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Researchers have combined neuroimaging and virtual reality in a new study to identify the key brain regions that help people maintain their sense of direction.
The findings suggest that these brain regions may serve as the brain’s ‘neural compass’, helping a person navigate from one location to another.
Study author Russell Epstein, from the University of Pennsylvania in the US, hopes these results may be helpful in supporting people with neurodegenerative diseases who are at risk of becoming disorientated and lost.
“Losing your sense of direction is something that can happen in neurodegenerative diseases,” says Epstein. “So, continuing to explore the function of these two brain regions may help with early detection or monitoring progression of these diseases.”
A previous study found that up to 60% of people living with dementia, a neurodegenerative disease affecting memory, will become lost at some stage. Similar studies have shown that those who are 65 years and older are more at risk of disorientating themselves.
While previous studies in rats have suggested that certain head direction cells in the brain could support a “neural compass”, up until now researchers have found it challenging to identify similar tools in human brains.
The researchers collected neuroimaging data of 15 participants while they played a taxi-cab game that involved the participants driving around in a virtual reality city. In the game, participants navigated their way through the virtual city to find passengers who they were then required to take to a goal store. The participants returned a couple of days later to play the game for a second time.
Researchers hooked the participants up to fMRI machines while they were playing the game. The data from these fMRIs showed there were 2 brain regions that represented direction facing forward while participants moved around in the game. These regions are known as the retrosplenial complex (RSC) and the superior parietal lobe (SPL).
“These findings demonstrate the critical roles of RSC and SPL in representing directional signals during active spatial navigation,” the authors write.
The researchers noticed this signal was also consistent across multiple tasks such as when participants picked up their ‘passengers’ in the game and then when they dropped them off at various locations.
Additional analysis by the researchers suggests that these brain regions keep track of direction relative to the north–south of a participant’s surroundings, almost like the brain’s very own compass.
“Crucially, this directional signal is stable across versions of the city with different visual features, locations within the city, and phases of the behavioural task,” write the authors. “Thus, exhibiting key characteristics of a ‘neural compass.’”
The researchers hope the success of their method will encourage future studies to more widely examine the brain regions involved in spatial direction and virtual navigation.
“We’re also interested in understanding how people navigate using both visual and internal cues,” says Epstein. “This would relate to the challenges faced by people with impaired vision.”
The results from this study have been published in the Journal of Neuroscience.