The epilepsy patients were having conventional ECoG electrodes placed on their brains anyway, so they allowed House to place the microECoG electrode arrays at the same time because "they were brave enough and kind enough to help us develop the technology for people who are paralyzed or have amputations," Greger says.
The researchers tested how well the microelectrodes could detect nerve signals from the brain that control arm movements. The two epilepsy patients sat up in their hospital beds and used one arm to move a wireless computer "mouse" over a high-quality electronic draftsman's tablet in front of them. The patients were told to reach their arm to one of two targets: one was forward to the left and the other was forward to the right.
The patients' arm movements were recorded on the tablet and fed into a computer, which also analyzed the signals coming from the microelectrodes placed on the area of each patient's brain controlling arm and hand movement.
The study showed that the microECoG electrodes could be used to distinguish brain signals ordering the arm to reach to the right or left, based on differences such as the power or amplitude of the brain waves.
Once the researchers develop more refined software to decode brain signals detected by microECoG in real-time, it will be tested by asking severe epilepsy patients to control a "virtual reality arm" in a computer using their thoughts.
Source: University of Utah
Full Caption:
Microwires emerging from the green and orange tubes connect to two arrays of 16 microelectrodes. Each array is embedded in a small mat of clear, rubbery silicone. The mats are barely visible in this image. These microelectrode arrays sit on the brain without penetrating it, a step toward longer-lived, less invasive versions of "neural interfaces" that in recent experiments elsewhere have allowed paralyzed people to control a computer cursor with their thoughts. The new microeletrode arrays were placed in two patients at the University of Utah who already were undergoing brain surgery for severe epilepsy. The larger, numbered, metallic electrodes are used to locate the source of epileptic seizures in the brain, so the patients allowed the micoelectrodes to be placed on their brains at the same time. Courtesy of University of Utah Department of Neurosurgery
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