Name: convection enhanced delivery of optogenetic adeno-associated viral vector to the cortex of rhesus macaque under guidance of online mri images
Uploaded: 2019-05-23T13:00:00
Description: Watch this Scientific Journal Video about Convection Enhanced Delivery of Optogenetic Adeno-associated Viral Vector to the Cortex of Rhesus Macaque Under Guidance of Online MRI Images at JoVE.com

This work was supported by American Heart Association postdoctoral fellowship (AY), Defense Advanced Research Projects Agency (DARPA) Reorganization and Plasticity to Accelerate Injury Recovery (REPAIR; N66001-10-C-2010), R01.NS073940, and by the UCSF Neuroscience Imaging Center. This work was also supported by the Eunice Kennedy Shiver National Institute of Child Health &#38; Human Development of the National Institutes of Health under Award Number K12HD073945, the Washington National Primate Research Center (WaNPCR, P51 OD010425), and the Center for Neurotechnology (CNT, a National Science Foundation Engineering Research Center under Grant EEC-1028725). We thank Camilo Diaz-Botia, Tim Hanson, Viktor Kharazia, Daniel Silversmith, Karen J. MacLeod, Juliana Milani, and Blakely Andrews for their help with the experiments and Nan Tian, Jiwei He, Peter Ledochowitsch, Michel Maharbiz, and Toni Haun for technical help.

All procedures have been approved by the University of California, San Francisco Institutional Animal Care and Use Committee (IACUC) and are compliant with the Guide for the Care and Use of Laboratory Animals. The following procedure was performed using two adult male rhesus macaques of 8 and 7 years of age, weighing 17.5 kg and 16.5 kg (monkey G and monkey J), respectively.
NOTE: Use standard aseptic techniques for all surgical procedures.
1. Baseline Imaging
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Here, we outline a feasible and efficient technique for achieving large-scale optogenetic expression in NHP primary somatosensory and motor cortex by MR-guided CED. The use of MR-guided CED presents significant advantages over traditional methods of viral infusion in the NHP brain. One such advantage is the ability to attain expression over large areas with fewer required infusions. For instance, with conventional methods, multiple injections of 1-2 &#181;L of the vector yield expression in a 2-3 mm diameter region<sup c...

Optogenetics is a powerful tool that allows for the manipulation of neural activity and the study of network connections in the brain. Implementing this technique in non-human primates (NHPs) has the potential to enhance our understanding of large-scale neural computation, cognition, and behavior in the primate brain. Although optogenetics has been successfully implemented in NHPs in recent years1,2,3,4,5,6,7, a challenge that researchers face is achieving high levels of expression across large brain areas in these animals. Here, we are providing an efficient and simplified approach to achieve high levels of optogenetic expression across large areas of the cortex in macaques. This technique has great potential to improve current optogenetic studies in these animals in combination with state-of-the-art recording8,9 and optical stimulation10 technologies.
Convection enhanced delivery (CED) is an established method of delivery of pharmacological agents and other large molecules, including viral vectors, to the central nervous system11,12,13. Whereas conventional delivery methods involve multiple low volume infusions distributed across small regions of the brain, CED can achieve broader and more even agent distribution with fewer infusions. Pressure-driven bulk fluid flow (convection) during infusion allows for more widely and uniformly distributed transduction of the target tissue when delivering viral vectors with CED. In recent studies, we demonstrated the transduction and subsequent optogenetic expression of large areas of primary motor (M1) and somatosensory (S1) cortices9 and thalamus14 using magnetic resonance (MR)-guided CED.
Here, we outline the use of CED to achieve optogenetic expression across large cortical areas with only a few cortical injections.

<table>
	<tbody>
		<tr>
			<td>0.2 mL High Pressure IV Tubing</td>
			<td>Smiths Medical Inc., Dublin, OH, USA</td>
			<td>533640</td>
			<td></td>
		</tr>
		<tr>
			<td>0.32 mm ID, 0.43 mm OD Silica Tubing</td>
			<td>Polymicro Technologies</td>
			<td>1068150027</td>
			<td></td>
		</tr>
		<tr>
			<td>0.45 mm ID, 0.76 mm OD Silica Tubing</td>
			<td>Polymicro Technologies</td>
			<td>1068150625</td>
			<td></td>
		</tr>
		<tr>
			<td>AAV2.5-CamKII-C1V1-EYFP</td>
			<td>Penn Vector Core, University of Pennsylvania</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>ABS plastic</td>
			<td>Stratasys, MN, USA</td>
			<td>ABSplus-P430</td>
			<td></td>
		</tr>
		<tr>
			<td>Antimicrobial incise drape</td>
			<td>3M</td>
			<td>6650EZ</td>
			<td>Ioban Drape</td>
		</tr>
		<tr>
			<td>Dental Acrylic</td>
			<td>Henry Schein, Inc.</td>
			<td>1013117</td>
			<td>Acrylic Bonding Agent</td>
		</tr>
		<tr>
			<td>Elevators</td>
			<td>VWR International, LLC.</td>
			<td>10196-564</td>
			<td>Langenbeck Elevator, Wide Tip</td>
		</tr>
		<tr>
			<td>Fine suture</td>
			<td>McKesson Medical-Surgical Inc.</td>
			<td>1034505</td>
			<td></td>
		</tr>
		<tr>
			<td>Gadoteridol</td>
			<td>Prohance, Bracco Diagnostics, Princeton, NJ</td>
			<td>0270-1111-04</td>
			<td></td>
		</tr>
		<tr>
			<td>Laser for light stimulation</td>
			<td>Omicron-Laserage, Germany</td>
			<td>PhoxX 488-60</td>
			<td></td>
		</tr>
		<tr>
			<td>MR compatible 3cc syringe</td>
			<td>Harvard apparatus, Holliston, MA, USA</td>
			<td>59-8377</td>
			<td></td>
		</tr>
		<tr>
			<td>MR Imaging Software</td>
			<td>Pixmeo</td>
			<td>OsiriX MD 10.0</td>
			<td></td>
		</tr>
		<tr>
			<td>MR-Compatible Pump</td>
			<td>Harvard apparatus, Holliston, MA, USA</td>
			<td>Harvard PHD 2000</td>
			<td></td>
		</tr>
		<tr>
			<td>MR-compatible stereotaxic frame</td>
			<td>KOPF</td>
			<td>1430M MRI</td>
			<td></td>
		</tr>
		<tr>
			<td>Perifix Clamp Style Catheter Connector</td>
			<td>B-Braun, Bethlehem, PA, USA</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Plastic Screws</td>
			<td>Plastics 1</td>
			<td>0-80 x 1/8N</td>
			<td>Nylon screws</td>
		</tr>
		<tr>
			<td>Titanium screws</td>
			<td>Crist Instrument Co., Inc.</td>
			<td>6-YCX-0312</td>
			<td>Self-tapping bone screws</td>
		</tr>
		<tr>
			<td>Trephine</td>
			<td>GerMedUSA Inc,</td>
			<td>SKU:GV70-42</td>
			<td></td>
		</tr>
		<tr>
			<td>uPrinter SE 3D printer</td>
			<td>Stratasys, MN, USA</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Vitamin E Capsule</td>
			<td>Pure Encapsulations, LLC.</td>
			<td>DE1</td>
			<td></td>
		</tr>
		<tr>
			<td>Wet sterile absorbable gelatin</td>
			<td>Pfizer Inc.</td>
			<td>AZL0009034201</td>
			<td>Gelfoam</td>
		</tr>
	</tbody>
</table>

convection enhanced delivery of optogenetic adeno-associated viral vector to the cortex of rhesus macaque under guidance of online mri images

In non-human primate (NHP) optogenetics, infecting large cortical areas with viral vectors is often a difficult and time-consuming task. Here, we demonstrate the use of magnetic resonance (MR)-guided convection enhanced delivery (CED) of optogenetic viral vectors into primary somatosensory (S1) and motor (M1) cortices of macaques to obtain efficient, widespread cortical expression of light-sensitive ion channels. Adeno-associated viral (AAV) vectors encoding the red-shifted opsin C1V1 fused to yellow fluorescent protein (EYFP) were injected into the cortex of rhesus macaques under MR-guided CED. Three months post-infusion, epifluorescent imaging confirmed large regions of optogenetic expression (&#62;130 mm2) in M1 and S1 in two macaques. Furthermore, we were able to record reliable light-evoked electrophysiology responses from the expressing areas using micro-electrocorticographic arrays. Later histological analysis and immunostaining against the reporter revealed widespread and dense optogenetic expression in M1 and S1 corresponding to the distribution indicated by epifluorescent imaging. This technique enables us to obtain expression across large areas of the cortex within a shorter period of time with minimal damage compared to the traditional techniques and can be an optimal approach for optogenetic viral delivery in large animals such as NHPs. This approach demonstrates great potential for network-level manipulation of neural circuits with cell-type specificity in animal models evolutionarily close to humans.&#160;

Convection Enhanced Delivery (CED) under MRI Guidance
The spread of the viral vector was monitored during CED infusion under the guidance of online MR images (Figure 3A). In this study, S1 and M1 of two monkeys were targeted (Figure 3B). The three-dimensional distribution volumes were estimated in a post-hoc analysis of the MR images (<strong class="xfi...

Watch this Scientific Journal Video about Convection Enhanced Delivery of Optogenetic Adeno-associated Viral Vector to the Cortex of Rhesus Macaque Under Guidance of Online MRI Images at JoVE.com

Convection Enhanced Delivery of Optogenetic Adeno-associated Viral Vector to the Cortex of Rhesus Macaque Under Guidance of Online MRI Images

Here, we demonstrate magnetic resonance (MR)-guided convection enhanced delivery (CED) of viral vectors into the cortex as an efficient and simplified approach for achieving optogenetic expression across large cortical areas in the macaque brain.

In non-human primate (NHP) optogenetics, infecting large cortical areas with viral vectors is often a difficult and time-consuming task. Here, we ...

Convection enhanced delivery, or CED, of optogenetic viral vectors in non human primates will enable researchers to manipulate neural activity at a large scale to understand complex neural computations and behaviors. With CED we can achieve high optogenetic expression across large regions of the primate brain with only a few injections in a short amount of time compared to traditional methods. Magnetic resonance or MR compatible chamber implantation is performed using standard practice in non human primate surgeries, the procedure is described in detail in the text protocol and outlined briefly in this video.Following animal sedation, positioning, and initial incision as described in the text protocol, create a circular craniotomy to cover the preplanned trajectories for injections using a trephine. Create an indentation at the center of the planned craniotomy sufficiently deep in the skull to anchor the trephine using the adjustable centering point of the trephine. Once the center has been made, lower the trephine onto the skull and rotate the trephine clockwise and counterclockwise while applying downward pressure until the bone cap can be removed with forceps.After lifting the dura as detailed in the text protocol, cut the dura from the center to the edge of the craniotomy and continue along the edge with fine ophthalmic scissors. Mount the cylindrical custom made convection enhanced delivery MR compatible chamber to the skull on top of the craniotomy to provide cannula support during infusion such that the curvature of the chamber flange aligns well with the curvature of the skull. Secure the implants to the skull using either plastic screws and dental acrylic or a few titanium screws.Soon after implanting the MR compatible chamber and inserting the cannula injection grid into the chamber, fill the grid with 0.9%saline for visualizing the injection locations via MR anatomical images. Also fill the chamber cavities with wet sterile absorbable gel foam to maintain the moisture of the brain. Cover the skin and the cylinder with a sterile antimicrobial incise drape to maintain the sterility of the cylinders during transport and MR infusions.Place a vitamin E capsule to mark the top of the injection grid for positive identification. While the animal remains intubated, detach the endotracheal tube from the anesthesia circuit and reattach it to a portable MR compatible isoflurane machine. Transport the animal to the MRI scanner.Acquire T1 images to calculate the distance from the top of the injection grid and the cortical surface. The vitamin E capsule is clearly visible in T1 images and should be used as a marker for the top of the injection grid. Acquire T2 images to determine the optimal cannula guides for each site based on the targeted site of infusion.The cannula grid is filled with saline which is best visible in T2 images. Using the MR imaging software, scroll through the coronal and sagittal planes to find the target location of infusion. After thawing the viral vector for a few hours at room temperature, mix the viral vector with the MR contrast agent gadoteridol by pipette or vortex mixing.Load the mixed virus into 0.2 milliliter high pressure IV tubing. Using high pressure IV tubing, connect a long extension line to an MR compatible three milliliter syringe and prime with saline. Connect the other end of the long extension tubing to the 0.2 milliliter IV tubing loaded with the virus.Then attach the reflux resistant cannula with a one milliliter stepped tip to the distal end of this assembly with a clamp style catheter connector. Lastly set the syringe in an MR compatible pump. Using the obtained baseline anatomical MR images, select the cannula injection grid location and insertion depth needed to reach the target infusion site.Mark the insertion depth on the cannula using sterile tape. Begin the infusion at a rate of one microliter per minute and visually validate the flow of the fluid in the infusion line by observing the ejection of fluid from the cannula tip. Insert the cannula manually through the injection grid to the target depth while maintaining flow in the infusion line as this will prevent the penetrated tissue from clogging the cannula during insertion.Now acquire fast flash T1-weighted images for online monitoring of the viral vector infusion. After infusing approximately 10 microliters of the vector such that enough virus is infused to detect in the MR scanner, obtain MR images to verify correct cannula placement as evident by the observed spread of the virus. If the depth of the inserted cannula is incorrect, adjust the depth accordingly or slowly remove the cannula and reattempt the insertion.Monitor the infusion via guidance of online MR images. Increase the infusion rate to five microliters per minute by one microliter per minute steps every few minutes. It is important to increase the infusion rate slowly and not to exceed five microliters per minute as high infusion rates could cause tissue damage.After infusing approximately 40 microliters of the viral vector, begin reducing the infusion rate by one microliter per minute steps. Stop the infusion after approximately 50 microliters is injected. Leave the cannula in place for ten minutes.Slowly remove the cannula from the brain and move to the next location. Cover the cylinder with a sterile drape at the end of injections before animal transport, then transport the animal back to the operating room. Histological analyses on serial coronal sections reveal large scale optogenetic expression around the infusion sites.Shown here is the baseline coronal MR image and the spread of the contrast agent after the infusion for the same MR coronal slice. A coronal tissue section is shown from approximately the same. Peroxidase staining reflects expression of the yellow fluorescent protein or EYFP reporter.Good alignment is observed between the area of EYFP expression, measured with surface epifluorescense and with histological staining. These include the region of vector spread estimated from MR images. White dots indicate injection sites and the entire black region represents the area exposed by the craniotomy.Shown here is a low magnification image of the coronal sections stained with anti GFP antibody showing the medial lateral aspect of YFP expression in the somatosensory cortex. The black arrowhead indicates the location of the cannula track. The adjacent tissue is shown at greater magnification to show laminar distribution of the YFP positive cells.Densely populated regions of YFP positive cells are located predominately in layers two through three and five through six. Further enlargement reveals typical pyramidal cells in layers two through three, layer five, and layer six. It is important to leave the cannula in place for 10 minutes after the flow has stopped.This will ensure that the virus has percolated into the surrounding targeted neural tissue. CED is an efficient approach to achieve uniformly high expression levels across large brain regions in mammals. It has the potential to expand our understanding of neural circuits and connectivity.After viral transduction by CED, subsequent optogenetic stimulation experiments can be paired with electrical recording and behavioral essays to reveal the complex circuit dynamics within the brain. This technique has been previously employed by Yazdan-Shahmorad and colleagues in 2018 in which optogenetic neural modulation was used to induce network wide connectivity changes in the sensory motor cortex.

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Neuroscience

Intracranial Injection of Adeno-associated Viral Vectors

Intracranial injection of viral vectors engineered to express a fluorescent protein is a versatile labeling technique for visualization of specific subsets of cells in different brain regions both in vivo and in brain sections. Unlike the injection of fluorescent dyes, viral labeling offers targeting of individual cell types and is less expensive and time consuming than establishing transgenic mouse lines. In this technique, an adeno-associated viral (AAV) vector is injected intracranially using stereotaxic coordinates, a micropipette and an automated pump for precise delivery of AAV to the desired area with minimal damage to the surrounding tissue. Injection parameters can be tailored to individual experiments by adjusting the animal age at injection, injection location, volume of injection, rate of injection, AAV serotype and the promoter driving gene expression. Depending on the conditions chosen, virally-induced transgene expression can allow visualization of groups of cells, individual cells or fine cellular processes, down to the level of dendritic spines. The experiment shown here depicts an injection of double-stranded AAV expressing green fluorescent protein for the labeling of neurons and glia in the mouse primary visual cortex.

Here we present the intracranial injection of AAV vectors for fluorescent labeling of neurons and glia in the visual cortex.

Intracranial injection of viral vectors engineered to express a fluorescent protein is a versatile labeling technique for visualization of specific ...

Simultaneous Electroencephalography, Real-time Measurement of Lactate Concentration and Optogenetic Manipulation of Neuronal Activity in the Rodent Cerebral Cortex

Although the brain represents less than 5% of the body by mass, it utilizes approximately one quarter of the glucose used by the body at rest1. The function of non rapid eye movement sleep (NREMS), the largest portion of sleep by time, is uncertain. However, one salient feature of NREMS is a significant reduction in the rate of cerebral glucose utilization relative to wakefulness2-4. This and other findings have led to the widely held belief that sleep serves a function related to cerebral metabolism. Yet, the mechanisms underlying the reduction in cerebral glucose metabolism during NREMS remain to be elucidated.
	One phenomenon associated with NREMS that might impact cerebral metabolic rate is the occurrence of slow waves, oscillations at frequencies less than 4 Hz, in the electroencephalogram5,6. These slow waves detected at the level of the skull or cerebral cortical surface reflect the oscillations of underlying neurons between a depolarized/up state and a hyperpolarized/down state7. During the down state, cells do not undergo action potentials for intervals of up to several hundred milliseconds. Restoration of ionic concentration gradients subsequent to action potentials represents a significant metabolic load on the cell8; absence of action potentials during down states associated with NREMS may contribute to reduced metabolism relative to wake.
	Two technical challenges had to be addressed in order for this hypothetical relationship to be tested. First, it was necessary to measure cerebral glycolytic metabolism with a temporal resolution reflective of the dynamics of the cerebral EEG (that is, over seconds rather than minutes). To do so, we measured the concentration of lactate, the product of aerobic glycolysis, and therefore a readout of the rate of glucose metabolism in the brains of mice. Lactate was measured using a lactate oxidase based real time sensor embedded in the frontal cortex. The sensing mechanism consists of a platinum-iridium electrode surrounded by a layer of lactate oxidase molecules. Metabolism of lactate by lactate oxidase produces hydrogen peroxide, which produces a current in the platinum-iridium electrode. So a ramping up of cerebral glycolysis provides an increase in the concentration of substrate for lactate oxidase, which then is reflected in increased current at the sensing electrode. It was additionally necessary to measure these variables while manipulating the excitability of the cerebral cortex, in order to isolate this variable from other facets of NREMS.
	We devised an experimental system for simultaneous measurement of neuronal activity via the elecetroencephalogram, measurement of glycolytic flux via a lactate biosensor, and manipulation of cerebral cortical neuronal activity via optogenetic activation of pyramidal neurons. We have utilized this system to document the relationship between sleep-related electroencephalographic waveforms and the moment-to-moment dynamics of lactate concentration in the cerebral cortex. The protocol may be useful for any individual interested in studying, in freely behaving rodents, the relationship between neuronal activity measured at the electroencephalographic level and cellular energetics within the brain.

A procedure is described for manipulating the activity of cerebral cortical pyramidal neurons optogenetically while the electroencephalogram, electromyogram, and cerebral lactate concentration are monitored. Experimental recordings are performed on cable-tethered mice while they undergo spontaneous sleep/wake cycles. Optogenetic equipment is assembled in our laboratory; recording equipment is commercially available.

Although the brain represents less than 5% of the body  by mass, it utilizes approximately one quarter of the glucose used by the body  at rest1. The ...

Optogenetic Functional MRI

The investigation of the functional connectivity of precise neural circuits across the entire intact brain can be achieved through optogenetic functional magnetic resonance imaging (ofMRI), which is a novel technique that combines the relatively high spatial resolution of high-field fMRI with the precision of optogenetic stimulation. Fiber optics that enable delivery of specific wavelengths of light deep into the brain in vivo are implanted into regions of interest in order to specifically stimulate targeted cell types that have been genetically induced to express light-sensitive trans-membrane conductance channels, called opsins. fMRI is used to provide a non-invasive method of determining the brain's global dynamic response to optogenetic stimulation of specific neural circuits through measurement of the blood-oxygen-level-dependent (BOLD) signal, which provides an indirect measurement of neuronal activity. This protocol describes the construction of fiber optic implants, the implantation surgeries, the imaging with photostimulation and the data analysis required to successfully perform ofMRI. In summary, the precise stimulation and whole-brain monitoring ability of ofMRI are crucial factors in making ofMRI a powerful tool for the study of the connectomics of the brain in both healthy and diseased states.

This protocol describes the steps and data analysis required to successfully perform optogenetic functional magnetic resonance imaging (ofMRI). ofMRI is a novel technique that combines high-field fMRI readout with optogenetic stimulation, allowing for cell type-specific mapping of functional neural circuits and their dynamics across the whole living brain.

The investigation of the functional connectivity of precise neural circuits across the entire intact brain can be achieved through optogenetic functional ...

Subpial Adeno-associated Virus 9 (AAV9) Vector Delivery in Adult Mice

The successful development of a subpial adeno-associated virus 9 (AAV9) vector delivery technique in adult rats and pigs has been reported on previously. Using subpially-placed polyethylene catheters (PE-10 or PE-5) for AAV9 delivery, potent transgene expression through the spinal parenchyma (white and gray matter) in subpially-injected spinal segments has been demonstrated. Because of the wide range of transgenic mouse models of neurodegenerative diseases, there is a strong desire for the development of a potent central nervous system (CNS)-targeted vector delivery technique in adult mice. Accordingly, the present study describes the development of a spinal subpial vector delivery device and technique to permit safe and effective spinal AAV9 delivery in adult C57BL/6J mice. In spinally immobilized and anesthetized mice, the pia mater (cervical 1 and lumbar 1-2 spinal segmental level) was incised with a sharp 34 G needle using an XYZ manipulator. A second XYZ manipulator was then used to advance a blunt 36G needle into the lumbar and/or cervical subpial space. The AAV9 vector (3-5 &#181;L; 1.2 x 1013 genome copies (gc)) encoding green fluorescent protein (GFP) was then injected subpially. After injections, neurological function (motor and sensory) was assessed periodically, and animals were perfusion-fixed 14 days after AAV9 delivery with 4% paraformaldehyde. Analysis of horizontal or transverse spinal cord sections showed transgene expression throughout the entire spinal cord, in both gray and white matter. In addition, intense retrogradely-mediated GFP expression was seen in the descending motor axons and neurons in the motor cortex, nucleus ruber, and formatio reticularis. No neurological dysfunction was noted in any animals. These data show that the subpial vector delivery technique can successfully be used in adult mice, without causing procedure-related spinal cord injury, and is associated with highly potent transgene expression throughout the spinal neuraxis.

Subpial Adeno-associated Virus 9 AAV9 Vector Delivery in Adult Mice

The goal of the present study was to develop and validate the potency and safety of spinal adeno-associated virus 9 (AAV9)-mediated gene delivery by using a novel subpial gene delivery technique in adult mice.

The successful development of a subpial adeno-associated virus 9 (AAV9) vector delivery technique in adult rats and pigs has been reported on previously. ...

Methods and Tips for Intravenous Administration of Adeno-associated Virus to Rats and Evaluation of Central Nervous System Transduction

Adeno-associated virus (AAV) vectors are a key reagent in the neurosciences for clustered regularly interspaced short palindromic repeats (CRISPR), optogenetics, cre-lox targeting, etc. The purpose of this manuscript is to aid the investigator attempting expansive central nervous system (CNS) gene transfer in the rat via tail vein injection of AAV. Wide-scale expression is relevant for conditions with widespread pathology, and a rat model is significant due to its greater size and physiologic similarities to humans compared to mice. In this example application, a wide-scale neuronal transduction is used to mimic a neurodegenerative disease that affects the entire spinal cord, amyotrophic lateral sclerosis (ALS). The efficient wide-scale CNS transduction can also be used to deliver therapeutic protein factors in pre-clinical studies. After a post-injection expression interval of several weeks, the effects of the transduction are evaluated. For a green fluorescent protein (GFP) control vector, the amount of GFP in the cerebellum is estimated quickly and reliably by a basic imaging program. For motor disease phenotypes that are induced by the ALS related protein transactive response DNA-binding protein of 43 kDa (TDP-43), the deficits are scored by escape reflex and rotarod. Beyond disease modeling and gene therapy, there are diverse potential applications for the wide-scale gene targeting described here. The expanded use of this method will aid in expediting hypothesis testing in the neurosciences and neurogenetics.

Methods for a wide-scale central nervous system gene delivery in the rat are covered. In this example, the purpose is to mimic a disease that affects the entire spinal cord. The widespread transduction can be used to deliver a therapeutic protein to the CNS from a one-time, peripheral administration.

Adeno-associated virus (AAV) vectors are a key reagent in the neurosciences for clustered regularly interspaced short palindromic repeats (CRISPR), ...

Adeno-associated Virus-mediated Transgene Expression in Genetically Defined Neurons of the Spinal Cord

Selective manipulation of spinal neuronal subpopulations has mainly been achieved by two different methods: 1) Intersectional genetics, whereby double or triple transgenic mice are generated in order to achieve selective expression of a reporter or effector gene (e.g., from the Rosa26 locus) in the desired spinal population. 2) Intraspinal injection of Cre-dependent recombinant adeno-associated virus (rAAV); here Cre-dependent AAV vectors coding for the reporter or effector gene of choice are injected into the spinal cord of mice expressing Cre recombinase in the desired neuronal subpopulation. This protocol describes how to generate Cre-dependent rAAV vectors and how to transduce neurons in the dorsal horn of the lumbar spinal cord segments L3-L5 with rAAVs. As the lumbar spinal segments L3-L5 are innervated by those peripheral sensory neurons that transmit sensory information from the hindlimbs, spontaneous behavior and responses to sensory tests applied to the hindlimb ipsilateral to the injection side can be analyzed in order to interrogate the function of the manipulated neurons in sensory processing. We provide examples of how this technique can be used to analyze genetically defined subsets of spinal neurons. The main advantages of virus-mediated transgene expression in Cre transgenic mice compared to classical reporter mouse-induced transgene expression are the following: 1) Different Cre-dependent rAAVs encoding various reporter or effector proteins can be injected into a single Cre transgenic line, thus overcoming the need to create several multiple transgenic mouse lines. 2) Intraspinal injection limits manipulation of Cre-expressing cells to the injection site and to the time after injection. The main disadvantages are: 1) Reporter gene expression from rAAVs is more variable. 2) Surgery is required to transduce the spinal neurons of interest. Which of the two methods is more appropriate depends on the neuron population and research question to be addressed.

Intraspinal injection of recombinase dependent recombinant adeno-associated virus (rAAV) can be used to manipulate any genetically labelled cell type in the spinal cord. Here we describe how to transduce neurons in the dorsal horn of the lumbar spinal cord. This technique enables functional interrogation of the manipulated neuron subtype.

Selective manipulation of spinal neuronal subpopulations has mainly been achieved by two different methods: 1) Intersectional genetics, whereby double or ...

Automated Segmentation of Cortical Grey Matter from T1-Weighted MRI Images

Within neuroimaging research, a number of recent studies have discussed the impact of between-study differences in volumetric findings that are thought to result from the use of different segmentation tools to generate brain volumes. Here, processing pipelines for seven automated tools that can be used to segment grey matter within the brain are presented. The protocol provides an initial step for researchers aiming to find the most accurate method for generating grey matter volumes from T1-weighted MRI scans. Steps to undertake detailed visual quality control are also included in the manuscript. This protocol covers a range of potential segmentation tools and encourages users to compare the performance of these tools within a subset of their data before selecting one to apply to a full cohort. Furthermore, the protocol may be further generalized to the segmentation of other brain regions.

This protocol describes the process of applying seven different automated segmentation tools to structural T1-weighted MRI scans to delineate grey matter regions that can be used for the quantification of grey matter volume.

Within neuroimaging research, a number of recent studies have discussed the impact of between-study differences in volumetric findings that are thought to ...

Direct Intrathecal Injection of Recombinant Adeno-associated Viruses in Adult Mice

Intrathecal (IT) injection of adeno-associated virus (AAV) has drawn considerable interest in CNS gene therapy by virtue of its safety, noninvasiveness, and excellent transduction efficacy in the CNS.&#160;Previous studies have demonstrated the therapeutic potency of AAV-delivered gene therapy in neurodegenerative disorders by IT administration. However, high rates of unpredictable failure due to the technical limitation of IT administration in small animals have been reported. Here, we established a scoring system to indicate the success extent of lumbar puncture in small animals by adding 1% lidocaine hydrochloride into the injection solution. We further show that the extent of transient weakness following injection can predict the transduction efficiency of AAV. Thus, this IT injection method can be used to optimize therapeutic trials in mouse models of CNS diseases that afflict wide regions of the CNS.

Here we present a direct intrathecal injection technique using 1% lidocaine hydrochloride in a viral solution to ensure efficient adeno-associated virus delivery to small animals and establish a scoring system to predict transduction efficiency in the central nervous system according to the degree of transient weakness induced by lidocaine.

Intrathecal (IT) injection of adeno-associated virus (AAV) has drawn considerable interest in CNS gene therapy by virtue of its safety, noninvasiveness, ...

Delivery of Antibodies into the Murine Brain via Convection-enhanced Delivery

Convection-enhanced delivery (CED) is a neurosurgical technique enabling effective perfusion of large brain volumes using a catheter system. Such an approach provides a safe delivery method by-passing the blood brain barrier (BBB), thus allowing treatment with therapeutics with poor BBB-permeability or those for which systemic exposure is not desired, e.g., due to toxicity. CED requires optimization of the catheter design, injection protocol, and properties of the infusate. With this protocol we describe how to perform CED of a solution containing up to 20 &#181;g of an antibody into the caudate putamen of mice. It describes preparation of step catheters, testing them in vitro and performing the CED in mice using a ramping injection program. The protocol can be readily adjusted for other infusion volumes and can be used for injecting various tracers or pharmacologically active or inactive substances, including chemotherapeutics, cytokines, viral particles, and liposomes.

Convection-enhanced delivery (CED) is a method enabling effective delivery of therapeutics into the brain by direct perfusion of large tissue volumes. The procedure requires the use of catheters and an optimized injection procedure. This protocol describes a methodology for CED of an antibody into a mouse brain.

Convection-enhanced delivery (CED) is a neurosurgical technique enabling effective perfusion of large brain volumes using a catheter system. Such an ...

Electrocorticographic Recording of Cerebral Cortex Areas Manipulated Using an Adeno-Associated Virus Targeting Cofilin in Mice

The use of electrocorticographic (ECoG) recordings in rodents is relevant to sleep research and to the study of a wide range of neurological conditions. Adeno-associated viruses (AAVs) are increasingly used to improve understanding of brain circuits and their functions. The AAV-mediated manipulation of specific cell populations and/or of precise molecular components has been tremendously useful to identify new sleep regulatory circuits/molecules and key proteins contributing to the adverse effects of sleep loss. For instance, inhibiting activity of the filamentous actin-severing protein&#160;cofilin&#160;using AAV prevents sleep deprivation-induced memory impairment. Here, a protocol is&#160;described that combines the manipulation of cofilin function in a cerebral cortex area with the recording of ECoG activity to examine whether cortical cofilin modulates the wakefulness and sleep ECoG signals. AAV injection is performed during the same surgical procedure as the implantation of ECoG and electromyographic (EMG) electrodes in adult male and female mice. Mice are anesthetized, and their heads are shaved. After skin cleaning and incision, stereotaxic coordinates of the motor cortex are determined, and the skull is pierced at this location. A cannula prefilled with an AAV expressing cofilinS3D, an inactive form of cofilin, is slowly positioned in the cortical tissue. After AAV infusion, gold-covered screws (ECoG electrodes) are screwed through the skull and cemented to the skull with gold wires inserted in the neck muscles (EMG electrodes). The animals are allowed three weeks to recover and to ensure sufficient expression of cofilinS3D. The infected area and cell type are verified using immunohistochemistry, and the ECoG is analyzed using visual identification of vigilance states and spectral analysis. In summary, this combined methodological approach allows the investigation of the precise contribution of molecular components regulating neuronal morphology and connectivity to the regulation of synchronized cerebral cortex activity during wakefulness and sleep.

This article describes a protocol for the manipulation of molecular targets in the cerebral cortex using adeno-associated viruses and for monitoring the effects of this manipulation during wakefulness and sleep using electrocorticographic recordings.

The use of electrocorticographic (ECoG) recordings in rodents is relevant to sleep research and to the study of a wide range of neurological conditions. ...