Have you ever had trouble sleeping in a new place?
你在新环境中有过入睡困难的问题吗？
Lots of people do.
大多数人都会遇到这个问题。
And now researchers from Brown University in Rhode Island think they know why.
当前，来自美国罗德岛州布朗大学的研究者可能知道了答案。
They found that one-half of the brain "remains more awake" than the other half when people are trying to sleep in a new place.
研究者们发现，人们试图在新的环境下入睡时，大脑的一半会比另一半更清醒。
This appears to be a case of the brain keeping people ready for trouble in a new place, the researchers said.
研究者称，在新的环境下，大脑会让人们随时处在备战意外和麻烦的状态下。

The sleep findings were reported in Current Biology and by Brown University.
《当代生物学》杂志和布朗大学均报道了此次睡眠研究发现。
In their report, the researchers said many people report they have a harder time sleeping the first night at a hotel or other places outside their home.
研究者在报告中说，许多人反映他们在酒店和别的地方睡觉时，第一晚会出现入睡困难的情况。
They call it, "first-night effect."
他们将其称之为"首夜效应"。
"In Japan they say, 'if you change your pillow, you can't sleep,'" said Yuka Sasaki, one of the report's authors."You don't sleep very well in a new place.We all know about it."
本次报道的作者之一尤嘉·佐佐木说道："在日本人们会说，'换了枕头就睡不好觉'"。"新的环境不利于睡眠。这点我们是知道的。"
The researchers measured brain waves for 35 volunteers over two nights in a laboratory. The two nights were a week apart.
研究者在实验室里测量了35名志愿者两个晚上的脑电波。两个晚上的测验中间隔了一周。
They found during the first night the left hemisphere of the brain was more active than the right hemisphere.This was during the first deep-sleep period, the researchers said.
他们发现，第一晚，志愿者左半脑比右半脑更活跃。研究者说这发生在第一次深度睡眠期间。
Sasaki said a lot of questions remain.
佐佐木称，这次调查还存在着许多疑问。
Researchers did not keep measuring brain waves all night long.So, they don't know if the left hemisphere keeps "watch" all night.Or whether it "works in shifts" with the right hemisphere later in the night.
研究者没有测量志愿者整夜的脑电波。因此，他们不清楚左半脑是否整夜都保持清醒。又或者说，左右半脑轮换工作，右半脑在后半夜比较清醒。
They also do not know why the extra brain activity, at least during the first phase of deep sleep, is always on the left hemisphere.
他们也不清楚为什么大脑额外的活动，至少是在第一次深度睡眠期，总是位于左半脑。
For some, this research may be calming. It is good to know that our brain is "looking out for us," in a new place.
这次研究可能会对一些人起到安慰作用。因为他们知道了大脑在新的环境下会"看护他们"。
But it may not help with sleep. That extra brain activity, at least according to this new research, makes it harder to get the sleep people need to wake up well rested in the morning.
但知道了原因可能并不会对睡眠有帮助。依据本次新的研究，大脑额外的活动会让人们难以得到所需的睡眠，这样他们清晨醒来就不会精力充沛。

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