Researchers have developed a technique that allows people to control a robotic arm using only their minds. The research has the potential to help millions of people who are paralyzed or have neurodegenerative diseases.
The technique lets people operate the robotic arm to reach and grasp objects in a complex 3D environment using only their thoughts, without a brain implant. The noninvasive technique — electroencephalography (EEG)-based brain-computer interface — records weak electrical activity of the subject’s brain through a specialized EEG cap fitted with 64 electrodes. It converts the subject’s thoughts into actions by advanced signal processing and machine learning.
Eight healthy human subjects completed the experimental sessions of the study wearing the EEG cap. Subjects gradually learned to imagine moving their own arms without actually moving them to control a robotic arm in 3D space. They started from learning to control a virtual cursor on a computer screen, and then learned to control a robotic arm to reach and grasp objects in fixed locations on a table. Eventually, they were able to move the robotic arm to reach and grasp objects in random locations on a table, and move objects from the table to a three-layer shelf by only thinking about these movements.
All eight subjects could control a robotic arm to pick up objects in fixed locations with an average success rate above 80 percent, and move objects from the table onto the shelf with an average success rate above 70 percent.
The brain-computer interface technology works due to the geography of the motor cortex — the area of the cerebrum that governs movement. When humans move, or think about a movement, neurons in the motor cortex produce tiny electric currents. Thinking about a different movement activates a new assortment of neurons, a phenomenon confirmed by cross-validation using functional MRI. Sorting out these assortments using advanced signal processing laid the groundwork for the brain-computer interface.
The next step in this work will be to further develop the brain-computer interface technology so it can realize a brain-controlled robotic prosthetic limb attached to a person’s body or examine how this technology could work with someone who has had a stroke or is paralyzed.