|
The neuronal signals for smiles usually start in the cortex of our brain. From there they travel to the deeper part, the brainstem -- which, in terms of evolution, also happens to be one of the oldest parts of our brain. From there, a nerve that's large enough to be visible to the naked eye, called the seventh cranial nerve, carries the signal in front of the ear to the more central part of the face, where it reaches the smile muscle. 微笑的神经信号通常开始于我们的大脑皮质。他们从那里传输到更深的部分，脑干——它从进化的角度来讲，也恰好是我们的大脑最古老的部分之一。从那里，一根可以大到肉眼可见的称为第七脑神经的神经，把耳朵前面的信号传到面部更中央的部分，那里它可以到达微笑肌。 The smile muscle is attached from the mouth to the cheekbone. When this nerve fires, the muscle is activated, the corners of our mouth are pulled up, and we look happy. And if it is a true smile, one that signifies real enjoyment by its wearer, then a branch of the facial nerve also activates little muscles around the eyes, leading to wrinkling around the eyes in addition to a mouth smile. 微笑肌附在口腔到颧骨上。当这个神经点燃时，肌肉被激活，我们的嘴角被拉起，然后我们就看起来是快乐的。如果它是一个真正的微笑，表示笑着的人真正的愉悦，那么面部神经的分支也会激活眼睛周围的小肌肉，导致眼睛周围的皱纹，除非它只是一个嘴角的微笑。 | 
