The Roll of Consciousness on Brain Activity

From the perspective of modern neuroscience, there is no functional roll of consciousness, and consciousness is often considered as just a byproduct of brain activity, or "bystander." But is that good way of thinking? I think this discussion is easily leads to the hard problem of consciousness, and there is no way out here. 

I think that one of the appropriate ways to understand consciousness is trying to understand the functional roll of it. Consciousness is preserved on the long evolutional history, at least for human, so it is reasonable to think that there must be some kind of evolutionaly advantage of having consciousness.

There is severtal way to think about the roll of consciousness, and one of these approach is its roll on brain activity. 

＊This article is still being written.