You’re strolling along the overcrowded sidewalks of New York City. How do you avoid accidentally bumping into someone along the way?

You’re in the parking lot of Walmart. How do you find the space for your car to park in?

Well, it all comes down to your brain’s adeptness in navigating places and its ability to keep track of where someone or something is in a shared environment. 

A study at UCLA revealed that our brain generates a universal code to mark ourselves first, then other people with respect to our position. 

To find out how the brain pulls off such a feat, the team observed epilepsy patients who have had electrodes implanted on their brains. The electrodes in question placed in the medial temporal lobe of the brain of the patients control their seizures.

The medial temporal lobe is thought to regulate navigation. Experiments on rodents discovered that the neurons in medial temporal lobe, known as grid cells and place cells, serve as a navigational guidance system, much like a GPS device. Moreover, low-frequency neural oscillations generated by these cells, known as theta rhythms, help rodents know where they are as they move from one place to another.

For the study, the team made use of a special backpack, which was invented as a part of the National Institutes of Health’s BRAIN Initiative project. At the core, the backpack houses a computer system that can wirelessly communicate with the brain electrodes. 

So, wearing this backpack, each patient was instructed to walk around an empty room, ferret out a hidden spot and mark it for future searches. 

The backpack enabled researchers to catalog the patients’  brain waves, eye movement and paths through the room in real time.

In the subsequent step, the team asked a group of participants to search the room where the epilepsy patients were. 

As they continued with their assignments, they recorded the participants brain activity and found that their brain waves flowed in a unique pattern, indicating that each of the participant’s brain had identified the walls as well as recognized other boundaries.

Our brains generate a universal code to locate where we and other people are in a shared environment.
Picture shows an epilepsy patient (in the corner) and a participant walking by. Credit: Suthana lab, UCLA.

Interestingly enough, the brains of epilepsy patients exhibited similar flows while they sat in the room and saw someone else drew closer to the location of the hidden spot, suggesting that our brains generate these same waves to track how other people move.

The study also found that the magnitude of attention we pay at something determines the level of efficiency our brains map out our environment. This was observed in the patients’ brain waves when the participants explored and hunted for the hidden spot in the room.

In the future, the team hopes to scale up their experiments by exploring how the brain reacts in more complex social situations. 

The study has been published in the journal Nature, and it’s titled “Boundary-anchored neural mechanisms of location-encoding for self and others.”