Monday, November 25, 2013

For Locusts, The Company You Keep Shapes What You Learn

A team of scientists has shown how the environment shapes learning and memory by training locusts like Pavlov's dog to associate different smells with reward or punishment..."When we presented solitary locusts with an unfamiliar odour together with toxic food, they assigned it an aversive ('bad') value. But if the locust is in a crowd and starting to change towards gregarious, it assigns an appetitive ('good') value to the same odour. Ecologically, this makes sense because, being a gregarious locust, it should find and eat toxic plants to defend itself against predators. "Then we asked, if a solitary locust has already learned about an odour and then it finds itself in a crowd, what would happen to its memories? Can it switch the value that it has assigned to the odour, or more precisely, does crowding change the value of a previous memory from aversive to appetitive? We found that locusts cannot do this: they are stuck with the value of their already acquired memories. However, strikingly we found that locusts in this transitional period also cannot form any new aversive memories, while they can still form new appetitive memories. more

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