Thanks @kasumbisa.bsky.social !!

Thanks!

Thanks a lot @dlevenstein.bsky.social !! These NREM packets/cycles are indeed mysterious :)

Thanks @thomasandrillon.bsky.social !!

Thanks @apeyrache.bsky.social !!

Many thanks to all co-authors and collaborators across the years: Chloe Froidevaux, Julien Schmidt, Baptiste Barillot, @mickaeltanter.bsky.social , Anthony Herrel, @marksblumberg.bsky.social and Paul-Antoine Libourel.

Read the full paper here: rdcu.be/eWJHb 8/8

Our findings challenge the notion that REM sleep “exist” in lizards but instead give a central place the infraslow rhythm, as a conserved fundamental building block of sleep architecture, dating back its apparition to the common ancestor of amniotes about 320 million years ago. 7/8

Finally, skin brightness – but not skin color – recorded in darkness in the sleeping panther chameleon oscillates at this infraslow rhythm, possibly reflecting blood oxygenation, and bouts of eye movements occurred markedly during one half of the cycle, which could be a marker of vigilance. 6/8

Functional ultrasound imaging showed that the whole brain oscillates at this infraslow rhythm, with blood flow coupled to neural signals during sleep in the bearded dragon and during NREM sleep in mice - but that this coupling disappears during REM sleep (in mice) and wake (in both species). 5/8

All 7 species recorded -the tokay and leopard geckos, the Sudan plated lizard, Argentine tegu, Egyptian rock agama, bearded dragon and panther chameleon- show brain waves synchronized with heart rate, respiratory rate, muscle tone and eye movements - as previously demonstrated during NREM sleep. 4/8

By recording in seven evolutionarily-distant lizard species, we show that neural signals display an infraslow rhythm (period ~100 sec) during sleep, like that previously described in mice and humans (period ~50 sec). The longer period in reptiles could be explained by their lower temperature. 3/8

This marks the accomplishment of a collaboration with Paul-Antoine Libourel started in 2019, with whom we used functional ultrasound imaging in bearded dragons to investigate whether they “possess” REM sleep. 6 years later, we come up with new data shedding a new light on sleep state evolution. 2/8

Merci Adrien !

Thanks Guy !

Merci Jeremie !

Merci Aude !!

Thanks Jerome !!

Huge thanks to all my mentors over the years for their time, help, and advice. In particular @mickaeltanter.bsky.social, @apeyrache.bsky.social, K. Benchenane and @faurelab.bsky.social. Very grateful 🙏.