Later today I’ll lose consciousness for a few hours to rest and repair. There’s a good chance you will, too. Yet as ubiquitous as sleep is, we know very little about which parts of the brain are fundamental to staying awake.

Thanks to a recent experiment that stimulated the brains of anaesthetised macaques, we have a clearer idea of just which neurological structures might be primarily responsible for switching us on each day.

The results not only help us to better understand the processes behind anaesthesia; for those trapped in vegetative or comatose states by illness or injury it could mean a pathway out again.