This is Scientific American — 60-Second Science. I'm Christopher Intagliata.
Pregnancy brings big physical changes to a woman's body. But what three neuroscientists were more interested in was, what does it do to the woman's brain? "We were in our 30s, and we were thinking I'd like to have a baby, but look at this, look at this." Susana Carmona, a neuroscientist at the University of Carlos the Third in Madrid.
"And then we realized most of this data came from animal studies. And that there were no solid studies about what really happens to your brain when you get pregnant. And that's how we convinced the boss we should do that even without any funding at this point."
Carmona and her team took MRI scans of 25 women's brains, before and after their first child. They found that parts of the brain dealing with social cognition actually shrunk—reduced in volume—in women who successfully conceived and had kids. That's compared to no changes among control women, and no changes in men—whether they were new fathers or not.
Shrinking sounds bad though: why would you want less grey matter? But Carmona says less does not result in deficits in thinking or memory, and might actually be the result of a good thing: the fine-tuning of connections between neurons. "When you have a lot of routes that arrive to a different place, and there's one that is the shorter and the faster one, the optimal thing would be to close the rest so you never get lost, from point A to point B."
Hormonal fluxes cause similar fine-tuning in the adolescent brain—and hormones might be the culprit for these changes as well. Changes that can last at least two years after pregnancy. The study is in the journal Nature Neuroscience.
The effect of all this? Could be a boost in maternal attachment. Fewer hostile feelings towards the baby, and more pleasure playing together. As for Carmona and her two colleagues? They decided not to wait til the study was complete to start their families. "We decided that whatever happens to your brain, we wanted to be mothers."
Thanks for listening for Scientific American — 60-Second Science Science. I'm Christopher Intagliata.
怀孕会使女性的身体发生巨大的生理变化 。但让三位神经学家更感兴趣的是，怀孕会对女性的大脑产生什么影响？“我们在三十多岁时，都想有一个孩子，但是看看这个，看看这个 。”苏珊娜·卡莫纳是马德里马德里卡洛斯三世大学的神经学家 。
“然后我们意识到这些数据大部分来自动物研究 。而对于怀孕后大脑所发生的变化并没有可信的研究 。所以我们说服了负责人，即使目前没有任何资金我们也应该做这项研究 。”
卡莫纳和她的团队对25位女性的大脑进行了核磁共振扫描，分别在她们孕前和生完第一胎后进行扫描 。他们发现，大脑处理社会认知的部分的确缩小了，对于那些已经成功怀孕并且已经生下宝宝的女性来说，大脑这一部分的体积缩小了 。而对于未孕女性而言，没有任何变化，对于男性而言，无论他们是否刚刚晋升为父亲，这部分也没有任何变化 。
虽然脑部萎缩听起来很糟糕，不过为什么你希望灰质减少？卡莫纳表示，灰质减少不会引起思维迟钝或者记忆力减退，这可能是好事所带来的结果：神经元细胞连接的微调 。“当你有很多路线到达不同的地方时，有一条路线更短更快，最优方案是关闭其余的干扰路线，这样你从A点到B点就永远不会迷路了 。”
荷尔蒙波动会导致青少年的大脑发生类似的微调，荷尔蒙可能也是孕妇大脑发生变化的罪魁祸首 。一些变化会在怀孕之后持续至少两年之久 。这项研究发表在《自然神经科学》期刊上 。
这会产生的影响？可能会增加母体依恋 。对宝宝的敌意减少，同时与宝宝在一起的乐趣会增多 。那对于卡莫纳和她的两个同事呢？她们决定不等到研究完成后再开始家庭 。“我们已经决定，无论怀孕让大脑发生什么，我们都想成为母亲 。”
谢谢大家收听科学美国人——60秒科学 。我是克里斯托弗·因塔利亚塔 。
1. be interested in 感兴趣的；有兴趣的；关心的；
例句：He is more interested in the turf than in working.
2. happen to （尤指不愉快的事）发生（在…身上）；(某人)遭到；遇到；
例句：She fell to brooding about what had happened to her.
3. deal with 处理；应付；与…打交道；
例句：In dealing with the problem he was cautious to an extreme.
4. result in 导致；引起；造成；
例句：A gas leak can result in a fire.