Optics and brain and cognitive science researchers aim to see if neurons can transport light like fiber-optic communications channels.
Neurons, the cells in brains and spinal cords that make up the central nervous system, communicate by firing electrical pulses. But scientists have found hints that neurons may transmit light as well, which would profoundly change current models of how the nervous system works.
Researchers from the University of Rochester have begun an ambitious project to study if living neurons can transmit light through their axons-the long, tail-like nerve fibers of neurons that resemble optical fibers. The John Templeton Foundation provided a three-year, $1.5 million grant to support the research.
"There are scientific papers offering indications that light transport could happen in neuron axons, but there's still not clear experimental evidence," says the principal investigator, Pablo Postigo, a professor at Rochester's Institute of Optics. "Scientists have shown that there is ultra-weak photon emission in the brain, but no one understands why the light is there."
If light is at play and scientists can understand why, it could have major implications for medically treating brain diseases and drastically change the way physicians heal the brain. But measuring optical transport between neurons would be no easy task.
"A neuron's axon is less than two microns wide, so if you want to measure the optical properties, you need to use nanophotonic techniques," says Postigo. "If there is light transmission, it may happen with very tiny amounts of light, even a single photon at a time."
Postigo, an expert in nanophotonics, will design probes that are able to interact optically with living neurons. He is partnering with Michel Telias, an assistant professor of ophthalmology and of neuroscience and a member of the Center for Visual Science, who specializes in measuring the electrical properties of neurons and their action potentials.
Using the photonic nanoprobes, the researchers will inject light into the neuron axon and detect the outcoming photons. If the neuron's axon can transmit light, they will measure the light's wavelengths and intensities.
