Do songbirds sing of Alzheimer's?

The dulcet notes of songbirds do more than please the ear--they provide one of the best models of how the brain modifies connections between neurons in order to learn.

About 3 weeks after birth, songbirds begin to listen silently to the singing of a tutor, usually their father. After this period, which lasts about 2 weeks, the juvenile birds start to rehearse their song, apparently reinforcing the neural circuits established when they memorized it.

Researchers over the years have pinpointed specific regions of the avian brain crucial to these distinct phases of song learning. Now, investigators studying zebra finches have unearthed a protein, which they named synelfin, that may play a role in the memorization phase.

An area of the brain implicated in song memorization makes synelfin in large quantities until approximately 35 days after birth, report David F. Clayton and his coworkers from the University of Illinois at Urbana-Champaign in the August Neuron. Synelfin production in this area then falls dramatically, virtually disappearing by adulthood, they further report.

Adding to the suspicion that learning involves synelfin, Clayton's group notes two possible links between the protein and Alzheimer's disease, a neurodegenerative disorder that ravages memory. First, synelfin's shape resembles that of apolipoprotein E (apo E); scientists contend that possessing certain forms of apo E dramatically increase a person's chance of getting Alzheimer's. Second, researchers have recently found fragments of the human version of synelfin clumped together with a protein called beta-amyloid in the dense brain plaques that are a hallmark of Alzheimer's disease.

"I think the link [of synelfin] to Alzheimer's is very strong. Certainly, this is a protein that's at the scene of the crime," says Clayton.