Frankenstein's Cat: Cuddling Up to Biotech's Brave New Beasts (19 page)

Still, the robo-bugs aren’t
quite
ready for their tour of duty. Our directional control is still pretty crude. Ultimately, we’ll want to do more than make an insect simply veer left. We’ll want to be able to command it to turn, say, precisely 35 degrees to the left or navigate a complicated three-dimensional space, such as a chimney or pipe. There’s also the matter of the surveillance equipment. So far, the main focus has been on building insects that we can steer, but for these cyborgs to be useful, we’ll need to outfit them with various sensors and make sure that they can successfully collect and transmit environmental information. And though the cyborg insects power their own flight—something that completely robotic fliers cannot do—the surveillance equipment will need to get its electricity from somewhere.

One intriguing possibility is to use the insect’s own wings as a source of power. In 2011, a team of researchers from the University of Michigan announced that they had accomplished just that by building miniature generators out of ceramic and brass. Each tiny generator was a flattened spiral—imagine the head of a thumbtack, if it were shaped from a tight coil of metal rather than a single flat sheet—measuring 0.2 inches across. When they were mounted on the beetle’s thorax, these generators transformed the insect’s wing vibrations into electrical energy. With some refinement, the researchers note, these energy-harvesting devices could be used to power the equipment toted around by cyborg bugs.

*   *   *

Insects could give us a cyborg-animal air force, zooming around the skies and searching for signs of danger. But for terrestrial missions, for our cyborg-animal army, we’d have to look elsewhere. We’d have to look to a lab at the State University of New York (SUNY) Downstate, where researchers have built a remote-controlled rat.

We’ve been rooting around in rat brains for ages; neuroscientists often send electrical signals directly into rodents’ skulls to elicit certain reactions and behaviors. Usually, however, this work requires hooking a rodent up to a system of cables, severely restricting its movement. When the SUNY team, led by the neuroscientist John Chapin, began their work more than a decade ago, they wanted to create something different—a method for delivering these electrical pulses wirelessly. They hoped that such a system would free researchers (and rats) from a cumbersome experimental setup, and enable all sorts of new scientific feats. A wireless system would allow scientists to manipulate a rat’s movements and behaviors while it was roaming freely and give us a robo-rodent suitable for all sorts of special operations. Rats have an excellent sense of smell, so cyborg rats could be trained to detect the scent of explosives, for instance, and then steered to a field suspected to contain land mines. (The task would pose no danger to the animals, which are too light to set off mines.) Or they could be directed into collapsed buildings and tasked with sniffing out humans trapped beneath the rubble, performing a job similar to the one Maharbiz imagines for his cyborg insects. “They could fit through crawl spaces that a bloodhound never could,” says Linda Hermer-Vazquez, a neuroscientist who was part of the SUNY team at the time.

But before any of that could happen, the SUNY scientists had to figure out how to build this kind of robo-rat. They began by opening up a rat’s skull and implanting steel wires in its brain. The wires ran from the brain out through a large hole in the skull, and into a backpack harnessed to the rodent. (“Backpack” seems to be a favorite euphemism among the cyborg-animal crowd.) This rat pack, as it were, contained a suite of electronics, including a microprocessor and a receiver capable of picking up distant signals. Chapin or one of his colleagues could sit five hundred yards away from the rat and use a laptop to transmit a message to the receiver, which relayed the signal to the microprocessor, which sent an electric charge down the wires and into the rat’s brain.

To direct the animal’s movements, the scientists implanted electrodes in the somatosensory cortex, the brain region that processes touch sensations. Zapping one area of the cortex made the rat feel as though the left side of its face was being touched. Stimulating a different part of the cortex produced the same phantom feeling on the right side of the rat’s face. The goal was to teach the rodent to turn in the opposite direction of the sensation. (Though that seems counterintuitive, it actually works with the rat’s natural instincts. To a rodent, a sensation on the right side of the face indicates the presence of an obstacle and prompts the animal to scurry away from it.)

During the training process, the SUNY scientists used an unconventional system of reinforcement. When the rat turned in the correct direction, the researchers used a third wire to send an electrical pulse into what’s known as the medial forebrain bundle (MFB), a region of the brain involved in processing pleasure. Studies in humans and other animals have shown that direct activation of the MFB just plain feels good. (When the scientists gave the rats the chance to stimulate their own MFBs by pressing down on a lever, the animals did so furiously—hitting the lever as many as two hundred times in twenty minutes.) So sending a jolt of electricity zinging down to a rat’s MFB acted as a virtual reward for good behavior. Over the course of ten sessions, the robo-rats learned to respond to the cues and rewards being piped into their brains. Scientists managed to direct the rodents through a challenging obstacle course, coaxing them to climb a ladder, traverse a narrow plank, scramble down a flight of stairs, squirm through a hoop, and then navigate their way down a steep ramp.

As a final demonstration, the researchers simulated the kind of search-and-rescue task a robo-rat might be asked to perform in the real world. They rubbed tissues against their forearms and taught the rodents to identify this human odor. They constructed a small Plexiglas arena, filled it with a thick layer of sawdust, and buried human-scented tissues inside. When they released the robo-rats into the arena, the animals tracked down the tissues in less than a minute. The scientists also discovered that the rats that received MFB rewards found the target odors faster and dug for them more energetically than rodents that had been trained with conventional food rewards. As Hermer-Vazquez recalls: “The robo-rats were incredibly motivated and very accurate.”

*   *   *

Whether it’s rescue rat-bots or bomb-sniffing beetle drones, electronics are helping us create new beasts of burden, allowing us to conscript creatures into the modern animal workforce. These are no mere donkeys, poked and prodded into carrying our bags up steep hills; these animals’ brains are being taken hostage, their nervous systems forced to cooperate with our plans. As Maharbiz wrote in an account of his research, “[W]e wanted to be sure we could deliver signals directly into the insect’s own neuromuscular circuitry, so that even if the insect attempted to do something else, we could provide a countercommand. Any insect that could ignore our commands would make for a crummy robot.”

Is it wrong to take the reins of another creature’s nervous system? It certainly
feels
wrong. When we dictate the movements of sentient beings, we turn them into mere machines, no different than those remote-controlled airplanes Maharbiz was trying to emulate. Many animal liberationists and philosophers have argued that one of our obligations to animals is “noninterference”—that animals have the right to be the leaders of their own lives and that we have a duty to leave them alone. Cyborg animals represent an extreme violation of that responsibility. And unlike in wildlife tracking projects, in which our meddling may help save species, deploying cyborg insects and rodents on the battlefield isn’t going to do much to benefit animals.

The trouble is that we have to balance this intrusion into the life of another living being against the good that animal-machine mash-ups could do. It’s possible to care about animals and want to spare them needless suffering, and yet also decide that sometimes human welfare (say, the life of an American soldier) comes first. In fact, most Americans take this view, according to the psychologist Harold Herzog, who specializes in untangling our relationships with other species. After all, if you insist that an animal’s life is worth exactly the same as a human one, no matter what, Herzog says, “you can end up at untenable places.” (Such as deciding that you should flip a coin to decide whether to save a puppy or a child from a burning building.) Herzog has found that our attitudes toward other species are nuanced, complicated, and often inconsistent. It’s not unusual, he says, to wish we could do without animal experimentation but still be grateful for the lifesaving drugs and treatments such research has made possible. It’s not strange to wish scientists would stop squirting shampoo into rabbits’ eyes and simultaneously want them to use as many bunnies as they need to find a cure for cancer.

Unless we rule out all use of animals for human purposes, we have to evaluate each application on a case-by-case basis, weighing pain against gain. In the case of the robo-beasts, the animals are anesthetized when the electronics are implanted in their bodies, but recovering from surgery isn’t painless. The devices themselves may cause stress, and being piloted around a lab by an ambitious postdoc can’t be any great picnic. But the price that animals have to pay for this research is relatively small. (Maharbiz notes that his beetles had normal lifespans—which, in insects, is a none-too-impressive several months—and “flew, ate, and mated just like regular beetles.”) Remotely guided rats aren’t exactly a cure for cancer, but if they can hunt down mines or find earthquake victims trapped in rubble, they could certainly save human lives. So while the cyborg research can seem creepy, I’m glad that there are scientists out there who are doing it.

The details matter, however. I wouldn’t be so keen on the research if the cost to animals were greater—if, say, each electric jolt we sent to an animal’s brain caused excruciating pain. Nor would I want to see robo-rats used to string lights along the branches of Christmas trees—an actual suggestion the SUNY researchers made in their patent application.
*
There’s a species effect in play, too. I have no special affection for insects or rodents, and I’d find it a lot harder to sanction the creation of robo-dogs or robo-bonobos.
^†
Maharbiz has noticed this inconsistency, too, though it’s not clear where that leaves us, ethically speaking. “Where do you draw the line?” he wonders. “Is there a Disney effect: ‘Anything cuter than bunnies I will not neuro-control’?” Or should we base our judgments of cyborg projects on something else? Should we make an ethical distinction between forcing muscles to contract (as Maharbiz’s wing electrodes do) and simply rewarding an animal for moving the way we want (as Hermer’s brain electrodes do)? Or is it how we
use
the cyborgs that matters?

For his part, Maharbiz says he’s motivated more by the challenge of seeing what he can make insects do than by imagining how his work will ultimately be used. “Maybe I’m an example of a horrible amoral scientist,” he says, “but I think it would be fabulous to show, for example, that I could get a beetle to do a barrel roll, which it would never do in nature.” Everyone’s ethical barometer is set differently, and we won’t all welcome the notion of a barrel-rolling beetle. That’s fine with Maharbiz, who notes that most of us haven’t sat down and thought through what it means to take over an animal’s body, to physically force their muscles and minds to do our bidding. Why would we? Until recently, the idea seemed like pure science fiction. One of the ways his work can be useful, Maharbiz says, is “to get people to think about whether this is something we want to do.”

*   *   *

Our options for mind manipulation are expanding as well. While Maharbiz and others are using electrodes and wires to physically force neurons to fire, some geneticists and neuroscientists are developing an alternative approach, engineering animals whose brains can be controlled with flashes of light. The technique, which comes from the hot, young field of optogenetics, relies on opsins, a class of light-sensitive molecules that bacteria, fungi, and plants use to sense sunlight and convert it into energy. In 2005, scientists discovered that they could put opsin genes into mammalian brain cells using an unlikely assistant: a virus. Viruses are experts at delivering DNA; whenever they infect a cell, they dump their own genomes inside. In the early days of genetic engineering, biologists realized that they could get viruses to carry other genes into cells, too. In optogenetics, scientists insert an opsin gene into a virus, then inject the modified virus into the brain of a mouse. The virus infects the neurons, depositing the opsin DNA inside.

The mouse’s neurons begin to manufacture their own opsins and install them in their membranes, the thin, fatty layer that surrounds each cell. In the membrane, the opsins operate as light-sensitive channels; when scientists shine a light on the mouse’s brain, the opsin channels open and electrically charged particles rush into the cell. The influx changes the voltage inside the neuron. Different opsins respond to light in different ways—some usher positively charged particles into a neuron, making it more likely to fire. Others admit negatively charged particles, which suppress neural activity.
*
By attaching a little snippet of regulatory DNA to the front of the opsin gene, researchers can make sure that only certain kinds of neurons produce the light-sensitive molecule. As a result, they can engineer a mouse’s brain so that one type of neuron, in one brain circuit or region, responds to a flash of light, while its neighbor is unaffected.

Equipped with this technology, we can make mice do the darnedest things. By turning certain neurons on and off, we can make rodents suddenly fall asleep or awaken. Or we can use a beam of light to activate a set of neurons involved in aggression, turning an otherwise calm mouse into a prizefighter who indiscriminately attacks other rodents—or even inanimate objects. These kinds of experiments hold huge promise for basic research; toggling a neural circuit on and off helps scientists puzzle out how those neurons affect behavior.