Flat microscope for brain analysis
Image: "FlatScope" is part of US DARPA's Neural Engineering System Design project.
US-based researchers are developing a 'flat' microscope - FlatScope - alongside software, to decode and trigger neurons on the surface of the brain.
The research is part of a DARPA-funded $65 million project to develop a high-resolution neural interface that will provide an alternate path for sight and sound to be delivered to the brain.
The so-called Neural Engineering System Design (NESD) program hopes to compensate for a person's loss of vision or hearing by delivering digital information directly to parts of the brain that can process it.
According to the researchers from Electrical and Computer Engineering at Rice University, their laboratory prototype, still under development, will rest on the surface of the brain and detect optical signals from neurons in the cortex.
Professor Jacob Robinson and colleagues will first focus on vision and develop an optical hardware and software interface that will detect signals from modified neurons that generate light when active.
Crucially, the interface will monitor and stimulate hundreds of thousands of neurons in the cortex.
As Robinson points out: "State-of-the-art systems have only 16 electrodes, and that creates a real practical limit on how well we can capture and represent information from the brain."
"The inspiration comes from advances in semiconductor manufacturing," he adds. "We're able to create extremely dense processors with billions of elements on a chip for the phone in your pocket. So why not apply these advances to neural interfaces?"
The researchers are also collaborating with neuroscientist Professor Vincent Pieribone from Yale University, and colleagues, who are investigating bioluminescence and hope to program neurons with proteins that release a photon when triggered.
"The idea of manipulating cells to create light when there's an electrical impulse is not extremely far-fetched in the sense that we are already using fluorescence to measure electrical activity," highlights Robinson.
FlatScope is related to Rice's 'FlatCam', developed by Robinson's colleagues, Professors Richard Baraniuk and Ashok Veeraraghavan, to eliminate the need for bulky lenses in cameras.
Rice researchers (from left) Ashok Veeraraghavan, Jacob Robinson and Caleb Kemere will create a high-resolution, wireless neural interface that can be implanted on the cortex.
Alongside the hardware, the researchers are modifying FlatCam algorithms to handle data from the brain interface.
"The microscope we're building captures three-dimensional images, so we'll be able to see not only the surface but also to a certain depth below," says Veeraraghavan. "At the moment we don't know the limit, but we hope we can see 500 microns deep in tissue."
"That should get us to the dense layers of cortex where we think most of the computations are actually happening, where the neurons connect to each other," adds fellow researcher, Professor Caleb Kemere.