That feeling is caused by the capsaicin molecules in the peppers activating the capsaicin receptors on our tongue - the more capsaicin, the hotter the pepper.

VOA: standard.2010.05.04

These kinds of molecules which activate genes, they're activating the process of transcription.

这种分子能够激活基因,激活了转录过程

耶鲁公开课 - 生物医学工程探索课程节选

You can put somebody in an MRI machine now and have them read a book and look at what parts of their brain become activated when they're reading and what parts stop activating when they stop reading, so you can learn where in their brain is reading done.

现在如果有人躺在核磁共振仪中进行阅读,我们就可以看到,在阅读时,大脑哪些部位变得活跃,停止阅读时哪些部位停止活动,这样我们就知道了,大脑中什么部位是和阅读相关的

耶鲁公开课 - 生物医学工程探索课程节选

It really produces its effects primarily by just activating the so-called capsaicin receptor."

VOA: standard.2010.05.04