Sleep, wakefulness and consciousness

Selected key events: WAKING provided evidence for a potentially evolutionary conserved role of amino-acid transport and in particular glial-dependent glutamate recycling in sleep/wake regulation using Drosophila and mouse models[1]. At the neuronal networks level, this team demonstrated the distinct, but complementary and synergistic roles of histamine and orexin in cortical activation/wakefulness, leading to the concept of behavioral context-dependent control of wakefulness[2]. Challenging electrophysiological recording in lizards have led the SLEEP team to confirm and extend the existence of two different sleep states in reptiles, providing new concepts on the evolutionary origin of paradoxical (or REM) sleep[3]. While the function of paradoxical sleep remains elusive, SLEEP elucidated the networks responsible for one of its key features, muscle atonia[4]. Forgetting further showed that paradoxical sleep plays a major role in consolidation of remote long-term emotional memory in mice[5], and also induces a long-term reorganization of neuronal activity in emotion related limbic areas. In an interesting parallel, DYCOG (PAM) observed that dreams attenuate the emotional intensity of waking-life memories[6]. With respect to the interaction between sensory processing and vigilance states, NEUROPAIN, using surface and intracerebral recordings in humans, challenged the inhibitory function attributed to sleep spindles on nociceptive stimuli perception as assessed with cortical or autonomic reactivity [7]. They further showed that cortical downstates induce hyperpolarization of thalamic cells, triggering spindles[8]. Linking sensory processing to conscious cognitive states, CAP demonstrated that listening to preferred music leads to improved cognitive functioning in comatose and post-comatose patients, as revealed with electrophysiological, behavioral[9], physiological[10] and functional connectivity[11] FMRI measures.

Collaborative aspects: The collaborations between CRNL teams have led to the publication of a large number of peer-reviewed articles and reviews, contracts and the co-tutoring of students. For example, through intracellular recordings in mouse thalamus, a collaboration between the SLEEP , WAKING, CMO and Forgetting teams has shown that cortical slow oscillations slightly precede thalamic spindles during slow wave sleep[12]. The DYCOG (PAM) and CMO teams have demonstrated the incorporation of fragmented visuo-olfactory episodic memory into dreams and its association with memory performance[13]. A CAP-WAKING led investigation of biological markers of circadian rhythmicity in comatose patients suggests that CR may be a prerequisite for coma recovery with a potential but still unproven favorable effect on brain function[14] . To promote interactions between CNRL teams and other laboratories in the Lyon area, a CRNL sleep and consciousness day is organized every year with a program including an invited conference and presentations of ongoing projects results by CRNL members.

[1] Farca et al. 2017, Aboudhiaf et al. 2018

[2] Parmentier et al. 2016

[3] Libourel et al. PLOSBiol 2018

[4] Valencia Garcia et al.Nat Commun 2018

[5] Rosier  et al. Sleep 2018

[6] Vallat et al. PlosOne 2017

[7] Claude et al, J Physiol 2015

[8] Mak-McCully et al, Nat Commun 2017

[9] Heine et al, Brain Injury, 2017

[10] Luauté et al, Ann Phys Rehabil Med, 2018

[11] Heine et al, Front Psychol, 2015

[12] Urbain et al Cell Report 2019

[13] Plailly et al. Scientific reports 2019

[14] Gobert et al. J Pineal Res. 2019