MIT researchers identify brain region that saves us from being lost in space

CAMBRIDGE, Mass. -- Researchers at the Massachusetts Institute of Technology have found that a sugar cube-sized piece of the brain helps prevent us from being lost in space.

In a study to be published in Thursday's (April 9) issue of Nature, Russell Epstein and Nancy Kanwisher of MIT's Department of Brain and Cognitive Sciences found that a part of the brain called the parahippocampal cortex is involved in perceiving the local environment. The parahippocampal cortex gets very active when people look at photographs of indoor or outdoor scenes, but not when they look at photos of faces or objects.


"When you walk into a room, you don't spend five minutes trying to get your bearings," said Epstein, a postdoctoral fellow. "These processes happen very quickly and automatically, much like the response we see in the parahippocampal cortex when people view scenes."



The parahippocampal cortex feeds information to the hippocampus, which is in charge of establishing memories and is involved in encoding spatial memory in rats. "Our results could have consequences for how spatial memory is set up," said Epstein, who has a PhD in computer vision, the study of how to create machines that "see."

The area of the brain that the researchers named the parahipppocampal place area (PPA) reacts consistently to complex scenes such as open fields, city streets, store interiors or empty rooms. The only thing the images have in common is that they are all places in which people could imagine walking around.

When subjects were shown pictures of places such as a Somerville, Mass., street lined with cars and triple-deckers, empty rooms and rooms filled with furniture, the PPA "lit up." The brain's reaction was just as strong to an empty room as a room full of furniture, while pictures of faces, furniture alone or distorted scenes that no longer represented a coherent space elicited a negligible or weak response.




It makes sense that humans have an innate ability to "know where we are in the world," Epstein said. "Babies and rats use information about the shape of their environment to orient themselves, and we think the PPA might be the part of the adult human brain that extracts this information.

"To me, this is a fascinating subject," said Epstein, who pointed out that it's extremely difficult to get a computer to "see" with any semblance of the ease and accuracy with which humans take in and process visual information. "It's really incredible that we have this ability to look at our surroundings and almost immediately know where we are."

This research is sponsored by NIMH and the Human Frontiers Foundation.

Topics: Neuroscience, Biology


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