Diese Arbeit wurde von den kanadischen Instituten für Gesundheitsforschung und Naturwissenschaften unterstützt.

<ol>
	<li>Buzsaki, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Theta+rhythm+of+navigation:+link+between+path+integration+and+landmark+navigation,+episodic+and+semantic+memory.">Theta rhythm of navigation: link between path integration and landmark navigation, episodic and semantic memory.</a> Hippocampus. 15 (7), 827-840 (2005).</li><li>Sanders, H., Renno-Costa, C., Idiart, M., Lisman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Grid+Cells+and+Place+Cells:+An+Integrated+View+of+their+Navigational+and+Memory+Function.">Grid Cells and Place Cells: An Integrated View of their Navigational and Memory Function.</a> Trends Neurosci. 38 (12), 763-775 (2015).</li><li>O'Keefe, J., Recce, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phase+relationship+between+hippocampal+place+units+and+the+EEG+theta+rhythm.">Phase relationship between hippocampal place units and the EEG theta rhythm.</a> Hippocampus. 3 (3), 317-330 (1993).</li><li>Winson, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Loss+of+hippocampal+theta+rhythm+results+in+spatial+memory+deficit+in+the+rat.">Loss of hippocampal theta rhythm results in spatial memory deficit in the rat.</a> Science. 201 (4351), 160-163 (1978).</li><li>M'Harzi, M., Jarrard, L. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strategy+selection+in+a+task+with+spatial+and+nonspatial+components:+effects+of+fimbria-fornix+lesions+in+rats.">Strategy selection in a task with spatial and nonspatial components: effects of fimbria-fornix lesions in rats.</a> Behav Neural Biol. 58 (3), 171-179 (1992).</li><li>Osipova, D., 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=Theta+and+gamma+oscillations+predict+encoding+and+retrieval+of+declarative+memory.">Theta and gamma oscillations predict encoding and retrieval of declarative memory.</a> J Neurosci. 26 (28), 7523-7531 (2006).</li><li>Stumpf, C., Petsche, H., Gogolak, 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+significance+of+the+rabbit's+septum+as+a+relay+station+between+the+midbrain+and+the+hippocampus.+II.+The+differential+influence+of+drugs+upon+both+the+septal+cell+firing+pattern+and+the+hippocampus+theta+activity.">The significance of the rabbit's septum as a relay station between the midbrain and the hippocampus. II. The differential influence of drugs upon both the septal cell firing pattern and the hippocampus theta activity.</a> Electroencephalogr Clin Neurophysiol. 14, 212-219 (1962).</li><li>Mitchell, S. J., Ranck, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+theta+rhythm+in+medial+entorhinal+cortex+of+freely+moving+rats.">Generation of theta rhythm in medial entorhinal cortex of freely moving rats.</a> Brain Res. 189 (1), 49-66 (1980).</li><li>Alonso, A., Garcia-Austt, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neuronal+sources+of+theta+rhythm+in+the+entorhinal+cortex+of+the+rat.+I.+Laminar+distribution+of+theta+field+potentials.">Neuronal sources of theta rhythm in the entorhinal cortex of the rat. I. Laminar distribution of theta field potentials.</a> Exp Brain Res. 67 (3), 493-501 (1987).</li><li>Vertes, R. P., Kocsis, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Brainstem-diencephalo-septohippocampal+systems+controlling+the+theta+rhythm+of+the+hippocampus.">Brainstem-diencephalo-septohippocampal systems controlling the theta rhythm of the hippocampus.</a> Neuroscience. 81 (4), 893-926 (1997).</li><li>Bland, B. H., Colom, L. V., Konopacki, J., Roth, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intracellular+records+of+carbachol-induced+theta+rhythm+in+hippocampal+slices.">Intracellular records of carbachol-induced theta rhythm in hippocampal slices.</a> Brain Res. 447 (2), 364-368 (1988).</li><li>Cobb, S. R., Buhl, E. H., Halasy, K., Paulsen, O., Somogyi, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synchronization+of+neuronal+activity+in+hippocampus+by+individual+GABAergic+interneurons.">Synchronization of neuronal activity in hippocampus by individual GABAergic interneurons.</a> Nature. 378 (6552), 75-78 (1995).</li><li>Williams, J. H., Kauer, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Properties+of+carbachol-induced+oscillatory+activity+in+rat+hippocampus.">Properties of carbachol-induced oscillatory activity in rat hippocampus.</a> J Neurophysiol. 78 (5), 2631-2640 (1997).</li><li>Chapman, C. A., Lacaille, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cholinergic+induction+of+theta-frequency+oscillations+in+hippocampal+inhibitory+interneurons+and+pacing+of+pyramidal+cell+firing.">Cholinergic induction of theta-frequency oscillations in hippocampal inhibitory interneurons and pacing of pyramidal cell firing.</a> J Neurosci. 19 (19), 8637-8645 (1999).</li><li>Strata, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intrinsic+oscillations+in+CA3+hippocampal+pyramids:+physiological+relevance+to+theta+rhythm+generation.">Intrinsic oscillations in CA3 hippocampal pyramids: physiological relevance to theta rhythm generation.</a> Hippocampus. 8 (6), 666-679 (1998).</li><li>Kocsis, B., Bragin, A., Buzsaki, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interdependence+of+multiple+theta+generators+in+the+hippocampus:+a+partial+coherence+analysis.">Interdependence of multiple theta generators in the hippocampus: a partial coherence analysis.</a> J Neurosci. 19 (14), 6200-6212 (1999).</li><li>Fellous, J. M., Sejnowski, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cholinergic+induction+of+oscillations+in+the+hippocampal+slice+in+the+slow+(0.5-2+Hz),+theta+(5-12+Hz),+and+gamma+(35-70+Hz)+bands.">Cholinergic induction of oscillations in the hippocampal slice in the slow (0.5-2 Hz), theta (5-12 Hz), and gamma (35-70 Hz) bands.</a> Hippocampus. 10 (2), 187-197 (2000).</li><li>Gillies, M. J., 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+model+of+atropine-resistant+theta+oscillations+in+rat+hippocampal+area+CA1.">A model of atropine-resistant theta oscillations in rat hippocampal area CA1.</a> J Physiol. 543 (Pt 3), 779-793 (2002).</li><li>Gloveli, 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=Orthogonal+arrangement+of+rhythm-generating+microcircuits+in+the+hippocampus.">Orthogonal arrangement of rhythm-generating microcircuits in the hippocampus.</a> Proc Natl Acad Sci U S A. 102 (37), 13295-13300 (2005).</li><li>Konopacki, J., Eckersdorf, B., Kowalczyk, T., Golebiewski, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Firing+cell+repertoire+during+carbachol-induced+theta+rhythm+in+rat+hippocampal+formation+slices.">Firing cell repertoire during carbachol-induced theta rhythm in rat hippocampal formation slices.</a> Eur J Neurosci. 23 (7), 1811-1818 (2006).</li><li>Hajos, N., 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=Maintaining+network+activity+in+submerged+hippocampal+slices:+importance+of+oxygen+supply.">Maintaining network activity in submerged hippocampal slices: importance of oxygen supply.</a> Eur J Neurosci. 29 (2), 319-327 (2009).</li><li>Manseau, F., Goutagny, R., Danik, M., Williams, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+hippocamposeptal+pathway+generates+rhythmic+firing+of+GABAergic+neurons+in+the+medial+septum+and+diagonal+bands:+an+investigation+using+a+complete+septohippocampal+preparation+in+vitro.">The hippocamposeptal pathway generates rhythmic firing of GABAergic neurons in the medial septum and diagonal bands: an investigation using a complete septohippocampal preparation in vitro.</a> J Neurosci. 28 (15), 4096-4107 (2008).</li><li>Goutagny, R., Jackson, J., Williams, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-generated+theta+oscillations+in+the+hippocampus.">Self-generated theta oscillations in the hippocampus.</a> Nat Neurosci. 12 (12), 1491-1493 (2009).</li><li>Jackson, J., Goutagny, R., Williams, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fast+and+slow+gamma+rhythms+are+intrinsically+and+independently+generated+in+the+subiculum.">Fast and slow gamma rhythms are intrinsically and independently generated in the subiculum.</a> J Neurosci. 31 (34), 12104-12117 (2011).</li><li>Amilhon, B., 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=Parvalbumin+Interneurons+of+Hippocampus+Tune+Population+Activity+at+Theta+Frequency.">Parvalbumin Interneurons of Hippocampus Tune Population Activity at Theta Frequency.</a> Neuron. 86 (5), 1277-1289 (2015).</li><li>Huh, C. 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=Excitatory+Inputs+Determine+Phase-Locking+Strength+and+Spike-Timing+of+CA1+Stratum+Oriens/Alveus+Parvalbumin+and+Somatostatin+Interneurons+during+Intrinsically+Generated+Hippocampal+Theta+Rhythm.">Excitatory Inputs Determine Phase-Locking Strength and Spike-Timing of CA1 Stratum Oriens/Alveus Parvalbumin and Somatostatin Interneurons during Intrinsically Generated Hippocampal Theta Rhythm.</a> J Neurosci. 36 (25), 6605-6622 (2016).</li><li>Gu, N., 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=NMDA-dependent+phase+synchronization+between+septal+and+temporal+CA3+hippocampal+networks.">NMDA-dependent phase synchronization between septal and temporal CA3 hippocampal networks.</a> J Neurosci. 33 (19), 8276-8287 (2013).</li><li>Jackson, J., 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=Reversal+of+theta+rhythm+flow+through+intact+hippocampal+circuits.">Reversal of theta rhythm flow through intact hippocampal circuits.</a> Nat Neurosci. 17 (10), 1362-1370 (2014).</li><li>Gonzalez-Burgos, G., Lewis, D. 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Die Autoren erklären keine konkurrierenden kommerziellen oder finanziellen Interessen.

Während elektrophysiologische Aufnahmen von akuten Hippocampusscheiben eine Standard- In-vitro- Technik darstellen, unterscheiden sich die hier vorgestellten Methoden erheblich vom klassischen Ansatz. Anders als die dünnen Scheibenpräparate, bei denen spezifische Zellschichten an der Oberfläche sichtbar sind und direkt untersucht werden können, sind die intakten Hippocampuspräparate eher in in vivo- Konfigurationen verwandt, bei denen Elektroden in gezielte Hirnregionen abgesenkt werden,...

Hippocampale Theta-Oszillationen (4 - 12 Hz) gehören zu den vorherrschenden Formen der rhythmischen Aktivität im Säugetiergehirn und werden geglaubt, um Schlüsselrollen in kognitiven Funktionen wie die Verarbeitung von räumlich-zeitlichen Informationen und die Bildung episodischer Erinnerungen 1 , 2 , 3 zu spielen . Während mehrere In-vivo- Studien, die das Verhältnis von theta-modulierten Ort-Zellen mit räumlichen Navigations- und Läsionsstudien hervorheben, sowie klinische Evidenz unterstützen die Ansicht, dass hippocampale Theta-Oszillationen in die Gedächtnisbildung 4 , 5 , 6 involviert sind, Mit der Erzeugung von hippocampalen Theta-Oszillationen sind noch nicht vollständig verstanden In frühen In-vivo- Untersuchungen wurde vorgeschlagen, dass die Theta-Aktivität hauptsächlich von extrinsischen Oszillatoren, insbesondere rhythmischen Inputs, abhingVon afferenten Hirnstrukturen wie dem Septum und dem entorhinalen Kortex 7 , 8 , 9 , 10 . Eine Rolle für intrinsische Faktoren - interne Konnektivität von hippocampalen neuronalen Netzwerken zusammen mit den Eigenschaften von Hippocampusneuronen - wurde auch auf der Basis von in vitro Beobachtungen 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 postuliert. Abgesehen von einigen Landmarkstudien 19 , 20 , 21 sind jedoch Schwierigkeiten bei der Entwicklung von Ansätzen, die physiologisch realistische Populationsaktivitäten in einer einfachen In-vitro- Schichtvorbereitung replizieren könntenS hat seit langem eine detailliertere experimentelle Untersuchung der intrinsischen Fähigkeiten des Hippocampus und der verwandten Gebiete zur Selbst-Erzeugung von Theta-Schwingungen verzögert. Ein wichtiger Nachteil der Standard- In-vitro- Dünnschicht-Versuchsanpassung ist, dass die 3D-zelluläre und synaptische Organisation von Hirnstrukturen in der Regel kompromittiert wird. Dies bedeutet, dass viele Formen von konzertierten Netzwerkaktivitäten, die auf räumlich verteilten Zellanordnungen basieren, von lokalisierten Gruppen (≤1 mm Radius) bis hin zu Populationen von Neuronen, die sich über ein oder mehrere Gehirnbereiche (&gt; 1 mm) erstrecken, nicht unterstützt werden können. Angesichts dieser Überlegungen war eine andere Art von Ansatz erforderlich, um zu untersuchen, wie Theta-Oszillationen im Hippocampus entstehen und sich auf verwandte kortikale und subkortikale Ausgangsstrukturen ausbreiten. In den letzten Jahren wurde die anfängliche Entwicklung der &quot;kompletten septo-hippocampalen&quot; Präparation zur bidirektionalen Intera untersuchtCtions der beiden Strukturen 22 und die anschließende Evolution der &quot;isolierten Hippocampus&quot; -Präparation haben ergeben, dass intrinsische Theta-Oszillationen spontan im Hippocampus ohne externe rhythmische Input 23 auftreten . Der Wert dieser Ansätze liegt in der ersten Einsicht, dass die gesamte funktionale Struktur dieser Regionen bewahrt werden musste, um als ein Theta-Rhythmus-Generator in vitro zu funktionieren 22 .

<table border="0" cellpadding="0" cellspacing="0" width="820">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:319px;">Reagents</td>
			<td style="width:135px;"></td>
			<td style="width:119px;"></td>
			<td style="width:247px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium Chloride</td>
			<td>Sigma Aldrich</td>
			<td>S9625</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sucrose</td>
			<td>Sigma Aldrich</td>
			<td>S9378</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium Bicarbonate</td>
			<td>Sigma Aldrich</td>
			<td>S5761</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">NaH2PO4 - sodium phosphate monobasic</td>
			<td>Sigma Aldrich</td>
			<td>S8282</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Magnesium sulfate</td>
			<td>Sigma Aldrich</td>
			<td>M7506</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Potassium Chloride</td>
			<td>Sigma Aldrich</td>
			<td>P3911</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">D-(+)-Glucose</td>
			<td>Sigma Aldrich</td>
			<td>G7528</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Calcium chloride dihydrate</td>
			<td>Sigma Aldrich</td>
			<td>C5080</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium Ascorbate</td>
			<td>Sigma Aldrich</td>
			<td>A7631-25G</td>
			<td></td>
		</tr>
		<tr height="30">
			<td height="30" style="height:30px;width:319px;">Name</td>
			<td style="width:135px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Standard Dissecting Scissors</td>
			<td>Fisher Scientific</td>
			<td>08-951-25</td>
			<td>brain extraction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Scalpel Handle #4, 14cm</td>
			<td>WPI</td>
			<td>500237</td>
			<td>brain extraction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Filter forceps, flat jaws, straight (11cm)</td>
			<td>WPI</td>
			<td>500456</td>
			<td>brain extraction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Paragon Stainless Steel Scalpel Blades #20</td>
			<td>Ultident</td>
			<td>02-90010-20</td>
			<td>brain extraction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Fine Point Curved Dissecting Scissors</td>
			<td>Thermo Fisher Scientific</td>
			<td>711999</td>
			<td>brain extraction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Teflon (PTFE) -coated thin spatula</td>
			<td>VWR</td>
			<td>82027-534</td>
			<td>hippocampal preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hayman Style Microspatula</td>
			<td>Fisher Scientific</td>
			<td>21-401-25A</td>
			<td>hippocampal preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Lab spoon</td>
			<td>Fisher Scientific</td>
			<td>14-375-20</td>
			<td>hippocampal preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Borosilicate Glass Pasteur Pipets</td>
			<td>Fisher Scientific</td>
			<td>13-678-20A</td>
			<td>hippocampal preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Droper</td>
			<td>Fisher Scientific</td>
			<td></td>
			<td>hippocampal preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Razor blades Single edged</td>
			<td>VWR</td>
			<td>55411-055</td>
			<td>hippocampal preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Lens paper (4X6 inch)</td>
			<td>VWR</td>
			<td>52846-001</td>
			<td>hippocampal preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Glass petri dishes (100 x 20 mm)</td>
			<td>VWR</td>
			<td>25354-080</td>
			<td>hippocampal preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Plastic tray for ice; size 30 x 20 x 5 cm</td>
			<td>n.a.</td>
			<td>n.a.</td>
			<td>hippocampal preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Single Inline Solution Heater</td>
			<td>Warner Instruments</td>
			<td>SH-27B</td>
			<td>perfusion system</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Aquarium air stones for bubbling</td>
			<td>n.a.</td>
			<td>n.a.</td>
			<td>perfusion system</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Tygon E-3603 tubing (ID 1/16 OD 1/8)</td>
			<td>Fisherbrand</td>
			<td>14-171-129</td>
			<td>perfusion system</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Electric Skillet</td>
			<td>Black &#38; Decker</td>
			<td>n.a.</td>
			<td>perfusion system</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">95% O2/5% CO2 gas mixture (carbogen)&#160;</td>
			<td>Vitalaire</td>
			<td>SG466204A</td>
			<td>perfusion system</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Glass bottles/flasks (4 x 1 L)</td>
			<td>n.a.</td>
			<td>n.a.</td>
			<td>perfusion system</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Submerged recording Chamber</td>
			<td>custom design (FM)</td>
			<td>n.a.</td>
			<td style="width:247px;">Commercial alternative may be used</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Glass pipettes (1.5 / 0.84 OD/ID (mm) )</td>
			<td>WPI</td>
			<td>1B150F-4</td>
			<td>electrophysiology</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hum Bug 50/60 Hz Noise Eliminator</td>
			<td>Quest Scientific</td>
			<td>Q-Humbug</td>
			<td>electrophysiology</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Multiclamp 700B patch-clamp amplifier</td>
			<td>Molecular devices</td>
			<td>MULTICLAMP</td>
			<td>electrophysiology</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Multiclamp 700B Commander Program</td>
			<td>Molecular devices</td>
			<td>MULTICLAMP</td>
			<td>electrophysiology</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Digital/Analogue converter</td>
			<td>Molecular devices</td>
			<td>DDI440</td>
			<td>electrophysiology</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">PCLAMP10</td>
			<td>Molecular devices</td>
			<td>PCLAMP10</td>
			<td>electrophysiology</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Vibration isolation table&#160;</td>
			<td>Newport</td>
			<td>n.a.</td>
			<td>electrophysiology</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Micromanipulators (manually operated )</td>
			<td>Siskiyou&#160;</td>
			<td>MX130</td>
			<td>electrophysiology (LFP)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Micromanipulators (automated)</td>
			<td>Siskiyou&#160;</td>
			<td>MC1000e</td>
			<td>electrophysiology (patch)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Audio monitor&#160;</td>
			<td>A-M Systems</td>
			<td>Model 3300</td>
			<td>electrophysiology</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Micropipette/Patch pipette puller</td>
			<td>Sutter</td>
			<td>P-97</td>
			<td>electrophysiology</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Custom-built upright fluorescence microscope</td>
			<td>Siskiyou</td>
			<td>n.a.</td>
			<td>Imaging</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Analogue video camera</td>
			<td>COHU</td>
			<td>4912-2000/0000</td>
			<td>Imaging</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Digital frame grabber with imaging software</td>
			<td>EPIX, Inc</td>
			<td>PIXCI-SV7</td>
			<td>Imaging</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Olympus 2.5x objective</td>
			<td>Olympus</td>
			<td>MPLFLN</td>
			<td>Imaging</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Olympus 40x water immersion objective</td>
			<td>Olympus</td>
			<td>UIS2 LUMPLFLN</td>
			<td>Imaging</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Custom-made light-emitting diode (LED) system&#160;</td>
			<td>custom</td>
			<td>n.a.</td>
			<td>optogenetic stimulation (Amhilon et al., 2015)</td>
		</tr>
		<tr height="30">
			<td height="30" style="height:30px;width:319px;">Name</td>
			<td style="width:135px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Animals</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:319px;">PV::Cre (KI) mice</td>
			<td style="width:135px;">Jackson Laboratory</td>
			<td style="width:119px;">stock number 008069</td>
			<td style="width:247px;">Allow&#160; Cre-directed gene expression in PV interneurons</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:319px;">Constitutive-conditional Ai9 mice (R26-lox-stop-lox-tdTomato (KI))</td>
			<td style="width:135px;">Jackson Laboratory</td>
			<td style="width:119px;">stock number 007905</td>
			<td style="width:247px;">Express TdTomato following Cre-mediated recombination</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:319px;">Ai32 mice (R26-lox-stop-lox-ChR2(H134R)-EYFP</td>
			<td style="width:135px;">Jackson Laboratory</td>
			<td style="width:119px;">stock 
			number 012569</td>
			<td style="width:247px;">Express the improved channelrhodopsin-2/EYFP fusion protein following exposure to Cre recombinase</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">PVChY mice</td>
			<td>In house breeding</td>
			<td>n.a.</td>
			<td style="width:247px;">Offspring obtained from cross-breeding the PV-Cre line with Ai32 mice (R26-lox-stop-lox-ChR2(H134R)-EYFP</td>
		</tr>
	</tbody>
</table>

tuning in the hippocampal theta band in vitro: methodologies for recording from the isolated rodent septohippocampal circuit

Dieses Protokoll beschreibt die Verfahren für die Vorbereitung und Aufzeichnung aus dem isolierten ganzen Hippocampus, von WT und transgenen Mäusen, zusammen mit den jüngsten Verbesserungen in Methoden und Anwendungen für das Studium der Theta-Oszillationen. Es wird eine einfache Charakterisierung des isolierten Hippocampuspräparates vorgestellt, wobei die Beziehung zwischen internen hippocampalen Theta-Oszillatoren zusammen mit der Aktivität von Pyramidenzellen und GABAergischen Interneuronen der Cornu-Ammoni-1 (CA1) und Subiculum (SUB) -Flächen untersucht wird. Insgesamt zeigen wir, dass der isolierte Hippocampus in der Lage ist, intrinsische Theta-Oszillationen in vitro zu erzeugen, und die innerhalb des Hippocampus erzeugte Rhythmizität kann durch optogenetische Stimulation von parvalbumin-positiven (PV) Interneuronen präzise manipuliert werden. Die in vitro isolierte Hippocampuspräparation bietet eine einmalige Gelegenheit, simultane Feld- und intrazelluläre Patch-Clamp-Aufnahmen von visuell identifiziertem neu zu verwendenRons, um die Mechanismen zu verstehen, die der Theta-Rhythmus-Generation zugrunde liegen.

<html> Dieser Abschnitt veranschaulicht Beispiele für Ergebnisse, die durch das Studium der Theta-Oszillationen in der Maus isolierten Hippocampus-Präparation in vitro erhalten werden können . Das Sektionsverfahren zum Extrahieren des isolierten Hippocampus ist in Fig. 1 dargestellt . Mit dieser Vorbereitung können intrinsische Theta-Oszillationen bei der Platzierung von Mehrfachfeld-Elektroden untersucht werden, wobei die Gesamtaktivität und di...

Watch this Scientific Journal Video about Tuning in the Hippocampal Theta Band In Vitro: Methodologies for Recording from the Isolated Rodent Septohippocampal Circuit at JoVE.com

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

Hier präsentieren wir ein Protokoll zur Aufzeichnung von rhythmischen neuronalen Netzwerk-Theta und Gamma-Oszillationen aus einer isolierten ganzen Hippocampus-Präparation. Wir beschreiben die experimentellen Schritte von der Extraktion des Hippocampus bis hin zu Details der Feld-, Einheits- und Ganzzell-Patch-Clamp-Aufnahmen sowie der optogenetischen Stimulation des Theta-Rhythmus.

Tuning in der Hippocampal Theta Band<em&gt; In vitro</em&gt;: Methoden für die Aufnahme aus dem isolierten Nagetier Septohippocampal Circuit

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

tuning-hippocampal-theta-band-vitro-methodologies-for-recording-from

Research

JoVE Journal

Neuroscience

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

9.7K Aufrufe.  McGill University.  Hier präsentieren wir ein Protokoll zur Aufzeichnung von rhythmischen neuronalen Netzwerk-Theta und Gamma-Oszillationen aus einer isolierten ganzen Hippocampus-Präparation. Wir beschreiben die experimentellen Schritte von der Extraktion des Hippocampus bis hin zu Details der Feld-, Einheits- und Ganzzell-Patch-Clamp-Aufnahmen sowie der optogenetischen Stimulation des Theta-Rhythmus. 

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

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.

Retrograde Fluoreszenzmarkierung Ermöglicht Gezielte Extracellular Einzel-Einheit Aufnahme von identifizierten Neuronen<em&gt; In vivo</em

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

Forschung

Neurowissenschaften

Investigations on Alterations of Hippocampal Circuit Function Following Mild Traumatic Brain Injury

Traumatic Brain Injury (TBI) afflicts more than 1.7 million people in the United States each year and even mild TBI can lead to persistent neurological impairments 1. Two pervasive and disabling symptoms experienced by TBI survivors, memory deficits and a reduction in seizure threshold, are thought to be mediated by TBI-induced hippocampal dysfunction 2,3. In order to demonstrate how altered hippocampal circuit function adversely affects behavior after TBI in mice, we employ lateral fluid percussion injury, a commonly used animal model of TBI that recreates many features of human TBI including neuronal cell loss, gliosis, and ionic perturbation 4-6.
	Here we demonstrate a combinatorial method for investigating TBI-induced hippocampal dysfunction. Our approach incorporates multiple ex vivo physiological techniques together with animal behavior and biochemical analysis, in order to analyze post-TBI changes in the hippocampus. We begin with the experimental injury paradigm along with behavioral analysis to assess cognitive disability following TBI. Next, we feature three distinct ex vivo recording techniques: extracellular field potential recording, visualized whole-cell patch-clamping, and voltage sensitive dye recording. Finally, we demonstrate a method for regionally dissecting subregions of the hippocampus that can be useful for detailed analysis of neurochemical and metabolic alterations post-TBI.
	These methods have been used to examine the alterations in hippocampal circuitry following TBI and to probe the opposing changes in network circuit function that occur in the dentate gyrus and CA1 subregions of the hippocampus (see Figure 1). The ability to analyze the post-TBI changes in each subregion is essential to understanding the underlying mechanisms contributing to TBI-induced behavioral and cognitive deficits. 
	The multi-faceted system outlined here allows investigators to push past characterization of phenomenology induced by a disease state (in this case TBI) and determine the mechanisms responsible for the observed pathology associated with TBI.

A multi-faceted approach to investigating functional changes to hippocampal circuitry is explained. Electrophysiological techniques are described along with the injury protocol, behavioral testing and regional dissection method. The combination of these techniques can be applied in similar fashion for other brain regions and scientific questions.

Untersuchungen über Veränderungen der hippokampalen Schaltung Funktion Nach Mild Traumatic Brain Injury

Traumatic Brain Injury (TBI) afflicts more than 1.7 million people in the United States each year and even mild TBI can lead to persistent neurological ...

Dual Electrophysiological Recordings of Synaptically-evoked Astroglial and Neuronal Responses in Acute Hippocampal Slices

Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs through activation of their ion channels and neurotransmitter receptors, and process information in part through activity-dependent release of gliotransmitters. Furthermore, astrocytes constitute the main uptake system for glutamate, contribute to potassium spatial buffering, as well as to GABA clearance. These cells therefore constantly monitor synaptic activity, and are thereby sensitive indicators for alterations in synaptically-released glutamate, GABA and extracellular potassium levels. Additionally, alterations in astroglial uptake activity or buffering capacity can have severe effects on neuronal functions, and might be overlooked when characterizing physiopathological situations or knockout mice. Dual recording of neuronal and astroglial activities is therefore an important method to study alterations in synaptic strength associated to concomitant changes in astroglial uptake and buffering capacities. Here we describe how to prepare hippocampal slices, how to identify stratum radiatum astrocytes, and how to record simultaneously neuronal and astroglial electrophysiological responses. Furthermore, we describe how to isolate pharmacologically the synaptically-evoked astroglial currents.

The preparation of acute brain slices from isolated hippocampi, as well as the simultaneous electrophysiological recordings of astrocytes and neurons in stratum radiatum during stimulation of schaffer collaterals is described. The pharmacological isolation of astroglial potassium and glutamate transporter currents is demonstrated.

Dual-Elektrophysiologische Recordings synaptisch-evozierte astrogliale und neuronale Antworten in Acute Hippocampusschnitte

Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs ...

Multi-unit Recording Methods to Characterize Neural Activity in the Locust (Schistocerca Americana) Olfactory Circuits

Detection and interpretation of olfactory cues are critical for the survival of many organisms. Remarkably, species across phyla have strikingly similar olfactory systems suggesting that the biological approach to chemical sensing has been optimized over evolutionary time1. In the insect olfactory system, odorants are transduced by olfactory receptor neurons (ORN) in the antenna, which convert chemical stimuli into trains of action potentials. Sensory input from the ORNs is then relayed to the antennal lobe (AL; a structure analogous to the vertebrate olfactory bulb). In the AL, neural representations for odors take the form of spatiotemporal firing patterns distributed across ensembles of principal neurons (PNs; also referred to as projection neurons)2,3. The AL output is subsequently processed by Kenyon cells (KCs) in the downstream mushroom body (MB), a structure associated with olfactory memory and learning4,5. Here, we present electrophysiological recording techniques to monitor odor-evoked neural responses in these olfactory circuits.
First, we present a single sensillum recording method to study odor-evoked responses at the level of populations of ORNs6,7. We discuss the use of saline filled sharpened glass pipettes as electrodes to extracellularly monitor ORN responses. Next, we present a method to extracellularly monitor PN responses using a commercial 16-channel electrode3. A similar approach using a custom-made 8-channel twisted wire tetrode is demonstrated for Kenyon cell recordings8. We provide details of our experimental setup and present representative recording traces for each of these techniques.

Multi-unit Recording Methods to Characterize Neural Activity in the Locust Schistocerca Americana Olfactory Circuits

We demonstrate variations of the extracellular multi-unit recording technique to characterize odor-evoked responses in the first three stages of the invertebrate olfactory pathway. These techniques can easily be adapted to examine ensemble activity in other neural systems as well.

Multi-unit Recording Methoden zur neuronalen Aktivität in der Locust Charakterisieren (<em&gt; Schistocerca Americana</em&gt;) Olfaktorische Circuits

Detection and interpretation of olfactory cues are critical for the survival  of many organisms. Remarkably, species across phyla have strikingly similar ...

Direct Intraventricular Delivery of Drugs to the Rodent Central Nervous System

Due to an inability to cross the blood brain barrier, certain drugs need to be directly delivered into the central nervous system (CNS). Our lab focuses specifically on antisense oligonucleotides (ASOs), though the techniques shown in the video here can also be used to deliver a plethora of other drugs to the CNS. Antisense oligonucleotides (ASOs) have the capability to knockdown sequence-specific targets 1 as well as shift isoform ratios of specific genes 2. To achieve widespread gene knockdown or splicing in the CNS of mice, the ASOs can be delivered into the brain using two separate routes of administration, both of which we demonstrate in the video.
The first uses Alzet osmotic pumps, connected to a catheter that is surgically implanted into the lateral ventricle. This allows the ASOs to be continuously infused into the CNS for a designated period of time. The second involves a single bolus injection of a high concentration of ASO into the right lateral ventricle. Both methods use the mouse cerebral ventricular system to deliver the ASO to the entire brain and spinal cord, though depending on the needs of the study, one method may be preferred over the other.

We describe a method to target drugs to the central nervous system by either implanting a catheter or performing a bolus injection into the right lateral ventricle in mice. We focus specifically on the delivery of antisense oligonucleotides. This technique is readily adaptable to other drugs and to rats.

Direkt Intraventrikuläre Abgabe von Arzneimitteln an die Nager Central Nervous System

Due to an inability to cross the blood brain barrier, certain drugs need to be directly delivered into the central nervous system (CNS). Our lab focuses ...

An In-vitro Preparation of Isolated Enteric Neurons and Glia from the Myenteric Plexus of the Adult Mouse

The enteric nervous system is a vast network of neurons and glia running the length of the gastrointestinal tract that functionally controls gastrointestinal motility. A procedure for the isolation and culture of a mixed population of neurons and glia from the myenteric plexus is described. The primary cultures can be maintained for over 7 days, with connections developing among the neurons and glia. The longitudinal muscle strip with the attached myenteric plexus is stripped from the underlying circular muscle of the mouse ileum or colon and subjected to enzymatic digestion. In sterile conditions, the isolated neuronal and glia population are preserved within the pellet following centrifugation and plated on coverslips. Within 24-48 hr, neurite outgrowth occurs and neurons can be identified by pan-neuronal markers. After two days in culture, isolated neurons fire action potentials as observed by patch clamp studies. Furthermore, enteric glia can also be identified by GFAP staining. A network of neurons and glia in close apposition forms within 5 - 7 days. Enteric neurons can be individually and directly studied using methods such as immunohistochemistry, electrophysiology, calcium imaging, and single-cell PCR. Furthermore, this procedure can be performed in genetically modified animals. This methodology is simple to perform and inexpensive. Overall, this protocol exposes the components of the enteric nervous system in an easily manipulated manner so that we may better discover the functionality of the ENS in normal and disease states.

An In-vitro Preparation of Isolated Enteric Neurons and Glia from the Myenteric Plexus of the Adult Mouse

We demonstrate a cell culture protocol for the direct study of neuronal and glial components of the enteric nervous system. A neuron/glia mixed culture on coverslips is prepared from the myenteric plexus of adult mouse providing the ability to examine individual neuron and glia function by electrophysiology, immunohistochemical, etc.

Ein<em&gt; In-vitro</em&gt; Vorbereitung von isolierten Neuronen und Glia Enteric vom Plexus myentericus der erwachsenen Maus

The enteric nervous system is a vast network of neurons and glia running the length of the gastrointestinal tract that functionally controls ...

Utilizing Combined Methodologies to Define the Role of Plasma Membrane Delivery During Axon Branching and Neuronal Morphogenesis

During neural development, growing axons extend to multiple synaptic partners by elaborating axonal branches. Axon branching is promoted by extracellular guidance cues like netrin-1 and results in dramatic increases to the surface area of the axonal plasma membrane. Netrin-1-dependent axon branching likely involves temporal and spatial control of plasma membrane expansion, the components of which are supplied through exocytic vesicle fusion. These fusion events are preceded by formation of SNARE complexes, comprising a v-SNARE, such as VAMP2 (vesicle-associated membrane protein 2), and plasma membrane t-SNAREs, syntaxin-1 and SNAP25 (synaptosomal-associated protein 25). Detailed herein isa multi-pronged approach used to examine the role of SNARE mediated exocytosis in axon branching. The strength of the combined approach is data acquisition at a range of spatial and temporal resolutions, spanning from the dynamics of single vesicle fusion events in individual neurons to SNARE complex formation and axon branching in populations of cultured neurons. This protocol takes advantage of established biochemical approaches to assay levels of endogenous SNARE complexes and Total Internal Reflection Fluorescence (TIRF) microscopy of cortical neurons expressing VAMP2 tagged with a pH-sensitive GFP (VAMP2-pHlourin) to identify netrin-1 dependent changes in exocytic activity in individual neurons. To elucidate the timing of netrin-1-dependent branching, time-lapse differential interference contrast (DIC) microscopy of single neurons over the order of hours is utilized. Fixed cell immunofluorescence paired with botulinum neurotoxins that cleave SNARE machinery and block exocytosis demonstrates that netrin-1 dependent axon branching requires SNARE-mediated exocytic activity.

Light microscopy techniques coupled with biochemical assays elucidate the involvement of SNARE-mediated exocytosis in netrin-dependent axon branching. This combination of techniques permits identification of molecular mechanisms controlling axon branching and cell shape change.

Kombinierte Methodiken Verwendung der Rolle der Plasmamembran Lieferung Während Axon Branching und Neuronale Morphogenese zu definieren

During neural development, growing axons extend to multiple synaptic partners by elaborating axonal branches. Axon branching is promoted by extracellular ...

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.

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.

Recording Gamma-Band-Oszillationen in Nucleus pedunculopontinus Neurons

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

Personalized Needles for Microinjections in the Rodent Brain

Microinjections have been used for a long time for the delivery of drugs or toxins within specific brain areas and, more recently, they have been used to deliver gene or cell therapy products. Unfortunately, current microinjection techniques use steel or glass needles that are suboptimal for multiple reasons: in particular, steel needles may cause tissue damage, and glass needles may bend when lowered deeply into the brain, missing the target region. In this article, we describe a protocol to prepare and use quartz needles that combine a number of useful features. These needles do not produce detectable tissue damage and, being very rigid, ensure reliable delivery in the desired brain region even when using deep coordinates. Moreover, it is possible to personalize the design of the needle by making multiple holes of the desired diameter. Multiple holes facilitate the injection of large amounts of solution within a larger area, whereas large holes facilitate the injection of cells. In addition, these quartz needles can be cleaned and re-used, such that the procedure becomes cost-effective.

We describe here a protocol for microinjection in the rodent brain that uses quartz needles. These needles do not produce detectable tissue damage and ensure reliable delivery even in deep regions. Moreover, they can be adapted to research needs by personalized designs and can be re-used.

Personalisierte Nadeln für Mikroinjektionen im Nagetier Gehirn

Microinjections have been used for a long time for the delivery of drugs or toxins within specific brain areas and, more recently, they have been used to ...

Recording Synaptic Plasticity in Acute Hippocampal Slices Maintained in a Small-volume Recycling-, Perfusion-, and Submersion-type Chamber System

Even though experiments on brain slices have been in use since 1951, problems remain that reduce the probability of achieving a stable and successful analysis of synaptic transmission modulation when performing field potential or intracellular recordings. This manuscript describes methodological aspects that might be helpful in improving experimental conditions for the maintenance of acute brain slices and for recording field excitatory postsynaptic potentials in a commercially available submersion chamber with an outflow-carbogenation unit. The outflow-carbogenation helps to stabilize the oxygen level in experiments that rely on the recycling of a small buffer reservoir to enhance the cost-efficiency of drug experiments. In addition, the manuscript presents representative experiments that examine the effects of different carbogenation modes and stimulation paradigms on the activity-dependent synaptic plasticity of synaptic transmission.

This protocol describes the stabilization of the oxygen level in a small volume of recycled buffer and methodological aspects of recording activity-dependent synaptic plasticity in submerged acute hippocampal slices.

Aufnahme synaptische Plastizität in akuten Hippocampal Scheiben gepflegt in einem kleinvolumigen Recycling - Perfusions- und untertauchen-Typ-Kammer-System

Even though experiments on brain slices have been in use since 1951, problems remain that reduce the probability of achieving a stable and successful ...

Tuning in der Hippocampal Theta Band

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Retrograde Fluoreszenzmarkierung Ermöglicht Gezielte Extracellular Einzel-Einheit Aufnahme von identifizierten Neuronen