This is hard to determine because certain function of the brain could be picked up by other parts of the brain.
I'm inclined to say that it's somewhere in the stem/base of the brain.
Problem is, removing this could cause severe impairements in general, so you can't say: "conciousness is removed" because you removed the brainstem.
Similar to ripping out the power cord of a computer means, the computer turns off (stops working).
