We thank Dr. Larry D. Frye for editorial help with this manuscript. This work was supported by Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research 24300129 (to M.L.), 25890005 (to Y.O.) and 26640025 (to Y.T.), the National Agriculture and Food Research Organization (to Y.U.), the World Premier International Research Center Initiative (WPI) from the Ministry of Education, Culture, Sports, Science, and Technology (to Y.O., Y.T., Y.U. and M.L.) and the Nestl&#233; Nutrition Council, Japan (to M.L.).

Ethics Statement: Procedures involving animal subjects have been approved by the Institutional Animal Experiment Committee at the University of Tsukuba.
1. Preparation of Electrodes and Cables for EEG/EMG Recordings
<ol>
	<li>Prepare EEG/EMG recording electrode according to the following procedure. 
	Note: The electrode is disposable and can be used only for 1 animal. Plan carefully the wiring configuration for all connectors. Place marks on the connectors for the correct orientation.
	...

<ol>
	<li>Berger, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=&#220;ber+das+Elektrenkephalogramm+des+Menschen.">&#220;ber das Elektrenkephalogramm des Menschen.</a> Arch. Psych. 87 (1), 527-570 (1929).</li><li>Tobler, I., Deboer, T., Fischer, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sleep+and+sleep+regulation+in+normal+and+prion+protein-deficient+mice.">Sleep and sleep regulation in normal and prion protein-deficient mice.</a> J. Neurosci. 17 (5), 1869-1879 (1997).</li><li>Kohtoh, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Algorithm+for+sleep+scoring+in+experimental+animals+based+on+fast+Fourier+transform+power+spectrum+analysis+of+the+electroencephalogram.">Algorithm for sleep scoring in experimental animals based on fast Fourier transform power spectrum analysis of the electroencephalogram.</a> Sleep Biol. Rhythm. 6 (3), 163-171 (2008).</li><li>Rosenbaum, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Warum m&#252;ssen wir schlafen? : eine neue Theorie des Schlafes. , (1892).</li><li>Kubota, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kuniomi+Ishimori+and+the+first+discovery+of+sleep-inducing+substances+in+the+brain.">Kuniomi Ishimori and the first discovery of sleep-inducing substances in the brain.</a> Neurosci. Res. 6 (6), 497-518 (1989).</li><li>Ishimori, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=True+cause+of+sleep:+a+hypnogenic+substance+as+evidenced+in+the+brain+of+sleep-deprived+animals.">True cause of sleep: a hypnogenic substance as evidenced in the brain of sleep-deprived animals.</a> Tokyo Igakkai Zasshi. 23, 429-457 (1909).</li><li>Legendre, R., Pieron, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recherches+sur+le+besoin+de+sommeil+cons&#233;cutif+&#224;+une+veille+prolong&#233;e.">Recherches sur le besoin de sommeil cons&#233;cutif &#224; une veille prolong&#233;e.</a> Z. Allegem. Physiol. 14, 235-262 (1913).</li><li>Inou&#233;, S., Honda, K., Komoda, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sleep+as+neuronal+detoxification+and+restitution.">Sleep as neuronal detoxification and restitution.</a> Behav. Brain. Res. 69 (1-2), 91-96 (1995).</li><li>Urade, Y., Hayaishi, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prostaglandin+D2+and+sleep/wake+regulation.">Prostaglandin D2 and sleep/wake regulation.</a> Sleep Med. Rev. 15 (6), 411-418 (2011).</li><li>Ueno, R., Ishikawa, Y., Nakayama, T., Hayaishi, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prostaglandin+D2+induces+sleep+when+microinjected+into+the+preoptic+area+of+conscious+rats.">Prostaglandin D2 induces sleep when microinjected into the preoptic area of conscious rats.</a> Biochem. Biophys. Res. Commun. 109 (2), 576-582 (1982).</li><li>Krueger, J. M., Walter, J., Dinarello, C. A., Wolff, S. M., Chedid, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sleep-promoting+effects+of+endogenous+pyrogen+(interleukin-1).">Sleep-promoting effects of endogenous pyrogen (interleukin-1).</a> Am. J. Physiol. 246 (6 Pt 2), R994-R999 (1984).</li><li>Porkka-Heiskanen, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adenosine:+a+mediator+of+the+sleep-inducing+effects+of+prolonged+wakefulness.">Adenosine: a mediator of the sleep-inducing effects of prolonged wakefulness.</a> Science. 276 (5316), 1265-1268 (1997).</li><li>Garcia-Garcia, F., Acosta-Pena, E., Venebra-Munoz, A., Murillo-Rodriguez, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sleep-inducing+factors.">Sleep-inducing factors.</a> CNS Neurol. Disord. Drug. Targets. 8 (4), 235-244 (2009).</li><li>Huitron-Resendiz, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Urotensin+II+modulates+rapid+eye+movement+sleep+through+activation+of+brainstem+cholinergic+neurons.">Urotensin II modulates rapid eye movement sleep through activation of brainstem cholinergic neurons.</a> J. Neurosci. 25 (23), 5465-5474 (2005).</li><li>Wilkins, R. H., Brody, I. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Encephalitis+lethargica.">Encephalitis lethargica.</a> Arch. Neurol. 18 (3), 324-328 (1968).</li><li>von Economo, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Die+encephalitis+lethargica.">Die encephalitis lethargica.</a> Wien. Klin. Wochenschr. 30, 581-585 (1917).</li><li>Moruzzi, G., Magoun, H. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Brain+stem+reticular+formation+and+activation+of+the+EEG.">Brain stem reticular formation and activation of the EEG.</a> Electroencephalogr. Clin. Neurophysiol. 1 (4), 455-473 (1949).</li><li>Saper, C. B., Fuller, P. M., Pedersen, N. P., Lu, J., Scammell, T. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sleep+state+switching.">Sleep state switching.</a> Neuron. 68 (6), 1023-1042 (2010).</li><li>Jones, B. E., Krnjevic , K., L, D. e. s. c. a. r. r. i. e. s., S, M. i. r. c. e. a. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Progress in Brain Research. 145, 157-169 (2004).</li><li>Saper, C. B., Scammell, T. E., Lu, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypothalamic+regulation+of+sleep+and+circadian+rhythms.">Hypothalamic regulation of sleep and circadian rhythms.</a> Nature. 437 (7063), 1257-1263 (2005).</li><li>Fort, P., Bassetti, C. L., Luppi, P. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alternating+vigilance+states:+new+insights+regarding+neuronal+networks+and+mechanisms.">Alternating vigilance states: new insights regarding neuronal networks and mechanisms.</a> Eur. J. Neurosci. 29 (9), 1741-1753 (2009).</li><li>Lu, J., Sherman, D., Devor, M., Saper, C. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+putative+flip-flop+switch+for+control+of+REM+sleep.">A putative flip-flop switch for control of REM sleep.</a> Nature. 441 (7093), 589-594 (2006).</li><li>Paxinos, G., Franklin, K. B. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The mouse brain in stereotaxic coordinates. , (2001).</li><li>Lazarus, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Arousal+effect+of+caffeine+depends+on+adenosine+A2A+receptors+in+the+shell+of+the+nucleus+accumbens.">Arousal effect of caffeine depends on adenosine A2A receptors in the shell of the nucleus accumbens.</a> J. Neurosci. 31 (27), 10067-10075 (2011).</li><li>Huang, Z. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adenosine+A2A,+but+not+A1,+receptors+mediate+the+arousal+effect+of+caffeine.">Adenosine A2A, but not A1, receptors mediate the arousal effect of caffeine.</a> Nat. Neurosci. 8 (7), 858-859 (2005).</li><li>Qu, W. M., Huang, Z. L., Xu, X. H., Matsumoto, N., Urade, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dopaminergic+D1+and+D2+receptors+are+essential+for+the+arousal+effect+of+modafinil.">Dopaminergic D1 and D2 receptors are essential for the arousal effect of modafinil.</a> J. Neurosci. 28 (34), 8462-8469 (2008).</li><li>Huang, Z. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Arousal+effect+of+orexin+A+depends+on+activation+of+the+histaminergic+system.">Arousal effect of orexin A depends on activation of the histaminergic system.</a> Proc. Natl. Acad. Sci. USA. 98 (17), 9965-9970 (2001).</li><li>Xu, Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+mouse+model+mimicking+human+first+night+effect+for+the+evaluation+of+hypnotics.">A mouse model mimicking human first night effect for the evaluation of hypnotics.</a> Pharmacol. Biochem. Behav. 116, 129-136 (2014).</li><li>Cho, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Marine+polyphenol+phlorotannins+promote+non-rapid+eye+movement+sleep+in+mice+via+the+benzodiazepine+site+of+the+GABAA+receptor.">Marine polyphenol phlorotannins promote non-rapid eye movement sleep in mice via the benzodiazepine site of the GABAA receptor.</a> Psychopharmacol. 231 (14), 2825-2837 (2014).</li><li>Liu, Y. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Piromelatine+exerts+antinociceptive+effect+via+melatonin,+opioid,+and+5HT1A+receptors+and+hypnotic+effect+via+melatonin+receptors+in+a+mouse+model+of+neuropathic+pain.">Piromelatine exerts antinociceptive effect via melatonin, opioid, and 5HT1A receptors and hypnotic effect via melatonin receptors in a mouse model of neuropathic pain.</a> Psychopharmacol. 231 (20), 3973-3985 (2014).</li><li>Qu, W. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipocalin-type+prostaglandin+D+synthase+produces+prostaglandin+D2+involved+in+regulation+of+physiological+sleep.">Lipocalin-type prostaglandin D synthase produces prostaglandin D2 involved in regulation of physiological sleep.</a> Proc. Natl. Acad. Sci. 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The authors Yujiro Tauguchi and Sayaka Kohtoh are employees of Kissei Comtech Co., Ltd that develops SleepSign software for acquisition and automatic scoring of EEG/EMG data used in this article.

This protocol describes a set-up for EEG/EMG recordings that allows the assessment of sleep and wakefulness under low-noise, cost-effective, and high-throughput conditions. Due to the small size of the EEG/EMG electrode head assembly, this system can be combined with other implants for intra-brain experiments, including optogenetics (optical fiber implantation) or, in conjunction with simultaneous cannula implantation, microinfusion of drugs into the mouse brain.31 Moreover, the design of the electrode head as...

Technical advances have often precipitated quantum leaps in the understanding of neurobiological processes. For example, Hans Berger&#39;s discovery in 1929 that electrical potentials recorded from the human scalp took the form of sinusoidal waves, the frequency of which was directly related to the level of wakefulness of the subject, led to rapid advances in the understanding of sleep-wake regulation, in both animals and humans alike.1 To this day the electroencephlogram (EEG), in conjunction with the electromyogram (EMG), i.e., electrical activity produced by skeletal muscles, represents the data &#34;backbone&#34; of nearly every experimental and clinical assessment that seeks to correlate behavior and physiology with the activity of cortical neurons in behaving animals, including humans. In most basic sleep research laboratories these EEG recordings are performed by using a cable-based system (Figure 1) wherein acquired data is subjected off-line to pattern and spectrum analysis [e.g., applying a fast Fourier transform (FFT) algorithm] to determine the vigilance state of the subject being recorded.2, 3 Sleep consists of rapid-eye movement (REM) and non-REM (NREM) sleep. REM sleep is characterized by a rapid low-voltage EEG, random eye movement, and muscle atonia, a state in which the muscles are effectively paralyzed. REM sleep is also known as paradoxical sleep, because the brain activity resembles that of wakefulness, whereas the body is largely disconnected from the brain and appears to be in deep sleep. By contrast, motor neurons are stimulated during NREM sleep but there is no eye movement. Human NREM sleep can be divided into 4 stages, whereby stage 4 is called deep sleep or slow-wave sleep and is identified by large, slow brain waves with delta activity between 0.5 - 4 Hz in the EEG. On the other hand, a subdivision between phases of NREM sleep in smaller animals, like rats and mice, has not been established, mostly because they do not have long consolidated periods of sleep as seen in humans.
Over the years, and on the basis of EEG interpretation, several models of sleep-wake regulation, both circuit- and humoral-based, have been proposed. The neural and cellular basis of the need for sleep or, alternatively, &#34;sleep drive,&#34; remains unresolved, but has been conceptualized as a homeostatic pressure that builds during the waking period and is dissipated by sleep. One theory is that endogenous somnogenic factors accumulate during wakefulness and that their gradual accumulation is the underpinning of sleep homeostatic pressure. While the first formal hypothesis that sleep is regulated by humoral factors has been credited to Rosenbaum&#39;s work published in 18924, it was Ishimori5, 6 and Pieron7 who independently, and over 100 years ago, demonstrated the existence of sleep-promoting chemicals. Both researchers proposed, and indeed proved, that hypnogenic substances or &#39;hypnotoxins&#39; were present in the cerebral spinal fluid (CSF) of sleep-deprived dogs.8 Over the past century several additional putative hypnogenic substances implicated in the sleep homeostatic process have been identified (for review, see ref. 9), including prostaglandin (PG) D2,10 cytokines,11 adenosine,12 anandamide,13 and the urotensin II peptide.14
Experimental work by Economo15, 16, Moruzzi and Magoun17, and others in the early and mid-20th century produced findings that inspired circuit-based theories of sleep and wakefulness and, to a certain degree, overshadowed the then prevailing humoral theory of sleep. To date, several &#34;circuit models&#34; have been proposed, each informed by data of varying quality and quantity (for review, see ref. 18). One model, for example, proposes that slow-wave sleep is generated through adenosine-mediated inhibition of acetylcholine release from cholinergic neurons in the basal forebrain, an area mainly consisiting of the nucleus of the horizontal limb of the diagonal band of Broca and the substantia inominata.19 Another popular model of sleep/wake regulation describes a flip-flop switch mechanism on the basis of mutually inhibitory interactions between sleep-inducing neurons in the ventrolateral preoptic area and wake-inducing neurons in the hypothalamus and brain stem.18, 20, 21 Moreover, for the switching in and out of REM sleep, a similar reciprocally inhibitory interaction has been proposed for areas in the brain stem, that is the ventral periaqueductal gray, lateral pontine tegmentum, and sublaterodorsal nucleus.22 Collectively, these models have proven valuable heuristics and afforded important interpretative frameworks for studies in sleep research; however, a yet fuller understanding of the molecular mechanisms and circuits regulating the sleep-wake cycle will require a more complete knowledge of its components. The system for polygraphic recording detailed below should aid in this goal.

<table border="0" cellpadding="0" cellspacing="0" width="729">
	<tbody>
		<tr height="19">
			<td height="19" style="height:19px;width:216px;">4-pin header</td>
			<td style="width:143px;">Hirose</td>
			<td style="width:167px;">A3B-4PA-2DSA(71)</td>
			<td style="width:205px;"></td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;width:216px;">Ampicillin</td>
			<td style="width:143px;">Meiji Seika</td>
			<td style="width:167px;">N/A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Analog-to-digital converter</td>
			<td style="width:143px;">Contec</td>
			<td style="width:167px;">AD16-16U(PCIEV)</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Caffeine</td>
			<td style="width:143px;">Sigma</td>
			<td style="width:167px;">C0750</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Carbide cutter</td>
			<td style="width:143px;">Minitor</td>
			<td style="width:167px;">B1055</td>
			<td></td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;width:216px;">Crimp housing</td>
			<td style="width:143px;">Hirose</td>
			<td style="width:167px;">DF11-4DS-2C</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Crimp socket</td>
			<td style="width:143px;">Hirose</td>
			<td style="width:167px;">DF11-30SC</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Dental cement (Toughron Rebase)</td>
			<td style="width:143px;">Miki Chemical Product</td>
			<td style="width:167px;">N/A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Epoxy adhesive</td>
			<td style="width:143px;">Konishi</td>
			<td style="width:167px;">#16351</td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:216px;">FFC/FPC connector</td>
			<td style="width:143px;">Honda Tsushin Kogyo</td>
			<td style="width:167px;">FFC-10BMEP1(B)</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Flat cable</td>
			<td style="width:143px;">Hitachi Cable</td>
			<td style="width:167px;">20528-ST LF</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">Instant glue (Aron Alpha A)</td>
			<td style="width:143px;">Toagosei</td>
			<td style="width:167px;">N/A</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Meloxicam</td>
			<td style="width:143px;">Boehringer Ingelheim</td>
			<td style="width:167px;">N/A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Pentobarbital</td>
			<td style="width:143px;">Kyoritsu Seiyaku</td>
			<td style="width:167px;">N/A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Signal amplifier</td>
			<td style="width:143px;">Biotex</td>
			<td style="width:167px;">N/A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Sleep recording chamber</td>
			<td style="width:143px;">APL</td>
			<td style="width:167px;">N/A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">SleepSign software</td>
			<td style="width:143px;">Kissei Comtec</td>
			<td style="width:167px;">N/A</td>
			<td>for EEG/EMG recording/analysis</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Slip ring</td>
			<td style="width:143px;">Biotex</td>
			<td style="width:167px;">N/A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Stainless steel screw</td>
			<td style="width:143px;">Yamazaki</td>
			<td style="width:167px;">N/A</td>
			<td>&#966;1.0&#215;2.0</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Stainless steel wire</td>
			<td style="width:143px;">Cooner Wire</td>
			<td style="width:167px;">AS633</td>
			<td></td>
		</tr>
	</tbody>
</table>

polygraphic recording procedure for measuring sleep in mice

Recording of the epidural electroencephalogram (EEG) and electromyogram (EMG) in small animals, like mice and rats, has been pivotal to study the homeodynamics and circuitry of sleep-wake regulation. In many laboratories, a cable-based sleep recording system is used to monitor the EEG and EMG in freely behaving mice in combination with computer software for automatic scoring of the vigilance states on the basis of power spectrum analysis of EEG data. A description of this system is detailed herein. Steel screws are implanted over the frontal cortical area and the parietal area of 1 hemisphere for monitoring EEG signals. In addition, EMG activity is monitored by the bilateral placement of wires in both neck muscles. Non-rapid eye movement (Non-REM; NREM) sleep is characterized by large, slow brain waves with delta activity below 4 Hz in the EEG, whereas a shift from low-frequency delta activity to a rapid low-voltage EEG in the theta range between 6 and 10 Hz can be observed at the transition from NREM to REM sleep. By contrast, wakefulness is identified by low- to moderate-voltage brain waves in the EEG trace and significant EMG activity.

Figure 1B illustrates examples of the mouse EEG in the different vigilance states. As shown in Table 1, epochs are classified as NREM sleep if the EEG shows large, slow brain waves with a delta rhythm below 4 Hz and the EMG has only a weak or no signal. Epochs are classified as REM sleep if the EEG shows rapid low-voltage brain waves in the theta range between 6 and 10 Hz and the EMG shows low amplitude. Other epochs should be classified as wakefulness (<...

Watch this Scientific Journal Video about Polygraphic Recording Procedure for Measuring Sleep in Mice at JoVE.com

Polygraphic Recording Procedure for Measuring Sleep in Mice

The recording of electroencephalogram (EEG) and electromyogram (EMG) in freely behaving mice is a critical step to correlate behavior and physiology with sleep and wakefulness. The experimental protocol described herein provides a cable-based system for acquiring EEG and EMG recordings in mice.

Recording of the epidural electroencephalogram (EEG) and electromyogram (EMG) in small animals, like mice and rats, has been pivotal to study the ...

The overall goal of this polygraphic recording procedure is to determine the vigilant state of mice and measure the time spent in wakefulness, rapid eye movement sleep or non-rapid eye movement sleep. This method can help answer key questions in nearly every neuroscience field that seeks to correlate behavior and physiology with the activity of cortical neurons in behaving animals. The main advantage of this technique is that it can record a lot of nodes, electroencephalogram and electromyogram and can be combined with other brain implants such as optic fibers and infusion cannulas.Visual demonstration of this method is very important because the implantation of the electrode needs to be performed properly and the quality of the electrode is extremely critical to judge the physical states. Demonstrating the procedure will be Yohko Takata, a postdoc from my laboratory. Before starting, sterilize all the surgical tools in a hot bead sterilizer.Once the mouse is confirmed as anesthetized by a toe pinch, shave off the hair on the head and neck. Next, secure the house to the stereotaxic frame and fix the head between the two ear bars. Then, apply ophthalmic ointment to the eyes to prevent dryness.Proceed with cleansing the shaved skin with alcohol and iodine based scrubs. Then, cut along the midline with a scalpel to expose the skull and secure the skin to the side using clips to keep the surgical area open. Using a carbide cutter with a 0.8 millimeter drill, make two holes.Put one hole over the frontal cortical area. Put the second hole over the parietal area of the right hemisphere. Next, using a jeweler's screwdriver, screw stainless steel EEG recording screws into the holes.Insert the screws with just two to two and a half turns to obtain epidural positioning over the cortex. The screws should not wiggle once inserted. This is very important.Now, fix the electrode assembly with the pins upward to the skull. The electrodes must be attached straight on. Use a cotton swab to help secure the electrode's position and glue the electrode down using cyanoacrylate followed by dental cement.Next, make small holes in the trapezius and insert the EMG electrode into those holes. Then, suture the skin with 0.1 millimeter diameter silk thread. Now, remove the mouse from the stereotaxic frame and place it on a heat pad.Give the mouse intraperitoneal injections of ampicillin and meloxicam and monitor the mouse until it regains sternal recumbency. Then, house the mouse alone. One week after implanting the electrodes, transfer the mouse to an experimental cage in a soundproof recording chamber.Secure the EEG/EMG electrode assembly on the mouse to a recording cable connected to a slip ring. Connect the AD converter cable to an EEG/EMG signal filter amplifier connected to the slip ring. Use an AD converter to convert the signal to a 128 hertz digital signal and, finally, record the signal to a computer.Habituate the mouse for two to three days in the recording chamber. If the EEG/EMG recording includes drug administrations, gently handle the mouse on each day as those there was a drug administration being given. Subsequently, start the EEG/EMG recording software.To begin, click on the Data file information tab and click the box next to the File name. Enter a file name and click Save. Then, from the Recording condition tab, select all the EEG/EMG channels which need to be recorded.Also, select the Sampling frequency under this tab. Now, in the Channel information tab, check if the selected channels are displayed properly. Once confirmed, start the record by first selecting the Timer setting tab.Then, click monitor to display EEG and EMG. If the signals are displayed correctly, set the clock time for the beginning and end of the recording in the Main Timer area. Then, click the Monitor button to start the recording.Now, record the signals under baseline conditions and different treatment conditions over several days. When the experiment is finished, euthanize the mouse with pentobarbital. Start the software for EEG/EMG analysis.Open the EEG/EMG raw data, which is a KCD file. Click the Sleep tab and set the Epoch time to 10 seconds. Then, select Multi-screening to automatically score all ten second epochs into three stages on the basis of the amplitudes of the EEG and the EMG and based on the power spectral analysis of the EEG.Next, click on the FFT condition for EEG tab. There, set the parameters for the power spectral analysis. Use 256 datum points corresponding to every two seconds of EEG, use the hamming window function, and use an average of five spectra per epoch.Then click Ok.Now, click Start Screening to begin the automatic screening. Then, open the stored data, which is saved in a RAF file format and check the results of the automatic screening. As needed, correct the results if they do not meet the standard criteria.To make a correction, click and hold the left mouse button on an incorrectly scored epoch and drag the cursor across the string of incorrectly scored epochs. Release the left mouse button and select the correct behavioral state in the popup window. Under baseline conditions, the mice exhibited a clear circadian sleep-wake rhythm consistent with their nocturnal nature.During the 12 hour light period, the mice averaged 6.7 hours of NREM sleep and 0.9 hours of REM sleep. Whereas, during their 12 hour dark period, wakefulness was predominant. Other measurements were also recorded.These included the sleep epoch distribution, their mean durations and the stage transitions for each vigilant state. The EEG power spectrums for NREM and REM sleep show a strong EEG power density in the frequency range of 0.5 to four hertz for NREM sleep compared to a power density from six to 10 hertz for REM sleep. To assess the impact of caffeine on sleep, C57 black 6 mice were treated with a vehicle on one day and with caffeine on the next day.Intraperitoneal injections of caffeine were given early in the light cycle. As expected, the recording revealed the caffeine increased the amount of wakefulness in the mice. A three-fold increase in wakefulness occurred for three hours after the injection.Once mastered, the electrode implantation procedure can be done in less than 20 minutes. Scoring and correcting the EEG data for a 24 hour period can be done in about 30 minutes. After watching this video, you should have a good understanding of how to set up recording of electroencephalogram and electromyogram in mice and how to assess if and how long an animal is awake or asleep.

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22.9K vistas.  University of Tsukuba. The overall goal of this polygraphic recording procedure is to determine the vigilant state of mice and measure the time spent in wakefulness, rapid eye movement sleep or non-rapid eye movement sleep. This method can help answer key questions in nearly every neuroscience field that seeks to correlate behavior and physiology with the activity of cortical neurons in behaving animals. The main advantage of this technique is that it can record a lot of nodes, electroencephalogram and electromyogr...