Thought Experiments
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TECHNOLOGY QUARTERLY January 6th 2018 BRAIN-COMPUTER INTERFACES Thought experiments 20180106_TQbrain.indd 1 06/12/2017 10:24 TECHNOLOGY QUARTERLY Brain-computer interfaces Brains and machines Thought experiments Brain-computer interfaces sound like the stuff of science fiction. Andrew Palmer sorts the reality from the hype N THE gleaming facilities of the Wyss Centre A channel of communication of this sort requires a for Bio and Neuroengineering in Geneva, a lab brain-computer interface (BCI). Such things are al- technician takes a well plate out of an incuba- ready in use. Since 2004, 13 paralysed people have ALSO IN THIS TQ tor. Each well contains a tiny piece of brain tis- been implanted with a system called BrainGate, first Non-invasive devices sue derived from human stem cells and sitting developed at Brown University (a handful of others Headache on top of an array of electrodes. A screen dis- have been given a similar device). An array of small Iplayswhatthe electrodesare pickingup: the character- electrodes, called a Utah array, is implanted into the Implants istic peak-and-trough wave forms offiring neurons. motor cortex, a strip of the brain that governs move- Inside intelligence To see these signals emanating from disembodied ment. These electrodes detect the neurons that fire tissue is weird. The firingofa neuron is the basic build- when someone intends to move his hands and arms. Data processing ing block of intelligence. Aggregated and combined, These signals are sent through wires that poke out of Translation required such “action potentials” retrieve every memory, guide the person’sskull to a decoder, where theyare translat- every movement and marshal every thought. As you ed into a variety of outputs, from moving a cursor to Brain scan read this sentence, neurons are firing all over your controlling a limb. Eberhard Fetz brain: to make sense of the shapes of the letters on the The system has allowed a woman paralysed by a Looking for page; to turn those shapes into phonemes and those stroke to use a robotic arm to take her first sip of coffee serendipity phonemes into words; and to confer meaning on without help from a caregiver. It has also been used by Grey matter, red tape those words. a paralysed person to type ata rate ofeightwords a mi- This symphony of signals is bewilderingly com- nute. It has even reanimated useless human limbs. In a plex. There are as many as 85bn neurons in an adult study led by Bob Kirsch of Case Western Reserve Uni- human brain, and a typical neuron has10,000 connec- versity, published in the Lancet this year, BrainGate tions to othersuch cells. The job ofmappingthese con- was deployed artificially to stimulate muscles in the nections is still in its early stages. But as the brain gives arms of William Kochevar, who was paralysed in a cy- up its secrets, remarkable possibilities have opened cling accident. As a result, he was able to feed himself up: of decoding neural activity and using that code to for the first time in eight years. control external devices. Interactions between brains and machines have 1 The Economist January 6th 2018 1 TECHNOLOGY QUARTERLY Brain-computer interfaces 2 changed lives in other ways, too. The opening ceremony of the cells in the visual cortex of macaque mon- football World Cup in Brazil in 2014 featured a paraplegic man keys encoded 50 different aspects of a per- who used a mind-controlled robotic exoskeleton to kick a ball. A son’s face, from skin colour to eye spacing. recent study by Ujwal Chaudhary of the University of Tübingen That enabled them to predict the appear- and four co-authors relied on a technique called functional near- ance of faces that monkeys were shown infrared spectroscopy (fNIRS), which beams infrared light into the from the brain signalstheydetected, with a brain, to put yes/no questions to four locked-in patients who had spooky degree of accuracy. But conducting been completely immobilised by Lou Gehrig’s disease; the pa- scientific research on human brains is tients’ mental responses showed up as identifiable patterns of harder, for regulatory reasons and because blood oxygenation. they are larger and more complex. Neural activity can be stimulated as well as recorded. Cochlear Ultimately Even when BCI breakthroughs are implants convert sound into electrical signals and send them into it may be made on humans in the lab, they are diffi- the brain. Deep-brain stimulation uses electrical pulses, delivered cult to translate into clinical practice. Wired via implanted electrodes, to help control Parkinson’s disease. The possible to magazine first reported breathlessly on the technique has also been used to treat other movement disorders then new BrainGate system back in 2005. and mental-health conditions. NeuroPace, a Silicon Valley firm, meld An early attempt to commercialise the monitors brain activity for signs of imminent epileptic seizures technology, by a company called Cyberki- and delivers electrical stimulation to stop them. together netics, foundered. It took NeuroPace 20 It is easy to see how brain-computer interfaces could be ap- years to develop its technologies and nego- plied to other sensory inputs and outputs. Researchers at the Uni- human and tiate regulatory approval, and it expects versity ofCalifornia, Berkeley, have deconstructed electrical activ- artificial that only 500 people will have its elec- ity in the temporal lobe when someone is listening to con- trodes implanted this year. versation; these patterns can be used to predict what word intelligence Current BCI technologies often require someone has heard. The brain also produces similar signals when experts to operate them. “It is not much use someone imagines hearing spoken words, which may open the if you have to have someone with a mas- door to a speech-processing device for people with conditions ters in neural engineering standing next to such as aphasia (the inability to understand or produce speech). the patient,” says Leigh Hochberg, a neu- Researchers at the same university have used changes in blood rologist and professor at Brown University, who is one of the key oxygenation in the brain to reconstruct, fuzzily, film clips that peo- figures behind BrainGate. Whenever wires pass through the skull ple were watching. Nowimagine a device thatcould work the oth- and scalp, there is an infection risk. Implants also tend to move er way, stimulating the visual cortex of blind people in order to slightly within the brain, which can harm the cells it is recording project images into their mind’s eye. from; and the brain’s immune response to foreign bodies can If the possibilities of BCIs are enormous, however, so are the create scarring around electrodes, making them less effective. problems. The most advanced science is being conducted in ani- Moreover, existing implants record only a tiny selection of the mals. Tinysilicon probescalled Neuropixelshave been developed brain’s signals. The Utah arrays used by the BrainGate consor- by researchers at the Howard Hughes Institute, the Allen Institute tium, for example, might pick up the firing of just a couple of hun- and University College London to monitor cellular-level activity dred neurons out of that 85bn total. In a paper published in 2011, in multiple brain regions in mice and rats. Scientists at the Univer- Ian Stevenson and Konrad Kording of Northwestern University sity ofCalifornia, San Diego, have built a BCI that can predict from showed thatthe numberofsimultaneouslyrecorded neurons had priorneural activity what songa zebra finch will sing. Researchers doubled every seven years since the 1950s (see chart). This falls far at the California Institute of Technology have worked out how shortofMoore’slaw, which hasseen computingpowerdouble ev-1 2 The Economist January 6th 2018 TECHNOLOGY QUARTERLY Brain-computer interfaces 2 ery two years. Indeed, the Wyss Centre in Geneva exists because it is so hard to get neurotechnology out of the lab and into clinical practice. John Donoghue, who heads the centre, is another of the pioneers of the BrainGate system. He says it is designed to help promising ideas cross several “valleys of death”. One is financial: the combi- nation oflengthy paybackperiods and deep technology scares off most investors. Another is the need for multidisciplinary exper- tise to get better interfaces built and management skills to keep complex projects on track. Yet another is the state of neuroscience itself. “At its core, this is based on understanding how the brain works, and we just don’t,” says Dr Donoghue. Me, myselfand AI This odd mixture of extraordinary achievement and halting pro- gress now has a new ingredient: Silicon Valley. In October 2016 Bryan Johnson, an entrepreneur who had made a fortune by sell- ing his payments company, Braintree, announced an investment of $100m in Kernel, a firm he has founded to “read and write neu- ral code”. Mr Johnson reckons that the rise ofartificial intelligence (AI) will demand a concomitant upgrade in human capabilities. “I find it hard to imagine a world by 2050 where we have not inter- vened to improve ourselves,” he says, picturing an ability to ac- quire new skills at will orto communicate telepathically with oth- ers. Last February Kernel snapped up Kendall Research Systems, a spinoff from the Massachusetts Institute of Technology (MIT) that works on neural interfaces. Kernel is not alone in seeing BCIs as a way forhumans to co-ex- ist with AI rather than be subjugated to it. In 2016 Elon Musk, the boss of SpaceX and Tesla, founded a new company called Neura- link, which is also working to create new forms of implants. He Non-invasive devices has gathered together an impressive group of co-founders and set a goal of developing a BCI for clinical use in people with disabil- ities by 2021.