2018年经济学人 “一孕傻三年”有科学依据(2)（在线收听）

Pregnancy, then, does indeed do things to a woman’s brain.

那么怀孕确实对母亲的大脑有影响。

But what exactly those things mean is hard to tease out.

但是具体对大脑有什么影响很难弄清。

Neuroscientists do not really understand how the brain works.

神经系统科学家还未弄清大脑是如何工作的。

That makes it difficult to predict how a change in the organ’s structure will alter the way it functions.

这致使科学家很难预测器官结构的变化是如何改变其功能。

Some of the changes took place in the hippocampi.

这些变化也包括海马体的变化。

These are a pair of small, banana-shaped structures buried deep in the brain, one in each hemisphere, that are known to be important for forming memories.

海马体是大脑深处分处两个半球的一对香蕉型的小组织。众所周知海马体在记忆形成方面有非常重要的作用。

Administering a few simple cognitive tests to the new mothers—including tests of memory—revealed no obvious changes in performance.

他们对一些新妈妈进行了一些包括记忆力测试在内的简单认知测试，测试显示她们的感知能力并没有明显的变化。

And the hippocampi had partially regrown within two years.

并且海马体的某些部位在两年内会再生。

But DrHoekzema and her colleagues point out that most of the more permanent reductions in grey matter happened across several parts of the brain that,

但是赫克塞马博士和她的同事们指出，大部分的灰质永久性减少是发生在大脑的一些区域，

in other experiments, have been found to be associated with the processing of social information, and with reasoning about other people’s states of mind.

在其他的实验中，她们发现大脑中的这些区域与处理社会信息以及推测其他人的心理状态密切相关。

That would make sense from an evolutionary point of view.

从进化的角度来看，这是有道理的。

Human babies are helpless, and, in order to care for one, a mother must be good at inferring what it needs.

人类的婴儿是弱小的，为了照顾他们，母亲必须善于判断他们的需要。

The rewiring may also affect how well women bond with their infants.

神经的重塑也可能影响母亲与新生儿的联系。

After the women in DrHoekzema’s study had given birth, the research team administered a standard psychological test designed to measure how attached those women had become to their babies.

参与DrHoekzema研究的女性分娩后，研究团队进行了一项标准心理测试，旨在测量这些女性对其婴儿的依恋程度。

The ones with the greatest reductions in grey-matter volume were, on the whole, the most strongly bonded.

总体上，脑灰质体积减少最大的对婴儿的依恋程度最强。

Ascribing all this to a reduction in grey-matter volume, rather than an increase, sounds counter-intuitive.

将所有这一切归因于脑灰质体积的减少而不是增加听起来好像不对。

But DrHoekzema reckons it is probably evidence of a process called synaptic pruning, in which little-used connections between neurons are allowed to wither away, while the most-used become stronger.

但是DrHoekzema猜想这可能是突触修剪过程的证据。在突触修剪过程中神经元之间很少使用的连接逐渐萎缩，而最常用的连接则变得更强。

That is thought to make neural circuitry more efficient, not less so.

这样可以提高而非降低脑回路的效率。

She points out that the surge of sex hormones people experience during adolescence is thought to cause a great deal of synaptic pruning, moulding a child’s brain into an adult one.

她指出青少年期间性激素的激增会造成大规模的突触修剪从而将儿童的大脑塑造成成人的。

So it is reasonable to assume that the even greater hormonal surge experienced during pregnancy might have a similar effect.

因此推测怀孕期间更强的激素激增可能具有类似的效果是合理的。

When it comes to the brain, after all, bigger is not necessarily better.

毕竟当谈到大脑，更大不一定意味着更好。