Measuring blood flow in the brain is critical for responding to a range of neurological problems, including stroke, traumatic brain injury (TBI) and vascular dementia. But existing techniques, including magnetic resonance imaging and computed tomography, are expensive and therefore not widely available.

Researchers from the USC Neurorestoration Center and the California Institute of Technology (Caltech) have built a simple, noninvasive alternative. The device takes a technique currently used in animal studies known as speckle contrast optical spectroscopy (SCOS) and adapts it for potential clinical use in humans. It works by capturing images of scattered laser light with an affordable, high-resolution camera.

“It’s really that simple. Tiny blood cells pass through a laser beam, and the way the light scatters allows us to measure blood flow and volume in the brain,” said Charles Liu, MD, Ph.D., professor of clinical neurological surgery, urology and surgery at the Keck School of Medicine of USC, director of the USC Neurorestoration Center and co-senior author of the new research.

Grid cells are a class of specialized neurons in a brain region called the entorhinal cortex, which is known to support spatial navigation and some memory processes. Past neuroscience studies have found that as humans and other animals move in their surroundings, these cells fire following a grid-like pattern, creating a sort of internal map of the environment.

Researchers at the Medical Faculty of Heidelberg University, the German Cancer Research Center and EBRI recently carried out a study aimed at shedding new light on the processes via which grid cells encode an animal’s position in space and contribute to spatial navigation. Their findings, published in Nature Neuroscience, suggest that rather than creating and retaining a single global map, these cells produce multiple local maps that can guide the future behavior of animals in their surrounding space.

“Soon after the discovery of grid cells by the group of May-Britt and Edvard Moser, it was proposed that these neurons might support path integration,” Kevin Allen, senior author of the paper, told Medical Xpress. “In this fundamental navigation process, an animal estimates its position by continuously integrating self-motion cues, even in the absence of external landmarks. However, most previous studies of grid cells were conducted in environments rich in external cues, making it difficult to isolate the path-integration processes.”