He said that sleep was not a passive response to lack of stimulation but an active process, rather like an instinct.

他说睡眠并非由于缺乏刺激而做出的消极反应而更像是一种本能的积极反应。

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Other memory busters include depression, anxiety and a simple lack of stimulation all of which keep us from paying full attention to our surroundings.

其他导致记忆力损坏的因素包括沮丧、焦虑和缺乏刺激。这些都使我们不能全神贯注于我们的环境。

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Deep brain stimulation has shown promise in treatments of Parkinson's disease, epilepsy and depression, but it has a number of side effects, stemming in part from its lack of specificity.

强烈的脑部刺激用在帕金森、癫痫以及抑郁症上具有很好的治疗效果，但它有一些负面影响，部分是由于它缺乏识别细胞的特异性。

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It is not so simple to take a long dead species, make enough of them so they don't die of isolation and lack of social stimulation and then find an environment that is close enough and safe enough compared with that which they once roamed.

CNN: Don't clone a Neanderthal baby