translation.en: One big problem we have -- to try to understand how this really works at a very molecular mechanistic level -- is that we can't study the brains in detail, in living people.
translation.zh: 我们面临的一大问题是—— 想要在分子和功能机制层面上 搞清楚这个过程是如何发生的—— 但我们还无法研究 活体人类大脑活动的细节问题。