (the “sender”) to a missile deployer (the “receiver”). If a missile is launched erroneously, is the sender or receiver of the brain waves responsible? Was the receiver acting and thinking as themselves? Did they have free will? These are questions we will be addressing in the not-so-distant future.

Interested?

Further Reading:

  • The Duke University Study: Pais-Vieira, M., Lebedev, M., Kunicki, C., Wang, J., & Nicolelis, M. A. (2013). A brain-to-brain interface for real-time sharing of sensorimotor information.Scientific reports, 3.
  • The Wake Forest Study: Deadwyler, S. A., Berger, T. W., Sweatt, A. J., Song, D., Chan, R. H., Opris, I., Gerhardt, G.A., Marmarelis, V. Z., & Hampson, R. E. (2013). Donor/recipient enhancement of memory in rat hippocampus. Frontiers in systems neuroscience, 7.
  • The University of Washington Study: Rao, R. P., Stocco, A., Bryan, M., Sarma, D., Youngquist, T. M., Wu, J., & Prat, C. S. (2014). A direct brain-to-brain interface in humans. PloS one, 9(11), e111332.
  • The Barcelona/Starlab Study: Grau,C., Ginhoux, R., Riera, A., Nguyen, T. L., Chauvat, H., Berg, M., Amengual, J. L., Pascual-Leone, A., & Ruffini, G. (2014). Conscious brain-to-brain communication in humans using non-invasive technologies. PloS one, 9(8), e105225

Image Credit: Vincent Bellet from Flickr

About The Author

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Stephanie Nelli

Stephanie, a current graduate student, is 1) amazed by the sophistication of the human brain, 2) constantly having internal debates about ethics and morality, and 3) happily exploring both of these things and their intersection in sunny San Diego.