时差N小时 人类大脑为何沟壑密布(下)

Scientists at the University of Rio de Janeiro have been trying to figure out what accounts for the folds.

里约热内卢大学的科学家试图找出沟壑的成因。

One idea postulated¹ that as brains evolve and the more neurons they have, the more folds are required to allow neurons to form connections.

其中一项理论推断随着大脑不断进化，大脑的神经元越来越多，那么神经元相连需要的沟壑也越来越多。

But elephants have nearly twice as many folds in their brains yet have fewer neurons than we do, so that theory seems improbable.

不过，大象的大脑沟壑几乎是人类的两倍多，但神经元却比人类大脑少，因此这项理论难以成立。

The researchers have, however, determined² that how human brains fold follows the same physical principles guiding folds and creases³ resulting from crumpling⁴ a sheet of paper.

然而，研究学家从揉成团的纸中推论出，人脑形成沟壑与纸张折叠和起皱遵循同样的物理规律。

That’s interesting because it enabled the scientists to reason that the two main factors determining a brain’s shape are the surface area and thickness of the outer layer cortex.

有趣的是，科学家推论出，大脑的形状主要是由大脑皮层的表面积和厚度2个因素决定的。

The larger the cortex surface area, the more folds a brain will have. But greater thickness results in fewer folds.

大脑皮层的表面积越大，沟壑就越多。而厚度越大，沟壑就越少。

Same goes for a piece of paper.

纸张也遵循同样的原理。

1 postulated   

v.假定，假设( postulate的过去式和过去分词 )

参考例句：

• They postulated a 500-year lifespan for a plastic container. 他们假定塑料容器的寿命为500年。
• Freud postulated that we all have a death instinct as well as a life instinct. 弗洛伊德曾假定我们所有人都有生存本能和死亡本能。 来自辞典例句

2 determined   

adj.坚定的；有决心的

参考例句：

• I have determined on going to Tibet after graduation.我已决定毕业后去西藏。
• He determined to view the rooms behind the office.他决定查看一下办公室后面的房间。

3 creases   

（使…）起折痕，弄皱( crease的第三人称单数 )； （皮肤）皱起，使起皱纹

参考例句：

• She smoothed the creases out of her skirt. 她把裙子上的皱褶弄平。
• She ironed out all the creases in the shirt. 她熨平了衬衣上的所有皱褶。

4 crumpling   

压皱，弄皱( crumple的现在分词 )； 变皱

参考例句：

• His crumpling body bent low from years of carrying heavy loads. 由于经年累月的负重，他那皱巴巴的身子被压得弯弯的。
• This apparently took the starch out of the fast-crumpling opposition. 这显然使正在迅速崩溃的反对党泄了气。