你可以去研究他们的脑电波。

You could study their brain waves.

一种聪明的方法便是去观察脑电波。

One clever method is to look at their brain waves.

大脑也发出脑电波，这可在脑电图上记录下来。

Electrical activity emanating from the brain is displayed in the form of brainwaves.

在第二和第三阶段，慢脑电波，它出现在我们还未醒时，夹杂着我们所知的简短快速脉冲纺锤波。

In the second and third stages, slow brain waves - which occur when we are not awake - were interspersed with brief rapid pulses - known as spindles.