Hot-Wiring Human
John Cornwell's article "Hot-Wiring Humans" appeared in The Sunday Times magazine, June 20, 2004.
Best, Imelda, Cork.
June 20, 2004
Hot-wiring humans
By John Cornwell
(excerpt)
Electrodes are being planted into the brains of Parkinson's sufferers. Spinal implants could soon cure paraplegia. Robots might one day fight our wars. Are people about to become cyborgs?
Radcliffe Infirmary, Oxford, nine o'clock on a spring morning. Togged out in operation blues and clogs, I am feeling queasy as I enter the operating theatre to observe my first brain-implant procedure. The patient is Susan Brandon, a 62-year-old retired schoolteacher from Reading, a Parkinson's patient these past 12 years, who suffers from rigidity punctuated by uncontrollable tremors in her limbs. Chatting before the operation, she told me: "I'll be shopping in John Lewis and I'm suddenly frozen, rooted to the spot, unable to move forward or back."
Susan is putting herself through this drastic operation for a very modest reason: she wants her old life back. Her symptoms have been controlled in recent years with a drug called apomorphine, involving the insertion every morning of a needle into her stomach controlled by a pump, which is cumbersome and often lets her down.
She is to receive two electrode implants deep in her brain, to be attached to wires that will run under her skin to a miniature battery-operated pulse generator that will be sewn into her chest. The electrodes will permanently stimulate cells deep in her brain to alleviate her symptoms. Amazingly, she will remain awake throughout the procedure: the best indication that things have not gone to plan — a haemorrhage, for example — is the patient's own report of symptoms. The operation will cost the NHS some £30,000. Her local authority, Berkshire, thinks the money well spent, as the apomorphine regime costs £10,000 each year. The electrodes will last her the rest of her life.
I am standing next to the surgeon, Professor Tipu Aziz. Originally from Bangladesh, he is one of the leading implantists in the world, having done more than a thousand such ops since 1991. He has quick, delicate fingers, a Sancho Panza moustache, and an idiosyncratic sense of humour. A Chemical Brothers track belts out from the CD player behind us ("I like this stuff when I go to work," he says). Leaning over his patient, he quips: "Brain surgery is such fun, isn't it!" From inside the head frame, which forms part of the system for a stereotactic contraption that guides the probe into her brain, Susan smiles wanly.
There are 10 attending medical staff: the theatre is tense. Brain surgery earned a bad name in the 1940s and 50s, when hundreds of thousands of patients underwent lobotomies for a wide range of conditions, from schizophrenia to depression. All too often the recipients became vegetables. But new implant technologies, matching human living tissue with intricate mechanical devices, have prompted a new era in psychosurgery.
The prospects, according to the implant practitioners and their advocates, are thrilling. But there are deep concerns. Are we on the brink of a new epoch of surveillance, mind control, and the melding of human and machine existence?
Like the biblical tree of good and evil, the quest for a bionic man has huge potential for human benefit as well as for ill. Researchers are set to create a new generation of prosthetic applications: making the deaf hear, the blind see, the dumb speak, the paralysed move. They are poised to conquer pain and treat illnesses like depression and Parkinson's. Beyond that lie once-unthinkable possibilities based on the interaction between minds and machines in the fields of military technology and surveillance. Millions of animals have already been implanted with "identity cards" the size of a grain of rice. How long before humans will be similarly tagged? Researchers are experimenting with implants that enable them to direct the movements of rats in inhospitable environments — like miniature St Bernard dogs. The same technique promises implants that control mechanical devices by the act of thinking alone. Most controversial of all — raising spectres familiar in the Johnny Mnemonic and Matrix movies — scientists believe there is potential for boosting brain power and controlling emotions.
Before he starts the operation, Aziz asks Susan to make leg, foot, arm and hand movements in order to demonstrate her tremors and rigidity. Administering a local anaesthetic into the scalp, Aziz uses a
diathermic needle to make an incision in the flesh on the left side of her skull, above the temple, pinning back the small flap of scalp tissue in order to expose an area of bone. "I haven't shaved her head," he tells me. "I've given it a good antiseptic wash. I don't like to send my patients home looking as if they've had brain surgery." Everybody laughs, including Susan.
Next he puts the frame holding the stereotactic contraption in place and begins to drill into the bone. It is a hand drill, its head 2.7mm in diameter; she feels no pain, there is no noise, but she can feel the vibration. Now begins the trickiest part. Aziz inserts a tiny hollow probe, containing a lead with an electrode head, through the hole. He guides it with computer-assisted precision through about 18cm of brain matter, monitoring its progress with a machine that measures tissue resistance, until it reaches the sub-thalamic nucleus (a deep region of the brain connected with speech and movement). Now that Aziz has reached the optimal target, an assistant sends electrical impulses through the lead to the electrode head.
Parkinson's reduces the firing potential of neurones, or brain cells, in areas of the brain associated with limb and hand movement. The electrical stimulus from the implanted electrode gets the neurones firing once more in a regular pattern. Nicely oscillating nerve cells will then deliver appropriate "messages", composed of refined electrical discharges and associated natural chemicals, to their target regions.
Aziz says he has used the technique to alleviate intractable pain. "It's worked with stroke pain, cluster headaches and phantom limb, when people have an agonising sense of pain in an amputated extremity." The theory, he tells me, is the same. "Nervous pain is caused by a disturbance in the firing patterns following trauma, and the electrode implants reinstate and maintain virtually normal oscillations, reducing or expelling the pain."
He now asks Susan to exercise her right leg, which is controlled by the left brain. To the delight of everybody in the theatre she begins to make vigorous, well-controlled cycling movements with her leg followed by wide circular movements. She has not done this for years. Then she demonstrates an unaccustomed dexterity in her right arm and hand. "Oh wow!" says Aziz. "That's just amazing." Susan smiles weakly. Aziz prepares to treat the right side of her brain. By the time he finishes, Susan has been in surgery for nearly
two hours.
The electrodes implanted into Susan's brain are made of platinum iridium, a soft but durable metal that looks rather like a silver strand of thin spaghetti. Essential to the task of hitting the right spot are new techniques of magnetic resonance imaging, which enable the investigator to explore the topography of an individual brain without devastating what they probe.
The Parkinson's procedure at Radcliffe Infirmary is routine now, and successful in 90% of patients: damage or death occurs, says Aziz, in only one in a thousand cases. But implant technology is in its infancy. Aziz believes we're on the brink of a revolution, driven by innovations in materials, by nanotechnology (the engineering science of the very small) and by the discovery of an extraordinary symbiosis between silicon and nerve cells.
I am sitting in a Cambridge laboratory with a sandy-haired 38-year-old researcher, Ed Tarte, while he demonstrates a design for a tiny electrochemical device he calls an "interface implant", which is set to make Aziz's electrical probe look decidedly low-tech. "If a working mechanism like this had been implanted in time in the spinal cord of Christopher Reeve," he tells me, "he might be walking and moving normally today."
Made of polymer, and containing hundreds of tiny "tunnels" through its length, the size of the implant will be a centimetre long with a diameter no bigger than that of an average pencil lead. Its parts and operations are so small and complex that he can only display them magnified on a screen. "We're attempting," he says, "to bridge the scar tissue of a spinal-cord injury. It will connect healthy nerve fibres above the scar to those below which have lost contact with the brain, a bit like mending a broken connection in an electric circuit."
Tarte heads a team in Cambridge University's materials science department, which works with researchers in the chemistry department and the Cambridge Centre for Brain Repair at Addenbrooke's hospital. He is a nerdy, ageless fellow with the air of an internet-cafe denizen. But this exterior masks his membership of a remarkable elite of scientists who work on the interface between microchip wizardry and living bodies — the coming reality of bionic man.
The expertise of the likes of Ed Tarte ranges across a daunting combination of specialities: superconductivity, quantum physics, computer science, neuroscience, magnetic resonance technology, biochemistry, physiology, materials science and neurology. There is no overall name for their ilk, but "bionicists" might fit the bill.
There are two kinds of pioneering techniques powering the expansion of the "interface" field: miniaturisation, and the "love affair", as some scientists call it, between synthetic materials and living tissue. Since 2000 the semiconductor industry has been producing nanochips with features measuring less than 100 nanometres: about one-thousandth of the thickness of a human hair. This descent into the microscopic realm spells massively enhanced computer power as well as the ability to make implants that can reside non-invasively within our exquisite nervous systems. At the same time, scientists have been coaxing brain and nerve cells to grow in intimate combination with silicon and polymer circuits, etched by laser technology to create an ideal habitat for the proliferation of living nerve cells that develop branch-like connections with each other.
At the Max Planck Institute for Biochemistry, just outside Munich, Peter Fromherz has exploited the neurones of snails and leeches to make a prototype "neurochip". These neurones, which are large compared with mammalian ones, are puffed onto silicon chips andplaced over transistors. As the neurones grow and make
conections, the transistors amplify their tiny electrical blips. Fromherz started last year with just 20 neurones; now he is planning a prodigious 15,000-cell neurone-transistor chip. He is creating, in short, a living computer, further reducing the barrier between live and inanimate matter. Living circuitry of this kind could one day be the basis of computer-controlled artificial limbs, for it heralds the prospect of mechanical computers speaking to our biology. But there are other extraordinary strategies much closer to realisation.
Tarte explains a spectacular recent advance in his own research. When he first started working on the "interface" to bridge the scar-tissue barrier of an injured spinal cord, he created a device he nicknamed "shotgun". The idea was to allow the living nerve fibres to find their own way through a series of micro-electrode tunnels to connect with severed fibres beyond the scar-tissue barrier and stimulate signalling and regrowth. The process, however, was not sophisticated enough. "Now we have engineered electrodes with chemical properties that attract specific types of nerve fibres to precise locations within the device, in order to match them with their corresponding nerve-fibre types below the scar tissue," he says. The comment evinces the importance of creating implants that mimic the chemical as well as electrical properties of the nervous system.
Pharmaceutical therapies target brain chemicals, and electrodes target the delicate electrical blips of nerve cells; the new generation of implants aims to influence both in concert. In Tarte's new design, nerve fibres regulating finger and hand movement, for example, will now make exact connections with their corresponding fibres below the scar tissue.
But the key to huge advances in implants is an array of new synthetic materials. The initiated talk of "DNA chips", "biocompatible monomers", "plasma transistors", materials that possess "shape memory". A crude illustration would be the kind of plastic water tank that you can squeeze through a narrow trap door and then expand to its proper size up in the attic. In new implant technology, materials change shape and size at different temperatures. Keyhole surgeons aim one day to insert implants with a diameter of no more than a piece of string, which will then expand at body temperature. At the outer reaches of "shape memory" are liquid materials that harden inside the body. Researchers are working on a "smart" gel that will form an implant to obtain feedback control from the pancreas of a diabetes sufferer.
Behind the pioneering work on new materials and miniaturisation is the ambition of medical scientists to take on ever greater clinical challenges. Crude "interfaces" for loss of function have been in use
since the invention of false teeth and peg legs. From contact lenses to silicone breast implants, from artificial hearts to pacemakers, the post-war era has seen incredible advances in prosthetic aids.
The most impressive example involves the implant of electrodes to compensate for deafness. Some 50,000 cochlear aids have been inserted involving the implant of a chip that stimulates amplified aural signals. Composed of an induction coil and an electrode array, the implant converts sound waves into weak electric currents, which are delivered to the vicinity of the auditory nerve in the inner ear. The auditory nerve is stimulated and transmits impulses to the brain, which recognises them as auditory signals. Users often describe the sound characteristics as "synthetic", but this perception changes over time, and even the profoundly deaf have benefited.
The biggest challenge is the bionic eye. At the Massachusetts Eye and Ear Infirmary at Harvard Medical School, a group is working on vision computer chips. The strategy: insert two chips in the vicinity of the optic nerve, which is assumed to be intact. One will contain a solar panel that will start up a laser beam in response to photons of light. The beam will then strike a second panel that sends signals along the optic nerve to the appropriate visual cortex in the brain. At the far reaches of research are plans to create an electronic eye simulating the cones and rods in the living eye, opening up potential for an eye beyond the capabilities of the human eye; operating, for example, at both telescopic and microscopic levels.
But will the marriage of silicon, microprocessing and the nervous system promise the reality of a bionic human, as in the TV series The Six Million Dollar Man? Michio Kaku, the American guru of the future, has doubts. "Although it may be possible to connect the human body to a mechanical arm," he says, "the stunts of the bionic man would put intolerable stresses on our skeletal system, rendering most superhuman feats impossible."
But the science-fiction fantasies of the 1970s already look outmoded compared with the bid to control machines by thought: "psychokinesis". At Emory University in Georgia, the neurologist Philip Kennedy has implanted a tiny electrode, made of glass coated with chemicals that act as nerve growth factors (taken from the human knee), into the brain of a patient. Clusters of brain cells converge on the electrode, which can transmit signals to a receiver outside the brain. After suitable training, a paralysed patient has been able to move a cursor on a computer screen by "willing" its action. It is a short step to imagining the prodigious actions that a computer might control, given the right machinery.
Similar experiments have been performed with animal models. John Chapin of the Hahnemann School of Medicine in Philadelphia has trained rats to press a lever in order to experience a sense of electronically induced pleasure. He has analysed the cortical activity involved via electrodes implanted in the animals' brains, feeding these patterns into a computer that controls a robot arm. In time the rats learn that they do not need to press the lever, but by willing an action can control the distant operation of a robot arm for their reward. Chapin's colleague Miguel Nicolelis at Duke University in North Carolina has wired monkey brains to control robot arms that simulate the action of real arms. Nicolelis has conducted an experiment involving the control of a robot arm at MIT's Touch Lab in Massachusetts by a monkey at Duke University 600 miles away.
The first to benefit from such advances will be quadriplegics, but there are obvious military applications in the robotic potential for
sophisticated operations in hazardous terrain by controllers at a distance. Just as cruise missiles, guided by satellites, hit targets as small as a bunker door hundreds of miles away, commanders of the future will be able to control robot soldiers on the ground from a safe distance. But what of the scope for controlling animals and humans from a distance?
Sanjiv Talwar, a bioengineer at the State University of New York, is working on remote-controlled "roborats" which he manipulates in specific directions by stimulating electrical probes implanted in their brains. Instructions are transmitted to a radio receiver strapped on the animal's back. One probe stimulates a reward centre in the rat's brain; two other probes stimulate brain regions that process signals from its left and right whiskers so as to control movement — to run, climb, turn left or right. Roborats fitted with micro-cameras could soon be employed finding earthquake victims or in bomb-disposal work.
The idea of controlling the feelings and volition of humans by implants, effectively making them cyborgs, is still in the realm of science fiction. Neuroscientists argue that however intimate and interactive the robots of the future, and however embedded and invisible the computers, they will tend to respect our body boundaries.
Enthusiasm for a cyborg existence, merging human and machine nature, has long been a dream of researchers on the outer edges of AI (artificial intelligence). A noted cyborg prophet is the American inventor Ray Kurzweil, author of "The Age of Spiritual Machines" and a leader in speech-recognition technology. Kurzweil believes we are set to expand our potentials into superhuman activities. His mission statement for the future of implants brooks neither doubt nor delay: "Given a choice, people will prefer to keep their bones from crumbling, their skin supple, their life systems strong and vital. Improving our lives through neural implants on the mental level, and nanotechnology-enhanced bodies on the physical level, will be popular and compelling."
Similarly buoyed up on the promise of a brave new cyborg future is Kevin Warwick, a cybernetics researcher at Reading University who has been experimenting with transferring emotional feelings via electrodes. His wife, Irena, has agreed to have an implant stitched into her brain that will receive emotional signals relayed from Warwick's brain to discover if they can experience each other's feelings. The results of this ongoing piece of research are as yet inconclusive; but the ambition itself is more interesting than the actuality.
Kevin Warwick's anxieties are altogether different. He worries that with the ever-increasing sophistication of machines, it will be we humans who become a "lower form of life". If we can't beat the ever-expanding power and intelligence of machines, he is saying, then let's join them: "We humans can evolve into cyborgs."
The long-term debate about the contrast between humans and the machines of our devising looks set to heat up in the near future. The nub of the dispute is whether human consciousness itself can be replicated in machines, and whether computer intelligence will outstrip human intelligence at every level. Roger Penrose, the Oxford mathematician, insists that there are kinds of mathematics that are non-computational and can only be solved by humans. He was moved to write a fierce book on the subject, The Emperor's New Mind, to combat the views of one machine-intelligence enthusiast, the American scientist Hans Moravec.
But Penrose warns that if computers and computer-guided robots outstrip us, it would be a naive hope that we could collaborate with them to resolve the world's troubles: "If the computer-guided robots turn out to be our superiors in every respect, then will they not find they can run the world better without the need of us at all?" At worst, our "mind children" might do away with us. At best, he thinks, they'd turn us into their pets.
The short-term future of machine-human interpenetration lies with the prosthetic ambitions of surgeons like Tipu Aziz and patients like Susan Brandon. Three weeks after her operation, Susan tells me she is functioning better than she has for years. "It's a miracle. I am my old self again, no tremor and no rigidity. The apomorphine pump was a blessed nuisance and was only in place 12 hours a day; I was always being caught out. The electrode implants give me 24-hour relief." She says she had no discomfort after the operation and cannot feel the impulse generator. She is now completely off the apomorphine.
Aziz's aims are strictly limited compared with the outer reaches of implant dreams. He wants to give his patients a normal everyday life rather than abilities beyond the given of nature. Exorbitantly expensive, still relatively crude, the technology is in its infancy. In time, with improved stereotactic surgery, the cost of the operation may come down. For the present, its expense is justified by the savings on alternative therapies like apomorphine. And there's also the research feedback. Neurosurgeons like Aziz are eager to extend the technique to depression. While psychiatrists, such as Raj Persaud of the Maudsley, have gone on record issuing caution, stressing the psychological complexity of human depression, a research team in Louvain, Belgium, has already pioneered the successful use of deep-brain stimulation for such obsessive-compulsive disorders as phobias and anxieties.
Meanwhile, the array of synthetic materials, miniaturisation, and sophisticated scanning is poised to take implant technology to new levels of application. The first huge step could be to get Christopher Reeve out of his wheelchair. But given the allure of financial rewards in the realms of entertainment and the military, Kurzweil's cyborg dreams, and Roger Penrose's machine-intelligence nightmares, may not be far behind.
This is a science and technology that requires vigilance, and attentiveness to social and ethical consequences. New genetics and repro-technology caught out the ethicists, as research speedily outstripped our moral norms. The advent of the new "interfaces" could equally find us napping.
Best, Imelda, Cork.
June 20, 2004
Hot-wiring humans
By John Cornwell
(excerpt)
Electrodes are being planted into the brains of Parkinson's sufferers. Spinal implants could soon cure paraplegia. Robots might one day fight our wars. Are people about to become cyborgs?
Radcliffe Infirmary, Oxford, nine o'clock on a spring morning. Togged out in operation blues and clogs, I am feeling queasy as I enter the operating theatre to observe my first brain-implant procedure. The patient is Susan Brandon, a 62-year-old retired schoolteacher from Reading, a Parkinson's patient these past 12 years, who suffers from rigidity punctuated by uncontrollable tremors in her limbs. Chatting before the operation, she told me: "I'll be shopping in John Lewis and I'm suddenly frozen, rooted to the spot, unable to move forward or back."
Susan is putting herself through this drastic operation for a very modest reason: she wants her old life back. Her symptoms have been controlled in recent years with a drug called apomorphine, involving the insertion every morning of a needle into her stomach controlled by a pump, which is cumbersome and often lets her down.
She is to receive two electrode implants deep in her brain, to be attached to wires that will run under her skin to a miniature battery-operated pulse generator that will be sewn into her chest. The electrodes will permanently stimulate cells deep in her brain to alleviate her symptoms. Amazingly, she will remain awake throughout the procedure: the best indication that things have not gone to plan — a haemorrhage, for example — is the patient's own report of symptoms. The operation will cost the NHS some £30,000. Her local authority, Berkshire, thinks the money well spent, as the apomorphine regime costs £10,000 each year. The electrodes will last her the rest of her life.
I am standing next to the surgeon, Professor Tipu Aziz. Originally from Bangladesh, he is one of the leading implantists in the world, having done more than a thousand such ops since 1991. He has quick, delicate fingers, a Sancho Panza moustache, and an idiosyncratic sense of humour. A Chemical Brothers track belts out from the CD player behind us ("I like this stuff when I go to work," he says). Leaning over his patient, he quips: "Brain surgery is such fun, isn't it!" From inside the head frame, which forms part of the system for a stereotactic contraption that guides the probe into her brain, Susan smiles wanly.
There are 10 attending medical staff: the theatre is tense. Brain surgery earned a bad name in the 1940s and 50s, when hundreds of thousands of patients underwent lobotomies for a wide range of conditions, from schizophrenia to depression. All too often the recipients became vegetables. But new implant technologies, matching human living tissue with intricate mechanical devices, have prompted a new era in psychosurgery.
The prospects, according to the implant practitioners and their advocates, are thrilling. But there are deep concerns. Are we on the brink of a new epoch of surveillance, mind control, and the melding of human and machine existence?
Like the biblical tree of good and evil, the quest for a bionic man has huge potential for human benefit as well as for ill. Researchers are set to create a new generation of prosthetic applications: making the deaf hear, the blind see, the dumb speak, the paralysed move. They are poised to conquer pain and treat illnesses like depression and Parkinson's. Beyond that lie once-unthinkable possibilities based on the interaction between minds and machines in the fields of military technology and surveillance. Millions of animals have already been implanted with "identity cards" the size of a grain of rice. How long before humans will be similarly tagged? Researchers are experimenting with implants that enable them to direct the movements of rats in inhospitable environments — like miniature St Bernard dogs. The same technique promises implants that control mechanical devices by the act of thinking alone. Most controversial of all — raising spectres familiar in the Johnny Mnemonic and Matrix movies — scientists believe there is potential for boosting brain power and controlling emotions.
Before he starts the operation, Aziz asks Susan to make leg, foot, arm and hand movements in order to demonstrate her tremors and rigidity. Administering a local anaesthetic into the scalp, Aziz uses a
diathermic needle to make an incision in the flesh on the left side of her skull, above the temple, pinning back the small flap of scalp tissue in order to expose an area of bone. "I haven't shaved her head," he tells me. "I've given it a good antiseptic wash. I don't like to send my patients home looking as if they've had brain surgery." Everybody laughs, including Susan.
Next he puts the frame holding the stereotactic contraption in place and begins to drill into the bone. It is a hand drill, its head 2.7mm in diameter; she feels no pain, there is no noise, but she can feel the vibration. Now begins the trickiest part. Aziz inserts a tiny hollow probe, containing a lead with an electrode head, through the hole. He guides it with computer-assisted precision through about 18cm of brain matter, monitoring its progress with a machine that measures tissue resistance, until it reaches the sub-thalamic nucleus (a deep region of the brain connected with speech and movement). Now that Aziz has reached the optimal target, an assistant sends electrical impulses through the lead to the electrode head.
Parkinson's reduces the firing potential of neurones, or brain cells, in areas of the brain associated with limb and hand movement. The electrical stimulus from the implanted electrode gets the neurones firing once more in a regular pattern. Nicely oscillating nerve cells will then deliver appropriate "messages", composed of refined electrical discharges and associated natural chemicals, to their target regions.
Aziz says he has used the technique to alleviate intractable pain. "It's worked with stroke pain, cluster headaches and phantom limb, when people have an agonising sense of pain in an amputated extremity." The theory, he tells me, is the same. "Nervous pain is caused by a disturbance in the firing patterns following trauma, and the electrode implants reinstate and maintain virtually normal oscillations, reducing or expelling the pain."
He now asks Susan to exercise her right leg, which is controlled by the left brain. To the delight of everybody in the theatre she begins to make vigorous, well-controlled cycling movements with her leg followed by wide circular movements. She has not done this for years. Then she demonstrates an unaccustomed dexterity in her right arm and hand. "Oh wow!" says Aziz. "That's just amazing." Susan smiles weakly. Aziz prepares to treat the right side of her brain. By the time he finishes, Susan has been in surgery for nearly
two hours.
The electrodes implanted into Susan's brain are made of platinum iridium, a soft but durable metal that looks rather like a silver strand of thin spaghetti. Essential to the task of hitting the right spot are new techniques of magnetic resonance imaging, which enable the investigator to explore the topography of an individual brain without devastating what they probe.
The Parkinson's procedure at Radcliffe Infirmary is routine now, and successful in 90% of patients: damage or death occurs, says Aziz, in only one in a thousand cases. But implant technology is in its infancy. Aziz believes we're on the brink of a revolution, driven by innovations in materials, by nanotechnology (the engineering science of the very small) and by the discovery of an extraordinary symbiosis between silicon and nerve cells.
I am sitting in a Cambridge laboratory with a sandy-haired 38-year-old researcher, Ed Tarte, while he demonstrates a design for a tiny electrochemical device he calls an "interface implant", which is set to make Aziz's electrical probe look decidedly low-tech. "If a working mechanism like this had been implanted in time in the spinal cord of Christopher Reeve," he tells me, "he might be walking and moving normally today."
Made of polymer, and containing hundreds of tiny "tunnels" through its length, the size of the implant will be a centimetre long with a diameter no bigger than that of an average pencil lead. Its parts and operations are so small and complex that he can only display them magnified on a screen. "We're attempting," he says, "to bridge the scar tissue of a spinal-cord injury. It will connect healthy nerve fibres above the scar to those below which have lost contact with the brain, a bit like mending a broken connection in an electric circuit."
Tarte heads a team in Cambridge University's materials science department, which works with researchers in the chemistry department and the Cambridge Centre for Brain Repair at Addenbrooke's hospital. He is a nerdy, ageless fellow with the air of an internet-cafe denizen. But this exterior masks his membership of a remarkable elite of scientists who work on the interface between microchip wizardry and living bodies — the coming reality of bionic man.
The expertise of the likes of Ed Tarte ranges across a daunting combination of specialities: superconductivity, quantum physics, computer science, neuroscience, magnetic resonance technology, biochemistry, physiology, materials science and neurology. There is no overall name for their ilk, but "bionicists" might fit the bill.
There are two kinds of pioneering techniques powering the expansion of the "interface" field: miniaturisation, and the "love affair", as some scientists call it, between synthetic materials and living tissue. Since 2000 the semiconductor industry has been producing nanochips with features measuring less than 100 nanometres: about one-thousandth of the thickness of a human hair. This descent into the microscopic realm spells massively enhanced computer power as well as the ability to make implants that can reside non-invasively within our exquisite nervous systems. At the same time, scientists have been coaxing brain and nerve cells to grow in intimate combination with silicon and polymer circuits, etched by laser technology to create an ideal habitat for the proliferation of living nerve cells that develop branch-like connections with each other.
At the Max Planck Institute for Biochemistry, just outside Munich, Peter Fromherz has exploited the neurones of snails and leeches to make a prototype "neurochip". These neurones, which are large compared with mammalian ones, are puffed onto silicon chips andplaced over transistors. As the neurones grow and make
conections, the transistors amplify their tiny electrical blips. Fromherz started last year with just 20 neurones; now he is planning a prodigious 15,000-cell neurone-transistor chip. He is creating, in short, a living computer, further reducing the barrier between live and inanimate matter. Living circuitry of this kind could one day be the basis of computer-controlled artificial limbs, for it heralds the prospect of mechanical computers speaking to our biology. But there are other extraordinary strategies much closer to realisation.
Tarte explains a spectacular recent advance in his own research. When he first started working on the "interface" to bridge the scar-tissue barrier of an injured spinal cord, he created a device he nicknamed "shotgun". The idea was to allow the living nerve fibres to find their own way through a series of micro-electrode tunnels to connect with severed fibres beyond the scar-tissue barrier and stimulate signalling and regrowth. The process, however, was not sophisticated enough. "Now we have engineered electrodes with chemical properties that attract specific types of nerve fibres to precise locations within the device, in order to match them with their corresponding nerve-fibre types below the scar tissue," he says. The comment evinces the importance of creating implants that mimic the chemical as well as electrical properties of the nervous system.
Pharmaceutical therapies target brain chemicals, and electrodes target the delicate electrical blips of nerve cells; the new generation of implants aims to influence both in concert. In Tarte's new design, nerve fibres regulating finger and hand movement, for example, will now make exact connections with their corresponding fibres below the scar tissue.
But the key to huge advances in implants is an array of new synthetic materials. The initiated talk of "DNA chips", "biocompatible monomers", "plasma transistors", materials that possess "shape memory". A crude illustration would be the kind of plastic water tank that you can squeeze through a narrow trap door and then expand to its proper size up in the attic. In new implant technology, materials change shape and size at different temperatures. Keyhole surgeons aim one day to insert implants with a diameter of no more than a piece of string, which will then expand at body temperature. At the outer reaches of "shape memory" are liquid materials that harden inside the body. Researchers are working on a "smart" gel that will form an implant to obtain feedback control from the pancreas of a diabetes sufferer.
Behind the pioneering work on new materials and miniaturisation is the ambition of medical scientists to take on ever greater clinical challenges. Crude "interfaces" for loss of function have been in use
since the invention of false teeth and peg legs. From contact lenses to silicone breast implants, from artificial hearts to pacemakers, the post-war era has seen incredible advances in prosthetic aids.
The most impressive example involves the implant of electrodes to compensate for deafness. Some 50,000 cochlear aids have been inserted involving the implant of a chip that stimulates amplified aural signals. Composed of an induction coil and an electrode array, the implant converts sound waves into weak electric currents, which are delivered to the vicinity of the auditory nerve in the inner ear. The auditory nerve is stimulated and transmits impulses to the brain, which recognises them as auditory signals. Users often describe the sound characteristics as "synthetic", but this perception changes over time, and even the profoundly deaf have benefited.
The biggest challenge is the bionic eye. At the Massachusetts Eye and Ear Infirmary at Harvard Medical School, a group is working on vision computer chips. The strategy: insert two chips in the vicinity of the optic nerve, which is assumed to be intact. One will contain a solar panel that will start up a laser beam in response to photons of light. The beam will then strike a second panel that sends signals along the optic nerve to the appropriate visual cortex in the brain. At the far reaches of research are plans to create an electronic eye simulating the cones and rods in the living eye, opening up potential for an eye beyond the capabilities of the human eye; operating, for example, at both telescopic and microscopic levels.
But will the marriage of silicon, microprocessing and the nervous system promise the reality of a bionic human, as in the TV series The Six Million Dollar Man? Michio Kaku, the American guru of the future, has doubts. "Although it may be possible to connect the human body to a mechanical arm," he says, "the stunts of the bionic man would put intolerable stresses on our skeletal system, rendering most superhuman feats impossible."
But the science-fiction fantasies of the 1970s already look outmoded compared with the bid to control machines by thought: "psychokinesis". At Emory University in Georgia, the neurologist Philip Kennedy has implanted a tiny electrode, made of glass coated with chemicals that act as nerve growth factors (taken from the human knee), into the brain of a patient. Clusters of brain cells converge on the electrode, which can transmit signals to a receiver outside the brain. After suitable training, a paralysed patient has been able to move a cursor on a computer screen by "willing" its action. It is a short step to imagining the prodigious actions that a computer might control, given the right machinery.
Similar experiments have been performed with animal models. John Chapin of the Hahnemann School of Medicine in Philadelphia has trained rats to press a lever in order to experience a sense of electronically induced pleasure. He has analysed the cortical activity involved via electrodes implanted in the animals' brains, feeding these patterns into a computer that controls a robot arm. In time the rats learn that they do not need to press the lever, but by willing an action can control the distant operation of a robot arm for their reward. Chapin's colleague Miguel Nicolelis at Duke University in North Carolina has wired monkey brains to control robot arms that simulate the action of real arms. Nicolelis has conducted an experiment involving the control of a robot arm at MIT's Touch Lab in Massachusetts by a monkey at Duke University 600 miles away.
The first to benefit from such advances will be quadriplegics, but there are obvious military applications in the robotic potential for
sophisticated operations in hazardous terrain by controllers at a distance. Just as cruise missiles, guided by satellites, hit targets as small as a bunker door hundreds of miles away, commanders of the future will be able to control robot soldiers on the ground from a safe distance. But what of the scope for controlling animals and humans from a distance?
Sanjiv Talwar, a bioengineer at the State University of New York, is working on remote-controlled "roborats" which he manipulates in specific directions by stimulating electrical probes implanted in their brains. Instructions are transmitted to a radio receiver strapped on the animal's back. One probe stimulates a reward centre in the rat's brain; two other probes stimulate brain regions that process signals from its left and right whiskers so as to control movement — to run, climb, turn left or right. Roborats fitted with micro-cameras could soon be employed finding earthquake victims or in bomb-disposal work.
The idea of controlling the feelings and volition of humans by implants, effectively making them cyborgs, is still in the realm of science fiction. Neuroscientists argue that however intimate and interactive the robots of the future, and however embedded and invisible the computers, they will tend to respect our body boundaries.
Enthusiasm for a cyborg existence, merging human and machine nature, has long been a dream of researchers on the outer edges of AI (artificial intelligence). A noted cyborg prophet is the American inventor Ray Kurzweil, author of "The Age of Spiritual Machines" and a leader in speech-recognition technology. Kurzweil believes we are set to expand our potentials into superhuman activities. His mission statement for the future of implants brooks neither doubt nor delay: "Given a choice, people will prefer to keep their bones from crumbling, their skin supple, their life systems strong and vital. Improving our lives through neural implants on the mental level, and nanotechnology-enhanced bodies on the physical level, will be popular and compelling."
Similarly buoyed up on the promise of a brave new cyborg future is Kevin Warwick, a cybernetics researcher at Reading University who has been experimenting with transferring emotional feelings via electrodes. His wife, Irena, has agreed to have an implant stitched into her brain that will receive emotional signals relayed from Warwick's brain to discover if they can experience each other's feelings. The results of this ongoing piece of research are as yet inconclusive; but the ambition itself is more interesting than the actuality.
Kevin Warwick's anxieties are altogether different. He worries that with the ever-increasing sophistication of machines, it will be we humans who become a "lower form of life". If we can't beat the ever-expanding power and intelligence of machines, he is saying, then let's join them: "We humans can evolve into cyborgs."
The long-term debate about the contrast between humans and the machines of our devising looks set to heat up in the near future. The nub of the dispute is whether human consciousness itself can be replicated in machines, and whether computer intelligence will outstrip human intelligence at every level. Roger Penrose, the Oxford mathematician, insists that there are kinds of mathematics that are non-computational and can only be solved by humans. He was moved to write a fierce book on the subject, The Emperor's New Mind, to combat the views of one machine-intelligence enthusiast, the American scientist Hans Moravec.
But Penrose warns that if computers and computer-guided robots outstrip us, it would be a naive hope that we could collaborate with them to resolve the world's troubles: "If the computer-guided robots turn out to be our superiors in every respect, then will they not find they can run the world better without the need of us at all?" At worst, our "mind children" might do away with us. At best, he thinks, they'd turn us into their pets.
The short-term future of machine-human interpenetration lies with the prosthetic ambitions of surgeons like Tipu Aziz and patients like Susan Brandon. Three weeks after her operation, Susan tells me she is functioning better than she has for years. "It's a miracle. I am my old self again, no tremor and no rigidity. The apomorphine pump was a blessed nuisance and was only in place 12 hours a day; I was always being caught out. The electrode implants give me 24-hour relief." She says she had no discomfort after the operation and cannot feel the impulse generator. She is now completely off the apomorphine.
Aziz's aims are strictly limited compared with the outer reaches of implant dreams. He wants to give his patients a normal everyday life rather than abilities beyond the given of nature. Exorbitantly expensive, still relatively crude, the technology is in its infancy. In time, with improved stereotactic surgery, the cost of the operation may come down. For the present, its expense is justified by the savings on alternative therapies like apomorphine. And there's also the research feedback. Neurosurgeons like Aziz are eager to extend the technique to depression. While psychiatrists, such as Raj Persaud of the Maudsley, have gone on record issuing caution, stressing the psychological complexity of human depression, a research team in Louvain, Belgium, has already pioneered the successful use of deep-brain stimulation for such obsessive-compulsive disorders as phobias and anxieties.
Meanwhile, the array of synthetic materials, miniaturisation, and sophisticated scanning is poised to take implant technology to new levels of application. The first huge step could be to get Christopher Reeve out of his wheelchair. But given the allure of financial rewards in the realms of entertainment and the military, Kurzweil's cyborg dreams, and Roger Penrose's machine-intelligence nightmares, may not be far behind.
This is a science and technology that requires vigilance, and attentiveness to social and ethical consequences. New genetics and repro-technology caught out the ethicists, as research speedily outstripped our moral norms. The advent of the new "interfaces" could equally find us napping.
Omega - 21. Jun, 14:09
