Right at the bench; left at the table and chairs; straight through the sliding doors.
It may sound like a simple set of directions, but there’s no shortage of benches at the University of California, Los Angeles, the setting for one of the most high-tech yet naturalistic studies of human learning and memory to date. Study participants have to learn to navigate a real-world maze across the sprawling campus. They then don wearable devices that track their movements while electrodes implanted deep in their brains capture electrical changes as they log and retrieve memories along the way.
“We don’t make all our memories sitting in front of a computer in a lab,” says study investigator Cory Inman, assistant professor of psychology at the University of Utah in Salt Lake City. Inman became involved in the memory-maze experiment as a postdoctoral researcher in Nanthia Suthana’s lab at the University of California, Los Angeles because, he says, he was eager to move studies of human learning and memory out of the lab and into the wild.
“The memories we make — the ones that really matter to us, that help shape who we are and our identities — those memories are made at the real scales of life: going to the park; going to the aquarium; going skiing with your family or friends,” Inman adds.
Inman and Suthana are part of a small but mighty league of crafty young researchers collaborating with people with epilepsy to unlock the mysteries of memory. About 2,500 people with epilepsy in the United States have devices implanted in their brains that record the electrical signals associated with their seizures and generate signals to disrupt those seizures. As a bonus, the implants are helping researchers answer questions that have been difficult to pursue in the lab: How do our brains discern relevant people and places from irrelevant ones? What is the brain signature of remembering or recognizing something important? And can we improve the brain’s capacity to form, store and recall memories?
Suthana, associate professor of psychiatry, neurosurgery, bioengineering and psychology — and, by all accounts, the crew’s creative captain — was a postdoc studying the role of the hippocampus in learning and memory when an implantable device made by NeuroPace was approved to monitor and treat epilepsy in 2013. “I knew that a lot of these patients had devices put in the hippocampus,” Suthana says. “I thought, ‘This is going to change everything. We can have those people carry out their tasks of daily living and record from this brain area.’ We’ve never been able to do that before.”
In the 1970s, live brain-recording studies in freely moving rats revealed “place cells” in the hippocampus and “grid cells” in the nearby entorhinal cortex — neurons that encode where the animals are in space and help them get where they want to go, like a GPS system and a compass. The work earned John O’Keefe, May-Britt Moser and Edvard Moser the Nobel Prize in Physiology or Medicine in 2014.
But many studies of human memory and navigation had to rely instead on virtual tasks, wherein participants navigate a computer maze or imagine moving through the real world, either from the belly of an MRI scanner or tethered by scalp electrodes to other large machines. “In rodents, the way your brain represents all these aspects of navigation is different when you’re sitting or lying somewhere and doing a virtual task,” says Nick Turk-Browne, professor of psychology and director of the Wu Tsai Institute at Yale University, who is an East Coast member of the “memory-in-the-wild league.” It stood to reason, he says, that human brains might treat these tasks differently, too.