Duke University researchers have brought the world and important step closer to its first fully-functional wheelchair that can be controlled by the mind. The extraordinary breakthrough saw the research team produce a working wireless brain-machine interface (BMI), which during laboratory trial allowed monkeys to successfully move the chair using only their minds.

Published this week in Nature’s Scientific Reports, the study involved the implantation of microelectrode arrays directly into the brains of two rhesus monkeys. These are the areas of the brain that are associated with the movement of limbs and intention of movement. The electrodes were then linked wirelessly to the BMI, which monitored brain activity in order to translate cortical impulses to actual physical movement of the chair.

In order to familiarize the monkeys and their brains with how the chairs worked, they were introduced to the wheelchairs and allowed to get used to how they operated before the study itself took place. During the process, the research teams monitored cortical activity in order to create an algorithm that would translate specific brain impulses into commands for acceleration and steering.

The test then involved having the monkeys use brain power alone to control the wheelchairs, in order to steer them toward a bowl of fruit. While the position of the fruit remained the same throughout, the wheelchair itself was positioned differently for each test, in order to gauge the scope of the monkey’s ability to control them.

The results were surprisingly impressive.

“Prolonged BMI use leads to the assimilation of the artificial tool, e.g. robotic or virtual arms/legs, into the body representations found in the subject’s cortex,” wrote the researchers.

“Some evidence of such integration has been reported already for manually controlled wheelchairs,”

“Our current observations of neuronal tuning to wheelchair kinematics and target distance after the transition to BMI control adds to these findings and suggests new directions for future scientific inquiries on how prolonged BMI operation affects cortical representation of the sense of self and the peri-personal space.”

The team behind the study believes that the same technology and techniques could eventually be used in human patients, both for the control of artificial limbs and in the creation of functional mind-controlled wheelchairs for epilepsy and Parkinson’s disease sufferers.

(A) The mobile robotic wheelchair, which seats a monkey, was moved from one of the three starting locations (dashed circles) to a grape dispenser. The wireless recording system records the spiking activities from the monkey’s head stage, and sends the activities to the wireless receiver to decode the wheelchair movement. (B) Schematic of the brain regions from which we recorded units tuned to either velocity or steering. Red dots correspond to units in M1, blue from PMd and green from the somatosensory cortex. (C) Three video frames show Monkey K drive toward the grape dispenser. The right panel shows the average driving trajectories (dark blue) from the three different starting locations (green circle) to the grape dispenser (red circle). The light blue ellipses are the standard deviation of the trajectories.

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