The way our brains track other people’s positions is unusually consistent between brains

When you move through space, it turns out that the human brain forms eerily similar brain waves of spatial consciousness. Scientists discovered this after devising a method to scan our brain during free movements, as opposed to lying still in a scanner.

“Our results imply that our brain creates a universal signature to put ourselves in someone’s shoes,” explained neurosurgeon Nanthia Suthana of the University of California, Los Angeles.

Previous studies on rats have revealed low-frequency brain waves that help rodents track their position when exploring a new site – by defining site boundaries. Similar waves that define boundaries have also been identified in humans, but only when moving in a virtual environment, while still remaining for brain scans.

“We wanted to explore this idea in humans – and test whether they could monitor others around them as well – but they were hampered by existing technology,” said neuroscientist Matthias Stangl of UCLA.

So Stangl and colleagues created a mobile brain scanner, made up of a backpack with a computer that wirelessly connects to electrodes built into the brain (a system called intracranial electroencephalography) to help them study how our brains form and recall spatial memories.

Wireless recording device. (Suthana Laboratory / UCLA)

Their subjects were five patients with epilepsy who already had an electrode implanted in their brains to control seizures. These implants lie in the medial-temporal lobe – parts of our brain that are thought to encode long-term, intentional memories and spatial cognition.

Participants participated in a 15-minute navigation task where they sought to find and learn the locations of hidden targets in the room. This was followed by a 15-minute observation task where their participants had to watch someone else sail in the room and press a button when the other person crossed the unmarked target locations.

The researchers saw that as participants approached the physical boundary — like a room wall — the flow of low-frequency oscillations in their brains increased. The same thing happened when they watched someone else approach the walls.

“We found that oscillatory changes associated with boundaries are strikingly similar between tasks that require self-navigation relative to observing another person,” they wrote in their paper.

Recent research on rats and bats has also found that the same group of hippocampal neurons encodes both the animal and the location of other species.

The power of these brain space wave views, shown below, also increased when participants were focused on finding their target location. The oscillation signals were not continuous and did not change the amount that appeared, but only their strength.

Visualized map of the strength of the brain waves of the boundaries of the room.  (Suthana Laboratory, UCLA)(Suthana Laboratory / UCLA)

Above: Visualized map of brainwave power boundaries of the room with red color representing larger amounts of energy in brainwave signals.

“Our results support the idea that in certain mental states, this pattern of brain waves can help us recognize boundaries,” Stangl said. “In this case, it was when people were focused on the goal and chasing something.”

The measured electrical activity oscillates in a frequency range called theta waves. These light but pronounced waves are mostly generated during navigation, so it is not surprising that they are visible in such a task.

Interestingly, somewhat buzzing gamma waves also appeared in similar patterns, with slightly more variation between different conditions. These are the waves we produce when we use more of our brain to think, drawing experiences into our working memory.

The team believes that the brain waves they observed are generated by multiple groups of neurons that may include cells that encode specifically for boundaries, objects, and other boundaries and target objects. A better understanding of this neural language can help us unravel brain disorders.

And in an exciting development, they made their backpack designs available to other researchers. We can soon expect to learn even more about our brainwave patterns in complex social situations.

Their research was published in Nature.

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