In the extras at the back of Nexus I described the brain-implant experiments that have given humans bionic eyes and ears and the ability to control robotic arms, even from thousands of miles away.

Just in the year that has passed since the writing of Nexus, more impressive work has been done. A team of researchers led by Thomas Berger has demonstrated that a digital chip can repair the impairment of a mouse’s memory that occurs with brain damage to part of the brain called the hippocampus. Berger’s team then went further and showed that they could improve mouse memory through the same brain implant. Another experiment by Sam Deadwyler and colleagues at Wake Forest University placed specialized brain implants in the frontal cortex of rhesus monkeys who were then trained on a “delayed match and sample” test – a kind of monkey IQ test. Later, the monkeys had their test scores lowered by the administration of cocaine. But if the implant was switched into an active mode, it could correct this impairment, and even more. The frontal cortex device could actually raise the test scores of monkeys well beyond the scores of normal monkeys who lacked the implant. So in animals, at least, we’ve used brain implants to boost both memory and intelligence.

Of course, the most transformative thing about the Nexus technology isn’t mere augmentation – it’s communication directly from one mind to another. Here also there has been progress. In an experiment by Miguel Nicolelis and colleagues, two rats, thousands of miles apart (one at Duke University in North Carolina, the other in Brazil) both had implants placed in the motor cortices of their respective brains. Nicolelis and colleagues showed that they could train one rat to respond to a series of lights by pulling the correct lever. The other rat, who had never seen these lights or levers before, would, in turn, pull the right lever most of the time, based simply on the input to its brain from the trained rat thousands of miles away.

A similar study, funded by DARPA (the Defense Advanced Research Projects Agency inside the US Department of Defense), involved two monkeys, each with an implant in its auditory cortex – the part of the brain responsible for processing sound. The researchers showed that they could play a sound for one monkey and that the second monkey – in a soundproofed room – could hear that sound via the neural link, and could even identify what the sound was. The research, by the way, was conducted as part of DARPA’s “Advanced Battlefield Communications” program – a program with the goal of enhancing communication and coordination between soldiers, their squad-mates, and command.

Progress towards Nexus, in short, continues apace.