human neuron

James Cavallini/Science Source

Century of Science: Theme

Our brains, our futures

from ScienceNews

Neuroscience grows up

A century ago, science’s understanding of the brain was primitive, like astronomy before telescopes. Doctors knew that certain brain injuries caused specific problems, like loss of speech or vision. Anatomists had identified nerve cells, or neurons, as key components of the brain and nervous system.

But those findings offered a fuzzy view. Nobody knew how cells collectively manage the brain’s sophisticated control of behavior, memory or emotions. And nobody knew how neurons communicate, or the intricacies of their connections. For that matter, the research field known as neuroscience — the science of the nervous system — did not exist, becoming known as such only in the 1960s.

black and white sketches of the brain with numbered sections
At the beginning of the 20th century, German neurologist Korbinian Brodmann drew brain maps that parceled the human cerebral cortex — the outer layer of the brain that handles higher-order thinking — into discrete, numbered areas.Volgi archive/Alamy Stock Photo

Over the last hundred years, brain scientists have built their telescopes. Powerful technologies for peering inward have revealed cellular constellations that would have astonished the early brain science pioneers. They’ve revealed that at least a hundred different kinds of brain cells communicate with dozens of distinct chemicals. A single neuron, scientists have discovered, can connect to tens of thousands of other cells. Today’s view of the brain is breathtaking. 

Yet neuroscience, though no longer in its infancy, is far from mature.

Learning about the brain is “a slow process. Because it’s so complex … it hits the wall of our understanding.”

Christof Koch, neuroscientist

“We’re somewhere probably at the beginning of the middle part,” says Christof Koch, a neuroscientist at the Allen Institute in Seattle. “Or at the end of the beginning.”

Learning about the brain is “a slow process,” Koch says. “Because it’s so complex … it hits the wall of our understanding.”

Today, making sense of the brain’s vexing complexity is harder than ever. Advanced technologies and expanded computing capacity churn out torrents of information. “We have vastly more data, bits of information, than we ever had before, period,” says Koch. Yet we still don’t have a satisfying explanation of how the brain operates. We may never understand brains in the way we understand rainbows, or black holes, or DNA.

Deeper revelations may come from studying the source of the brain’s own exceptional power — the vast arrays of neural connections that move information from one part of the brain to another. Using the latest brain mapping technologies, scientists have begun drawing detailed maps of those neural highways, compiling a comprehensive atlas of the brain’s communication systems, known as the connectome.

Today’s tools, such as powerful magnetic resonance imaging machines, reveal the complex webs of connections between brain areas, links that many scientists believe are central to the human brain’s astonishing capabilities.Philippe Psaila/Science Source

In the days before sophisticated scanners and high-powered computers, scientists had to rely on natural events, such as unlucky injuries to certain parts of the brain, to make deductions about how the brain worked.

Those rare events emphasized the roles of certain brain areas, instead of the connections between them, says Michael D. Fox, a neuroscientist and neurologist who directs the Center for Brain Circuit Therapeutics at Brigham and Women’s Hospital in Boston.

A stroke damaging a certain part of the brain, for instance, robs a person of language. Damage to another region paralyzes an arm. These one-to-one correspondences suggested the brain was built of compartments, each responsible for a single job. But with some exceptions, the brain doesn’t work that way, scientists now know. It turns out that the dot on the map is less important than the roads leading in and out. 

“With the building of the human connectome, this wiring diagram of the human brain, we all of a sudden had the resources and the tools to begin to look at [the brain] differently,” Fox says.

“With the building of the human connectome, this wiring diagram of the human brain, we all of a sudden had the resources and the tools to begin to look at [the brain] differently.”

Michael D. Fox, neuroscientist and neurologist

Scientists don’t yet know how to read some parts of their new connectome maps but are already starting to use brain cartography to treat disorders. That’s the main goal of Fox’s new center, dedicated to changing brain circuits in ways that alleviate disorders such as Parkinson’s disease, obsessive-compulsive disorder and depression. “Maybe for the first time in history, we’ve got the tools to map these symptoms onto human brain circuits, and we’ve got the tools to intervene and modulate these circuits,” Fox says.

The goal sounds grandiose, but Fox doesn’t think it’s a stretch. “I don’t want to wait 50 years,” Fox says. “My deadline is a decade from now.”

Whether it’s 10 years from now or 50 or more, by imagining what’s ahead, we can remind ourselves of the progress that’s already been made, of the neural galaxies that have been discovered and mapped. And we can allow ourselves a moment of wonder at what might come next.

The three fictional vignettes that follow illustrate some of those future possibilities. No doubt they will be wrong in the details, but each is rooted in research that’s underway today, as described in accompanying explanations of the scientific basis for these imagined scenarios.
— Laura Sanders


Future #1: Brain bots

futuristic animation of two people looking at a projection of a neural net
Glenn Harvey

Sarah had made up her mind. Her afternoon was cleared and her appointment was locked in. After five years, she was going to get her neural net removed. As she drove to the clinic, she felt confident that she was making the right call. Mostly.

The millions of nanobots in her brain had given her life back to her, by helping her mind to work again. They had done their job. It was time to get them out.

Sarah’s gorgeous, perfect baby was born on the summer solstice, June 20, just before midnight. But the following months had tipped Sarah into a dark postpartum depression.

Unable to feel much of anything, Sarah barely moved through those early days. She rarely looked at the baby. She forgot to eat. She would sit in a dark room, air conditioner on full blast, for hours, staring at nothing. Those endless days stretched until an unseasonably hot September morning. Her mother watched the baby while Sarah’s husband drove her to the Institute for Neuroprosthetics, a low-slung brick building in the suburbs of Nashville.

Inside, she had barely listened as the clinic coordinator described the technology one last time. An injection would deliver the nanobots to her blood. Then a magnet would guide them up to the head. A fast, strong pulse of ultrasound would open the blood-brain barrier temporarily, allowing an army of minuscule particles to slip in.

Powered by the molecular motion inherent in her brain, the nanobots would spread out to form a web of microscopic electrodes. That neural network could pinpoint where Sarah’s brain circuitry was misfiring, and begin to repair it.

Powered by the molecular motion inherent in her brain, the nanobots would spread out to form a web of microscopic electrodes. That neural network could pinpoint where Sarah’s brain circuitry was misfiring, and begin to repair it.

Over the following weeks, Sarah’s nanobots learned the neural rhythms of her brain as she moved through her life with debilitating depression. With powerful computational help — and regular tinkering by the clinic technologist, a young guy named Jerome — the system soon learned to spot the earliest neural rumblings of a deteriorating mood. Once those warning signs were clear, Sarah’s web of nanobots began to end the episodes with gentle but persuasive electrical nudges. 

After months of gray, Sarah’s laugh started to reappear, though sometimes at the wrong times. Jerome had warned her that initially, she might experience some blips. She recalled the day she and her husband took the baby to a family birthday party. In the middle of a story about her uncle’s dementia treatment, Sarah’s squawks of laughter silenced the room.

Those closest to her understood, but most of the family didn’t know about the millions of bots working to shore up her brain.

After a few months and some adjustments, Sarah’s emotions evened out. The numb, cold depression was gone. Gone too were the inappropriate bursts of laughter, flashes of white rage and insatiable appetites. She was able to settle in with her new family, and feel — really feel — the joy of it all.

But was this joy hers alone? Maybe it belonged to the nanobots, the army of tiny ever-vigilant helpers, reworking and evening out her brain. Without her neural net, she might have been teary watching her daughter, still her baby, walk into her kindergarten classroom on the first day. Instead, Sarah waved, turned and went to work, feeling only slightly wistful, nothing more intense than that.

That search for herself is what drove her back to the clinic, five years after she welcomed the nanobots in.

Sarah settled into the familiar brown leather chair in a treatment room. “Jerome, do you think I’m ready?” she asked.

“Most def,” he said, nodding in an uncomplicated way that only a young person can pull off.

“But what if this is ‘me’ now?”  she asked. “Am I losing a part of myself?”

“Maybe,” Jerome said. “But maybe not. Plus, you could always get the bots back in later.”

Was this joy hers alone? Maybe it belonged to the nanobots, the army of tiny ever-vigilant helpers, reworking and evening out her brain.

Sarah’s question was hers to answer. But she wasn’t the only one asking it. She had joined a group of people who were also being treated at the clinic, a strange and thoughtful collection of people living with neural nets: Yvonne, a computational psychiatrist with Alzheimer’s disease, whose memories were being guarded by nanobots; John, whose nanobots were overriding his urges to use opioids; and Jill, a teenager with anorexia. Her nanobots made her hungry at mealtimes.

At their weekly meetings, everyone talked about their attempts to reconcile old identities with new, augmented ones. Yvonne would vent about her husband condescendingly telling her to “check her settings” when she forgot something. John was fighting the desire to mentally manufacture an opioid craving, just for the great feelings the nanobots delivered when they sensed trouble. And Jill was growing resentful of her technologist — and her parents — dictating her appetite.

The science supporting the success of neural nets was staggering; they were breathtaking in their efficiency at fixing huge problems like addiction, dementia and eating disorders. But the science couldn’t answer bigger questions of identity and control — what it means to be a person.

Jerome went over the simple extraction procedure: a quick ultrasound pulse to loosen the blood-brain barrier again, a strong magnet over the inside of Sarah’s elbow, and a blood draw. He looked at her. “You ready?”

She took a deep breath. “Yes.”

Past and present: Nudging the brain

In this story, Sarah received a treatment that doesn’t now exist. But the idea that scientists will be able to change certain brain networks — and improve health — is not fiction. It’s happening.

Already, a technique known as deep brain stimulation, or DBS, uses electrodes surgically implanted in people’s brains to tweak the behavior of brain cells.  Such electrode implants are helping reduce Parkinson’s tremors, epileptic seizures and uncontrollable movements caused by Tourette’s syndrome. Mood disorders like Sarah’s have been targeted, too.

The central idea of DBS — that the brain can be fixed by stimulating it — is not new. In the 1930s, psychiatrists discovered that a massive wallop of seizure-inducing electricity could sometimes relieve psychiatric symptoms. In the 1940s and 1950s, researchers studied whether more constrained electrical stimulation could help with disorders such as depression.

x-ray of electrodes in a person's skull
Electrodes penetrate deep into the brain of this 58-year-old person with Parkinson’s disease, a therapy that is being improved and applied to other conditions such as movement disorders, obsessive-compulsive disorder and depression.Zephyr/Science Source

In 1948, for instance, neurosurgeon Lawrence Pool of Columbia University’s Neurological Institute of New York implanted electrodes to stimulate the brain of a woman with severe Parkinson’s who had become depressed and lost weight. Soon, she began to “eat well, put on weight and react in a more cheerful manner,” Pool reported in 1954. The experiment ended three years later when one of the wires broke. “It is the writer’s conviction that focal controlled stimulation of the human brain is a new technique in psychosurgery that is here to stay,” Pool wrote.

“It is the writer’s conviction that focal controlled stimulation of the human brain is a new technique in psychosurgery that is here to stay.” 

Neurosurgeon Lawrence Pool, 1948

Over the last several decades, researchers have grown ever more precise in their abilities to effectively change brain activity. Companies such as Medtronic, St. Jude Medical (now Abbott), Boston Scientific and NeuroPace have developed new electrodes and new algorithms to make electrical stimulation more effective, providing a clinical option for people with epilepsy, tremors and Parkinson’s disease who cannot be helped by other treatments.

Approaches other than implanted electrodes are showing promise, too. Powerful magnetic fields, ultrasounds and even external electrodes can change brain activity from outside the skull, all with varying amounts of precision and power.

Compared with those early days, today’s scientists understand a lot more about how to selectively influence brain activity. But before a treatment such as Sarah’s is possible, two major challenges must be addressed: Doctors need better tools — nimble and powerful systems that are durable enough to work consistently inside the brain for years — and they need to know where in the brain to target the treatment — a location that differs among disorders, and even among people. These are big problems, but the various pieces needed for this sort of precision healing of the brain are beginning to coalesce.

The specs of the technology that will be capable of listening to brain activity and intervening as needed is anyone’s guess. Yet those tiny nanobots that snuck into Sarah’s brain from the blood do have roots in current research. For example, Caltech’s Mikhail Shapiro and colleagues are working toward nanoscale robots that roam the body and act as doctors.

“You could have thousands of electrodes safely interfacing with neurons. At that point, it becomes really standard medical practice.”

Cynthia Chestek, biomedical engineer

Other kinds of sensors are growing up, fast. Just in the last 20 years, electrodes have improved by an astonishing amount, becoming smaller, more flexible and less likely to scar the brain, says biomedical engineer Cynthia Chestek. When she began working on electrode development in the early 2000s, there were still unsolvable problems, she says, including the scars that big, stiff electrodes can leave, and the energy they require to operate. “We didn’t know if anybody was ever going to deal with them.”

But those unsolvable problems have largely been overcome, says Chestek, whose lab at the University of Michigan develops carbon fiber electrodes. Imagine several decades into the future, Chestek says. “You could have thousands of electrodes safely interfacing with neurons. At that point, it becomes really standard medical practice.”

Neural dust — minuscule electrodes powered by external ultrasounds — already can pick up nerve and muscle activity in rats. Neuropixels can record electrical activity from over 10,000 sites in mice’s brains. And mesh electrodes, called neural lace, have been injected into the brains of mice. Once inside the brain, these nets integrate into the tissue and record brain activity from many cells. So far, these mesh electrodes have captured neural activity in mice over months as the animals scurried around.

a gloved hand holds a roughly two-inch long device
Arrays of electrodes are getting smaller and more reliable, enabling an onslaught of data about brains at work. Shown is Neuropixels, an array created by the company Imec, that contains nearly 1,000 electrodes.imec

Other futuristic-sounding systems under development can be controlled with magnets, light or ultrasound. There are still problems to solve, Chestek says, but none of those problems are insurmountable. “We just need to figure out the last set of practical tricks,” she says.

Once scientists know how to reliably change brain activity, they need to know where to make the change. Precision targeting is complicated by the fact that ultimately, every part of the brain is connected to every other part, in a very Kevin Bacon way.  Scientists used to think of the brain as a collection of areas that did certain jobs; the “vision” area, the “emotion” area, and so on, says neurobiologist Rafael Yuste of Columbia University. “That model has been dissolving,” he says.

Advances in tractography — the study of the physical connections among groups of nerve cells — are pointing to which parts of these neural highways could be targeted to deal with certain problems. A study conducted at the University of Toronto of 482 DBS patients over 15 years, for instance, has shown how electrical stimulation of certain spots have predictable ripple effects elsewhere in the brain.

Another study of people with implanted electrodes illustrates brain networks in action. When certain electrodes were stimulated, people experienced immediate and obvious changes in their moods. Those electrodes, it turns out, were near neural tracts that converge in a brain region just behind and above the eyes called the lateral orbitofrontal cortex.

In the future, we might all have our personalized brain wiring diagrams mapped, says neuroscientist Michael D. Fox of Brigham and Women’s Hospital in Boston. And perhaps for any symptom — anxiety, or food craving, or addiction — doctors could find the brain circuit responsible. “Now we’ve got our target,” Fox says. “We can either hold the neuromodulation tool outside your scalp, or implant a tool inside your head, and we’re going to fix that circuit.”

The hurdles to building a nimble, powerful and precise system similar to the one that helped Sarah are high. But past successes suggest that innovative, aggressive research will find ways around current barriers. For people with mood disorders, addiction, dementia or any other ailment rooted in the brain, those advances can’t come soon enough.
— Laura Sanders

Future #2: Thoughts for sale

futuristic animation of people observing a person driving while wearing a neural monitor
Glenn Harvey

Javier had just been fired, but all he could think about was the potted palm tree in the corner of his office. It was too big to haul home, and his only work friend probably couldn’t adopt it. 

As the director of neural systems engagement at Zou headquarters in downtown Los Angeles, Javier had a spacious office with sunlight. His friend Al had neither. Al worked in a dim cubicle alongside the rest of the neuromonitors. Still, Javier made his way down to the second floor, reeling, thinking that he’d at least ask about the palm.

“They’re done with me,” he told Al quietly, not quite looking at him. “They’re done with the whole Signal program.”

Al shook his head. “I’m sorry, man.”

“That’s not the worst,” Javier says. “They’re moving all of the Signal data into the information market,” he hissed at Al with a dark look.

Al met Javier’s eyes and shook his head slowly. The friends had talked about this possibility before.

Zou was in the transportation business, an on-demand ride hailing and courier system that spanned the city. After the self-driving industry imploded because of too many accidents, Zou drove into L.A. with a promise of safety — so the company needed to make sure its drivers were the best.

That’s where Javier and his team came in. They collected drivers’ brain data with stretchy gray headbands and designed algorithms that sorted the good drivers from the bad with details straight from the drivers’ brains. The data included details about the timing and size of neural impulses that dashcams and accelerometers could only guess at. A quick scan of the data would reveal whether a driver was alert, distracted, overly aggressive or sleepy, for instance.

Every day and every night, torrents of brain data flowed from the company’s drivers as they maneuvered hot pink electric cars around the city, delivering people, food, packages and medicine.

Javier’s ambitious idea — the Signal program — had been to incentivize drivers with cash, using their brain data. Drivers with alert and focused brains earned bonuses automatically; a green power bar on-screen in the car showed minute-to-minute earnings. Drivers whose brains appeared sluggish or aggressive didn’t earn extra. Instead, they were warned. If the problem continued, they were fired.

Every day and every night, torrents of brain data flowed from the company’s drivers as they maneuvered hot pink electric cars around the city, delivering people, food, packages and medicine.

This carrot-and-stick system, developed by Javier and his team over a year, worked beautifully at first. But a few months in, accidents started creeping back up. 

Since the drivers began wearing the caps while on the roads, brain scores had been steadily improving. The bonuses were flowing. Three thousand people driving for countless hours in wild L.A. traffic, and the data appeared to show everyone’s brains alert and humming with focus. So why the uptick in accidents? Something was wrong with Javier’s system.

The problem, it turned out, was a basic truth about the brain: It changes. Human brains can learn, find creative solutions, remake themselves. Those properties are why some people become excellent drivers to begin with, threading their way past traffic and roadblocks to deliver their passengers efficiently. But those neural adjustments are also what confounded Zou.

Incentivized to maintain a certain type of brain activity, drivers’ brains quickly learned to produce that activity — even if it didn’t correspond to improved driving skill. The brains’ workarounds sparked an arms race that Javier ultimately lost. The neural engineers would find new brain signals that more reliably mapped to driving safety; the drivers’ brains would soon learn a way to get around it. That expensive, time-consuming loop ran for two years before Javier finally got sacked.

It turned out that the brain data was crap for improving drivers’ performance. But that brain data was still a veritable gold mine. The caps, worn by thousands of drivers, didn’t just collect neural data relevant to driving. Along with that came details like how the drivers’ brains responded to a certain style of music, how excited drivers got when they saw a digital billboard for a vacation resort and how they reacted to a politician’s promises. Companies, politicians, special interest groups, practically everybody, are desperate for these details, and Zou was now going to sell them.

It turned out that the brain data was crap for improving drivers’ performance. But that brain data was still a veritable gold mine.

Initially, Zou made the headsets a condition of employment, and the drivers had agreed to wear the caps while they were on the clock. Most seemed happy for the pay boost that the caps would bring. As a company, Zou was careful to stay far away from the secretive neuromonitoring that had been banned by the amended Declaration of Human Rights.

But now, Zou was going to require employees to wear the headsets when they weren’t driving. The caps would collect their data while they eat, while they grocery shop and while they talk with their kids, slurping up personal information that would then be sold.

Of course, the employees could refuse. They could decide to take off the caps and quit. “But what kind of choice is that?” Javier asked Al in a whisper, after unloading on him. “The drivers need money. Most of them would open up their skulls for a paycheck.”

Al shook his head, and then asked, “How much would they pay?”

“Who knows,” Javier said. “Maybe nothing. Maybe they’ll slip the data consent line into the standard 500-page employment contract, and say nothing more about it.”

“Want me to pass a tip on to my sister-in-law?” Al asked. “She’s the one at the Valley Media Group. They did that project a few years back on neural privacy.”

“I don’t know,” Javier said. “The move is bad, but maybe just low-key bad for these times. This is the way things are going, after all.”

With a defeated look, Javier shook his head one more time and started back up to his office. He had some decisions to make, including the one about the palm tree.

Past and present: Catching brain waves

Javier’s fictional program, Signal, was built with information gleaned externally from drivers’ brains. Caps that can monitor inner minds sound like a centerpiece of a futuristic dystopia, but today’s research is tiptoeing toward that possibility.

Some companies already sell brain monitoring systems made of electrodes that measure external brain waves with a method called electroencephalography, or EEG. For now, these headsets are sold as wellness devices for the data-driven human. For a few hundred dollars, you can own a headset that promises to fine-tune your meditation practice, make better decisions or even level up your golf game. EEG caps can measure alertness already; some controversial experiments have monitored schoolchildren as they listened to their teacher. 

a person seen from behind wearing a white EEG cap
Data from a technique that captures external brain waves, called electroencephalography or EEG, scientists can infer certain states of the brain, including whether a person is focused and paying attention.fotografixx/E+/Getty Images

The claims by these companies are big, and they haven’t been proven to deliver. “It is unclear whether consumer EEG devices can reveal much of anything,” ethicist Anna Wexler of the University of Pennsylvania argued in a commentary in Nature Biotechnology in 2019.  Still, improvements in these devices, and the algorithms that decode the signals they detect, may someday enable more sophisticated information to be reliably gleaned from the brain.  

For now, these brain signals are not monetized as they are imagined to be in the information marketplace Javier despises. But other types of personal data that we willingly exchange for access to our favorite digital services are regularly bought and sold. It’s not a far leap to see how certain types of neural data would be particularly valuable for educators, advertisers and politicians.  

The system in the story measured brain waves that could be used to infer drivers’ mental states —alertness, focus and sleepiness, for instance. Measured correctly, these neural signatures are easy to spot.

an EEG readout shows reactions during swerving events
In a recent experiment, people in an immersive driving simulator wore EEG caps as scientists monitored their brainwaves during swerving events. Such neural details may ultimately lead to ways to spot fatigue and drowsiness among drivers.Z. Cao et al/Scientific Reports 2019

EEG began in earnest in the 1920s, after the German psychiatrist Hans Berger used electrodes to record brain waves from people. In his 1929 paper introducing the method, Berger described simple brain waves that ripple during sleep and mental activity. He and other scientists began to scrutinize some of the prominent types of brain waves, such as alpha waves that come with being calm and relaxed.


As the technology improved, scientists were able to describe in more detail the signature blends of brain waves that accompany alertness, meditation, strenuous exercise and even the various stages of sleep. As early as 1937, scientists had begun describing the ebb and flow of various brain waves during sleep: alpha waves fragment and finally disappear; jiggy, jaggy bursts of activity called sleep spindles appear, as do certain types of slow waves.

“It is unclear whether consumer EEG devices can reveal much of anything.”

Anna Wexler, ethicist

With improvements in computing and technology, scientists have been able to get ever more sophisticated readings from brains of people as they go about their lives, including signs of surprise, pleasure and frustration. EEG has measured the attention of people as they watch television, in order to use the neural signals of viewers to predict whether a show will turn into a hit. Researchers have even put EEG headsets on drivers as they virtually navigated roads, an idea that provided inspiration for Signal’s system in this story.

Other types of neural signatures, it turns out, can provide even richer glimpses into the mind.

Physical movements, such as moving a finger, come with clear neural traces in the brain. That includes the movements that produce speech. A recent milestone in decoding such signals came in 2019; scientists at the University of California, San Francisco pulled full sentences out from the brain using neural signals alone. That milestone relied on implanted electrodes to extract the neural signals a person uses to control the muscles of the vocal tract.

Sophisticated visual scenes, including clips of movies that people were watching, can be gleaned from brain scans. Work by Jack Gallant and colleagues at the University of California, Berkeley built captivating visual scenes using data from people’s brains as they lay in a functional MRI scanner. A big red bird swooped across the screen, elephants marched in a row and Steve Martin walked across the screen, all impressionistic versions of images pulled from people’s brain activity.

That work, published in 2011, foreshadowed ever more complex brain-reading tricks. More recently, researchers used fMRI signals to re-create faces that people were seeing.

It’s like mind reading, sort of. On the left are clips of movie trailers. On the right are reconstructed images built from neural activity as people watched the videos, measured by fMRI.

But those types of things — muscle movements and visual scenes — are thought to be more straightforward than other more personalized aspects of the mind. Will our more nebulous thoughts, beliefs and memories ever be accessible?

It’s not impossible. Take a study from Japan, published in 2013. Scientists identified the contents of three sleeping people’s dreams, using a functional MRI machine. But re-creating those dreams required hours of someone telling a scientist about other dreams first. To get the data they wanted, scientists first needed to be invited into the dreamers’ minds, in a way. Those three people were awakened over 200 times each early in the experiments and asked to describe what they had been dreaming about. That allowed the scientists to build a personalized map between dream contents and brain activity for each person.

Some ethicists think that neural data ought to have the same sorts of protections as bodily organs have in many countries today.

Another big caveat: Most of these methods relied on fMRI — bulky, expensive and definitely non-portable equipment. Invented in 1990, the technique uses a powerful magnet to assess levels of oxygen in the brain, which can serve as a proxy for neural activity. That method has been incredibly powerful, but also comes with big caveats, researchers have learned. But more portable and more reliable ways to eavesdrop on the brain from the outside are moving forward fast. Companies such as Facebook and IBM are investing heavily in devices that can get inside our heads.

Ethicists, scientists and futurists have already called for special protections of neural data. The government of Chile, for instance, is considering a NeuroData protection effort, which would amend their constitution to include mental identity as a right. Some ethicists think that neural data ought to have the same sorts of protections as bodily organs have in many countries today. Legally, you can’t sell a liver; the same ought to be true for brain data, this argument goes. These types of debates will only grow more intense as mind-reading capabilities improve.
— Laura Sanders

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Future #3: Mind meld

futuristic animation of a scientist in the lab feeding a bird, while a monitor flashes with neural activity
Glenn Harvey

Sofia couldn’t sleep. Tomorrow was the big day. As the project manager for the Nobel Committee for Physiology or Medicine, she had overseen years of prize announcements, but never one like this.

At 11:30 a.m. Central European Summer Time tomorrow, the Nobel Prize in physiology or medicine would be given to a bird named Harry, a 16-year-old Clark’s nutcracker. Sofia smiled in the dark as she thought about how the news would land.

Harry was to be recognized for benefiting humankind “in his role as a pioneering memory collective that enhances human minds.” As such, Harry would share the prize (and the money) with his two human trainers.

Tomorrow morning, the world would be buzzing, Sofia knew. But as with every Nobel Prize, the story began long before the announcement. Early experiments always pave the way, and for Harry, it was no exception. Even in the 20th century, scientists had been dreaming of, and tinkering with, merging different kinds of minds.

The first forays into linked minds consisted of crude signals sent over the internet from people to animals with electrodes implanted in their brains. EEG signals from a person could make an anesthetized rat flick its tail, for instance. In those days, attempts at mind connections were dismissed by many as party tricks — fascinating, but scientifically vapid.

The first forays into linked minds consisted of crude signals sent over the internet from people to animals with electrodes implanted in their brains. In those days, attempts at mind connections were dismissed by many as party tricks — fascinating, but scientifically vapid.

As the technology got more precise and less invasive, human-to-human links grew seamless, inspired by ancient and intriguing examples of conjoined twins with shared awareness. External headsets could send and receive signals between brains, such as “silent speech” and sights and sounds.

These human-to-human connections turned out to be quite helpful for certain problems. As a girl, Sofia had read about a woman who had experienced a stroke. Afterward, the woman was linked up with a healthy man in order to relearn her arm movements. The helper took the lead, neurally, in directing the rehabilitative movements of the woman’s paralyzed arm. Gradually, more control was shifted to the injured woman’s brain as she rehearsed the neural patterns her stroke had scrambled. (The example had made an impression on young Sofia because the story she read focused on how the two people had fallen in love after their close connection — a titillating turn of events for a 10-year-old.)

Next, scientists began looking beyond the human brain for different types of skills that might boost our abilities. Other animals have different ways of seeing, feeling, experiencing and remembering the world. That’s where Harry came in.

Crows, ravens and other corvids have prodigious memories. That’s particularly true for Clark’s nutcrackers. These gray and black birds are able to remember the locations of an estimated 10,000 seed stashes at any given time. These powerful memory abilities soon caught the eye of human scientists eager to augment human memory.

The scientists weren’t talking about remembering where the car is parked in the airport lot. They set their sights higher. Done right, these enhancements could allow a person to build stunningly complete internal maps of their world, remembering every place they had ever been. And it turned out that these memory feats didn’t just stop at physical locations. Strengthening one type of memory led to improvements in other kinds of memories, too. The systems grew stronger all around.

Harry wasn’t the first bird to link up with humans, but he has been one of the best. As a young bird, Harry underwent several years of intense training aided by his favorite treat, whitebark pine seeds. Using a sophisticated implanted brain chip, he learned to merge his neural signals with those of a person who was having memory trouble or needed a temporary boost. The connection usually lasted for a few hours a day, but its effects, amazingly, endured. The effect was breathtaking, according to the people who have tried it.

The truly surprising thing was that the memory benefits lasted. Noticeable improvements in people’s memories held fast for months after a session with Harry. Harry had made history, and would be making it again soon after tomorrow’s announcement, Sofia thought.

Harry wasn’t the first bird to link up with humans, but he has been one of the best. Using a sophisticated implanted brain chip, he learned to merge his neural signals with those of a person who was having memory trouble or needed a temporary boost. The connection usually lasted for a few hours a day, but its effects, amazingly, endured.

By showing this sort of human-animal mind meld was possible, and beneficial, Harry and his trainers had helped create an entirely new field. Some scientists are now building on what Harry’s brain could do during these mingling sessions. Others are expanding to different animal abilities: Allowing people to “see” in the dark like echolocating bats, or “taste” with their arms like octopuses. Imagine doctors smelling diseases, an olfactory skill borrowed from dogs. News outlets were already starting to interview people with augmented animal awareness.

Still wide awake, Sofia’s mind ran back through the meetings she had held with her communications team over the past week. Tomorrow’s announcement would bring amusement and delight, but she also expected strong objections. The team was prepared for protests, lots of them.

Some religious groups had objected, arguing that human minds were not meant to be dispersed among multiple bodies, especially those of other species. Animal rights advocates had argued that this project was yet another step toward animal enslavement. Even some ethicists were riled by the research, concerned that the birds might develop ways of thinking and feeling that were humanlike, and that the human partners might somehow become corvidish. Some people held that merging minds across species, despite the potential benefits, was too risky.

Some ethicists were riled by the research, concerned that the birds might develop ways of thinking and feeling that were humanlike, and that the human partners might somehow become corvidish.

And of course, there were always the Borg people. Vehemently opposed to any efforts to link minds, these people formed a niche fandom devoted to the antique Star Trek television series. In the show, the Borg’s collective consciousness grew unstoppable, assimilating everyone and everything it met into itself, consuming identities and free will along the way.

As a general rule, Borg people were not taken seriously. But in the middle of the night, their objections seemed a smidge more substantial to Sofia. Then she thought of Harry flitting around, hiding seeds, and the threat faded away. Sofia marveled at how far the science had come since she was a girl, and how far it was bound to go. Fully exhausted, she rolled over, ready to sleep, ready for tomorrow. She smiled again as she thought about what she’d tell the Borgers, if the chance arose: For better or worse, resistance is futile.

Past and present: Linking brains

Accepting that a bird could win a Nobel Prize demands a pretty long flight of fancy. But scientists have already directly linked together multiple brains. 

Today, the technology that makes such connections possible is just getting off the ground. We are in the “Kitty Hawk” days of brain interface technologies, says computational neuroscientist Rajesh Rao of the University of Washington, who is working on brain-based communication systems. In the future, these systems will inevitably fly higher. 

Such technology might even take people beyond the confines of their bodies, creating a sort of extended cognition, possibly enabling new abilities, Rao says. “This direct connection between brains — maybe that’s another way we can make a leap in our human evolution.”

Rao helped organize a three-way direct brain chat, in which three people sent and received messages using only their minds while playing a game similar to Tetris. Signals from the thoughts of two players’ brains moved over the internet and into the back of the receiver’s brain, via a burst of magnetic stimulation designed to mimic information coming from the eyes. Senders could transmit signals that told the player to rotate a piece, for instance, before dropping it down. Those results, published in 2019 in Scientific Reports, represent the first time multiple people have communicated directly with their brains. 

A person wearing a tight-fitting device on her head looks at a computer screen
An EEG cap measures brain signals of a “sender” (shown) as she and two other people play a video game with their brains. Those signals form instructions that are sent directly to the brain of another player who can’t see the board but must decide what to do based on the instructions.Mark Stone/Univ. of Washington

Other projects have looped in animals, though no birds yet. At first, the attempts were basic. In 2013, brain signals from a person made an anesthetized rat twitch its tail. That system relied on a series of signals: First, external electrodes monitored a person’s intentions. Next, a computer translated those signals into a code. Then, focused ultrasound moved that code into the rat’s brain. Finally, the rat’s tail twitched. It was clunky, but it worked. 

Rat mind control has grown more sophisticated already. In 2019, people took control of six awake rats’ brains, guiding the animals’ movements through mazes via thought. A well-trained rat cyborg could reach turning accuracy of nearly 100 percent, the researchers reported. 

Human brains controlled rats as they moved through a maze with stairs, tunnels, pillars and platforms. To succeed, the rats had to make their way through the preset route within five minutes. The flashing arrows at the bottom indicate when the rat was directed to go forward, left or right.

Cockroaches have been co-opted, too, most notably by researchers at Shanghai Jiao Tong University in China in 2015. After receiving signals from a human, recorded by an external EEG system, the roaches were compelled to walk in S-shaped paths.

But those rats and roaches took commands from a person; they didn’t send information back. Continuous back-and-forth exchanges are a prerequisite for an accomplishment like Harry’s. 

These types of experiments are happening too. A recent study linked three monkeys’ brains, allowing their minds to collectively move an avatar arm on a 3-D screen. Each monkey was in charge of moving in two of three dimensions; left or right, up or down, and near or far. Those overlapping yet distinct jobs led the networked monkeys to flounder initially. But soon enough, their neural cooperation became seamless as they learned to move the avatar arm to be rewarded with a sip of juice. 

“This direct connection between brains — maybe that’s another way we can make a leap in our human evolution.”

Rajesh Rao, computational neuroscientist

A four-rat network, similarly, learned how to synchronize neural activities for a reward of water. This Brainet, as it was called by Miguel Nicolelis at Duke University and colleagues, was capable of feats that were equal to or better than individual rat brains. Brain signals that corresponded to a certain pattern of touches could be moved among three rats with high fidelity, the researchers found.

With technological improvements, the variety of signals that can move between brains will increase. And with that, these brain collectives might be able to accomplish even more. “One brain can do only so much, but if you bring many brains together, directly connected in a network, it’s possible that they could create inventions that no single mind could think of by itself,” Rao says. 

Groups of brains might be extra good at certain jobs. A collective of surgeons, for instance, could pool their expertise for a particularly difficult operation. A collective of fast-thinking pilots could drive a drone over hostile territory. A collective of intelligence experts could sift through murky espionage material. 

Capabilities might extend even more if other species are included. Animal brains are capable of feats that humans only dream of, such as dogs’ prodigious olfactory abilities, octopuses’ legs that can think for themselves and bats’ echolocation. 

Maybe one day, information from an animal’s brain might augment human brains — although it’s unlikely that the neural signals from a well-trained Clark’s nutcracker will be the top choice for a memory aid. Artificial intelligence, or even human intelligence, might make better memory partners. Whatever the source, these external “nodes” could ultimately expand a human brain’s connectome, the complex web of neural connections. 

Those expansions might be beneficial, even without a deep understanding of the series of network changes that it requires. What’s more, there’s a certain amount of leeway in this type of neural communication, says Rao. “Decoding can be a little sloppy,” he says. “The brain can adapt.” As long as good feedback is coming in, the brain can learn how to interpret these new signals, much like learning a new language.

This key property of the brain —  that it can change — is what makes the prospect of these kinds of new connections so exciting. There’s plenty of evidence that neural circuits can be strengthened, weakened, or even created anew, in response to incoming information. That sculpting could last longer than a temporary connection. “That could be how things might succeed in the end,” Rao says. 

“Part of me is connected and extended to this other human being. Is this me? Is this someone else? Am I doing this myself?”

Elisabeth Hildt, bioethicist

Still, connecting brains directly is fraught with ethical questions. “The very act of linking two brains together to transfer information raises a variety of ethical and safety concerns,” neuroethicist Karen Rommelfanger of Emory University and colleagues wrote in 2014 in Frontiers in Neuroengineering

One aspect, the idea of an “extended mind,” poses particularly wild conundrums, says bioethicist Elisabeth Hildt of the Illinois Institute of Technology in Chicago. “Part of me is connected and extended to this other human being,” she says. “Is this me? Is this someone else? Am I doing this myself?” she asks. 

Some scientists think it’s too early to contemplate what it might feel like to have our minds dispersed across multiple brains, human or animal. Others disagree. “It may be too late if we wait until we understand the brain to study the ethics of brain interfacing,” Rao says. “The technology is already racing ahead.” 

So feel free to mull over how it would feel to connect minds with a bird.  If you were the human who could link to the mind of Harry the Clark’s nutcracker, for instance, perhaps you might start to dream of flying. 
— Laura Sanders


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