In a demonstration of mind over matter, U.S. researchers say they've transmitted brain signals from one person into another person and gained control of that second person's hand movements.

University of Washington researchers used an upgraded version of a non-invasive brain-to-brain interface they first developed and demonstrated in 2013.

In the new version, a participant denoted as the "sender" was linked to an electroencephalography machine, which recorded his brain signals.

Those signal were sent over the Internet to a second study participant, considered the "receiver," fitted with a cap containing a transcranial magnetic stimulation coil placed over the portion of the brain involved in controlling hand movements, the researchers reported in the journal PLOS One.

As the sender played a computer video game that required him to mentally imagine firing a cannon to defend a city, the receiver sat in another building a half-mile away with his hand poised over a computer touchpad.

As the sender imagined his firing of the cannon, the signal caused a hand twitch in the receiver, firing the cannon on the sender's video game screen.

The accuracy of the brain-to-brain communication varied among participating pairs, varying from 25 percent to 83 percent, the researchers reported.

The researchers, recently awarded a $1 million grant by the W.M. Keck Foundation, say they will expand their work in hopes of decoding and transmitting more complex brain processes.

Those could include complex psychological and visual processes such as thoughts, concepts and rules, they say.

The research could result some day in "brain tutoring," the researchers suggest, with knowledge being sent directly from a teacher's brain to that of a student.

"Imagine someone who's a brilliant scientist but not a brilliant teacher. Complex knowledge is hard to explain -- we're limited by language," says study co-author Chantel Prat, an assistant professor of psychology.

In 2013, the UW research team was the first to demonstrate two human brains communicating remotely using non-invasive technology.

In the new study such technology, along with new software, was shown to be able to connect them closely in real time.

"The new study brings our brain-to-brain interfacing paradigm from an initial demonstration to something that is closer to a deliverable technology," says study co-author Andrea Stocco, a researcher at the university's Institute for Learning & Brain Sciences. "Now we have replicated our methods and know that they can work reliably with walk-in participants."