improved, with reduced risks from the implantation process, longer lifetimes once implanted, and a better ability to restore a recipient to something like normal life. Other internal body parts are also under development, and in some cases commercially available, from skin and blood to tiny implanted devices that automatically release insulin for diabetics. If we reach the point where the artificial versions are supe- rior in capacity or lifetime to natural organs, we might realize the dream of extending the human lifespan by bionic means.
As we imagine the Six Million Dollar Human coming into being through these physical prosthetics, we can also imagine mental pros- thetics that go beyond merely injecting electronic pulses into the brain. Such enhancements might, for instance, give the brain additional ca- pacity by holding data in an exterior module, retrieving it on com- mand, and recording whatever experiences are worthy of permanent storage. Or they could give the human brain new levels of computing power, or enable direct brain-to-brain or brain-to-machine commu- nication. Another approach might be to use chemical rather than neuroelectronic means to alter brain function.At least one company is developing an implantable chip that contains several hundred minute reservoirs that can be filled with any desired set of drugs, to be dis- pensed to the body in variable combinations and dosages under mi- croprocessor control.Although the immediate medical purpose of the device is to deliver therapeutic drugs, there is obvious further poten- tial to modify mental acuity, mood, and personality.
These bionic possibilities require technological advances at every level, as I will discuss later in this book, because the obstacles are formidable. For example, despite the improvement offered by cochlear implants, fully replicating human hearing is an enormous task; the current technology activates only a small fraction of the sensors in the inner ear, the 15,000 hair cells in the cochlea. Consider then what it would take to achieve a reasonable artificial version of human vision, which employs 130 million rod and cone sensors in each eye.There are problems with physical implants as well, and not only the difficult issue of linking a synthetic leg to a brain. If they are to break Olympic running records, runners equipped with bionic legs will need power