Neuroseminar: Maiken Nedergaard and Paul-Antoine Libourel

Why do animals sleep? An ecological and evolutionary puzzle

By recording brain activity in seven lizard species, humans, rats and pigeons, we demonstrate an infraslow brain rhythm during sleep in all species. This rhythm is tightly coupled with eye movements, muscle tone, heart and breathing rate in lizards, with skin brightness in chameleons and with pulsatile changes in cerebrovascular volume throughout sleep in bearded dragons and during non-rapid eye movement sleep in mice. These findings indicate that the infraslow rhythm is conserved across amniotes, questioning the evolution of sleep states.