Referred to the researchers affectionately as the “can,” the titanium-enclosed device measures 2.2 inches (56 mm) long, 1.65 inches (42 mm) wide, and 0.35 inches (9 mm) thick. That’s pretty small considering it contains an array of 100 electrodes, a lithium ion battery, and custom-designed ultralow-power integrated circuits, radio and infrared wireless transmitters, and a copper coil for recharging. The battery lasts up to seven hours before it needs recharging. When it is time to recharge, power is transferred to the battery wirelessly through the skin.
It’s not easy to stuff all this capability into such a small package. The study’s lead author, David Borton, explained in a university press release, “What makes the achievement discussed in this paper unique is how it integrated many individual innovations into a complete system with potential for neurospecific gain greater than the sum of its parts.”And testing so far indicates that the “brain radio,” small it may be, is robust. It has faithfully transmitted brain activity of three rhesus monkeys and three pigs for more than a year now and as long as 16 months in at least one animal, demonstrating that the implant has the kind of stability that will be needed if it’s going to be of use to humans someday.
The implant could also be a blessing to researchers as well. Current implants that connect to computers with a wire are inconvenient for a number of reasons – believe me, I know. While a postdoctoral fellow studying the motor cortex, I made several attempts to record neuronal activity in awake, freely moving rats. Aside from the rat being not at all happy with the gangly weight sitting atop its head and being constrained by a tether of wires, connections are often suspect and a moving rat often made for a noisy signal. We even got excited about a new, wireless transmitter that might solve all our problems. Except the rat clearly did not like having a rucksack/straight jacket strapped to its back.
It’ll still be a while before they make a “can” small enough for rats, but no doubt neuroscientists that work with primates will be excited about it. And if the technology helps people one day get robotics they can use, that’d be something we could all celebrate.