Published March 15, 2002

We are growing more intimate with our technology. Computers started out as large remote machines in air-conditioned rooms tended by white coated technicians. Subsequently they moved onto our desks, then under our arms, and now in our pockets. Soon, we’ll routinely put them inside our bodies and brains. Ultimately we will become more nonbiological than biological.

We already have devices to replace our hips, knees, shoulders, elbows, wrists, jaws, teeth, skin, arteries, veins, heart valves, arms, legs, feet, fingers, and toes. Systems to replace more complex organs (e.g., our hearts) are starting to work.

The age of neural implants is well under way. We have brain implants based on "neuromorphic" modeling (i.e., reverse engineering of the human brain and nervous system) for a rapidly growing list of brain regions. A friend of mine who became deaf while an adult can now engage in telephone conversations again because of his cochlear implant, a device which interfaces directly with his auditory cortex. He plans to replace it with a new model with a thousand levels of frequency discrimination, which will enable him to hear music once again. He has had the same melodies playing in his head for the past fifteen years, he laments, and is looking forward to hearing some new tunes. A future generation of cochlear implants now on the drawing board will provide levels of frequency discrimination that go significantly beyond that of "normal" hearing.

Researchers at MIT and Harvard are developing neural implants to replace damaged retinas. There are brain implants for Parkinson’s patients that communicate directly with the ventral posterior nucleus and subthalmic nucleus regions of the brain to reverse the most devastating symptoms of this disease. An implant for people with cerebral palsy and multiple sclerosis communicates with the ventral lateral thalamus and has been effective in controlling tremors. "Rather than treat the brain like soup, adding chemicals that enhance or suppress certain neurotransmitters," says Rick Trosch, an American physician helping to pioneer these therapies, "we’re now treating it like circuitry."

A variety of techniques are being developed to provide the communications bridge between the wet analog world of biological information processing and digital electronics. Researchers at Germany’s Max Planck Institute have developed noninvasive devices that can communicate with neurons in both directions. They demonstrated their "neuron transistor" by controlling the movements of a living leech from a personal computer. Similar technology has been used to reconnect leech neurons and to coax them to perform simple logical and arithmetic problems. Scientists are now experimenting with a new design called "quantum dots," which uses tiny crystals of semiconductor material to connect electronic devices with neurons.

These developments provide the promise of reconnecting broken neural pathways for people with nerve damage and spinal cord injuries. It has long been thought that recreating these pathways would only be feasible for recently injured patients because nerves gradually deteriorate when unused. A recent discovery, however, shows the feasibility of a neuroprosthetic system for patients with long-standing spinal cord injuries. Researchers at the University of Utah asked a group of long-term quadriplegic patients to move their limbs in a variety of ways and then observed the response of their brains using magnetic resonance imaging. Although the neural pathways to their limbs had been inactive for many years, the pattern of their brain activity when attempting to move their limbs was very close to that observed in non-disabled persons. We will, therefore, be able to place sensors in the brain of a paralyzed person (e.g., Christopher Reeve), which will be programmed to recognize the brain patterns associated with intended movements, and then stimulate the appropriate sequence of muscle movements. For those patients whose muscles no longer function, there are already designs for "nanoelectromechanical" systems (NEMS) that can expand and contract to replace damaged muscles and that can be activated by either real or artificial nerves.

Intelligent machines are already making their way into our blood stream. There are dozens of projects underway to create blood stream-based "biological microelectromechanical systems" (bioMEMS) to intelligently scout out pathogens and deliver medications in very precise ways. For example, a researcher at the University of Illinois at Chicago has created a tiny capsule with pores measuring only 7 nanometers. The pores let insulin out in a controlled manner but prevent antibodies from invading the capsule. These capsules have cured rats with type I Diabetes. Similar systems could precisely deliver dopamine to the brain for Parkinson’s patients, provide blood-clotting factors for patients with hemophilia, and deliver cancer drugs directly to tumor sites. A new design provides up to 20 substance-containing reservoirs that can release their cargo at programmed times and locations in the body.

Kensall Wise, an electrical engineer at the University of Michigan has developed a tiny neural probe that can provide precise monitoring of the electrical activity of patients with neural diseases. Future designs are expected to also deliver drugs to precise locations in the brain. Kazushi Ishiyama at Tohoku University in Japan has developed micromachines that use microscopic sized spinning screws to deliver drugs to small cancer tumors. A particularly innovative micromachine developed by Sandia National Labs has actual microteeth with a jaw that opens and closes to trap individual cells and then implant them with substances such as DNA, proteins or drugs. There are already at least four major scientific conferences on bioMEMS and other approaches to developing micro and nano scale machines to go into the body and blood stream.

One of the leading proponents of "nanomedicine," and author of a book with the same name is Robert Freitas, Research Scientist at nanotechnology firm Zyvex Corp. Freitas’ ambitious manuscript is a comprehensive road map to rearchitecting our biological heritage. One of Freitas’ designs is to replace (or augment) our red blood cells with artificial "respirocytes," that would enable us to hold our breath for four hours, or to do a top-speed sprint for 15 minutes without taking a breath (another formidable challenge for athletic contest drug tests). He envisions micron-size artificial platelets which could achieve hemostatis (bleeding control) up to 1,000 times faster than biological platelets. Freitas describes nanorobotic microbivores that will download software to destroy specific infections hundreds of times faster than antibiotics, and that will be effective against all bacterial, viral and fungal infections with no limitations of drug resistance.

The coming merger of human and machine. The compelling benefits in overcoming profound diseases and disabilities will keep these technologies on a rapid course, but medical applications represent only the early adoption phase. As the technologies become established, there will be no barriers to using them for the expansion of human potential. Moreover, all of the underlying technologies are accelerating. The power of computation has grown at a double exponential rate for all of the past century, and will continue to do so well into this century through the power of three-dimensional computing. Communication bandwidths and the pace of brain reverse engineering are also quickening. Meanwhile, according to my models, the size of technology is shrinking at a rate of 5.6 per linear dimension per decade, which will make nanotechnology ubiquitous during the 2020s.

By the end of this decade, computing will disappear as a discrete technology that we need to carry with us. We’ll routinely have high-resolution images encompassing the entire visual field written directly to our retinas from our eyeglasses and contact lenses (DoD is already using technology along these lines from Microvision, a company based in Bothell, Washington). We’ll have very high-speed wireless connection to the Internet at all times. The electronics for all of this will be embedded in our clothing. These very personal computers circa 2010 will enable us to meet with each other in full immersion, visual-auditory, virtual reality environments as well as augment our vision with location and time specific information at all times.

By 2030, electronics will utilize molecule-sized circuits, the reverse engineering of the human brain will have been completed, and bioMEMS will have evolved into bioNEMS (biological nanoelectromechanical systems). It will be routine to have billions of nanobots (i.e., nano-scale robots) coursing through the capillaries of our brains, communicating with each other (over a wireless local area network), as well as with our biological neurons and with the Internet. One application will be to provide full immersion virtual reality that encompasses all of our senses. When we want to enter a virtual reality environment, the nanobots replace the signals from our real senses with the signals that our brain would receive if we were actually in the virtual environment.

We will have a panoply of virtual environments to choose from, including Earthly worlds that we are familiar with, as well as those with no Earthly counterpart. We will be able to go to these virtual places, and have any kind of interaction with other real (as well as simulated) people, ranging from business negotiations to sensual encounters. In virtual reality, we won’t be restricted to a single personality as we will be able to change our appearance and become other people.

"Experience beamers" will beam their entire flow of sensory experiences as well as the neurological correlates of their emotional reactions out on the web just as people today beam their bedroom images from their web cams. A popular pastime will be to plug in to someone else’s sensory-emotional beam and experience what it’s like to be someone else, à la the plot concept of the movie "Being John Malkovich." There will also be a vast selection of archived experiences to choose from. The design of virtual environments, and the creation of archived full-immersion experiences will become new art forms.

The most important application of circa 2030 nanobots will be to literally expand our minds. We’re limited today to a mere hundred trillion interneuronal connections, which we will be able to augment by adding virtual connections via nanobot communication. This will provide us with the opportunity to vastly expand our pattern recognition abilities, memories, and overall thinking capacity as well as to directly interface with powerful forms of nonbiological intelligence.

It’s important to note that once nonbiological intelligence gets a foothold in our brains (a threshold we’ve already passed), it will grow exponentially, as is the accelerating nature of information-based technologies. Note that a one inch cube of nanotube circuitry (which is already working at small scales in laboratories) will be at least a million times more powerful than the human brain. By 2040, the nonbiological portion of our intelligence will be far more powerful than the biological portion. It will, however, still be part of the human-machine civilization, having been derived from human intelligence, i.e., created by humans (or machines created by humans) and based at least in part on the reverse engineering of the human nervous system.

Stephen Hawking recently commented in the German magazine Focus that computer intelligence will surpass that of humans within a few decades. He advocated that we "develop as quickly as possible technologies that make possible a direct connection between brain and computer, so that artificial brains contribute to human intelligence rather than opposing it." Hawking can take comfort that the development program he is recommending is well under way.