University of Washington researchers have taken a first step in showing how humans can interact with virtual realities via direct brain stimulation. They described the first demonstration of humans playing a simple, two-dimensional computer game using only input from direct brain stimulation -- 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 phosphene, which are perceived as blobs or bars of light. To signal which direction to move, the researchers generated a phosphene through transcranial magnetic stimulation, a well-known technique that uses a magnetic coil placed near the skull to directly and noninvasively stimulate a specific area of the brain. 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 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 (transcranial magnetic stimulation) 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. The initial experiment used binary information 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 -- from cameras to infrared, ultrasound, or laser rangefinders -- 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.