People used to think that our mental meshwork, the dense connections formed among the 100 billion or so neurons inside our skulls, was largely fixed by the time we reached adulthood.

• 人们过去一直认为，我们的神经网状结构，我们头盖骨下那数以千亿记的神经元之间的那种紧密联系，在我们成年的时候就已经固定不变了。