Medicine Nobel: How the brain makes sense of place

The 2014 Nobel Prize in Physiology or Medicine has been awarded to three neuroscientists, John O’Keefe, May-Britt Moser and Edvard I. Moser, for their discoveries of brain cells that allow us to make sense of place and location and navigate our environment.

In 1971, O’Keefe, then working at University College London, identified “place cells” in an area of the brain called the hippocampus. In rats, specific place cells activated when a rat was in a specific location, making up a map of the room inside the rat’s brain.

More than 30 years later, the Mosers discovered “grid cells,” that allow our brains to create coordinates and navigate between points.

Arne Ekstrom, associate professor at the UC Davis Center for Neuroscience, is building on the work of O’Keefe and the Mosers to understand how the brain can navigate a real or virtual environment.

“It is incredibly exciting that the Nobel committee has chosen to recognize and honor the seminal work of John O’Keefe and Edvard and May-Brit Moser,” Ekstrom said in an email.  “Their work has completely changed our perspective on the interface between brain and behavior, providing a critical and previously non-existent link between the activity of individual neurons and higher order cognition.”

Their work demonstrates that changes in the activity of neurons in the hippocampus and entorhinal cortex underlie the ability to spatially navigate and remember information regarding where we are, Ekstrom said.  Dr. O’Keefe’s groundbreaking work in the 70s  ushered in decades of high-impact work elucidating how these cells change their firing pattern due to changes in spatial geometry, vestibular cues, and visual cues.  In this way, place cells provide not just a code for navigation but for memory more generally. His work has also influenced our understanding of the human brain, where the existence of place cells have been confirmed in rare neurosurgical patients who explore virtual reality while undergoing brain recordings, by suggesting that place cells may be one of many different cellular mechanisms for coding the details of memories.

The Mosers’ work has similarly been highly influential in our understanding of navigation by suggesting that neurons in the entorhinal cortex code for spatial environments by firing in a regular, grid-like fashion as a rat explores a spatial environment.  These cells differ, though, in several important ways from the place cells described by O’Keefe, in that they are less sensitive to changes in spatial geometry and provide a more detailed “metric” of space than place cells do.  Recent work has also confirmed the existence of grid-cells in human neurosurgical patients; their integration into a larger memory system in humans is just beginning to be explored, including by work here at UC-Davis.

More information:

— Arne Ekstrom’s Human Spatial Cognition Lab

New York Times profile of the winners

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