Neurons in the Nucleus papilio contribute to the control of eye movements during REM sleep

C Gutierrez Herrera,F Girard,A Bilella,M R Celio,T C Gent,D M Roccaro-Waldmeyer,A Adamantidis

doi:10.1038/s41467-019-13217-y

Abstract

Rapid eye movements (REM) are characteristic of the eponymous phase of sleep, yet the underlying motor commands remain an enigma. Here, we identified a cluster of Calbindin-D28K-expressing neurons in the Nucleus papilio (NPCalb), located in the dorsal paragigantocellular nucleus, which are active during REM sleep and project to the three contralateral eye-muscle nuclei. The firing of opto-tagged NPCalb neurons is augmented prior to the onset of eye movements during REM sleep. Optogenetic activation of NPCalb neurons triggers eye movements selectively during REM sleep, while their genetic ablation or optogenetic silencing suppresses them. None of these perturbations led to a change in the duration of REM sleep episodes. Our study provides the first evidence for a brainstem premotor command contributing to the control of eye movements selectively during REM sleep in the mammalian brain.

Highlights

To demonstrate the successful optogenetic stimulation of NPCalb neurons during in vivo experiments, we injected Calb1tm1.1(folA/Cre)/Hze/J murine line (Calb1)::Cre animals with AAV-EF1a-DIOhChR2(H134R)-YFP targeted to the NPCalb (AP: − 6.36 mm, ML: 0 mm; DV: − 4.2 mm) and chronically implanted fibre optics and four tetrodes attached to a Microdrive (Nanodrive, Cambridge Neurotech) as well as EEG/EMG four weeks later
Animals with the optic fibre above the 3N terminals were activated in a state specific manner, where 1 s continuous light was delivered at the onset of the REM sleep or wake episodes
Latency and Gaussian distributions analysis, animals with less than two REM sleep episodes in the hour of optogenetic stimulation or with poor EOG signals were not included in the analysis

Summary

Introduction

E, f Averaged probabilities e and latencies f of EMs in response to optogenetic stimulations of NPCalb neuron terminals in 3N during wakefulness and REM sleep (n = 4 mice per group; P = 0.43, t = 0.8895 for wake; P = 0.0016, t = 11.098 for REM; df = 3 in both experimental conditions tested). G Summary of the mean duration of wake, NREM and REM sleep bouts, during a 1 h period of light activation delivered every minute of NPCalb cell soma at 1 s continous light (n = 9 and 6, P = 0.79, t = 0.832), 10 Hz (n = 7 and 7, P = 0.69, t = 0.876), and 1 Hz (n = 7 and 5, P = 0.28, t = 0.0.65); df = 35, when comparing ChR2-transduced to control animals.

Results

Conclusion