WASHINGTON, Dec. 16 (Xinhua) -- With a specialized non-invasive brain cap, millions of people who are paralyzed or have neurodegenerative diseases may have a chance to control a robotic arm with their minds, according to a study released Wednesday.

Researchers at the University of Minnesota, including three Chinese scientists, have made a breakthrough recently: When research subjects put on a specialized non-invasive brain cap, they were able to move a robotic arm by simply imagining moving their own arms.

"This is the first time in the world that people can operate a robotic arm to reach and grasp objects in a complex 3D environment using only their thoughts without a brain implant," said one of the Chinese researchers Bin He, director of Institute for Engineering in Medicine at the University of Minnesota.

"Just by imagining moving their arms, they were able to move the robotic arm," He said Wednesday in a news release.

The non-invasive technique, named electroencephalography (EEG)-based brain-computer interface, records tiny electrical activities produced by neurons in the subjects' brain through a specialized, high-tech EEG cap fitted with 64 electrodes and converts the "thoughts" into action by advanced signal processing and machine learning.

Eight out of 13 healthy human subjects completed all the 15 experimental sessions of the study wearing the cap. Subjects gradually learned to imagine moving their own arms without actually moving them, to control a robotic arm to complete reach and automatic grasp tasks in three dimensions.

"Each subject began with virtual cursor control and progressed to robotic arm control with increasing complexity and dimensionality over time," said the study published in a Nature research journal named Scientific Reports.

Starting from reaching and grasping objects in fixed locations on a table, the subjects were then able to move the robotic arm to reach and grasp objects in random locations on a table, and finally to move objects from the table to a three-layer shelf by only thinking about these movements.@ "Most subjects exhibited improved performance over time in controlling both the virtual cursor and the robotic arm," the study said. All eight subjects could move 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.

"This is exciting as all subjects accomplished the tasks using a completely non-invasive technique. We see a big potential for this research to help people who are paralyzed or have neurodegenerative diseases to become more independent without a need for surgical implants," He said.

The next step would be a further development of this technology to realize a brain-controlled robotic prosthetic limb attached to one's body or examine how this technology could work with someone who has had a stroke or is paralyzed, He said.