Friday, April 3, 2009

Sleep & Memory: Lessons from Fruit Flies

Two new studies in the journal Science use fruit flies to examine the link between sleep and memory.

study shows that the connections between nerve cells in the brain increase during the day. Then these “synapses” decline during sleep. This reduction of synapses is prevented by sleep deprivation.

This suggests that sleep may “prune” less important connections. This may create space for the brain to store more important memories.

Author Paul Shaw said in
a statement that these results have practical implications.

“These data suggest the best thing you can do to make sure you stay sharp…is to make getting enough sleep a top priority," he said.

study used three-dimensional photos to look at protein levels in the brains of fruit flies. It focused on proteins that carry messages in the synapses between neurons.

These protein levels dropped by 30 percent to 40 percent during sleep. But the same proteins accumulated in the brains of fruit flies that were deprived of sleep by a “fly agitator.”

This suggests that sleep “resets” the brain. It empties the junk mail from the previous day. This prepares the brain for more learning the next day.

"Much of what we learn in a day, we don't really need to remember," author Chiara Cirelli said in
a statement. "If you've used up all the space, you can't learn more before you clean out the junk that is filling up your brain."

But can we really learn about ourselves by studying fruit flies? Why are they useful study subjects? And how do we study them anyway?

A TIME article provides some useful insights. Fruit flies are simple enough to study. But with a genome that has 14,000 genes, they are more complex than you may think.

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