"Living electrodes" made of nerve cells genetically modified to respond to light have been successfully implanted in the brains of animals. The hope is that they will provide a better and longer-lasting way to link brains with computers than conventional electrodes. "It allows our technology to be speaking the language of the nervous system, instead of electrical jolts, which is what is done now," says Kacy Cullen at the University of Pennsylvania. "When our implanted neurons are activated, the deeper part of the brain they are connected to then becomes activated by a natural synaptic mechanism."
Our neurons are firing all the time, receiving signals from other neurons and sending signals of their own. To get a better understanding of how the brain works, scientists often listen in to those signals to see what kind of messages certain neurons send and how often they send them. Doing that often requires researchers to implant an electrode into the brain, which when it's close enough to a neuron, can pick up on the electrical signals that propagate through the neuron. They either have to be rigid enough to penetrate the brain and remain straight or be inserted through needles that can keep them straight until they're safely in place. The problem is those rigid structures cause damage as they move through the brain and minimizing that damage is a goal that scientists are constantly working towards.
Unlike other research that focused on reading signals from the brains of paralyzed people or animals and translating them into the movements of an electronic arm or a cursor on a screen, Courtine's team used an electrode implanted in the monkey's brain to read the animal's intention to move its legs, then wirelessly transmitted that signal to other electrodes implanted along the animal's spine, past its injury. Those electrodes then fired in a pattern similar to the natural nerve signals that would come down the spine of a healthy animal.
Sometimes a technology that's been simmering in the laboratory or the clinic for decades makes the leap to mainstream consumption almost overnight. The precursor to this curious form of vacuum tube was invented at General Electric around 1920. It wasn't until 1940 that British scientists found a magnetron design that could pump out microwave energy at unprecedented power. That discovery fueled a crash program at the Massachusetts Institute of Technology to build airborne radar units, an advance that helped the Allies turn back Nazi Germany in Europe. The conflict had barely ended when a Raytheon engineer noticed that microwaves could also melt chocolate.
Science fiction has, for many years, looked to a future in which robots are intelligent and cyborgs are commonplace. The Terminator, The Matrix, Blade Runner and I, Robot are all good examples of this vision. But until the last decade, consideration of what this might actually mean in the future was unnecessary because it was all science fiction, not scientific reality. Now, however, science has not only done some catching up; it's also introduced practicalities that the original story lines didn't appear to include (and, in some cases, still don't include). What we consider here are several different experiments linking biology and technology together in a cybernetic way--essentially ultimately combining humans and machines in a relatively permanent merger.