The University of California, Berkeley, has been awarded 21.6 million U.S. dollars over four years to create a "window" into the brain that can help monitor and activate thousands to millions of individual neurons using light.
Researchers involved with the project, the public university in Northern California said Thursday, refer to the device as a cortical modem: a way of "reading" from and "writing" to the brain, like the input-output activity of internet modems.
"The ability to talk to the brain has the incredible potential to help compensate for neurological damage caused by degenerative diseases or injury," said project leader Ehud Isacoff, a UC Berkeley professor of molecular and cell biology and director of the Helen Wills Neuroscience Institute. "By encoding perceptions into the human cortex, you could allow the blind to see or the paralyzed to feel touch."
The funding came from the Defense Advanced Research Projects Agency (DARPA) of the U.S. Department of Defense.
The brain modem team includes 10 UC Berkeley faculty, along with researchers from Lawrence Berkeley National Laboratory, Argonne National Laboratory and the University of Paris, Descartes.
The project is one of six funded this year by DARPA's Neural Engineering System Design program, as part of the U.S. government's Brain Initiative, to develop implantable, biocompatible "neural interfaces" that can compensate for visual or hearing deficits.
The researchers' goal is to read from a million individual neurons and simultaneously stimulate 1,000 of them with single-cell accuracy. This would be a first step toward replacing a damaged eye with a device that directly talks to the visual part of the cerebral cortex, or relaying touch sensation from an artificial limb to the touch part of the cortex to help an amputee control an artificial limb.
To communicate with the brain, the team will first insert a gene into neurons that makes fluorescent proteins, which flash when the cell fires an action potential, and then a second gene that makes a light-activated "optogenetic" protein, which stimulates neurons in response to a pulse of light.
To read from and write to these neurons, a two-tiered device is required. The reading device is a miniaturized microscope that mounts on a small window in the skull and peers through the surface of the brain to visualize up to a million neurons at a time. The microscope is based on the "light field camera," which captures light through an array of lenses and reconstructs images computationally in any focus. The "light field microscope" will do the same to visualize vast numbers of neurons at different depths and monitor their activity.
For the writing component, the researchers are developing a means to project light patterns onto these neurons using 3D holograms, stimulating groups of neurons in a way that reflects normal brain activity.
Finally, the team plan to develop computational methods that identify the brain activity patterns associated with different sensory experiences, hoping to learn the rules well enough to generate "synthetic percepts."
The team of neuroscientists, engineers and computer scientists ultimately hopes to build a device for use in humans, and the goal during the four-year funding period is to create a prototype to read and write to the brains of model organisms, including zebrafish larvae, which are transparent, and mice, where neural activity and behavior can be monitored and controlled simultaneously via a transparent window in the skull.
"The kind of devices we are going to make will be incredible experimental tools for understanding brain function," Isacoff acknowledged. "And then, once we learn enough about the system and how it works, we will actually have devices that are useful in many ways."