时差N小时 人类大脑为何沟壑密布(下)（在线收听）

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 postulated 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, determined that how human brains fold follows the same physical principles guiding folds and creases resulting from crumpling 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。