Brain implants are going wireless. A newly developed implant
The implant is just 2 inches wide and weighs slightly less than a candy bar. It connects to a tiny implanted array of roughly 100 electrodes that are each a micron or so across. Together, they detect the activity of dozens of neurons in the brain. The device broadcasts up to 200 megabits per second, comparable to the current Wi-Fi standard, while requiring about 100 times less power. In experiments, the new system matched the performance of conventional wired systems.
In experiments, the researchers found the device could transmit data from three rhesus macaques as they walked on treadmills, measuring signals associated with the brain's motion commands that clearly matched the activity of leg muscles, revealing that the implant can help study how the brain controls the legs. They also used the device to study the brains of two rhesus monkeys as they slept and woke, showing distinct patterns of brain activity related to different stages of consciousness and the shifts between them.
For human patients, research that records which brain cells do what when people move their limbs is aiding scientists trying to develop brain implants that help control robotics using only the mind, which could one day allow people to overcome disabilities using bionic limbs or mechanical exoskeletons. However, such experiments usually tether subjects to computers via wires, significantly limiting the actions that investigators can record. "We can now access brain microcircuits wirelessly in freely moving, freely behaving animals rather easily, with lots of neural data at Internet speeds, streaming continuously," says study co-author Arto Nurmikko, a neuroengineer at Brown University. "It opens up new space in fundamental brain research."