A flexible film bristling with tiny sensors could make surgery safer for patients with a brain tumor or severe epilepsy.
The experimental film, which looks like Saran wrap, rests on the brain鈥檚 surface and detects the electrical activity of nerve cells below. It鈥檚 designed to help surgeons remove diseased tissue while preserving important functions like language and memory.
鈥淭his will enable us to do a better job,鈥� says , a neurosurgeon at Oregon Health and Science University who helped develop the film.
The technology is similar in concept to sensor grids already used in brain surgery. But the resolution is 100 times higher, says , an engineer at the University of California, San Diego, who is leading the development effort.
鈥淚magine that you鈥檙e looking on a clear night at the moon,鈥� Dayeh says, 鈥渢hen imagine [looking through] a telescope.鈥�
In addition to aiding surgery, the film should offer researchers a much clearer view of the neural activity responsible for functions including movement, speech, sensation, and even thought.
鈥淲e have these complex circuits in our brains,鈥� says , who directs the BRAIN Initiative at the National Institutes of Health, which has funded much of the film鈥檚 development. 鈥淭his will give us a better understanding of how they work.鈥�
Mapping an ailing brain
The film is intended to improve a process called functional brain mapping, which is often used when a person needs surgery to remove a brain tumor or tissue causing severe epileptic seizures.
During an operation, surgeons place a grid of sensors on the surface of an awake patient鈥檚 brain, taking care not to tear the delicate film. Then they ask the patient to do tasks, like counting or moving a finger.
Some of the tasks may be specific to a particular patient.
鈥淚f somebody is a mathematician, we鈥檒l give them a math formula,鈥� Raslan says. 鈥淚f somebody is a painter, we鈥檒l give them what鈥檚 called a visual cognition task.鈥�
The sensors show which brain areas become active during each activity. But the borders of these areas tend to be irregular, Raslan says.
鈥淚t鈥檚 like a shoreline,鈥� he says, 鈥渋t zigzags and it curves around.鈥�
The accuracy of a brain map depends on the number of sensors used.
鈥淭he clinical grid we use now uses one point of recording every one centimeter,鈥� Raslan says. 鈥淭he new grid uses at least 100 points.鈥�
That鈥檚 possible because each sensor on the new grid is 鈥渁 fraction of the diameter of the human hair,鈥� Dayeh says. And the grid itself is bonded to a plastic film so thin and flexible that it conforms to every contour of the brain鈥檚 surface.
From animals to humans
The device works well in animals. And in May, the FDA approved it for testing in people.
Dayeh and Raslan, who both hold a financial interest in the device, say the team is already working on a wireless version that could be implanted for up to 30 days. That would allow people with severe epilepsy to be monitored for seizures at home instead of in the hospital.
Ultimately, the researchers hope to use this diagnostic tool as a brain-computer interface for people who are unable to communicate or move.
That would allow them to 鈥渢ransduce their thoughts into actions,鈥� Dayeh says.
Scientists have already created this sort of brain computer interface using sensors implanted deep in the brain. But a grid on the brain鈥檚 surface would be safer, and could potentially detect the activity of many more neurons.
Tax dollars at work
Daye鈥檚 research is part of the federal , which was launched a decade ago to develop tools that would reveal the inner workings of the human brain.
The new grid is one of the tools, Ngai says. But it also promises to improve care for people with brain disorders.
鈥淯ltimately, the goal was to develop better ways of treating human beings,鈥� Ngai says, 鈥渁nd I think this gives us a pretty big stride toward that goal.
Future strides may come more slowly. This year, Congress cut BRAIN Initiative funding by about 40 percent.
Even so, Ngai says, the new sensor grid and its wireless counterpart show just how far the field has come.
A decade ago, Ngai says, some of the nation鈥檚 top electrical engineers and computer scientists said there was no way devices like these would work.
鈥淵ou look now,鈥� he says, 鈥渁nd it鈥檚 being done.鈥�
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