What is the reason for it?

原因何在?

《新英汉大辞典》

What it does mean is that, for whatever reason, this particular neuron was activated by this particular scene, almost certainly with a network of other neurons across the brain.

他确切的意思是：无论是处于什么原因，这个特别的神经元会被特别的场景激活，当然，是和大脑中同一个网状下的其它神经元一起工作的。

youdao

What was the reason for that - nobody knows; whether it was a war, a sprouting possibility to move to the biggest cities or a policy of kolkhoz sprawling, there is no exact answer.

至于什么原因，我们无从得知，是否因为一场战争，也可能移动到城市了，或者迁移到了巨大的集体农庄，没有人知道确切的答案。

youdao

"The FIA is not opposed to it, we are not and so what is the reason for it, " he added.

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He goes on to say that his reason for studying the brain is because it is what determines the ways humans interact with the world.

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