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  3. Researchers led by New York University neuroscientist Joseph LeDoux recently claimed to be the first scientists to erase a singl

Researchers led by New York University neuroscientist Joseph LeDoux recently claimed to be the first scientists to erase a singl

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问题     Researchers led by New York University neuroscientist Joseph LeDoux recently claimed to be the first scientists to erase a single memory. Working with rats, LeDoux’s team first【B1】______the animals to fear both a beep and a siren【B2】______giving them an electric shock every time either of the tones sounded. Then LeDoux gave half the rats the drug U0126, which is known to【B3】______with memory storage, and replayed the beep【B4】______electric shocks.
    A day later, when LeDoux【B5】______back both tones to the rats, the animals that hadn’t been given the drug were still fearful of both sounds.【B6】______the rats that had been given the memory-blocking drug weren’t【B7】______of the beep, which they had last heard while【B8】______the influence of U0126.
    【B9】______how U0126 exerts its amnesiac effect is【B10】______, but it may block the synthesis of proteins that help strengthen【B11】______between neurons and establish memories. The opportunity for erasure【B12】______during the act of retrieving a memory, because that’s【B13】______the memory is being updated and【B14】______again for long-term storage. " Only those memories that are activated are【B15】______," LeDoux says.
    Drugs like U0126 may someday【B16】______sufferers of traumatic memories. A small group of human studies have been done on a drug called propranolol, which blocks the action of stress neurotransmitters that help【B17】______memories in the brain, but LeDoux’s work shows the【B18】______for greater precision. " You might be able to【B19】______the traumatic impact of memories in people," says LeDoux. " The good news is you wouldn’t be【B20】______off their memory bank. "
【B14】
选项 A、enhanced
B、preserved
C、stabilized
D、declined
答案C
解析 动词辨析题。我们可根据前文对实验过程的描述，了解记忆的发展过程。老鼠首先通过在昕声音时遭受电击而记住了对两种声音的恐惧感，从而建立了某种记忆。再次听见任何一种声音之前，这种记忆相对稳定地存在。直到再次听到声音时，记忆被激活，并且其中实验组的老鼠记忆被改变，而一旦刺激过去，这种记忆又稳定下来。可见记忆经历了稳定，激活更新，再次稳定的过程，由此可知[C]stabilized“稳定”符合前文描述，为本题答案。根据后文的for long—term storage“成为长期记忆”，易排除[D]declined“衰退”。前文没有提到记忆的“提升，强化”，故谈不到again“再次”提升，可见[A]enhanced“提高”不合题意，故排除。由于文中涉及的记忆一直存在，只是得到激活和更新，不应表述为再次保存，因此[B]preserved“保存”也应排除。
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