A research team led by neuroengineers at Rice University has created wireless technology to remotely activate specific brain circuits in fruit flies in less than a second.
In a demonstration published in Natural materialsresearchers from Rice, Duke University, Brown University and Baylor College of Medicine used magnetic signals to activate targeted neurons that controlled the body position of fruit flies moving freely through an enclosure.
To study the brain or treat neurological disorders, the scientific community is looking for tools that are both incredibly precise, but also minimally invasive. Remotely controlling selected neural circuits with magnetic fields is something of a holy grail for neurotechnology. Our work takes an important step towards this goal because it increases the speed of remote magnetic control, bringing it closer to the natural speed of the brain. »
Jacob Robinson, study author, associate professor of electrical and computer engineering at Rice and member of Rice’s Neuroengineering Initiative
Robinson said the new technology activates neural circuits about 50 times faster than the best technology previously demonstrated for magnetic stimulation of genetically defined neurons.
“We made progress because the lead author, Charles Sebesta, came up with the idea of using a new ion channel sensitive to the rate of temperature change,” Robinson said. “By bringing together experts in genetic engineering, nanotechnology and electrical engineering, we were able to put all the pieces of the puzzle together and prove that this idea works. It was truly a team effort of world-class scientists with whom we have had the chance to work.”
The researchers used genetic engineering to express a special heat-sensitive ion channel in neurons that causes flies to partially spread their wings, a common mating gesture. The researchers then injected magnetic nanoparticles that could be heated with an applied magnetic field. An overhead camera observed the flies as they roamed freely in an enclosure atop an electromagnet. By altering the magnet’s field in a specific way, the researchers were able to heat the nanoparticles and activate the neurons. An analysis of the video of the experiments showed that the flies with the genetic modifications adopted the spread-wing posture about half a second after the change in magnetic field.
Robinson said the ability to activate genetically targeted cells at specific times could be a powerful tool for studying the brain, treating disease and developing technology for direct brain-machine communication.
Robinson is principal investigator on MOANA, an ambitious project to develop headset technology for non-surgical, wireless, brain-to-brain communication. Short for “Magnetic, Optical, and Acoustic Neural Access,” MOANA is being funded by the Defense Advanced Research Projects Agency (DARPA) to develop headset technology that can both “read” or decode neural activity in the visual cortex of person and “write,” or encode, that activity into another person’s brain. Magnetogenetic technology is one example.
Robinson’s team is working with the goal of partially restoring vision to blind patients. By stimulating parts of the brain associated with vision, MOANA researchers hope to give patients a sense of vision even if their eyes no longer work.
“The long-term goal of this work is to create methods to activate specific brain regions in humans for therapeutic purposes without ever having to perform surgery,” Robinson said. “To achieve the brain’s natural precision, we probably need to get a response of a few hundredths of a second, so there’s still a long way to go.”
Sebesta, C., et al. (2022) Subsecondary multichannel magnetic control of selected neural circuits in free-moving flies. Natural materials. doi.org/10.1038/s41563-022-01281-7.