Name: recording gamma band oscillations in pedunculopontine nucleus neurons
Uploaded: 2016-09-14T15:00:00
Description: Watch this Scientific Journal Video about Recording Gamma Band Oscillations in Pedunculopontine Nucleus Neurons at JoVE.com

This work was supported by core facilities of the Center for Translational Neuroscience supported by NIH award P20 GM103425 and P30 GM110702 to Dr. Garcia-Rill. This work was also supported by grants from FONCYT-Agencia Nacional de Promoci&#242;n Cient&#236;fica y Tecnol&#242;gica; BID 1728 OC.AR. PICT-2012-1769 and UBACYT 2014-2017 #20120130101305BA (to Dr. Urbano).

All experimental protocols were approved by the Institutional Animal Care and Use Committee of the University of Arkansas for Medical Sciences (Protocol number #3593) and were in agreement with the National Institutes of Health guidelines for the care and use of laboratory animals.
1. Preparation of Standard-artificial Cerebrospinal Fluid (aCSF)
<ol>
	<li>Preparation of Stock Solution A
	<ol>
		<li>Add 700 ml of distilled water to a clean 1 L beaker before adding chemicals.</li>
		<li>While cont...

<ol>
	<li>Profice, P., 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=Neurophysiological+evaluation+of+the+pedunculopontine+nucleus+in+humans.">Neurophysiological evaluation of the pedunculopontine nucleus in humans.</a> J. Neural. Transm (Vienna). 118 (10), 1423-1429 (2011).</li><li>Steriade, M., Datta, S., Pare, D., Oakson, G., Curro Dossi, R. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neuronal+activities+in+brain-stem+cholinergic+nuclei+related+to+tonic+activation+processes+in+thalamocortical+systems.">Neuronal activities in brain-stem cholinergic nuclei related to tonic activation processes in thalamocortical systems.</a> J. Neurosci. 10 (8), 2541-2559 (1990).</li><li>Steriade, M., Dossi, R. C., Pare, D., Oakson, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fast+oscillations+(20-40+Hz)+in+thalamocortical+systems+and+their+potentiation+by+mesopontine+cholinergic+nuclei+in+the+cat.">Fast oscillations (20-40 Hz) in thalamocortical systems and their potentiation by mesopontine cholinergic nuclei in the cat.</a> Proc. Natl. Acad. Sci. U.S.A. 88 (10), 4396-4400 (1991).</li><li>Deurveilher, S., Hennevin, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lesions+of+the+pedunculopontine+tegmental+nucleus+reduce+paradoxical+sleep+(PS)+propensity:+evidence+from+a+short-term+PS+deprivation+study+in+rats.">Lesions of the pedunculopontine tegmental nucleus reduce paradoxical sleep (PS) propensity: evidence from a short-term PS deprivation study in rats.</a> Eur. J. Neurosci. 13 (10), 1963-1976 (2001).</li><li>Steriade, M., Pare, D., Datta, S., Oakson, G., Curro Dossi, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Different+cellular+types+in+mesopontine+cholinergic+nuclei+related+to+ponto-geniculo-occipital+waves.">Different cellular types in mesopontine cholinergic nuclei related to ponto-geniculo-occipital waves.</a> J. Neurosci. 10 (8), 2560-2579 (1990).</li><li>Steckler, T., Inglis, W., Winn, P., Sahgal, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+pedunculopontine+tegmental+nucleus:+a+role+in+cognitive+processes?.">The pedunculopontine tegmental nucleus: a role in cognitive processes?.</a> Brain Res. Brain Res. Rev. 19 (3), 298-318 (1994).</li><li>Garcia-Rill, E., Simon, C., Smith, K., Kezunovic, N., Hyde, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+pedunculopontine+tegmental+nucleus:+from+basic+neuroscience+to+neurosurgical+applications:+arousal+from+slices+to+humans:+implications+for+DBS.">The pedunculopontine tegmental nucleus: from basic neuroscience to neurosurgical applications: arousal from slices to humans: implications for DBS.</a> J. Neural. Transm. 118 (10), 1397-1407 (2011).</li><li>Mazzone, P., 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=Implantation+of+human+pedunculopontine+nucleus:+a+safe+and+clinically+relevant+target+in+Parkinson's+disease.">Implantation of human pedunculopontine nucleus: a safe and clinically relevant target in Parkinson's disease.</a> Neuroreport. 16 (17), 1877-1881 (2005).</li><li>Simon, C., 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=Gamma+band+unit+activity+and+population+responses+in+the+pedunculopontine+nucleus.">Gamma band unit activity and population responses in the pedunculopontine nucleus.</a> J. Neurophysiol. 104 (1), 463-474 (2010).</li><li>Kezunovic, N., Urbano, F. J., Simon, C., Hyde, J., Smith, K., Garcia-Rill, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanism+behind+gamma+band+activity+in+pedunculopontine+nucleus+(PPN).">Mechanism behind gamma band activity in pedunculopontine nucleus (PPN).</a> Eur. J. Neurosci. 34 (3), 404-415 (2011).</li><li>Hyde, J. R., Kezunovic, N., Urbano, F. J., Garcia-Rill, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatiotemporal+properties+of+high+speed+calcium+oscillations+in+the+pedunculopontine+nucleus.">Spatiotemporal properties of high speed calcium oscillations in the pedunculopontine nucleus.</a> J. Appl. Physiol (1985). 115 (9), 1402-1414 (2013).</li><li>Llinas, R. R., Leznik, E., Urbano, F. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temporal+binding+via+cortical+coincidence+detection+of+specific+and+nonspecific+thalamocortical+inputs:+a+voltage-dependent+dye-imaging+study+in+mouse+brain+slices.">Temporal binding via cortical coincidence detection of specific and nonspecific thalamocortical inputs: a voltage-dependent dye-imaging study in mouse brain slices.</a> Proc. Natl. Acad. Sci. U.S.A. 99 (1), 449-454 (2002).</li><li>Boucetta, S., Cisse, Y., Mainville, L., Morales, M., Jones, B. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Discharge+profiles+across+the+sleep-waking+cycle+of+identified+cholinergic,+gabaergic,+and+glutamatergic+neurons+in+the+pontomesencephalic+tegmentum+of+the+rat.">Discharge profiles across the sleep-waking cycle of identified cholinergic, gabaergic, and glutamatergic neurons in the pontomesencephalic tegmentum of the rat.</a> J. Neurosci. 34 (13), 4708-4727 (2014).</li><li>Datta, S., Siwek, D. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single+cell+activity+patterns+of+pedunculopontine+tegmentum+neurons+across+the+sleep-wake+cycle+in+the+freely+moving+rats.">Single cell activity patterns of pedunculopontine tegmentum neurons across the sleep-wake cycle in the freely moving rats.</a> J. Neurosci. Res. 70 (4), 79-82 (2002).</li><li>Datta, S., Siwek, D. F., Stack, E. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+cholinergic+and+non-cholinergic+neurons+in+the+pons+expressing+phosphorylated+cyclic+adenosine+monophosphate+response+element-binding+protein+as+a+function+of+rapid+eye+movement+sleep.">Identification of cholinergic and non-cholinergic neurons in the pons expressing phosphorylated cyclic adenosine monophosphate response element-binding protein as a function of rapid eye movement sleep.</a> Neuroscience. 163 (1), 397-414 (2009).</li><li>Kayama, Y., Ohta, M., Jodo, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Firing+of+'possibly'+cholinergic+neurons+in+the+rat+laterodorsal+tegmental+nucleus+during+sleep+and+wakefulness.">Firing of 'possibly' cholinergic neurons in the rat laterodorsal tegmental nucleus during sleep and wakefulness.</a> Brain Res. 569 (2), 210-220 (1992).</li><li>Sakai, K., El Mansari, M., Jouvet, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inhibition+by+carbachol+microinjections+of+presumptive+cholinergic+PGO-on+neurons+in+freely+moving+cats.">Inhibition by carbachol microinjections of presumptive cholinergic PGO-on neurons in freely moving cats.</a> Brain Res. 527 (2), 213-223 (1990).</li><li>Lindsley, D. B., Bowden, J. W., 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=Effect+upon+the+EEG+of+acute+injury+to+the+brainstem+activating+system.">Effect upon the EEG of acute injury to the brainstem activating system.</a> Electroenceph. Clin. Neurophysiol. 1 (4), 475-486 (1949).</li><li>Moruzzi, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+sleep-waking+cycle.">The sleep-waking cycle.</a> Ergeb. Physiol. 64, 1-165 (1972).</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> Electroenceph. Clin. Neurophysiol. 1 (4), 455-473 (1949).</li><li>Steriade, M., Constantinescu, E., Apostol, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correlations+between+alterations+of+the+cortical+transaminase+activity+and+EEG+patterns+of+sleep+and+wakefulness+induced+by+brainstem+transections.">Correlations between alterations of the cortical transaminase activity and EEG patterns of sleep and wakefulness induced by brainstem transections.</a> Brain Res. 13 (1), 177-180 (1969).</li><li>Ishibashi, 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=Orexin+receptor+activation+generates+gamma+band+input+to+cholinergic+and+serotonergic+arousal+system+neurons+and+drives+an+intrinsic+Ca2++-dependent+resonance+in+LDT+and+PPT+cholinergic+neurons.">Orexin receptor activation generates gamma band input to cholinergic and serotonergic arousal system neurons and drives an intrinsic Ca2+ -dependent resonance in LDT and PPT cholinergic neurons.</a> Frontiers Neurol. 6, e120 (2015).</li><li>Brown, R. E., Winston, S., Basheer, R., Thakkar, M. M., McCarley, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrophysiological+characterization+of+neurons+in+the+dorsolateral+pontine+REM+sleep+induction+zone+of+the+rat:+intrinsic+membrane+properties+and+responses+to+carbachol+and+orexins.">Electrophysiological characterization of neurons in the dorsolateral pontine REM sleep induction zone of the rat: intrinsic membrane properties and responses to carbachol and orexins.</a> Neuroscience. 143 (3), 739-755 (2006).</li><li>Goetz, 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=On+the+role+of+the+pedunculopontine+nucleus+and+mesencephalic+reticular+formation+in+locomotion+in+non-human+primates.">On the role of the pedunculopontine nucleus and mesencephalic reticular formation in locomotion in non-human primates.</a> J. Neurosci. 36 (18), 4917-4929 (2016).</li><li>Fraix, V., 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=Pedunculopontine+nucleus+area+oscillations+during+stance,+stepping+and+freezing+in+Parkinson's+disease.">Pedunculopontine nucleus area oscillations during stance, stepping and freezing in Parkinson's disease.</a> PLOS ONE. 8 (12), e83919 (2013).</li><li>Luster, B., Hyde, J., D'Onofrio, S., Urbano, F. J., Garcia-Rill, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanisms+behind+gamma+band+activity+in+the+pedunculopontine+nucleus+(PPN).">Mechanisms behind gamma band activity in the pedunculopontine nucleus (PPN).</a> Abstr Soc Neurosci. 38, 257.20 (2014).</li><li>Luster, B., D'Onofrio, S., Urbano, F. J., Garcia-Rill, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-threshold+Ca2++channels+behind+gamma+band+activity+in+the+pedunculopontine+nucleus+(PPN).">High-threshold Ca2+ channels behind gamma band activity in the pedunculopontine nucleus (PPN).</a> Physiol. Rep. 3 (6), e12431 (2015).</li></ol>

PPN neurons have intrinsic properties that allow them to fire action potentials at beta/gamma band frequencies during in vivo recordings from animals that are awake or during REM sleep, but not during slow wave sleep2,3,5,13-17. Other authors have showed that brainstem transections at more anterior levels than PPN reduced gamma frequencies during EEG recordings. However, when brainstem lesions posterior to where this nucleus is located, the direct stimulation of PPN allowed the manifestation of cortic...

PPN nucleus is anatomically included in the caudal mesencephalic tegmentum. The PPN is a key component of RAS1. The PPN participates in the maintenance of behavioral activated states (i.e., waking, REM sleep)2. Electrical stimulation of the PPN in vivo induced fast oscillation (20 - 40 Hz) in the cortical EEG3, while bilateral PPN lesions in the rat reduced or eliminated REM sleep4. While a majority of PPN neurons fire action potentials at beta/gamma-band frequency (20 - 80 Hz), some neurons presented low rates of spontaneous firing (&#60; 10 Hz) 5. Furthermore, the PPN seems to be involved in other aspects of behavior such as motivation and attention6. Direct high frequency (40 - 60 Hz)7 electrical stimulation of PPN nucleus in decerebrate animals can promote locomotion. In recent years, deep brain stimulation (DBS) of PPN has been used to treat patients suffering from disorders involving gait deficits such as Parkinson&#39;s disease (PD)8.
Previous reports demonstrated that almost all PPN neurons can fire action potentials at gamma band frequency when depolarized using square current pulses9. Because of the drastic activation of voltage-gated potassium channels during square pulses depolarizations up to or under -25 mV. As a consequence, no robust gamma oscillations were observed after blocking action potentials generation using tetrodotoxin10. In an effort to bypass such a problem, 1 - 2 sec long depolarizing current ramps were used. Ramps gradually depolarized the membrane potential from resting values up to 0 mV, while partially inactivating voltage-gated potassium channels. Clear gamma band membrane oscillations were evident within the voltage dependence window of high threshold calcium channels (i.e., between -25 mV and -0 mV) 10. In conclusion, gamma band activity was observed in PPN neurons9, and both P/Q- and N-type voltage-gated calcium channels need to be activated in order to generate gamma band oscillations in the PPN10.
A series of studies determined the location of high threshold calcium channels in PPN neurons. Injecting the combination of dyes, ratiometric fluorescence imaging showed calcium transients through voltage-gated calcium channels that are activated in different dendrites when depolarized using current ramps11.
Intrinsic properties of PPN neurons have been suggested to allow simultaneous activation of these cells during waking and REM sleep, thus inducing high-frequency oscillatory neuronal activity between the RAS and thalamocortical loops. Such long-reaching interaction is considered to support a brain state capable of reliably assessing the world around us on a continuous basis12. Here, we describe the experimental conditions necessary to generate and maintain gamma band oscillation in PPN cells in vitro. This protocol has not been described previously, and would help a number of groups to study intrinsic membrane properties mediating gamma band activity at other brain areas. Moreover, current steps might lead to the erroneous conclusion that gamma band activity cannot be generated in these cells.

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			<td></td>
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		<tr height="40">
			<td height="40" style="height:40px;">Pump cartridge</td>
			<td>Cole-Parmer</td>
			<td>Masterflex 7519-85</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Pipette puller</td>
			<td>Sutter Instruments</td>
			<td>P-97</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Camera</td>
			<td>Q-Imaging</td>
			<td>RET-200R-F-M-12-C</td>
			<td></td>
		</tr>
		<tr height="33">
			<td height="33" style="height:33px;">Vibratome</td>
			<td>Leica Biosystems</td>
			<td>&#160;Leica VT1200 S</td>
			<td></td>
		</tr>
		<tr height="33">
			<td height="33" style="height:33px;">Refrigeration system</td>
			<td>Vibratome Instruments</td>
			<td>900R</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">microscope</td>
			<td>Nikon</td>
			<td>Eclipse E600FN</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">micromanipulator</td>
			<td>Sutter Instruments</td>
			<td>ROE-200</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">micromanipulator</td>
			<td>Sutter Instruments</td>
			<td>MPC-200</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">amplifier</td>
			<td>Molecular Devices</td>
			<td>Multiclamp 700B</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">A/D converter</td>
			<td>Molecular Devices</td>
			<td>Digidata 1440A</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">heater</td>
			<td>Warner Instruments</td>
			<td>TC-324B</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">pump</td>
			<td>Cole-Parmer</td>
			<td>Masterflex L/S 7519-20</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">pump cartridge</td>
			<td>Cole-Parmer</td>
			<td>Masterflex 7519-85</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">pipette puller</td>
			<td>Sutter Instruments</td>
			<td>P-97</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">camera</td>
			<td>Q-Imaging</td>
			<td>RET-200R-F-M-12-C</td>
			<td></td>
		</tr>
	</tbody>
</table>

recording gamma band oscillations in pedunculopontine nucleus neurons

Synaptic efferents from the PPN are known to modulate the neuronal activity of several intralaminar thalamic regions (e.g., the centrolateral/parafascicular; Cl/Pf nucleus). The activation of either the PPN or Cl/Pf nuclei in vivo has been described to induce the arousal of the animal and an increment in gamma band activity in the cortical electroencephalogram (EEG). The cellular mechanisms for the generation of gamma band oscillations in Reticular Activating System (RAS) neurons are the same as those found to generate gamma band oscillations in other brains nuclei. During current-clamp recordings of PPN neurons (from parasagittal slices from 9 - 25 day-old rats), the use of depolarizing square steps rapidly activated voltage-dependent potassium channels that prevented PPN neurons from being depolarized beyond -25 mV.
Injecting 1 - 2 sec long depolarizing current ramps gradually depolarized PPN membrane potential resting values towards 0 mV. However, injecting depolarizing square pulses generated gamma-band oscillations of membrane potential that showed to be smaller in amplitude compared to the oscillations generated by ramps. All experiments were performed in the presence of voltage-gated sodium channels and fast synaptic receptors blockers. It has been shown that the activation of high-threshold voltage-dependent calcium channels underlie gamma-band oscillatory activity in PPN neurons. Specific methodological and pharmacological interventions are described here, providing the necessary tools to induce and sustain PPN subthreshold gamma band oscillation in vitro.

Initially, gamma oscillations were evoked using square current pulses. Current clamp recording of PPN neurons in the presence of synaptic blockers and TTX was continuously monitored to assure that resting membrane potential was kept stable at ~-50 mV (Figure 1A). Two second long square current pulses were injected intracellularly by the patch clamp amplifier through the recording pipette, increasing their amplitude from 200 pA to 600 pA (Figure 1A). Membr...

Watch this Scientific Journal Video about Recording Gamma Band Oscillations in Pedunculopontine Nucleus Neurons at JoVE.com

Recording Gamma Band Oscillations in Pedunculopontine Nucleus Neurons

The pedunculopontine nucleus (PPN) is located in the brainstem and its neurons are maximally activated during waking and rapid eye movement (REM) sleep brain states. This work describes the experimental approach to record in vitro gamma band subthreshold membrane oscillation in PPN neurons.

Synaptic efferents from the PPN are known to modulate the neuronal activity of several intralaminar thalamic regions (e.g., the ...

The overall goal of this demonstration is to describe a method for detecting high threshold and subthreshold oscillations in pedunculopontine neurons. This method can help answer questions about, for example, how cells maintain their firing frequency. How do populations maintain their firing frequency?We know that circuits cannot maintain gamma band or 40 to 60 per second oscillations. Therefore, you require intrinsic membrane properties to maintain that kind of firing frequency. Demonstrating the procedure will be Susan Mahaffey and Dr.Stasia D'Onofrio.To prepare standard aCSF, first prepare stock solutions A and B and keep them refrigerated at four degrees Celsius for up to two weeks. Before each experiment, mix 50 milliliters of stock A with 50 milliliters of stock B.Then bring the mixture to one liter with distilled water and oxygenate it with carbogen at room temperature for at least 30 minutes. Transfer to a beaker for stirring and oxygenate.After bubbling, add the calcium chloride. Next, prepare sucrose aCSF by preparing stock solution C.Before each experiment, mix 300 milliliters of stock C with 600 milliliters of distilled water and oxygenate it with carbogen at room temperature for at least 30 minutes. After that, transfer 100 milliliters of sucrose aCSF solution to a clean beaker, place it on ice, and keep it oxygenated with carbogen.Now, fill up a vibratome cutting chamber with sucrose aCSF and keep it oxygenated. Turn on the glycerol-based refrigerating system coupled to the cutting chamber and wait 15 minutes to allow it to cool down to about four degrees Celsius. Next, remove the pup's brain by placing a spatula under the olfactory bulb and gently pushing it out from the most rostral area towards the most caudal area.Subsequently, place the brain into the ice-cold oxygenated sucrose aCSF. Make a parasagittal cut on the right hemisphere to remove approximately 1/3 of the hemisphere. Then, glue the trimmed side of the brain onto the metal disk.Subsequently, fix the metal disk to the vibratome cutting chamber and slice 400 micron sagittal sections containing the PPN. Keep the PPN slices at room temperature for 45 minutes prior to whole-cell patch clamp recording. In this procedure, transfer a slice to the submersion chamber, place a screen on top of it to hold the slice down, and perfuse it at 1.5 milliliters per minute with oxygenated aCSF containing the selected receptor antagonist.In order to isolate intrinsic membrane properties, what you need to do is block the fast synaptic transmission around the cell and also block the ability to generate action potentials, so you have to use synaptic blockers and tetrodotoxin, or TTX, in order to block action potentials. That way, the cell that you are patching is the one that generates those properties, and no synaptic input is responsible for those, and that's what we're studying here, intrinsic membrane property. After that, fill the recording patch pipette with intracellular high potassium solution.Insert the pipette in the headstage holder. Next, apply a small positive pressure using a one milliliter syringe connected to the pipette holder. Using a 4x objective together with the near infrared differential interference contrast optics, locate the PPN nucleus, which is dorsal to the superior cerebellar peduncle.Slowly lower the recording pipette to the PPN nucleus using a mechanical micromanipulater. Then position the recording pipette in the PPN pars compacta, which is located immediately dorsal to the posterior end of the peduncle. Using a 40x water immersion lens, bring the recording pipette in contact with the PPN neuron, and rapidly apply negative suction to form a seal with the cell.Use voltage clamp seal software to monitor the pipette resistance during negative suction. Then slowly increase the negative pressure. When the resistance value of the pipette reaches 80 to 100 megaohms, rapidly change the holding potential to 50 millivolts and release the negative pressure.Apply negative pressure continuously until the cell membrane is ruptured and electrical access is achieved in the wholesale configuration. Before suction, the resistance is low, in this case, 2.5 megaohms. As suction is applied, step amplitude decreases towards holding.When the seal is formed, note the resistance increases to 167 megaohms. With additional suction, a gigaseal is formed. Resistance briefly increases to 1.2 gigaohms before acquiring wholesale access.Continuously monitor the resting membrane potential of the PPN neuron being recording. If the resting membrane potential shifts towards depolarizing or hyperpolarizing values, apply a small amount of direct current to keep the optimal potential at 50 millivolts. The reason why we use current ramps is so that we can slowly depolarize the membrane without activating potassium channels that keep you from depolarizing the membrane sufficiently high to reach the threshold of these high-threshold calcium channels that we're studying.Shown here are the representative membrane potentials responding to the depolarizing two-second-long square steps of increasing current injected intracellularly through the recording pipette in the presence of synaptic blockers and TTX. This figure shows a power spectrum of the membrane oscillations induced by the indicated current steps in three recordings. The frequencies induced were all low in power and low in frequency.This figure shows the current ramps of 200, 400, and 700 picoamps and the membrane responses. Note that the membrane is sufficiently depolarized to reach 30 millivolts, at which high-threshold calcium channels begin to open, as in the blue recording, and the 10 millivolt level at which their oscillation amplitude is maximal, as in the red recording. This graph shows a power spectrum of the membrane oscillations induced by the current ramps in the corresponding three recordings.The frequencies induced by the 400 picoamp ramp were in the beta range, and by the 700 picoamp ramp were in the gamma range. Once mastered, this technique can be done in about an hour or less. When you're doing your recording, it's really important to make sure that you have a tight seal and that you have capacity compensation and series resistance well-monitored to make sure that there are no major changes during the recording procedure.Once you've isolated these oscillations, what you can do is test to determine if they're really mediated by N-type or P/Q-type calcium channels. You can use conotoxin to block N-type channel oscillations and agatoxin to block P/Q-type channel oscillations. As we developed this technique, it became much easier for you to demonstrate that indeed, high threshold calcium channels were dependent for intrinsic membrane oscillations, and it became a breakthrough in the field of sleep research to determine that the reticular activating system could actually generate gamma band oscillations by itself.

recording-gamma-band-oscillations-in-pedunculopontine-nucleus-neurons

Research

JoVE Journal

Neuroscience

Slice Preparation, Organotypic Tissue Culturing and Luciferase Recording of Clock Gene Activity in the Suprachiasmatic Nucleus

A central circadian (~24 hr) clock coordinating daily rhythms in physiology and behavior resides in the suprachiasmatic nucleus (SCN) located in the anterior hypothalamus. The clock is directly synchronized by light via the retina and optic nerve. Circadian oscillations are generated by interacting negative feedback loops of a number of so called "clock genes" and their protein products, including the Period (Per) genes. The core clock is also dependent on membrane depolarization, calcium and cAMP 1. The SCN shows daily oscillations in clock gene expression, metabolic activity and spontaneous electrical activity. Remarkably, this endogenous cyclic activity persists in adult tissue slices of the SCN 2-4. In this way, the biological clock can easily be studied in vitro, allowing molecular, electrophysiological and metabolic investigations of the pacemaker function.
The SCN is a small, well-defined bilateral structure located right above the optic chiasm 5. In the rat it contains ~8.000 neurons in each nucleus and has dimensions of approximately 947 &mu;m (length, rostrocaudal axis) x 424 &mu;m (width) x 390 &mu;m (height) 6. To dissect out the SCN it is necessary to cut a brain slice at the specific level of the brain where the SCN can be identified. Here, we describe the dissecting and slicing procedure of the SCN, which is similar for mouse and rat brains. Further, we show how to culture the dissected tissue organotypically on a membrane 7, a technique developed for SCN tissue culture by Yamazaki et al. 8. Finally, we demonstrate how transgenic tissue can be used for measuring expression of clock genes/proteins using dynamic luciferase reporter technology, a method that originally was used for circadian measurements by Geusz et al. 9. We here use SCN tissues from the transgenic knock-in PERIOD2::LUCIFERASE mice produced by Yoo et al. 10. The mice contain a fusion protein of PERIOD (PER) 2 and the firefly enzyme LUCIFERASE. When PER2 is translated in the presence of the substrate for luciferase, i.e. luciferin, the PER2 expression can be monitored as bioluminescence when luciferase catalyzes the oxidation of luciferin. The number of emitted photons positively correlates to the amount of produced PER2 protein, and the bioluminescence rhythms match the PER2 protein rhythm in vivo 10. In this way the cyclic variation in PER2 expression can be continuously monitored real time during many days. The protocol we follow for tissue culturing and real-time bioluminescence recording has been thoroughly described by Yamazaki and Takahashi 11.

The procedure of preparing slices containing the adult mouse hypothalamic suprachiasmatic nucleus (SCN), and a rapid way to culture the SCN tissue in organotypic culture condition, are reported. Further, the measurement of oscillatory clock gene protein expression using dynamic luciferase reporter technology is described.

A central circadian (~24 hr) clock coordinating daily rhythms in physiology and behavior resides in the suprachiasmatic nucleus (SCN) located in the ...

Large-scale Recording of Neurons by Movable Silicon Probes in Behaving Rodents

A major challenge in neuroscience is linking behavior to the collective activity of neural assemblies. Understanding of input-output relationships of neurons and circuits requires methods with the spatial selectivity and temporal resolution appropriate for mechanistic analysis of neural ensembles in the behaving animal, i.e. recording of representatively large samples of isolated single neurons. Ensemble monitoring of neuronal activity has progressed remarkably in the past decade in both small and large-brained animals, including human subjects1-11. Multiple-site recording with silicon-based devices are particularly effective because of their scalability, small volume and geometric design.
Here, we describe methods for recording multiple single neurons and local field potential in behaving rodents, using commercially available micro-machined silicon probes with custom-made accessory components. There are two basic options for interfacing silicon probes to preamplifiers: printed circuit boards and flexible cables. Probe supplying companies (<a href="http://www.neuronexustech.com/" >http://www.neuronexustech.com/</a>; <a href="http://www.sbmicrosystems.com/">http://www.sbmicrosystems.com/</a>; <a href="http://www.acreo.se/">http://www.acreo.se/</a>) usually provide the bonding service and deliver probes bonded to printed circuit boards or flexible cables. Here, we describe the implantation of a 4-shank, 32-site probe attached to flexible polyimide cable, and mounted on a movable microdrive. Each step of the probe preparation, microdrive construction and surgery is illustrated so that the end user can easily replicate the process.

We describe methods for large-scale recording of multiple single units and local field potential in behaving rodents with silicon probes. Drive fabrication, probe attachment to the drive and probe implantation processes are illustrated in sufficient details for easy replication.

A major challenge in neuroscience is linking behavior to the collective activity of neural assemblies. Understanding of input-output relationships of ...

Retrograde Fluorescent Labeling Allows for Targeted Extracellular Single-unit Recording from Identified Neurons In vivo

The overall goal of this method is to record single-unit responses from an identified population of neurons. In vivo electrophysiological recordings from individual neurons are critical for understanding how neural circuits function under natural conditions. Traditionally, these recordings have been performed 'blind', meaning the identity of the recorded cell is unknown at the start of the recording. Cellular identity can be subsequently determined via intracellular1, juxtacellular2 or loose-patch3 iontophoresis of dye, but these recordings cannot be pre-targeted to specific neurons in regions with functionally heterogeneous cell types. Fluorescent proteins can be expressed in a cell-type specific manner permitting visually-guided single-cell electrophysiology4-6. However, there are many model systems for which these genetic tools are not available. Even in genetically accessible model systems, the desired promoter may be unknown or genetically homogenous neurons may have varying projection patterns. Similarly, viral vectors have been used to label specific subgroups of projection neurons7, but use of this method is limited by toxicity and lack of trans-synaptic specificity. Thus, additional techniques that offer specific pre-visualization to record from identified single neurons in vivo are needed. Pre-visualization of the target neuron is particularly useful for challenging recording conditions, for which classical single-cell recordings are often prohibitively difficult8-11. The novel technique described in this paper uses retrograde transport of a fluorescent dye applied using tungsten needles to rapidly and selectively label a specific subset of cells within a particular brain region based on their unique axonal projections, thereby providing a visual cue to obtain targeted electrophysiological recordings from identified neurons in an intact circuit within a vertebrate CNS.
The most significant novel advancement of our method is the use of fluorescent labeling to target specific cell types in a non-genetically accessible model system. Weakly electric fish are an excellent model system for studying neural circuits in awake, behaving animals12. We utilized this technique to study sensory processing by "small cells" in the anterior exterolateral nucleus (ELa) of weakly electric mormyrid fish. "Small cells" are hypothesized to be time comparator neurons important for detecting submillisecond differences in the arrival times of presynaptic spikes13. However, anatomical features such as dense myelin, engulfing synapses, and small cell bodies have made it extremely difficult to record from these cells using traditional methods11, 14. Here we demonstrate that our novel method selectively labels these cells in 28% of preparations, allowing for reliable, robust recordings and characterization of responses to electrosensory stimulation.

Retrograde Fluorescent Labeling Allows for Targeted Extracellular Single-unit Recording from Identified Neurons In vivo

Retrograde transport of fluorescent dye labels a sub-population of neurons based on anatomical projection. Labeled axons can be visually targeted in vivo, permitting extracellular recording from identified axons. This technique facilitates recording when neurons cannot be labeled through genetic manipulation or are difficult to isolate using 'blind' in vivo approaches.

The overall goal of this method is to record single-unit responses from an identified population of neurons. In vivo electrophysiological recordings from ...

Recording Electrical Activity from Identified Neurons in the Intact Brain of Transgenic Fish

Understanding the cell physiology of neural circuits that regulate complex behaviors is greatly enhanced by using model systems in which this work can be performed in an intact brain preparation where the neural circuitry of the CNS remains intact. We use transgenic fish in which gonadotropin-releasing hormone (GnRH) neurons are genetically tagged with green fluorescent protein for identification in the intact brain. Fish have multiple populations of GnRH neurons, and their functions are dependent on their location in the brain and the GnRH gene that they express1 . We have focused our demonstration on GnRH3 neurons located in the terminal nerves (TN) associated with the olfactory bulbs using the intact brain of transgenic medaka fish (Figure 1B and C). Studies suggest that medaka TN-GnRH3 neurons are neuromodulatory, acting as a transmitter of information from the external environment to the central nervous system; they do not play a direct role in regulating pituitary-gonadal functions, as do the well-known hypothalamic GnRH1 neurons2, 3 .The tonic pattern of spontaneous action potential firing of TN-GnRH3 neurons is an intrinsic property4-6, the frequency of which is modulated by visual cues from conspecifics2 and the neuropeptide kisspeptin 15. In this video, we use a stable line of transgenic medaka in which TN-GnRH3 neurons express a transgene containing the promoter region of Gnrh3 linked to enhanced green fluorescent protein7 to show you how to identify neurons and monitor their electrical activity in the whole brain preparation6.

In this video, we will demonstrate how to record electrical activity from identified single neurons in a whole brain preparation, which preserves complex neural circuits. We use transgenic fish in which gonadotropin-releasing hormone (GnRH) neurons are genetically tagged with a fluorescent protein for identification in the intact brain preparation.

Understanding the cell physiology of neural circuits that regulate complex behaviors is greatly enhanced by using model systems in which this work can be ...

Intracellular Recording, Sensory Field Mapping, and Culturing Identified Neurons in the Leech, Hirudo medicinalis

The freshwater leech, Hirudo medicinalis, is a versatile model organism that has been used to address scientific questions in the fields of neurophysiology, neuroethology, and developmental biology. The goal of this report is to consolidate experimental techniques from the leech system into a single article that will be of use to physiologists with expertise in other nervous system preparations, or to biology students with little or no electrophysiology experience. We demonstrate how to dissect the leech for recording intracellularly from identified neural circuits in the ganglion. Next we show how individual cells of known function can be removed from the ganglion to be cultured in a Petri dish, and how to record from those neurons in culture. Then we demonstrate how to prepare a patch of innervated skin to be used for mapping sensory or motor fields. These leech preparations are still widely used to address basic electrical properties of neural networks, behavior, synaptogenesis, and development. They are also an appropriate training module for neuroscience or physiology teaching laboratories.

Intracellular Recording, Sensory Field Mapping, and Culturing Identified Neurons in the Leech, Hirudo medicinalis

This article describes three nervous system preparations using leeches: intracellular recording from neurons in ventral ganglia, culturing neurons from ventral ganglia, and recording from a patch of innervated skin to map sensory fields.

The freshwater leech, Hirudo medicinalis, is a versatile model organism that has been used to address scientific questions in the fields of ...

Simultaneous Electrophysiological Recording and Calcium Imaging of Suprachiasmatic Nucleus Neurons

Simultaneous electrophysiological and fluorescent imaging recording methods were used to study the role of changes of membrane potential or current in regulating the intracellular calcium concentration. Changing environmental conditions, such as the light-dark cycle, can modify neuronal and neural network activity and the expression of a family of circadian clock genes within the suprachiasmatic nucleus (SCN), the location of the master circadian clock in the mammalian brain. Excitatory synaptic transmission leads to an increase in the postsynaptic Ca2+ concentration that is believed to activate the signaling pathways that shifts the rhythmic expression of circadian clock genes. Hypothalamic slices containing the SCN were patch clamped using microelectrodes filled with an internal solution containing the calcium indicator bis-fura-2. After a seal was formed between the microelectrode and the SCN neuronal membrane, the membrane was ruptured using gentle suction and the calcium probe diffused into the neuron filling both the soma and dendrites. Quantitative ratiometric measurements of the intracellular calcium concentration were recorded simultaneously with membrane potential or current. Using these methods it is possible to study the role of changes of the intracellular calcium concentration produced by synaptic activity and action potential firing of individual neurons. In this presentation we demonstrate the methods to simultaneously record electrophysiological activity along with intracellular calcium from individual SCN neurons maintained in brain slices.

Procedures are described to perform simultaneous recordings of membrane potential or current and changes of intracellular calcium concentration. Suprachiasmatic nucleus neurons are filled with the calcium indicator bis-fura-2 using a patch clamp electrode in the whole cell patch clamp configuration.

Simultaneous electrophysiological and fluorescent imaging recording methods were used to study the role of changes of membrane potential or current in ...

Perforated Patch-clamp Recording of Mouse Olfactory Sensory Neurons in Intact Neuroepithelium: Functional Analysis of Neurons Expressing an Identified Odorant Receptor

Analyzing the physiological responses of olfactory sensory neurons (OSN) when stimulated with specific ligands is critical to understand the basis of olfactory-driven behaviors and their modulation. These coding properties depend heavily on the initial interaction between odor molecules and the olfactory receptor (OR) expressed in the OSNs. The identity, specificity and ligand spectrum of the expressed OR are critical. The probability to find the ligand of the OR expressed in an OSN chosen randomly within the epithelium is very low. To address this challenge, this protocol uses genetically tagged mice expressing the fluorescent protein GFP under the control of the promoter of defined ORs. OSNs are located in a tight and organized epithelium lining the nasal cavity, with neighboring cells influencing their maturation and function. Here we describe a method to isolate an intact olfactory epithelium and record through patch-clamp recordings the properties of OSNs expressing defined odorant receptors. The protocol allows one to characterize OSN membrane properties while keeping the influence of the neighboring tissue. Analysis of patch-clamp results yields&#160;a precise quantification of ligand/OR interactions, transduction pathways and pharmacology, OSNs&#39; coding properties and their modulation at the membrane level.&#160;

Analyzing the physiological properties of olfactory sensory neurons still faces technical limitations. Here we record them through perforated patch-clamp in an intact preparation of the olfactory epithelium in gene-targeted mice. This technique allows the characterization of membrane properties and responses to specific ligands of neurons expressing defined olfactory receptors.

Analyzing the physiological responses of olfactory sensory neurons (OSN) when stimulated with specific ligands is critical to understand the basis of ...

Tuning in the Hippocampal Theta Band In Vitro: Methodologies for Recording from the Isolated Rodent Septohippocampal Circuit

This protocol outlines the procedures for preparing and recording from the isolated whole hippocampus, of WT and transgenic mice, along with recent improvements in methodologies and applications for the study of theta oscillations. A simple characterization of the isolated hippocampal preparation is presented whereby the relationship between internal hippocampal theta oscillators is examined together with the activity of pyramidal cells, and GABAergic interneurons, of the cornu ammonis-1 (CA1) and subiculum (SUB) areas. Overall, we show that the isolated hippocampus is capable of generating intrinsic theta oscillations in vitro and that rhythmicity generated within the hippocampus can be precisely manipulated by optogenetic stimulation of parvalbumin-positive (PV) interneurons. The in vitro isolated hippocampal preparation offers a unique opportunity to use simultaneous field and intracellular patch-clamp recordings from visually-identified neurons to better understand the mechanisms underlying theta rhythm generation.

Tuning in the Hippocampal Theta Band In Vitro: Methodologies for Recording from the Isolated Rodent Septohippocampal Circuit

Here, we present a protocol for recording rhythmic neuronal network theta and gamma oscillations from an isolated whole hippocampal preparation. We describe the experimental steps from extraction of the hippocampus to details of field, unitary and whole-cell patch clamp recordings as well as optogenetic pacing of the theta rhythm.

This protocol outlines the procedures for preparing and recording from the isolated whole hippocampus, of WT and transgenic mice, along with recent ...

Optogenetic Entrainment of Hippocampal Theta Oscillations in Behaving Mice

Extensive data on relationships of neural network oscillations to behavior and organization of neuronal discharge across brain regions call for new tools to selectively manipulate brain rhythms. Here we describe an approach combining projection-specific optogenetics with extracellular electrophysiology for high-fidelity control of hippocampal theta oscillations (5-10 Hz) in behaving mice. The specificity of the optogenetic entrainment is achieved by targeting channelrhodopsin-2 (ChR2) to the GABAergic population of medial septal cells, crucially involved in the generation of hippocampal theta oscillations, and a local synchronized activation of a subset of inhibitory septal afferents in the hippocampus. The efficacy of the optogenetic rhythm control is verified by a simultaneous monitoring of the local field potential (LFP) across lamina of the CA1 area and/or of neuronal discharge. Using this readily implementable preparation we show efficacy of various optogenetic stimulation protocols for induction of theta oscillations and for the manipulation of their frequency and regularity. Finally, a combination of the theta rhythm control with projection-specific inhibition addresses the readout of particular aspects of the hippocampal synchronization by efferent regions.

We describe the use of optogenetics and electrophysiological recordings for selective manipulations of hippocampal theta oscillations (5-10 Hz) in behaving mice. The efficacy of the rhythm entrainment is monitored using local field potential. A combination of opto- and pharmacogenetic inhibition addresses the efferent readout of hippocampal synchronization.

Extensive data on relationships of neural network oscillations to behavior and organization of neuronal discharge across brain regions call for new tools ...

Preparations and Protocols for Whole Cell Patch Clamp Recording of Xenopus laevis Tectal Neurons

The Xenopus tadpole retinotectal circuit, comprised of the retinal ganglion cells (RGCs) in the eye which form synapses directly onto neurons in the optic tectum, is a popular model to study how neural circuits self-assemble. The ability to carry out whole cell patch clamp recordings from tectal neurons and to record RGC-evoked responses, either in vivo or using a whole brain preparation, has generated a large body of high-resolution data about the mechanisms underlying normal, and abnormal, circuit formation and function. Here we describe how to perform the in vivo preparation, the original whole brain preparation, and a more recently developed horizontal brain slice preparation for obtaining whole cell patch clamp recordings from tectal neurons. Each preparation has unique experimental advantages. The in vivo preparation enables the recording of the direct response of tectal neurons to visual stimuli projected onto the eye. The whole brain preparation allows for the RGC axons to be activated in a highly controlled manner, and the horizontal brain slice preparation allows recording from across all layers of the tectum.

Preparations and Protocols for Whole Cell Patch Clamp Recording of Xenopus laevis Tectal Neurons

In this paper, we discuss three brain preparations used for whole cell patch clamp recording to study the retinotectal circuit of Xenopus laevis tadpoles. Each preparation, with its own specific advantages, contributes to the experimental tractability of the Xenopus tadpole as a model to study neural circuit function.

The Xenopus tadpole retinotectal circuit, comprised of the retinal ganglion cells (RGCs) in the eye which form synapses directly onto neurons in the optic ...