CT scan of ischemic stroke. Image: Shutterstock

What Happens When an Internet-Connected Brain Has a Stroke?

Brian Anderson

Brian Anderson

How will future strokes affect humans if—and that’s a big If—all our brains are one day connected to each other via the internet?

CT scan of ischemic stroke. Image: Shutterstock

Imagine the flow of blood to part of your brain one day just stops. You're having a stroke, or, as it's sometimes called, a "brain attack." Now, imagine that your brain also happens to be connected via the internet to every other human brain in the world. What happens next?

It's a hypothetical future dilemma that can bend discussions around human brains adapting to technology to headier territory near the intersection of neuroscience, the internet of things, and public health. We're still a long way out from that future, to be sure, but it's something we're moving toward. How will future strokes affect humans if all our brains are one day connected to each other via the internet? It would seem, for now, a matter of teasing out the physical possibility of experiencing a stroke in a future where every human brain is jacked into a centralized network, and just how feasible, really, is the great human experiment of connecting all the world's brains together over the internet.

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There are two types of stroke. Either a ruptured blood vessel spills blood into your brain (hemorrhagic stroke), or, more likely, a blood clot plugs a cerebrovascular blood vessel (ischemic stroke). In either case, brain tissue is starved of oxygen and nutrients. Hence, brain attack. But the heart attack analogy goes only so far.

"Unlike the cardiac muscle, the brain tissue is a command center," said Dr. Daofen Chen, the program director who oversees the portfolio for motor systems and stroke rehabilitation at the National Institute of Neurological Disorders and Stroke, a wing of of the National Institutes of Health. It's almost like causing damage to a computer, Chen told me, because brain cells will start to die mere minutes after a stroke occurs. "Everything this computer does will be malfunctioning."

About 800,000 people have strokes annually in the US, according to the National Institute of Neurological Disorders and Stroke. Worldwide, around 15 million people have strokes each year. About 75 percent of all strokes, the NINDS reports, hit people above the age of 65, and the risk of experiencing one "more than doubles" each decade after the age of 55.

It is possible to recover from a brain attack. "The whole idea behind stroke recovery is trying to teach the brain to compensate for the part of the tissue that got lost during a stroke," Chen said. But according to him, there is "practically no cure" for strokes.

Would the stroke trigger a ripple effect across swaths of the network, potentially crippling the entirety of the network in a sort of mass cerebrovascular trauma?

If it can be assumed, then, that strokes will in fact still be physically possible whenever the moment comes that all human brains are connected to each other via the internet, what might a single stroke in just one person's brain bring to bear on the network of brains to which that individual's brain is connected? Would the stroke trigger a ripple effect across swaths of the network, potentially crippling the entirety of the network in a sort of mass cerebrovascular trauma? Would the stroke remain localized just to the brain of the individual experiencing the stroke? Or would it fall somewhere in between, depending on the severity of the stroke?

That's hard to say. Researchers today are perhaps only beginning to grasp the potential for direct brain-to-brain communication over the internet between just a couple of humans, to say nothing of building out the neuro-network architecture that would be required to jack billions of human brains into a centralized network.

A signal moment in direct noninvasive brain-to-brain interfacing over the internet happened in 2013. That's when Andrea Stocco, a researcher in the Cognition and Cognitive Dynamics Lab at the University of Washington, and a colleague, Rajesh Rao, demonstrated how it is possible to directly transmit information from one brain to another brain over the internet using encephalography (EEG, to record brain signals) and transcranial magnetic stimulation (TMS, to modulate brain signals).

The experiment was a computer game that involved saving a "city" from being obliterated by rockets fired by a "pirate ship"; to save the city, a subject must fire a "cannon" at the moving rocket, but only before it reaches the city. To test it, Rao (the "sender) and Stocco (the "receiver") sat on opposite ends of the UW campus. Rao, wearing an EEG helmet, sent a brain signal over the internet to Stocco, who wore a TMS coil over the left motor cortex area of his brain. The EEG recorded Rao's brain signal, and when that imagined hand movement was detected by the computer a "fire" command was transmitted over the internet to the TMS machine affixed to Stocco's head. At which point Stocco's right hand flicked upward, hitting the "fire" key. The city was saved.

Stocco told me the main intuition was that since technologies for recording signals from the brain and modulating electrical signals within the brain already existed, "there had to be a way to connect the two in a meaningful way." The bulk of their work, he added, went into creating a way to connect EEG and TMS technologies in such a way that a pair of humans could play a game in real time.

"The internet was a way to connect computers, and now it can be a way to connect brains," Stocco said in a release at the time. "We want to take the knowledge of a brain and transmit it directly from brain to brain."

Chen, who was not affiliated with the UW study, told me he thinks Stocco and Rao's experiment was technically not that advanced. "It's almost trivial, actually," to do what they did, said Chen, who nonetheless praised their experiment as an "inspiring" new effort in the development of applications with the potential to help patients with neurologic disorders.

In hindsight, Stocco thinks the internet played only an accidental role in the original 2013 experiment. "Because wireless internet is everywhere," he told me, "it just made it easy to transmit the signal from a computer and then analyze the EEG data to the computer that analyzes the TMS data." He said they likely would have used electrical wiring to transmit the brain signal if wireless internet wasn't available. "It would have worked anyway. But, of course, the idea that someone's brain signal was briefly available over the internet, and could potentially be broadcasted everywhere in the world, gave our experiment a very different vibe."

Stocco does think we're a long way from turning what is an enduring trope of science fiction into reality. In his view, there are two main obstacles in the way of being able to transmit and broadcast signals from all our brains over the internet. We don't currently have the technology to record from and stimulate large portions of the human brain, for one thing, at least not without having to implant electrodes through invasive surgery. And we still aren't able to make complete sense of everything the human brain even does, including all the ways it encodes information. Scientists are making headway on both fronts, Stocco said, "but it is still impossible to make any informative guess about if and when such a scenario and dynamic brain-to-brain collaboration would be possible."

"If our brains were connected via the internet I think strokes would be no more of an issue than they currently are"

Which brings us back to the original question: How will strokes afflict us if one day all our brains are connected to each other via the internet? That's assuming humans will still run the risk of stroke when that day comes.

Michael Cole thinks strokes would be calamitous for victims and their loved ones, but would otherwise have little effect on the other internet-connected brains comprising the network.

"If our brains were connected via the internet I think strokes would be no more of an issue than they currently are," said Cole, who heads up the Cole Neuroscience Lab at the Center for Molecular & Behavioral Neuroscience at Rutgers University.

The bigger problem would be technical glitches, he added, which likely would occur more often than brain glitches like strokes. But given this is currently fictional technology, Cole said it's hard to say at this point what the relative number of glitches would be.

Fictional, but for how long? Stocco told me they've been playing at the CCD Lab with the idea of using asynchronous brain-to-brain communication, "so that when a person experiences a stroke, signals from another person (or recorded signals from the same person's past) could be used to 'train' the damaged brain and speed up recovery." He imagines something like that could possibly happen in a scenario when brains are fully interconnected, and where a person's brain would be able to immediately access the missing signals. "Perhaps some algorithms could even help find the most appropriate ones dynamically." But he said that would be only a partial response.

"The fact is that if all of our brains were fully connected, then we have no idea what it would 'feel' like to be part of this network," Stoco said.

For some scientists, consciousness is tied tightly to the information processing and computation occurring in the brain. In this view, if brains in the future are connected via the internet then part of one person's consciousness effectively could be distributed over various information processing sites.

"We do not know whether this is the case," Stocco said. Other scientists, for example, believe consciousness to be completely dependent on a person's specific neural tissue. But if it is the case that part of someone's consciousness could be distributed over a range of info processing sites once all the world's brains are jacked into the internet, Stocco told me a damaged brain could simply offset its impediments by dynamically recruiting the resources of other brains. "Nobody knows for sure."

In other words, Stocco is suggesting that if you experience a brain attack your brain might be able to leverage someone else's brain to continue functioning normally.

X-ray of cerebrovascular accident. Image: Shutterstock

Then again, maybe all our brains already are connected via the internet.

"We are doing that," Chen said, bluntly. The interface is through one's thoughts "going to the mouth," he said. It's through the use of language, whether it's Chinese or English or Spanish, that can be typed or spoken in a way, including as video or even sign language. "It's the linguistic media, and then it's the form of media that got transferred to the other side," he explained. "In this case it's through the internet."

It's a sentiment shared by Cole: "In a very real way our brains are already 'connected via the Internet,' he told me, "primarily by way of eyes getting input and fingers typing on keyboards for output."

Cole thinks the effect of strokes on the internet now will in all likelihood be similar to how it would be if we upped the "bandwidth" on the brain's connectivity to and from the internet, and that, should we increase the bandwidth between our brains and the internet, "we'll have all sorts of noise." Noise from people getting tired, from people being perplexed while learning to use the internet for the first time, from needing to log off for need of sleep.

To deal with this noise, he said, the system—the network to which our internet-connected brains might all one day be part of—would generally need to be quite hearty. "This would make it so it's very likely to be robust to events like strokes."

Jacked In is a series about brains and technology. Follow along here.