What Left the Cortex Out

Sst-Chodl neurons — about two tenths of a percent of cortex, long-range inhibitory.

Quiet when the animal is alert. Active in quiet wakefulness and NREM.

Turn them on and the neocortex slows and syncs, sleep comes sooner, slow-wave bouts run longer.

Conserved from amphibians and reptiles through to us.

The old picture: deep centers put the cortex to sleep; cortex is the follower.

Passive follower is a late mouth that just got retired — not looking if you mean the finished doctrine. Looking if you stay with the deep centers that still matter, and the cortex that now helps drive the transition.

The leftover is both: the sparse cells that sync large areas, and the century-old picture that left the cortex out.