小编摘要：Do you have any unpleasant or terrible memories ? What do you want do with these memories ,to forget them ? If it is possible to erase these memories ,would you like to have a try ?
Yaël: Have any unpleasant memories, Don?
Don: Sure. Who doesn't?
Y: What would you say to having thempermanently erased from your brain?
D: Without losing other memories?
Y: Right. Scientists did just that withrats. They trained rats to fear two different sounds by sending a mild electricshock through the rats' paws when they played the sounds. This Pavloviantechnique resulted in the rats freezing up in nervous anticipation of the shocks every time theyheard either sound. Scientists wanted to know whether they could erase one ofthe memories without erasing the other one, even though both sounds result inthe same fear.
D: I didn't know scientists knew how toerase memories at all.
Y: They do. You see, long-term memoriesaren't nearly as solid as we like to think. They're actually very fragile.Every time we recall a long-term memory, it becomes malleable. Just beforeplaying one of the sounds, scientists injected half the rats with a chemicalthat interferes with memory reconsolidation. Thus, when they were in theprocess of remembering what accompanies the sound, the drug went to work.
D: Then what?
Y: When they played both sounds a day later,the rats that had been injected with the chemical did not freeze up when theyheard the sound that had accompanied the drug. They froze as usual when theyheard the second sound.
D: They had forgotten to be afraid. Hmm.This business makes me kind of nervous.
Y: I know what you mean, but for people withpost-traumatic stress disorder, selective memory erasure could prove enormouslyuseful.
D: True. I guess some fears are best laid torest.