When you navigate a space, it turns out that the human brain forms brain waves of similar spatial awareness. Scientists discovered this after they devised a method of scanning our brains during free movement, as opposed to sitting quietly in a scanner.
“Our results imply that our brain creates a universal signature to put us in someone else’s shoes,” said neurosurgeon Nanthia Suthana of the University of California, Los Angeles.
Previous studies in rats have shown that low-frequency brain waves help rodents keep track of their position when exploring a new place – by defining the boundaries of a place. Similar waves that define boundaries have also been identified in humans, but only when they navigated in a virtual environment while remaining motionless for brain scanning.
“We wanted to investigate this idea in people – and test whether they could monitor others around them – but they were hampered by existing technology,” said UCLA neurologist Matthias Stangl.
So Stangl and colleagues created a mobile brain scanner, consisting of a backpack with a computer that connects wirelessly to electrodes implanted in the brain (a system called intracranial electroencephalography) to help them study how our brains form and remember spatial memories.
Wireless recording device. (Suthana Laboratory / UCLA)
Their subjects were five patients with epilepsy who had already had electrodes implanted in their brains to control their seizures. These implants are located in the medial-temporal lobe – our bits of the brain are thought to encode long-term intentional memories and spatial cognition.
Participants participated in a 15-minute navigation task in which they were asked to find and find the locations of hidden targets in a room. This was followed by a 15-minute observation task in which their participants had to keep track of someone else navigating the room and press a button when the other person crossed the unmarked target locations.
The researchers saw that as participants approached a physical boundary – such as a room wall – the flow of low-frequency oscillations in their brains increased in strength. The same thing happened when they looked at someone else approaching the walls.
“We found that the oscillating changes related to borders were strikingly similar between tasks that required self-navigation compared to observing another person,” they wrote in their paper.
Recent studies in rats and bats have also found the same group of hippocampal neurons coding for both the animal’s own location and the location of others in their species.
The power of these representations of the brain waves of a space, seen below, also increased when participants were focused on finding their target location. The oscillation signals were not continuous and did not change the amount in which they occurred, but only their strength.
(Suthana Laboratory / UCLA)
Above: Visualized map of brain wave strength of camera boundaries in red representing higher amounts of power in brain wave 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, when people were focused on a goal and looking for something.”
The measured electrical activity ranged in a frequency range called theta waves. We generally produce these slow but pronounced waves while sailing, so it is not surprising to have them evident in such a task.
Interestingly, slightly more buzzy gamma waves have also appeared in similar models, with a slightly greater 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 several groups of neurons, which may include cells that specifically encode boundaries, objects, and other boundaries and objects of purpose. A better understanding of this neural language can help us to resolve brain disorders.
And, in an interesting development, they made the design of the backpack available to other researchers. Soon, we can expect to learn more about our brainwave patterns in complex social situations.
Their research was published in The nature.