Researchers from four different universities participated in a study that resulted in proof that human brains have “grid cells" that function much like a global positioning system for navigation. Grid cells are neurons that emit pulses of electricity in a regular pattern to map movement and they had previously been found to help rodents, bats and primates keep track of their relative location while navigating an unfamiliar environment.
The current study was led by NARSAD Young Investigator Grantee Joshua Jacobs, Ph.D., of Drexel University with the help of researchers from the University of California Los Angeles, the University of Pennsylvania and Thomas Jefferson University and their results were published on August 4th in Nature Neuroscience.
The research was conducted by having patients with severe epilepsy play navigational-based video games. As the 14 participants played the games, the researchers recorded brain activity through electrodes the patients have implanted deep inside their brains as part of their epilepsy treatment. The scientists studied the relation between how the participants navigated in the games and activity of individual neurons. As they analyzed the brain activity, they noticed a triangular grid-shaped pattern emerge that was correlated to navigation. The same patterns characteristic of rodent grid cells were found in humans as they navigated, Dr. Jacobs reported, showing that humans are using the “same neural mechanism.”
"Each grid cell responds at multiple spatial locations that are arranged in the shape of a grid," Dr. Jacobs said. "Without grid cells, it is likely that humans would frequently get lost or have to navigate based only on landmarks. Grid cells are thus critical for maintaining a sense of location in an environment."
The study found grid cells not only in the entorhinal cortex—where they are observed in rodents—but also, in a very different brain area, the cingulate cortex, suggesting that the grid patterns may be more prevalent in humans. The entorhinal cortex is part of the brain that has been studied in Alzheimer's disease research and according to Dr. Jacobs, understanding grid cells could help researchers understand why people with the disease often become disoriented. It could also help them show how to improve brain function in people suffering from the disease.
Read more about this research in a story from the New York Times.
Read the press release announcing this research.