May 23, 2013
About 40 years ago, researchers first began to suspect that we have neurons in our brains called “place cells.” They’re responsible for helping us (rats and humans alike) find our way in the world, navigating the environment with some internal sense of where we are, how far we’ve come, and how to find our way back home. All of this sounds like the work of maps. But our brains do impressively sophisticated mapping work, too, and in ways we never actively notice.
Every time you walk out your front door and past the mailbox, for instance, a neuron in your hippocampus fires as you move through that exact location – next to the mailbox – with a real-world precision down to as little as 30 centimeters. When you come home from work and pass the same spot at night, the neuron fires again, just as it will the next morning. “Each neuron cares for one place,” says Mayank Mehta, a neurophysicist at UCLA. “And it doesn’t care for any other place in the world.”
This is why these neurons are called “place cells.” And, in constantly shuffling patterns, they generate our cognitive maps of the world. Exactly how they do this, though, has remained a bit of an enigma. The latest research from Mehta and his colleagues, published this month in the online edition of the journal Science, provides more clues. It now appears as if all of the sensory cues around us – the smell of a pizzeria, the feel of a sidewalk, the sound of a passing bus – are much more integral to how our brains map our movement through space than scientists previously believed.
And the more scientists learn about how our brains construct cognitive maps of space, the more we may learn about how to design those spaces – streets, neighborhoods, cities – in the first place. Or, rather, we may learn more about the consequences of how we’ve built them so far. How could any urban planner, for starters, not love the idea that “place” is embedded in the brain?