( protein. But in the zebra finch brains...)One gene links newborn neurons with those that die in diseases such as Alzheimer's

In addition, studies from other laboratories have pointed to deficiencies in UCHL1 in degenerative diseases such as Alzheimer's and Parkinson's.

Experiments in mice confirmed the finding that low levels of UCHL1 correlate to the ability of neurons to be replaced. The researchers used similar techniques to assess UCHL1 in hippocampus and olfactory bulb neurons in mouse brains, areas where neurons are known to undergo spontaneous replacement. They found markedly low levels of UCHL1 in the replaceable neurons of both these regions.

"Low levels of UCHL1 appear to be a feature of replaceable neurons wherever they occur," says Lombardino.

The scientists also knew that, in songbirds, most neurons born during adulthood die, but a bird's active singing increases the survival rate of new neurons. They reasoned that, if UCHL1 levels are related to the death or survival of neurons, these levels should increase when birds are singing and when more new neurons thus have a chance of surviving. In another experiment the scientists allowed male finches to sing to a female before analyzing the birds' brain neurons. As predicted, the expression of UCHL1 in replaceable neurons, but not in nonreplaceable ones, increased in birds that were singing.

"These findings suggest that rising levels of UCHL1 may be associated with a reduced risk of neuronal death," says Nottebohm. "This study draws attention to the replaceable neurons of adult brain as a wonderful model system in which to study changes in genomic expression related to learning, aging and neurodegeneration, in addition to those that are related to the choreography of replacement itself."

"In addition, because we study birds that learn their songs, the story relates to a fascinating, learned behavior, so it offers the opportunity
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Source:Rockefeller University