Nancy Kanwisher and Russell Epstein, a postdoctoral fellow in her lab, were on a fishing expedition.
Thanks in part to Kanwisher’s earlier work, they knew there’s a blueberry-sized segment of the brain that’s specifically activated when we see a face. The question was, do other specialized realms exist?
The researchers were using functional MRI — the remarkable technology for non-invasively taking what are in effect movies of brain activity — to probe the issue. Kanwisher showed an image of a room with furniture to a student subject in the fMRI scanner. The machine’s computer display highlighted a region about the size of the small bit of brain that’s activated when we see a face.
Kanwisher suspected something about the image’s complexity — all that furniture — was activating the region. So, she displayed an image of the same room minus furniture.
“We got the same response to the scene with all the objects removed,” she says. “That little part of the subject’s brain was going like mad!”
The nugget of brain that “lit up” during those first experiments turns out to be activated specifically by places. And its discovery may help lead to an understanding of one of our key mental capabilities.
“When you enter a new place, you recognize almost instantly what you’re looking at,” says Kanwisher, an associate professor of brain and cognitive sciences. “That may seem trivial but it’s not. People in artificial intelligence are having a hell of a time trying to develop computers which can do that.”
The region the researchers discovered — dubbed the parahippocampal place area (PPA) — is activated by models as well as “real” places. “Layouts made out of Lego blocks drive that area strongly,” notes Kanwisher. The region even responds when subjects visualize a location.
“We can shout out the name of a place like Killian Court, and a student’s PPA will light up,” she says.
The scientist doubts there are many other brain regions like those specializing in faces and places. Still, the discoveries are reshaping traditional thinking about brain specialization.
Kanwisher often does her own stints in the fMRI scanner. “There’s nothing like watching a part of your own brain turn on as you’re looking at images of places, and shut off when some other stimulus appears,” she says, “to make a believer out of you.”