translation.en: When they get active, they need increased blood flow to supply that activity, and lucky for us, blood flow control to the brain is local, so if a bunch of neurons, say, right there get active and start firing, then blood flow increases just right there.
translation.zh: 当大脑变得活跃时， 他们需要更多的血液来支撑这样的活动。 正好，控制大脑的血液就存在与大脑中。 所以比如说这儿的一些神经元 变得活跃，开始传输信号， 接下来这儿的血液流量就会增加。