February 27, 2023 – You're walking down a busy sidewalk, weaving through people, pets, and strollers without colliding or losing your footing. How do you do it?
As latest research shows, you might have cells deep in your brain called grid cells to thank.
Scientists know that these cells help track your movements by keeping track of where you might have been, where you might be, where you might be going, and the direction you’re looking.
With the assistance of virtual reality and functional Magnetic resonance imaging or fMRI, Researchers have found that they can also help track the movements of the people around us.
The study, Published in Nature communicationsuggests that if these brain cells lose their functionality, it could develop into harder for people to search out their way around in rooms with plenty of moving people.
The researchers from Austria, Israel and the USA hope that their findings will help explain why some people affected by age or dementia lose their orientation in crowds.
A compass in your brain
Grid cells – positioned within the lower a part of the brain – fire in characteristic hexagonal patterns, generating grid-like codes that map your position in space in relation to other people and objects.
This creates an “internal compass,” researchers say, which helps you get from point A to point B without bumping into anyone along the best way..
“These signals could underlie our ability to move along a busy sidewalk or head toward a soccer goal by taking into account the position of players on the other team,” says lead study writer Isabella Wagner, PhD, assistant professor of cognitive neuroscience on the University of Vienna.
60 healthy adults took part within the study watched a pc screen while software recorded their eye movements and an fMRI monitored their brains. Each participant watched a computer-generated person walking in a virtual landscape. They then assumed a first-person role within the virtual space and were asked to follow the person's path.
As study participants watched the person walking and retraced their path, their grid cells lit up. And as they followed the opposite person, in addition they activated a network of related brain regions.
“We suspect that grid-like codes and associated network dynamics may serve to distribute information about the location of others throughout the brain,” the authors write. The “enables us to maneuver through crowded and dynamically changing environments such as those we encounter in everyday situations.”
Interestingly, the people whose grid cells glowed essentially the most when observing the person weren’t pretty much as good at copying the trail. This could appear surprising, but it surely also is sensible: The authors speculate that when brain cells work less efficiently, more cells and regions Fire to get the job done.
“This seemingly counterintuitive result shows that we still do not fully understand the complex mechanisms by which the brain processes important spatial information,” says Vikram Rao, MD, PhD, a neurologist on the University of California San Francisco who was not involved within the study.
Why this is significant: Aging, Alzheimer's and epilepsy
Studying these navigation processes within the healthy brain may also help us understand why they generally break down.
“Impaired visual-spatial information processing can be an early sign of neurodegenerative diseases, such as Alzheimer,” says Rao. “If we understand how the brain normally processes this information, we may be able to identify and reduce deficits in patients.”
Wagner says in a press release that with age and dementiaGrid cells develop into less effective.
“The result is that people can no longer find their way and their orientation is impaired,” she says.
The findings could also make clear epilepsy.
“In epilepsySeizures typically originate in the temporal lobe, which includes the entorhinal cortex,” says Rao, division director of UCSF's Comprehensive Epilepsy Center. “This study expands our understanding of brain circuits that may be relevant in people with epilepsy.”
Like all studies, this one had strengths and weaknesses.
The advantage of fMRI is that it’s non-invasive and might “measure activity in all brain regions simultaneously,” says Rao.
But there's a downside: It doesn't tell us what participants were considering. While they were watching the virtual person move, some can have planned their very own routes prematurely, which influenced the outcomes, Rao says.
Next Steps
Before these findings may also help doctors treat their patients, further research is required.
Wagner envisions follow-up studies “with older participants or with dementia patients in order to possibly develop a behavioral test or biomarker that can detect warning signals as early as possible.”
Her group is currently studying whether grid cells may also help us recognize other people, a capability which may be impaired in advanced dementia.