April 02, 2008 –
Biomedical engineering graduate students Mark Merlo (left) and Nick Gunn sport two versions of the XSense external appliance.
It was once science fiction. Without using sight or hearing or sophisticated equipment, soldiers on the battlefield sense an approaching enemy and know instinctively that danger is near. They have XSense, the ability to perceive objects that cannot be detected using their other senses.
Researchers in UCI’s Integrated Nanosystems Research Facility are leading the effort to help humans develop this sixth sense.
XSense (eXtra SENSory Engineering), is rooted in “sensory substitution,” the idea that nerves that govern specific senses can substitute for one another if they receive appropriate stimulation.
The concept works because of the brain’s plasticity, its ability to adapt to the absence or deterioration of one of our senses by rewiring itself. Thus, people missing a specific sense can be trained to compensate by developing other senses. A blind person learns to “read” by using his hands to feel Braille letters and a deaf person “hears” by using his eyes to read lips.
“In this case, instead of restoring lost senses, we are trying to create a “sixth sense,” says lead researcher Mark Bachman. “To restore vision, you can try to stimulate the optic nerve; to restore hearing you can get at the auditory nerve, but what nerve do you tap into to get infrared vision?
“Because of the principles of sensory substitution, you don’t have to; you can stimulate other nerves instead that can trigger people to develop that sixth sense.”
Researchers are building an apparatus that contains sensors and electrodes. The sensors in the device will detect heat or movement, causing them to deliver a stimulus – heat, vibration or sound – to a specific nerve. That stimulus is converted into appropriate electrical impulses that the brain can be trained to recognize, prompting it to “feel” an object it cannot see.
Trial and Error
With millions of nerves in the human body though, which ones can be tapped to send the necessary messages to the brain?
The answer will arrive through trial and error. “We start with the nerves that are easiest to get to,” says Bachman. “We still have to understand how we are going to take this information and deliver it to a human being so he can learn it.”
Because the mouth contains many nerves and is easily accessible, researchers are experimenting with a dental appliance that will provide sensory input to the tongue and roof of the mouth.
They are also working on two versions of a bone-conduction device that vibrates the skull with low-frequency sounds: one version is implanted into the bone behind the ear; the other is integrated into a head covering, a common baseball cap, for example.
Technology Provides Solutions
The project is powered by IT. “You have to map the sensory stimulus into something the brain is going to be able to interpret and you can’t do that without using a computer,” says Bachman. “To go after this goal in a serious way was not even possible until recently because computers and sensors have not been small enough until now. You could hardly have someone walking around with a giant Sony Cam on his head or a Dell computer on his back,” he grins.
“Now the sensor technology is so much smaller. With a device the size of my thumb, I can have all the power of a vast PC.”
— Anna Lynn Spitzer
