This study is a natural extension of work previously done in laboratory animals. In addition to the work linking together rat brains, Nicolelis’s laboratory is responsible for linking multiple primate brains into a “Brainet” (not to be confused with the BrainNet discussed above), in which the primates learned to cooperate in the performance of a common task via brain-computer interfaces (BCIs). This time, three primates were connected to the same computer with implanted BCIs and simultaneously tried to move a cursor to a target. The animals were not directly linked to each other in this case, and the challenge was for them to perform a feat of parallel processing, each directing its activity toward a goal while continuously compensating for the activity of the others.
Brain-to-brain interfaces also span across species, with humans using noninvasive methods similar to those in the BrainNet study to control cockroaches or rats that had surgically implanted brain interfaces. In one report, a human using a noninvasive brain interface linked, via computer, to the BCI of an anesthetized rat was able to move the animal’s tail. While in another study, a human controlled a rat as a freely moving cyborg.
The investigators in the new paper point out that it is the first report in which the brains of multiple humans have been linked in a completely noninvasive manner. They claim that the number of individuals whose brains could be networked is essentially unlimited. Yet the information being conveyed is currently very simple: a yes-or-no binary instruction. Other than being a very complex way to play a Tetris-like video game, where could these efforts lead?
The authors propose that information transfer using noninvasive approaches could be improved by simultaneously imaging brain activity using functional magnetic resonance imaging (fMRI) in order to increase the information a sender could transmit. But fMRI is not a simple procedure, and it would expand the complexity of an already extraordinarily complex approach to sharing information. The researchers also propose that TMS could be delivered, in a focused manner, to specific brain regions in order to elicit awareness of particular semantic content in the receiver’s brain.
Meanwhile the tools for more invasive—and perhaps more efficient—brain interfacing are developing rapidly. Elon Musk recently announced the development of a robotically implantable BCI containing 3,000 electrodes to provide extensive interaction between computers and nerve cells in the brain. While impressive in scope and sophistication, these efforts are dwarfed by government plans. The Defense Advanced Research Projects Agency (DARPA) has been leading engineering efforts to develop an implantable neural interface capable of engaging one million nerve cells simultaneously. While these BCIs are not being developed specifically for brain–to-brain interfacing, it is not difficult to imagine that they could be recruited for such purposes.
Even though the methods used here are noninvasive and therefore appear far less ominous than if a DARPA neural interface had been used, the technology still raises ethical concerns, particularly because the associated technologies are advancing so rapidly. For example, could some future embodiment of a brain-to-brain network enable a sender to have a coercive effect on a receiver, altering the latter’s sense of agency? Could a brain recording from a sender contain information that might someday be extracted and infringe on that person’s privacy? Could these efforts, at some point, compromise an individual’s sense of personhood?
This work takes us a step closer to the future Nicolelis imagined, in which, in the words of the late Nobel Prize–winning physicist Murray Gell-Man, “thoughts and feelings would be completely shared with none of the selectivity or deception that language permits.” In addition to being somewhat voyeuristic in this pursuit of complete openness, Nicolelis misses the point. One of the nuances of human language is that often what is not said is as important as what is. The content concealed in privacy of one’s mind is the core of individual autonomy. Whatever we stand to gain in collaboration or computing power by directly linking brains may come at the cost of things that are far more important.
Are you a scientist who specializes in neuroscience, cognitive science, or psychology? And have you read a recent peer-reviewed paper that you would like to write about? Please send suggestions to Mind Matters editor Gareth Cook. Gareth, a Pulitzer prize-winning journalist, is the series editor of Best American Infographics and can be reached at garethideas AT gmail.com or Twitter @garethideas.