Is There a Reducibility in Brains?

Evolution gave us censors to help us survive, and it may well be that there's a lot more going on out there. The individual configuration of molecules and a gas is not something that we make use of overall. We don't have sensers and don't care about the more detailed microscopic motions. But i guess my question would be, if we're trying to describe brains at the level of individual nurons, i'm sure that there's plenty of computational irreducibility in brains. Yet, there is some collective thing that happens in brains that is somehow pre ableand and useful, so to speak. So how do we find such pockets of reducibility in the