It's gone down a path towards maturation that's very difficult to go back up.

它在分化成熟的道路上越走越远,覆水难收了

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Well, one answer is neural maturation, growth of the brain.

答案之一就是神经元的成熟,也就是大脑的发育

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That process of maturation is called differentiation.

这种细胞成熟的过程称为分化

耶鲁公开课 - 生物医学工程探索课程节选