Imagine being able to control a wheelchair with your thoughts alone. That's exactly the goal that researchers are aiming for, and they may have accomplished it - with a monkey.
In this latest study, the researchers developed a brain-machine interface (BMI) that allows primates to use only their thoughts to navigate a robotic wheelchair. This accomplishment could be huge for creating wheelchairs for patients who lack the mobility to move their own wheelchairs.
"In some severely disabled people, even blinking is not possible," said Miguel Nicolelis, senior author of the new study and co-director for the Duke Center for Neuroengineering. "For them, using a wheelchair or device controlled by noninvasive measures like an EEG (a device that monitors brain waves through electrodes on the scalp) may not be sufficient. We show clearly that if you have intracranial implants, you get better control of a wheelchair than with noninvasive devices."
In 2012, the researchers implanted hundreds of hair-thin microfilaments in the premotor and somatosensory regions of the brains of two rhesus macaques. They then trained the animals to passive navigate a chair toward a bowl containing grapes. During the training phase, the scientists recorded the primates' large-scale electrical brain activity. Then they programmed a computer system to translate brain signals into digital motor commands that controlled the movement of the wheelchair.
In addition to examining the brain signals that corresponded to translational and rotational movement, scientists also found signs that the primates were contemplating their distance to the bowl of grapes.
"This was not a signal that was present in the beginning of the training, but something that emerged as an effect of the monkeys becoming proficient in this task," said Nicolelis. "This was a surprise. It demonstrates the brain's enormous flexibility to assimilate a device, in this case a wheelchair, and that device's spatial relationships to the surrounding world."
The findings could be huge for creating devices that can be controlled by the disabled. More specifically, it could give people mobility with practice over time. Currently, the researchers hope to expand the experiment by recording more neuronal signals to continue to increase the accuracy and fidelity of the primate BMI. They then hope to seek trials for an implanted device in humans.
