Cold Spring Harbor, NYScientists at Cold Spring Harbor Laboratory have used a genetic strategy in fruit flies to switch electrical activity in the insect brain on and off at will. In doing so, they have made the surprising discovery that switching off electrical activity in the brain blocks memory recall, but not initial formation of memory.
"The brain of the fly works very much like the brain of other animals, including humans. Flies are capable of learning just like Pavlov's dogs," says Dr. Tim Tully, one of the authors of the study, which appears in this week's issue of Nature. [May 24].
After ringing the dinner bell and presenting his dogs with food several times over a few days, the Russian physiologist Ivan Pavlov found that eventually, his dogs would display dinnertime behavior (drooling, excitement) on just the sound of the bell.
Today, all dog and cat owners are familiar with this form of "associative learning." They see it in action each time the sound of the can opener sends their furry friends running to the kitchen in anticipation of their supper.
What pet owners are actually seeing, however, is the retrieval of the "can opener:food" memory that has already been acquired and stored in the animal's brain. Now, the Cold Spring Harbor Laboratory researchers have found that memories based on associative learning can be formed in the absence of electrical activity in the fruit fly brain, but cannot be recalled.
Memory has three components: acquisition (learning), storage, and retrieval (recall). By training flies to avoid an odorand by switching off electrical activity in the brain at different times during or after trainingthe researchers could test whether electrical activity in the insect brain is necessary for the acquisition, storage, or retrieval phases of memory.
The scientists used a new genetic strategy to answer an age-old question in neurobiology: Is persistent electrical activity necessary for memory formation? "Th
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Contact: Peter W. Sherwood, Ph.D.
sherwood@cshl.org
516-367-6947
Cold Spring Harbor Laboratory
22-May-2001