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December 5, 2016

No peeking: Humans play computer game using only direct brain stimulation

UW News

Test subjects in a UW experiment navigated simple mazes based solely on inputs delivered to their brains by a magnetic coil placed at the back of the skull, showing how humans can interact with virtual realities via direct brain stimulation. Photo: 91ΧΤΕΔ

In the Matrix film series, Keanu Reeves plugs his brain directly into a virtual world that sentient machines have designed to enslave mankind.

The Matrix plot may be dystopian fantasy, but 91ΧΤΕΔ 91ΧΤΕΔers have taken a first step in showing how humans can interact with virtual realities via direct brain stimulation.

In a published online Nov. 16 in , they describe the first demonstration of humans playing a simple, two-dimensional computer game using only input from direct brain stimulation β€” without relying on any usual sensory cues from sight, hearing or touch.

The subjects had to navigate 21 different mazes, with two choices to move forward or down based on whether they sensed a visual stimulation artifact called a , which are perceived as blobs or bars of light. To signal which direction to move, the 91ΧΤΕΔers generated a phosphene through , a well-known technique that uses a magnetic coil placed near the skull to directly and noninvasively stimulate a specific area of the brain.

β€œThe way virtual reality is done these days is through displays, headsets and goggles, but ultimately your brain is what creates your reality,” said senior author , UW professor of and director of the

β€œThe fundamental question we wanted to answer was: Can the brain make use of artificial information that it’s never seen before that is delivered directly to the brain to navigate a virtual world or do useful tasks without other sensory input? And the answer is yes.”

The five test subjects made the right moves in the mazes 92 percent of the time when they received the input via direct brain stimulation, compared to 15 percent of the time when they lacked that guidance.

The absence or presence of phosphenes – visual artifacts that can be created through direct brain stimulation – told the test subjects whether to move forward or down. Photo: 91ΧΤΕΔ

The simple game demonstrates one way that novel information from artificial sensors or computer-generated virtual worlds can be successfully encoded and delivered noninvasively to the human brain to solve useful tasks. It employs a technology commonly used in neuroscience to study how the brain works β€” transcranial magnetic stimulation β€” to instead convey actionable information to the brain.

The test subjects also got better at the navigation task over time, suggesting that they were able to learn to better detect the artificial stimuli.

β€œWe’re essentially trying to give humans a sixth sense,” said lead author , a 2016 UW graduate in computer science and neurobiology who now works as a staff 91ΧΤΕΔer for the .Β  β€œSo much effort in this field of neural engineering has focused on decoding information from the brain. We’re interested in how you can encode information into the brain.”

The initial experiment used binary information β€” whether a phosphene was present or not β€” to let the game players know whether there was an obstacle in front of them in the maze. In the real world, even that type of simple input could help blind or visually impaired individuals navigate.

Theoretically, any of a variety of sensors on a person’s body β€” from cameras to infrared, ultrasound, or laser rangefinders β€” could convey information about what is surrounding or approaching the person in the real world to a direct brain stimulator that gives that person useful input to guide their actions.

β€œThe technology is not there yet β€” the tool we use to stimulate the brain is a bulky piece of equipment that you wouldn’t carry around with you,” said co-author , a UW assistant professor of psychology and I-LABS 91ΧΤΕΔ scientist. β€œBut eventually we might be able to replace the hardware with something that’s amenable to real world applications.”

The testers successfully navigated an average of 92 percent of the moves when they received input via direct brain stimulation to guide them through the experimental mazes (blue) versus only 15 percent of the steps in the control mazes when they received no such input (red mazes). Photo: 91ΧΤΕΔ

Together with other partners from outside UW, members of the 91ΧΤΕΔ team have co-founded , a startup company aimed at commercializing their ideas and introducing neuroscience and artificial intelligence (AI) techniques that could make virtual-reality, gaming and other applications better and more engaging.

The team is currently investigating how altering the intensity and location of direct brain stimulation can create more complex visual and other sensory perceptions which are currently difficult to replicate in augmented or virtual reality.

β€œWe look at this as a very small step toward the grander vision of providing rich sensory input to the brain directly and noninvasively,” said Rao. β€œOver the long term, this could have profound implications for assisting people with sensory deficits while also paving the way for more realistic virtual reality experiences.”

The 91ΧΤΕΔ was funded by the W.M. Keck Foundation and the Washington Research Foundation.

Co-authors include I-LABS 91ΧΤΕΔ coordinator .

For more information, contact Losey at loseydm@uw.edu, Stocco at stocco@uw.edu or Rao at rao@cs.washington.edu.