The team's now-patented approach relies on red and near-infrared (near-IR) light in the 600- to 1000-nm wavelength range, where it can be absorbed by cytochrome-c oxidase, the main light-sensitive molecule in mitochondria. This aids cellular respiration, the formation of adenosine triphosphate (ATP; an energy source essential for healthy brain function) molecules, modulation of oxidative stress, and reduced free radical production. It also triggers cell signaling and gene transcription.

"All of this leads to the positive effects of photobiomodulation," says Zubair Ahmed, a professor of neuroscience and the Neuroscience and Ophthalmology section lead.

In a series of tests on rodent subjects, the research team shone near-IR light at 660 nm and 810 nm into injured tissue for three days post-injury. Over the course of about a month, they found the PBM approach ultimately boosted numerous functions including cellular respiration and ATP formation. It also decreased cell death, neuronal damage, and inflammation, and stimulated regeneration of brain tissue.

PBM therapy reduced the activation of astrocytes and microglial cells, which contribute to inflammation in the brain after head trauma. The researchers also saw significant improvements in the subjects' performance of functional tests relating to balance and cognitive functions. And red light therapy -- at 810 nm specifically -- even accelerated recovery.