This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
The discoveries that the brain has defined systems that track an animal's whereabouts as it makes its way about the world were honored on Oct. 6 with the 2014 Nobel Prize in Physiology and Medicine going to three researchers.
John O’Keefe of University College London discovered in 1971 the aptly named “place cells”—a term that is more descriptive than the overused “brain GPS.” The place cells in a region of the crucial memory-forming hub, the hippocampus, switched on when a rat was at one location but not another.
Decades afterward, in 2005, the radiant Norwegian husband-and-wife team May-Britt and Edvard Moser of Norwegian University of Science and Technology in Trondheim—two former postdocs of O'Keefe—extended the original work by reporting the existence of “grid cells” in the nearby entorhinal cortex. Grid cells provide a set of coordinates that enable a rat to navigate through its environment in conjunction with other cells that recognize the positioning of the head and the borders of a room. The grid and place cells work in tandem to constitute an internal navigation system.
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The ultimate app, better than Waze or any other download, these place and grid cell systems probably give you that immediate sense of recognition of, yes, this is where I am. "That's my home, there's my office, there's the entrance to the metro." The "probably" in the penultimate sentence is because some of these things still need to go beyond rodent studies to be confirmed in humans, though evidence for place and grid cells has turned up in the human brain. A telling sign as well of their existence comes from news reports that appear daily on Alzheimer's patients wandering off into the night, a consequence of the dying of neurons in the entorhinal cortex and the hippocampus.
While you're learning about a piece of your neural anatomy that you may not have known you had, try reading "The Matrix in Your Head," a great account of this research by James Knierim, a professor of neurobiology at the University of Texas Medical School, that appeared in Scientific American Mind in 2007. In that article, Knierim wrote presciently: "This discovery is one of the most remarkable findings in the history of single-unit recordings of brain activity.
"Reading the paper announcing this discovery in my office for the first time, I realized immediately that I was reading a work of historic importance in neuroscience. No one had ever reported a neural response property that was so geometrically regular, so crystalline, so perfect. How could this even be possible? Yet the data were convincing. “This changes everything,” I muttered.
For the latest on the Mosers, read this story by Alison Abbot at Nature News—"Neuroscience: Brains of Norway"—that fortuitously was ready for publication when the announcement was made.
Image Source: Wikimedia Commons
