The Economist, November 2006

Learning protects newly formed brain cells in adult mammals

KEEPING mentally agile protects against dementia but until now no one has known exactly why. One possible reason was revealed at this week's annual Society for Neuroscience conference in Atlanta —at least, for rats.

Thousands of new brain cells or neurons grow each day in the brains of rats and, presumably, in the brains of people, too. But only those animals that actively engage in learning get to keep the new cells. In their mentally lazy companions new cells die after a couple of weeks.

Until relatively recently, scientists thought that no new neurons grew in the brains of adults and that every blow on the head or glass of wine after adolescence cut the number of brain cells.

Over the past decade, though, neuroscientists have realised that young neurons do continue to appear in the brains of mature mammals—but what they might do is only now being pieced together.

Many of these new brain cells are found in the hippocampus, a structure used to remember events, people and places. This suggested to Tracey Shors, of Rutgers University in New Jersey , that the cells might be involved in forming such memories.

 

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