Researchers have developed a cellphone-like sensor that relay signals from specific parts of the brain to aid paralysis patients control devices with thoughts.
A team of neuroengineers based at Brown University developed the fully implantable and rechargeable wireless brain sensor capable of relaying real-time broadband signals from up to 100 neurons in freely moving subjects.
Several copies of the novel low-power device, described in the Journal of Neural Engineering, have been performing well in animal models for more than year, a first in the brain-computer interface field.
Brain-computer interfaces could help people with severe paralysis control devices with their thoughts.
"This has features that are somewhat akin to a cell phone, except the conversation that is being sent out is the brain talking wirelessly," Arto Nurmikko, professor of engineering at Brown University said in a statement.
Neuroscientists can use such a device to observe, record, and analyse the signals emitted by scores of neurons in particular parts of the animal model's brain.
In the device, a pill-sized chip of electrodes implanted on the cortex sends signals through uniquely designed electrical connections into the device's laser-welded, hermetically sealed titanium "can". The can measures 2.2 inches long, 1.65 inches wide, and 0.35 inches thick.
That small volume houses an entire signal processing system: a lithium ion battery, ultralow-power integrated circuits designed at Brown for signal processing and conversion, wireless radio and infrared transmitters, and a copper coil for recharging � a "brain radio".
All the wireless and charging signals pass through an electromagnetically transparent sapphire window.
In all, the device looks like a miniature sardine can with a porthole.
However, what the team has packed inside makes it a major advance among brain-machine interfaces, said lead author David Borton, a former Brown graduate student.
"Most importantly, we show the first fully implanted neural interface microsystem operated wirelessly for more than 12 months in large animal models - a milestone for potential (human) clinical translation," said Borton.
The device transmits data at 24 Mbps via 3.2 and 3.8 Ghz microwave frequencies to an external receiver. After a two-hour charge, delivered wirelessly through the scalp via induction, it can operate for more than six hours.
"The device uses less than 100 milliwatts of power, a key figure of merit," Nurmikko said.
