Songbird Memory: A Little Slow On The Uptake?

June 26, 2009

Talk about your bird brains: A zebra finch's brain changes dramatically after hearing a new song, and even 24 hours later, the bird's still processing the information.

When the finches were exposed to new tunes from a member of its own species, the experience switches on and off thousands of genes, offering researchers a new insight into songbird memory.

The study will be published in this month's Proceedings of the National Academy of Sciences.

Principal investigator David Clayton, a professor of cell and developmental biology at the University of Illinois, said he and his colleagues had not expected to see so many genes involved, and thought that any changes in gene activity after a bird heard a new song would quickly dissipate. Instead, the changes in the bird's brain occurred within 30 minutes of exposure to a new song, downregulating genes that code for ion channel proteins, allowing ions to flow into the cell. Clayton theorizes this is the finch's way of protecting its brain from overstimulus.

"Whenever something unexpected and different comes along, such as the song of a new bird in the neighborhood, it's going to deform the listening bird's neural network," Clayton said. "And so the system has to basically absorb some of that, make some changes and not be overwhelmed by it. If you push the system around too much, cells die."

After the bird song has become familiar 24 hours later, a second set of changes occurs, whether or not the finch hears the song again. The genes that were flipped on return to their original state, and a new network--apparently focusing on energy metabolism--emerges. This suggests a lot is still going on in the brain, Clayton said.

"The most important thing in its whole life is the sound of another bird of its species singing," he said. "And what we found is that 24 hours after the experience its brain is still trying to make sense of what it heard."
(source)

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