(Science has made this 2006 feature looking at the history of place and grid cells freely available)
Research on how the brain knows where it is has bagged the 2014 Nobel Prize in physiology or medicine, the Nobel Committee has announced from Stockholm. One half of the prize goes to John O'Keefe, director of the Sainsbury Wellcome Centre for Neural Circuits and Behaviour at University College London. The other is for a husband-wife couple: May-Britt Moser, who is director of the Centre for Neural Computation in Trondheim, and Edvard Moser, director of the Kavli Institute for Systems Neuroscience in Trondheim.
In the 1970s, O'Keefe discovered the first component of this positioning system, a kind of nerve cell that is active when a rat is in a certain place in a room. Trying to learn more about how individual brain cells could control behavior, he recorded signals from individual nerve cells in a rat’s brain as the animal moved around a room. He noticed that a specific cell in the brain region called the hippocampus would signal each time the rat was in a specific part of the room. Different cells corresponded to different places, and O'Keefe concluded that these “place cells” allowed the rat to construct a mental map of the environment. The hippocampus stores multiple maps, based on the activity of place cell activities.
Place cells “set in motion an entire field” within neuroscience, says Loren Frank, a neuroscientist at the University of California, San Francisco. “Hundreds, if not thousands” of neuroscientists interested in how the brain perceives, remembers, and plans movement through space flocked to study the hippocampus’s role in spatial memory after O’Keefe’s original find, adds Lynn Nadel, a neuroscientist at the University of Arizona in Tucson, who collaborated with O’Keefe on a 1978 book about place cells.
Three decades later, May‐Britt and Edvard Moser were trying to figure out more about how the place cells work, when they discovered another set of cells in a neighboring part of the brain, the entorhinal cortex. Those cells, called “grid cells,” play a role similar to the grid on street maps that can help locate a specific street or point of interest. In a series of three papers in Science and Nature between 2004 and 2006, they laid out how the brain uses the grid cells to help animals find their way, even in the dark. “We’re over the moon about this discovery,” O'Keefe told Science in 2006 in a feature story on the history of place and grid cells.
"The discoveries of John O´Keefe, May‐Britt Moser and Edvard Moser have solved a problem that has occupied philosophers and scientists for centuries—how does the brain create a map of the space surrounding us and how can we navigate our way through a complex environment? How do we experience our environment?" the Nobel Committee says in its statement.
Recently, researchers have begun to manipulate these navigational neurons. A team earlier this year altered the positive and negative associations that mice had formed with specific locations, by triggering hippocampal place cells with lasers while simultaneously stimulating other brain cells. And although grid and place cells remain a focus of fundamental neuroscience research, there are hints of clinical relevance: The hippocampus and entorhinal cortex are among the first brain regions damaged in neurodegenerative diseases such as Alzheimer’s, One of the first symptoms in Alzheimer patients is that they lose their way and become disoriented easily.
Although the Nobel committee’s choice was a surprise to few in the neuroscience community, it still caught the Mosers and O’Keefe off-guard. O’Keefe latter was plugging away on grant proposals at home when he got the call. When May-Britt received the call from the Nobel Committee informing her of the prize this morning, her husband was on an airplane flying to Munich, she told Nobelprize.org in an interview. Upon landing, the news finally made it to him, he said in an interview: "Finally I found out, because there were 150 emails and 75 text messages that had come in the last two hours."