not only is more of the brain involved in play than was suspected 英语高手，求解

我不要它的翻译，请高手帮帮我分析一下这个句子的成分，Not only 开头不是倒装吗？等等。
原文整句是
not only is more of the brain involved in play than was suspected, but it also seems to active higher cognitive processes.

not only ...but also 句型前半句中采用部分倒装，因为该句前面部分谓语动词是be ，所以跟全部倒装形式相同， 只是该句前面加了more ...than这一比较结构所以稍显复杂。

not only…but also 不仅……而且

不仅是更多的大脑中参与演奏比被怀疑,似乎还活性更高的认知过程。 不是。