Newly generated neurons are specially selected during the formation and recall of new memories, according to a study in the March 2007 issue of Nature Neuroscience. These results suggest that these neurons make a special contribution to memory processing.
Paul Frankland and colleagues labeled newborn neurons in the mouse hippocampus -- an area of the brain important for memory -- and studied the expression of proteins that are activated upon the formation of new synapses. They found that by the time the new cells were four weeks old, they were much more likely than old cells to be activated when the mice performed a spatial learning task. These newborn cells were also preferentially reactivated when the animals were tested to see if they remembered previously learned spatial locations, suggesting that the neurons had been successfully incorporated into memory-related neural circuits.
Neurons were preferentially activated during learning for only a limited window of time after their birth however. By eight weeks, the young cells were no more likely to be recruited than older cells. The authors suggest that new neurons may therefore be born in the adult brain because they are important for learning.
Paul Frankland (Hospital for Sick Children, Toronto, Ontario, Canada)
Abstract available online.
(C) Nature Neuroscience press release.
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