# Fluorescent polysomnography and MCH neurogenetics

> **NIH NIH R01** · STANFORD UNIVERSITY · 2022 · $752,330

## Abstract

Abstract
We propose to develop and apply fluorescence-based polysomnography (fPSG) in zebrafish, a novel, non-
invasive method allowing neurogenetic and pharmacological interrogations of nervous system function
through whole brain and whole body imaging. fPSG combines custom light sheet microscopy with a new
zebrafish line “zPSG” carrying four transgenes expressing GCaMP7a [Tg(5xUAS:GCaMP7a)] in the brain
[Tg(α-tubulin:nls-Kal4FF)] and trunk muscles [Et(gSAIzGFFD109A)], and GFP in the heart [Tg(cmlc2:GFP)]
in order to capture brain wide Ca2+ activity (fEEG, fluorescent electroencephalogram), muscle Ca2+ activity
(fEMG, fluorescent electromyogram), heart rate (fECG, fluorescent electrocardiogram) as well as eye
movement (fEOG, fluorescent electrooculogram). Polysomnography (PSG) is a classic method used to
characterize sleep and diagnose sleep disorders and sleep abnormalities in neurological and psychiatric
disorders. Slow wave sleep (SWS, non-REM) and rapid eye movement sleep (REM, a.k.a. paradoxical
sleep, PS) are defined by specific electrophysiological PSG signatures based on recordings from the surface
of the neocortex (EEG), and voluntary or autonomous muscles (EMG+ECG+EOG). SWS-REM/PS have
only been reported so far in the more evolutionary-recent amniotic vertebrates: mammals, birds and reptiles.
It is unclear whether such neuronal and muscular dynamics are found in non-amniotic vertebrates such as
fishes and amphibians. In a first study we have found slow synchronous neural activity and traveling waves
of neural activity in the sleeping fish brain. We have coined these novel signatures: Slow Bursting Sleep
(SBS) and Propagating Wave Sleep (PWS) which share remarkable commonalities with SWS and PS/REM
states, respectively. We propose to develop and apply fPSG to fully characterize SBS (Aim 1) and PWS
(Aim 2) at the whole brain, body scale levels. After this full characterization, we will next investigate the
molecular and circuit underpinning of these dynamics by interrogating different neurogenetic contexts of
melanin-concentrating hormone (MCH) signaling, a conserved neuropeptidergic system which is involved in
mammalian sleep but whose role in fish sleep has been debated for over 30 years (Aim 3). Overall, this
proposal will (i) develop a new PSG methodology with whole brain-single cell resolution imaging and body
scale comprehension that could also be used with other fish models [e.g. cavefish, danionella, medaka], (ii)
establish the first neural definition of sleep in fish, (iii) uncover the role of MCH in fish sleep, and finally (iv)
shed light on whether common neural signatures of sleep emerged in the non-amniotic vertebrate brain over
450 million years ago. Importantly, fPSG tools and methodology can be extended to any neuroscience
question in the awake or asleep animal requiring whole brain imaging with cardiovascular, ocular and
voluntary muscles readouts (e.g. studies of the autonomic and non-autonomic systems).

## Key facts

- **NIH application ID:** 10400045
- **Project number:** 5R01HL151576-03
- **Recipient organization:** STANFORD UNIVERSITY
- **Principal Investigator:** Philippe Mourrain
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $752,330
- **Award type:** 5
- **Project period:** 2020-05-01 → 2024-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10400045

## Citation

> US National Institutes of Health, RePORTER application 10400045, Fluorescent polysomnography and MCH neurogenetics (5R01HL151576-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10400045. Licensed CC0.

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