Using a molecular method likely to become widely adopted by the field, researchers have discovered brain circuitry essential for alertness, or vigilance — and for brain states more generally. Strikingly, the same cell types and circuits are engaged during alertness in zebra fish and mice, species whose evolutionary forebears parted ways hundreds of millions of years ago. This suggests that the human brain is likely similarly wired for this state critical to survival.

https://www.sciencedaily.com/releases/2017/11/171104134443.htm