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All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.
PV-Cre knock-in male mice, 10-25 weeks old, were used. Mice were housed under standard conditions in the animal facility and kept on a 12-light/dark cycle.
1. Preparation of Tungsten Wire Arrays for LFP Recordings
<ol>
	<li>Glue one optic fiber to the wire array so that the tip of the fiber is at the level of the shortest wire and the fiber tip is in close proximity, but not touching the tungsten wires. Keep the angle of the fiber as small as possible in order to prevent tissue damage during implantation.</li>
</ol>
2. Optogenetic Stimulation and Electrophysiological Data Acquisition
<ol>
	<li>Check the light output from the patch cord. Estimate the light output from the fiber tip after connection depending on the transmission rate of the fiber implanted. Ensure that the light output from the fiber tip is between 5-15 mW to enable reliable entrainment.</li>
	<li>Connect the headstage preamplifier to the chronically implanted connector. Connect the fiber optic patch cord to the chronically implanted hippocampal fiber for optogenetic stimulation experiments. In control light stimulation experiments, the optic fiber is connected to a dummy ferrule connected to the headset.</li>
	<li>Place the mouse in the recording chamber.</li>
	<li>Open the software to control the stimulus generator to generate the stimulation protocol.</li>
	<li>Select the channel that controls the 473 nm DPSS laser.</li>
	<li>Open the software of the recording system. Click on &#34;ACQ&#34; to acquire and &#34;REC&#34; to record. Wait before initiation of the light stimulation to record the baseline behavior (e.g., 2 min to retrieve baseline speed or 30 min to extract the baseline place fields).</li>
	<li>Open the software to control the stimulus generator. Click &#34;File &#62; Open&#34; and select the protocol file of choice. Click &#34;Download and Start&#34; to initiate the light stimulation.</li>
</ol>

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>PV-Cre mice</td>
			<td>The Jackson Laboratory</td>
			<td>B6;129P2-Pvalbtm1(cre)Arbr/J</td>
			<td></td>
		</tr>
		<tr>
			<td>473 nm DPSS laser</td>
			<td>Laserglow Technologies, Toronto, ON, Canada</td>
			<td>R471005FX</td>
			<td>LRS-0473 Series</td>
		</tr>
		<tr>
			<td>593 nm DPSS laser</td>
			<td>Laserglow Technologies</td>
			<td>R591005FX</td>
			<td>LRS-0594 Series</td>
		</tr>
		<tr>
			<td>MC_Stimulus II</td>
			<td>Multichannel Systems, Reutlingen, Germany</td>
			<td>STG 4004</td>
			<td></td>
		</tr>
		<tr>
			<td>Tungsten wires</td>
			<td>California Fine Wire Company, Grover Beach, CA, USA</td>
			<td>CFW0010954</td>
			<td>40 &#181;m, 99.95%</td>
		</tr>
		<tr>
			<td>Headstage</td>
			<td>Neuralynx, Bozeman, Montana USA</td>
			<td>HS-8</td>
			<td>miniature headstage unity gain preamplifiers</td>
		</tr>
		<tr>
			<td>LED</td>
			<td>Neuralynx</td>
			<td>HS-LED-Red-omni-10V</td>
			<td></td>
		</tr>
		<tr>
			<td>MATLAB</td>
			<td>Mathworks, Natick, MA, USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>MC_Stimulus software</td>
			<td>Multichannel, Systems</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Multimode optic fiber</td>
			<td>ThorLabs, Dachau, Germany</td>
			<td>FG105LCA</td>
			<td>0.22 NA, Low-OH, &#216;105 &#181;m Core, 400 - 2400 nm</td>
		</tr>
		<tr>
			<td>Multimode fiber optic coupler</td>
			<td>Thorlabs</td>
			<td>FCMM50-50A-FC</td>
			<td>1x2 MM Coupler, 50:50 Split Ratio, 50 &#181;m GI Fibers, FC/PC</td>
		</tr>
	</tbody>
</table>

selective manipulation of theta oscillations in a mouse model

Source: Bender, F. et al., <a href="https://app.jove.com/v/57349">Optogenetic Entrainment of Hippocampal Theta Oscillations in Behaving Mice.</a> J. Vis. Exp (2018)
This video demonstrates a protocol to modulate theta oscillations in a genetically engineered mouse model with light-sensitive ion channels in its GABAergic medial septum neurons. By delivering light pulses to the hippocampus, the protocol aims to synchronize neuronal activity and generate theta oscillations, which are recorded as local field potentials.

Selective Manipulation of Theta Oscillations in a Mouse Model

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.
PV-Cre ...

Take a genetically engineered mouse with a surgically implanted optical fiber and recording electrode array assembly in the hippocampus.
The mouse medial septum contains light-sensitive ion channel-expressing GABAergic neurons, which project to interneurons in the hippocampus.
Connect a preamplifier to the implanted array connector to enhance recorded electrical signals.
Connect the patch cord to the implanted optical fiber for light delivery.
Record baseline neural activity without light stimulation.
Deliver light pulses of the desired frequency to the hippocampus, which activates the GABAergic neurons&#39; light-sensitive ion channels, causing positive ion influx and triggering action potentials.
This neuronal excitation causes the release of inhibitory neurotransmitters onto hippocampal interneurons, inhibiting them.
The rhythmic inhibition of interneurons by light stimulation balances excitatory and inhibitory inputs, synchronizing the firing of pyramidal neurons and producing rhythmic neural activity in the hippocampus, known as theta oscillations.

selective-manipulation-of-theta-oscillations-in-a-mouse-model

Research

JoVE Encyclopedia of Experiments

Neuroscience

Neurophysiology

Stimulation and Modulation Techniques

38 vues. Source : Bender, F. et al., Entraînement optogénétique des oscillations thêta de l’hippocampe chez les souris comportementales. J. Vis. Exp (2018) Cette vidéo présente un protocole permettant de moduler les oscillations thêta dans un modèle de souris génétiquement modifié avec des canaux ioniques sensibles à la lumière dans ses neurones du septum médial GABAergique. En délivrant des impulsions lumineuses à l’hippocampe, le protocole vise à synchroniser l’activité neurona...

Vidéo: Manipulation sélective des oscillations thêta dans un modèle murin - Concept

Automatic Detection of Highly Organized Theta Oscillations in the Murine EEG

Theta activity is generated in the septohippocampal system and can be recorded using deep intrahippocampal electrodes and implantable electroencephalography (EEG) radiotelemetry or tether system approaches. Pharmacologically, hippocampal theta is heterogeneous (see dualistic theory) and can be differentiated into type I and type II theta. These individual EEG subtypes are related to specific cognitive and behavioral states, such as arousal, exploration, learning and memory, higher integrative functions, etc. In neurodegenerative diseases such as Alzheimer&#39;s, structural and functional alterations of the septohippocampal system can result in impaired theta activity/oscillations. A standard quantitative analysis of the hippocampal EEG includes a Fast-Fourier-Transformation (FFT)-based frequency analysis. However, this procedure does not provide details about theta activity in general and highly-organized theta oscillations in particular. In order to obtain detailed information on highly-organized theta oscillations in the hippocampus, we have developed a new analytical approach. This approach allows for time- and cost-effective quantification of the duration of highly-organized theta oscillations and their frequency characteristics.

Theta activity in the hippocampus is related to specific cognitive and behavioral stages. Here, we describe an analytical method to detect highly-organized theta oscillations within the hippocampus using a time-frequency (i.e., wavelet analysis)-based approach.

Détection automatique de très organisé Oscillations Theta dans le murin EEG

Theta activity is generated in the septohippocampal system and can be recorded using deep intrahippocampal electrodes and implantable ...

Recherche

JoVE Journal

Sciences du comportement

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.

Tuning dans la bande Hippocampal Theta<em&gt; In Vitro</em&gt;: Méthodologies pour l&#39;enregistrement à partir du circuit de Septohippocampal de Rongeur isolé

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

Neurosciences

Recording Spatially Restricted Oscillations in the Hippocampus of Behaving Mice

The local field potential (LFP) emerges from ion movements across neural membranes. Since the voltage recorded by LFP electrodes reflects the summed electrical field of a large volume of brain tissue, extracting information about local activity is challenging. Studying neuronal microcircuits, however, requires a reliable distinction between truly local events and volume-conducted signals originating in distant brain areas. Current source density (CSD) analysis offers a solution for this problem by providing information about current sinks and sources in the vicinity of the electrodes. In brain areas with laminar cytoarchitecture such as the hippocampus, one-dimensional CSD can be obtained by estimating the second spatial derivative of the LFP. Here, we describe a method to record multilaminar LFPs using linear silicon probes implanted into the dorsal hippocampus. CSD traces are computed along individual shanks of the probe. This protocol thus describes a procedure to resolve spatially restricted neuronal network oscillations in the hippocampus of freely moving mice.

This protocol describes the recording of local field potentials with multi-shank linear silicon probes. Conversion of the signals using current source density analysis allows the reconstruction of local electrical activity in the mouse hippocampus. With this technique, spatially restricted brain oscillations can be studied in freely moving mice.

Enregistrement dans l’espace restreint des Oscillations dans l’hippocampe de se comporter de souris

The local field potential (LFP) emerges from ion movements across neural membranes. Since the voltage recorded by LFP electrodes reflects the summed ...

Selective Manipulation of Theta Oscillations in a Mouse Model

Transcription

Selective Manipulation of Theta Oscillations in a Mouse Model