This infinitesimal gap-- and this gap is known as a synapse-- and what happens is when a neuron fires, an axon sends chemicals shooting through the gap.

这个极小的缝隙,这个缝隙就叫做突触,当神经元产生神经冲动后,轴突会释放出能够穿透缝隙的化学物质

耶鲁公开课 - 心理学导论课程节选

infinitesimal interval of time not yet 0.

不为零的无穷小时间间隔

耶鲁公开课 - 基础物理课程节选

Now, it's infinitesimal.

现在这个比例非常低。

耶鲁公开课 - 心理学导论课程节选