That’s assuming consciousness actually emerges from the brain. We don’t really know. It's certainly associated with brains, but whether brains are it's cause is anyone's guess! After all, consciousness cannot be seen, it can only be experienced! So maybe a tree or a rock is conscious. How would we know? It's not as if they can communicate the fact to us!
Similarly, we are yet to explain how the universe "emerged" from God, or whatever name which we wish to give to that which apparently "caused" it!