This work is supported in part by American Heart Association Scientist Development Grant and NARSAD Young Investigator Award to Yingwei Mao.

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The authors have nothing to disclose.

זריקות stereotactic מוצלחות מסתמכות על שלושה גורמים: שמירה על העכבר בחיים, הגדרת נקודת האפס הנכונה לקואורדינטות (קצה המחט בצומת של גבחת וקו interaural), וקביעת העומק הנכון לנקודת האפס (קצה המחט רק נגיעה החיצונית של רקמת המוח). הכדאיות של עכברים היא חשובה. הישרדות ניתוח יכולה להסת...

העכבר כבר בשימוש נרחב בנוירוביולוגיה כי זה קל לתפעל גנטי. טכניקות נוקאאוט הגן מאפשרות לחוקרים לחקור כיצד כל גורם גנטי מעצב התנהגויות עכבר. יתר על כן, מערכת cre-loxP מספקת כלי רב ערך עבור דקיק ובתא type- נוקאאוט ספציפי גן בעכברים, המאפשר לחוקרים ללמוד תפקוד גן ברקמות שונות. 1 עם זאת, בפועל, דפוסי ביטוי של יזמי cre קשים לשליטה , ועד כה רבים cre נהגים הוקמו לא השיגו ביטוי ספציפי לאזור. 2,3 לחלופין, הזרקת stereotactic היא שיטה שמכוונת אזורים ספציפיים במוח של העכבר הבוגר. על ידי הזרקת וירוסים מהונדסים גנטי לבטא cDNA או shRNA, אפנון האזור ספציפי של ביטוי גנים יכול להיות מושגת. למרות שגודל המוח של כל עכבר משתנה, המיקום של אזורים מסוימים במוח ניתן לקבוע באמצעות coordi stereotacticנטס להגדיר מציוני הדרך בגולגולת של מוח העכבר. ציוני הדרך הנפוצות ביותר הן גבחת, למבדה, וקו interaural. באמצעות קואורדינטות מתקבלות מאטלס מוח, 4 המיקום המדויק של כל אזור במוח ניתן לזהות על ידי Antero-האחורי (/ P), (M / L) המדיאלי-צדדי, וגב-הגחון (D / V) צירים מ גבחת / צומת קו interaural. בדרך כלל וירוסים שהוחדר לתוך מוחם של עכברים מתויגים עם או חלבון אדום, או ירוק ניאון (RFP או GFP), כך שניתן תהיה אישרו זריקות על ידי מיקרוסקופ פלואורסצנטי. הערכות התנהגות של עכברים נחוצות במיוחד למחקר בסיסי של הפרעות פסיכיאטריות. סימפטומים של הפרעות פסיכיאטריות בחולים בדרך כלל כרוכים בהתנהגויות חריגות. חלק מהתנהגויות האנושיות אלה אבולוציונית שימור וניתן חיקה ישירות ונצפה בעכבר. לדוגמא, דיכאון יכול להיות מודל בעכבר על ידי מדידת ייאוש התנהגות. אנשים עם דיכאון לעתים קרובותen מרגיש כאילו שום דבר שהם עושים אי פעם לעזור, סימפטום שיכול סופו של דבר להוביל להתאבדות. במכרסמים, זה יכול להיות מודל באמצעות הבדיקה בכפייה לשחות (FST), אשר מודדת את כמות הזמן שעכבר שחיה לעומת צף בבריכה של מים (נתפס כויתור). פרדיגמה זו אומתה על ידי הצלת פנוטיפ עם תרופות נגד דיכאון. 7,8,9 עכברים שקבלו תרופות נגד דיכאון יבלה נייח זמן באופן משמעותי פחות בהשוואה לקבוצת ביקורת שלא טופלה. עוד מבחן התנהגותי, מבחן שדה הפתוח (OFT) נועד להעריך את התנועה בעכברים, וגם יכול לשמש כדי לנתח את הפנוטיפ החרדה בעכברים. 5,6 מבחן זה מבוסס על ההנחה שהעכברים מרגישים בטוחים יותר כאשר הם קרובים אל הקיר בשדה פתוח רומן. עכברים מסוג בר סופו של דבר יהיה לחקור את סביבת הרומן, כפי שהם בעלי חיים סקרנים. עם זאת, הוצאות פחות זמן במרכז השדה מציינת חרדה בעכבר, כמו העכבר לא יהיה מסוגל להתגבר על initiaפחד l הביא על ידי סביבת רומן. החרדה של העכבר, כמו לכמת ידי כמות הזמן מושקעת במרכז שדה פתוח, ניתן להשוות לחרדה קלינית בבני אדם, אשר שוהה בהפרעות פסיכיאטריות רבות. השילוב של זריקות stereotactic עם פרדיגמות התנהגות הוא דרך חדשנית לשנות את הביטוי של גן מסוים באזור מוח ממוקד. ההשפעה של ביטוי גנים מווסת על התנהגויות עכבר אז יכולה להיות נחושה. בניגוד לנוקאאוט המוח כולו, שיטה זו שימושית במיוחד כפי שרק מטרות אזורים ספציפיים במוח. בנוסף, זריקות stereotactic מבוצעות בדרך כלל בעכבר הסוג בר המבוגר, לכן, ביטוי גני אנדוגני נשמר לאורך שלבי התפתחות. שיטה זו תמנע את ההשפעה לבלבל אם נדרש הגן להישרדות בשלב העוברי או לאחר לידה של פיתוח. מגבלה עיקרית אחת היא שעכברי הניסוי צריך ללכת through ניתוח פולשני, שבו יש לי הגולגולות של עכברים שייפתח. יתר על כן, מידת אפנון גן נקבעת על ידי כייל והיעילות של הנגיף. הווירוס צריך להיות מוזרק לאזור הנכון באמצעות קואורדינטות stereotactic, אשר דורש מכשירים מיוחדים. אימות של הזריקה הנכונה יכולה להסתיים רק לאחר המוות. שיטה זו שימשה בעבר כדי לבדוק את מעורבותם של גנים ספציפיים במחלות נוירולוגיות שונות. לדוגמא, RNAi בתיווך ויראלי מיקוד גן Th (המאפשר דופמין להיות מסונתז) הוזרק לcompacta nigra substantia, וניתוח ההתנהגות של התנועה נערך. 10 מחקר נוסף המשמש להזרקת stereotactic של DISC1 השתקת lentivirus להעריך התנהגות עכבר ביחס לסכיזופרניה. מציאה של DISC1 הובילה לתנועה מוגברת בתגובה לחידוש (סימפטומים הקבלות חיוביים בסכיזופרניה), וחוסר תנועה גדולה יותר בFST. 11 כמו כן, מחקר נוסף מצא כי ביטוי יתר של 5-HT 1B הוביל להתנהגות גישוש עלתה בOFT, עולה בקנה אחד עם פנוטיפ נוגד חרדה בשיטה זו. 12 זריקות stereotactic יכולות לספק וירוס cre לגרום רקומבינציה בעכברי cre-loxP . שיטה זו שימשה למחוק את קולט Y2 באמיגדלה וגרעין המיטה של ​​terminalis stria סלקטיבי. על ניתוח התנהגות, עכברים אלה נמצאו פנוטיפ אנטי-דיכאון כאשר הגן נמחק באמיגדלה המרכזית, אבל אין פנוטיפ כאשר הגן נמחק באמיגדלה basolateral או גרעין המיטה של terminalis stria. 13 כך, טכניקה זו מספק כלי ייחודי כדי לחקור את ההשפעה הגנטית על התנהגות בעלי חיים.

<table><tbody><tr><td>Stereotactic Apparatus item 51725</td><td>Stoelting co.</td><td>51725</td><td></td></tr><tr><td>Quintessential stereotaxic pump&amp;nbsp;</td><td>Stoelting co.</td><td>53311</td><td></td></tr><tr><td>Injection Styringe, 65 RN</td><td>Hamilton</td><td>7633-01</td><td></td></tr><tr><td>DMEM</td><td>Sigma-Aldrich</td><td>D5796</td><td></td></tr><tr><td>PEI&amp;nbsp;</td><td>Polysciences Inc.</td><td>23966</td><td></td></tr><tr><td>Scissors</td><td>Fine Surgical Tools</td><td>14084-08</td><td></td></tr><tr><td>Blunt end forceps</td><td>Fine Surgical Tools</td><td>11002-12</td><td></td></tr><tr><td>Needle holder&amp;nbsp;</td><td>Fine Surgical Tools</td><td>12001-13</td><td></td></tr><tr><td>Drill</td><td>Ram Products Inc</td><td>Microtorque control box, Tech2000 handpiece</td><td>with pedal</td></tr><tr><td>Glass bead sterilizer</td><td>Inotech&amp;nbsp;</td><td>IS-400</td><td></td></tr><tr><td>Absorbable sutures&amp;nbsp;</td><td>Unify</td><td>M-K518r19</td><td>Absorbable, reverse cutting</td></tr><tr><td>Cotton swabs</td><td>VWR</td><td>89031-270</td><td></td></tr><tr><td>Heating pad</td><td>Gaymar</td><td>T-pump TP-500 PN11184-000</td><td></td></tr><tr><td>Artificial tears</td><td>Rugby</td><td>NDC 0536-6550-91</td><td></td></tr><tr><td>Disposable syringe</td><td>BD Syringe</td><td>309623</td><td></td></tr><tr><td>Cloth</td><td></td><td></td><td></td></tr><tr><td>Gloves&amp;nbsp;</td><td>Ansell</td><td>Senseitouch #7823</td><td></td></tr><tr><td>Avertin or other anesthetic</td><td>see recipe citation</td><td></td><td></td></tr><tr><td>Ketoprofen or other analgesic</td><td>see veternarian&amp;nbsp;</td><td></td><td></td></tr><tr><td>Tracking software</td><td>Noldus</td><td>Ethovision XT</td><td></td></tr><tr><td>Tracking Camera</td><td>Noldus</td><td>Media Recorder</td><td></td></tr></tbody></table>

applying stereotactic injection technique to study genetic effects on animal behaviors

הזרקת stereotactic היא טכניקה שימושית כדי לספק lentiviruses גבוה כייל לאזורים במוח ממוקדים בעכברים. Lentiviruses יכול גם ביטוי יתר או ביטוי גני מציאה באזור יחסית ממוקד ללא פגיעה משמעותית ברקמת המוח. לאחר התאוששות, העכבר המוזרק יכול להיבדק על משימות התנהגותיות שונות כגון מבחן להרחיב שדה (OFT) ומבחן הכפייה לשחות (FST). OFT נועד להעריך את התנועה ואת הפנוטיפ החרדה בעכברים על ידי מדידת משך זמן שמבלה עכבר במרכז שדה פתוח רומן. עכבר חרד יותר ישקיע פחות באופן משמעותי זמן במרכז שדה רומן השוואה לקבוצת ביקורת. FST מעריך את הפנוטיפ אנטי-דיכאון על ידי כימות את כמות הזמן שמבלים עכברים נייחים כאשר הניחו לדלי של מים. עכבר עם פנוטיפ אנטי-דיכאון יבלה נייח פחות זמן באופן משמעותי לעומת שליטת בעלי חיים. המטרה של פרוטוקול זה היא להשתמש בsterהזרקת eotactic של lentivirus בשיתוף עם בדיקות התנהגותיות להעריך כיצד גנטי גורמים לווסת התנהגויות של בעלי חיים.

<html> הזרקת stereotactic מדויקת מסתמכת במידה רבה על הגדרת הקואורדינטות הנכונות. קצה המחט המשמשת להזרקת הווירוס צריך להיות מוגדר באופן ישיר על הצומת של גבחת וקו interaural (איור 1). זה מועיל להשתמש סטראו כדי לברר אם או לא המחט ממוקמת כראוי. כאשר מסתכלים מבעד למיקרוסקופ, המח?...

Watch this Scientific Journal Video about Applying Stereotactic Injection Technique to Study Genetic Effects on Animal Behaviors at JoVE.com

Applying Stereotactic Injection Technique to Study Genetic Effects on Animal Behaviors

הזרקת stereotactic של lentiviruses להביע cDNAs או shRNAs יכול לווסת ביטוי גנים באזורים ספציפיים במוח של עכברים. כאן, אנו מציגים פרוטוקול לשלב זריקות stereotactic עם משימות התנהגותיות, כגון מבחן להרחיב שדה (OFT) ומבחן הכפייה לשחות (FST).

יישום טכניקת הזרקת stereotactic לחקר השפעות גנטיות על התנהגות בעלי החיים

Stereotactic injection is a useful technique to deliver high titer lentiviruses to targeted brain areas in mice. Lentiviruses can either overexpress or ...

applying-stereotactic-injection-technique-to-study-genetic-effects-on

Universidad de Cartagena UDEC

Research

JoVE Journal

Behavior

14.1K Views.  The Pennsylvania State University.  הזרקת stereotactic של lentiviruses להביע cDNAs או shRNAs יכול לווסת ביטוי גנים באזורים ספציפיים במוח של עכברים. כאן, אנו מציגים פרוטוקול לשלב זריקות stereotactic עם משימות התנהגותיות, כגון מבחן להרחיב שדה (OFT) ומבחן הכפייה לשחות (FST). 

Video: Applying Stereotactic Injection Technique to Study Genetic Effects on Animal Behaviors

Stereotactic Injection of MicroRNA-expressing Lentiviruses to the Mouse Hippocampus CA1 Region and Assessment of the Behavioral Outcome

MicroRNAs (miRNAs) are small regulatory single-stranded RNA molecules around 22 nucleotides long that may each target numerous mRNA transcripts and dim an entire gene expression pathway by inducing destruction and/or inhibiting translation of these targets. Several miRNAs play key roles in maintaining neuronal structure and function and in higher-level brain functions, and methods are sought for manipulating their levels for exploring these functions. Here, we present a direct in vivo method for examining the cognitive consequences of enforced miRNAs excess in mice by stereotactic injection of miRNA-encoding virus particles. Specifically, the current protocol involves injection into the hippocampal CA1 region, which contributes to mammalian memory consolidation, learning, and stress responses, and offers a convenient injection site. The coordinates are measured according to the mouse bregma and virus perfusion is digitally controlled and kept very slow. After injection, the surgery wound is sealed and the animals recover. Lentiviruses encoding silencers of the corresponding mRNA targets serve to implicate the specific miRNA/target interaction responsible for the observed effect, with na&iuml;ve mice, mice injected with saline and mice injected with "empty" lentivirus vectors as controls. One month post-injection, the animals are examined in the Morris Water Maze (MWM) for assessing their navigation learning and memory abilities. The MWM is a round tank filled with colored water with a small platform submerged 1 cm below the water surface. Steady visual cues around the tank allow for spatial navigation (sound and the earth's magnetic field may also assist the animals in navigating). Video camera monitoring enables measuring the route of swim and the time to find and amount the platform. The mouse is first taught that mounting the hidden platform offers an escape from the enforced swimming; it is then tested for using this escape and finally, the platform is removed and probe tests examine if the mouse remembers its previous location. Repeated tests over several consecutive days highlight improved performance of tested mice at shorter latencies to find and mount the platform, and as more direct routes to reach the platform or its location. Failure to show such improvement represents impaired learning and memory and/or anxiety, which may then be tested specifically (e.g. in the elevated plus maze). This approach enables validation of specific miRNAs and target transcripts in the studied cognitive and/or stress-related processes.

MicroRNAs have significant roles in brain structure and function. Here we describe a method to enforce hippocampal miRNA over-expression using stereotactic injection of an engineered miRNA-expressing lentivirus. This approach can serve as a relatively rapid way to assess the in vivo effects of over-expressed miRNAs in specific brain regions.

Lentiviruses הזרקת Stereotactic של microRNA-לבטא באזור CA1 היפוקמפוס העכבר והערכה של תוצאות ההתנהגות

MicroRNAs (miRNAs) are small regulatory single-stranded RNA molecules around 22 nucleotides long that may each target numerous mRNA transcripts and dim an ...

Stereotaxic Microinjection of Viral Vectors Expressing Cre Recombinase to Study the Role of Target Genes in Cocaine Conditioned Place Preference

Microinjecting recombinant adenoassociated viral (rAAV) vectors expressing Cre recombinase into distinct mouse brain regions to selectively knockout genes of interest allows for enhanced temporally- and regionally-specific control of gene deletion, compared to existing methods. While conditional deletion can also be achieved by mating mice that express Cre recombinase under the control of specific gene promoters with mice carrying a floxed gene, stereotaxic microinjection allows for targeting of discrete brain areas at experimenter-determined time points of interest. In the context of cocaine conditioned place preference, and other cocaine behavioral paradigms such as self-administration or psychomotor sensitization that can involve withdrawal, extinction and/or reinstatement phases, this technique is particularly useful in exploring the unique contribution of target genes to these distinct phases of behavioral models of cocaine-induced plasticity. Specifically, this technique allows for selective ablation of target genes during discrete phases of a behavior to test their contribution to the behavior across time. Ultimately, this understanding allows for more targeted therapeutics that are best able to address the most potent risk factors that present themselves during each phase of addictive behavior.

This article describes how to microinject viral vectors into mouse brain and then test in a conditioned place preference paradigm that includes an acquisition, extinction and reinstatement phase.

Microinjection Stereotaxic של וקטורים ויראליים הבעת Cre recombinase כדי ללמוד את התפקיד של גני מטרה בהעדפות מקום אוויר קוקאין

Microinjecting recombinant adenoassociated viral (rAAV) vectors expressing Cre recombinase into distinct mouse brain regions to selectively knockout genes ...

Stable and Efficient Genetic Modification of Cells in the Adult Mouse V-SVZ for the Analysis of Neural Stem Cell Autonomous and Non-autonomous Effects

Relatively quiescent somatic stem cells support life-long cell renewal in most adult tissues. Neural stem cells in the adult mammalian brain are restricted to two specific neurogenic niches: the subgranular zone of the dentate gyrus in the hippocampus and the ventricular-subventricular zone (V-SVZ; also called subependymal zone or SEZ) in the walls of the lateral ventricles. The development of in vivo gene transfer strategies for adult stem cell populations (i.e. those of the mammalian brain) resulting in long-term expression of desired transgenes in the stem cells and their derived progeny is a crucial tool in current biomedical and biotechnological research. Here, a direct in vivo method is presented for the stable genetic modification of adult mouse V-SVZ cells that takes advantage of the cell cycle-independent infection by LVs and the highly specialized cytoarchitecture of the V-SVZ niche. Specifically, the current protocol involves the injection of empty LVs (control) or LVs encoding specific transgene expression cassettes into either the V-SVZ itself, for the in vivo targeting of all types of cells in the niche, or into the lateral ventricle lumen, for the targeting of ependymal cells only. Expression cassettes are then integrated into the genome of the transduced cells and fluorescent proteins, also encoded by the LVs, allow the detection of the transduced cells for the analysis of cell autonomous and non-autonomous, niche-dependent effects in the labeled cells and their progeny.

Here we describe a procedure based on the use of lentiviral particles for the long-term genetic modification of neural stem cells and/or their adjacent ependymal cells in the adult ventricular-subventricular neurogenic niche which allows the separate analysis of cell autonomous and non-autonomous, niche-dependent effects on neural stem cells.

הנדסה גנטית יציבה ויעילה של תאי V-SVZ העכבר למבוגרים עבור הניתוח של הגזע עצבי נייד אוטונומי והשפעות חד אוטונומיות

Relatively quiescent somatic stem cells support life-long cell renewal in most adult tissues. Neural stem cells in the adult mammalian brain are ...

Developmental Biology

Rodent Brain Microinjection to Study Molecular Substrates of Motivated Behavior

Brain microinjection can aid elucidation of the molecular substrates of complex behaviors, such as motivation. For this purpose rodents can serve as appropriate models, partly because the response to behaviorally relevant stimuli and the circuitry parsing stimulus-action outcomes is astonishingly similar between humans and rodents. In studying molecular substrates of complex behaviors, the microinjection of reagents that modify, augment, or silence specific systems is an invaluable technique. However, it is crucial that the microinjection site is precisely targeted in order to aid interpretation of the results. We present a method for the manufacture of surgical implements and microinjection needles that enables accurate microinjection and unlimited customizability with minimal cost. Importantly, this technique can be successfully completed in awake rodents if conducted in conjunction with other JoVE articles that covered requisite surgical procedures. Additionally, there are many behavioral paradigms that are well suited for measuring motivation. The progressive ratio is a commonly used method that quantifies the efficacy of a reinforcer to maintain responding despite an (often exponentially) increasing work requirement. This assay is sensitive to reinforcer magnitude and pharmacological manipulations, which allows reinforcing efficacy and/ or motivation to be determined. We also present a straightforward approach to program operant software to accommodate a progressive ratio reinforcement schedule.

Rodents are an appropriate model to investigate the molecular substrates of behavior and complex psychiatric disorders. Brain microinjection in awake rodents can be used to elucidate disease substrates. An efficient and customizable brain microinjection method as well as the execution of an operant paradigm that quantifies motivation is presented.

מכרסמים מוח Microinjection לחקר מולקולריים מצעים של התנהגות מוטיבציה

Brain microinjection can aid elucidation of the molecular substrates of complex behaviors, such as motivation. For this purpose rodents can serve as ...

Modeling Brain Metastases Through Intracranial Injection and Magnetic Resonance Imaging

Metastatic spread of cancer is an unfortunate consequence of disease progression, aggressive cancer subtypes, and/or late diagnosis. Brain metastases are particularly devastating, difficult to treat, and confer a poor prognosis. While the precise incidence of brain metastases in the United States remains hard to estimate, it is likely to increase as extracranial therapies continue to become more efficacious in treating cancer. Thus, it is necessary to identify and develop novel therapeutic approaches to treat metastasis at this site. To this end, intracranial injection of cancer cells has become a well-established method in which to model brain metastasis. Previously, the inability to directly measure tumor growth has been a technical hindrance to this model; however, increasing availability and quality of small animal imaging modalities, such as magnetic resonance imaging (MRI), are vastly improving the ability to monitor tumor growth over time and infer changes within the brain during the experimental period. Herein, intracranial injection of murine mammary tumor cells into immunocompetent mice followed by MRI is demonstrated. The presented injection approach utilizes isoflurane anesthesia and a stereotactic setup with a digitally controlled, automated drill and needle injection to enhance precision, and reduce technical error. MRI is measured over time using a 9.4 Tesla instrument in The Ohio State University James Comprehensive Cancer Center Small Animal Imaging Shared Resource. Tumor volume measurements are demonstrated at each time point through use of ImageJ. Overall, this intracranial injection approach allows for precise injection, day-to-day monitoring, and accurate tumor volume measurements, which combined greatly enhance the utility of this model system to test novel hypotheses on the drivers of brain metastases.

Intracranial brain metastasis modeling is complicated by an inability to monitor tumor size and response to treatment with precise and timely methods. The presented methodology couples intracranial tumor injection with magnetic resonance imaging analysis, which when combined, cultivates precise and consistent injections, enhanced animal monitoring, and accurate tumor volume measurements.

מידול גרורות מוח באמצעות הזרקה תוך גולגולתית והדמיית תהודה מגנטית

Metastatic spread of cancer is an unfortunate consequence of disease progression, aggressive cancer subtypes, and/or late diagnosis. Brain metastases are ...

Cancer Research

Stereotaxic Surgery for Genetic Manipulation in Striatal Cells of Neonatal Mouse Brains

Many genes are expressed in embryonic brains, and some of them are continuously expressed in the brain after birth. For such persistently expressed genes, they may function to regulate the developmental process and/or physiological function in neonatal brains. To investigate neurobiological functions of specific genes in the brain, it is essential to inactivate genes in the brain. Here, we describe a simple stereotaxic method to inactivate gene expression in the striatum of transgenic mice at neonatal time windows. AAV-eGFP-Cre viruses were microinjected into the striatum of Ai14 reporter gene mice at postnatal day (P) 2 by stereotaxic brain surgery. The tdTomato reporter gene expression was detected in P14 striatum, suggesting a successful Cre-loxP mediated DNA recombination in AAV-transduced striatal cells. We further validated this technique by microinjecting AAV-eGFP-Cre viruses into P2Foxp2fl/fl mice. Double labeling of GFP and Foxp2 showed that GFP-positive cells lacked Foxp2 immunoreactivity in P9 striatum, suggesting the loss of Foxp2 protein in AAV-eGFP-Cre transduced striatal cells. Taken together, these results demonstrate an effective genetic deletion by stereotaxically microinjected AAV-eGFP-Cre viruses in specific neuronal populations in the neonatal brains of floxed transgenic mice. In conclusion, our stereotaxic technique provides an easy and simple platform for genetic manipulation in neonatal mouse brains. The technique can not only be used to delete genes in specific regions of neonatal brains, but it also can be used to inject pharmacological drugs, neuronal tracers, genetically modified optogenetics and chemogenetics proteins, neuronal activity indicators and other reagents into the striatum of neonatal mouse brains.

We describe a protocol of stereotaxic surgery with a homemade head-fixed device for microinjecting reagents into the striatum of neonatal mouse brains. This technique allows genetic manipulation in neuronal cells of specific regions of neonatal mouse brains.

ניתוח stereotaxic מניפולציה גנטית בתאים Striatal של מוח העכבר Neonatal

Many genes are expressed in embryonic brains, and some of them are continuously expressed in the brain after birth. For such persistently expressed genes, ...

Neuroscience

In Vivo Intracerebral Stereotaxic Injections for Optogenetic Stimulation of Long-Range Inputs in Mouse Brain Slices

Knowledge of cell-type specific synaptic connectivity is a crucial prerequisite for understanding brain-wide neuronal circuits. The functional investigation of long-range connections requires targeted recordings of single neurons combined with the specific stimulation of identified distant inputs. This is often difficult to achieve with conventional and electrical stimulation techniques, because axons from converging upstream brain areas may intermingle in the target region. The stereotaxic targeting of a specific brain region for virus-mediated expression of light-sensitive ion channels allows selective stimulation of axons originating from that region with light. Intracerebral stereotaxic injections can be used in well-delimited structures, such as the anterior thalamic nuclei, in addition to other subcortical or cortical areas throughout the brain.
Described here is a set of techniques for precise stereotaxic injection of viral vectors expressing channelrhodopsin in the mouse brain, followed by photostimulation of axon terminals in the brain slice preparation. These protocols are simple and widely applicable. In combination with whole-cell patch clamp recording from a postsynaptically connected neuron, photostimulation of axons allows the detection of functional synaptic connections, pharmacological characterization, and evaluation of their strength. In addition, biocytin filling of the recorded neuron can be used for post-hoc morphological identification of the postsynaptic neuron.

This protocol describes a set of methods to identify the cell-type specific functional connectivity of long-range inputs from distant brain regions using optogenetic stimulations in ex vivo brain slices.

בזריקות Vivo גרם סטריאוטקאית לגירוי מגנטי של תשומות לטווח ארוך בפרוסות המוח של העכבר

Knowledge of cell-type specific synaptic connectivity is a crucial prerequisite for understanding brain-wide neuronal circuits. The functional ...

Adaptable Angled Stereotactic Approach for Versatile Neuroscience Techniques

Stereotactic surgery is an essential tool in the modern neuroscience lab. However, the ability to precisely and accurately target difficult-to-reach brain regions still presents a challenge, particularly when targeting brain structures along the midline. These challenges include avoiding of the superior sagittal sinus and third ventricle and the ability to consistently target selective and discrete brain nuclei. In addition, more advanced neuroscience techniques (e.g., optogenetics, fiber photometry, and two-photon imaging) rely on targeted implantation of significant hardware to the brain, and spatial limitations are a common hindrance. Presented here is a modifiable protocol for stereotactic targeting of rodent brain structures using an angled coronal approach. It can be adapted to 1) mouse or rat models, 2) various neuroscience techniques, and 3) multiple brain regions. As a representative example, it includes the calculation of stereotactic coordinates for targeting of the mouse hypothalamic ventromedial nucleus (VMN) for an optogenetic inhibition experiment. This procedure begins with the bilateral microinjection of an adeno-associated virus (AAV) encoding a light-sensitive chloride channel (SwiChR++) to a Cre-dependent mouse model, followed by the angled bilateral implantation of fiberoptic cannulae. Using this approach, findings show that activation of a subset of VMN neurons is required for intact glucose counterregulatory responses to insulin-induced hypoglycemia.

Described here is a stereotactic procedure that can target challenging and difficult-to-reach brain regions (due to spatial limitations) using an angled coronal approach. This protocol is adaptable to both mouse and rat models and can be applied to diverse neuroscientific applications, including cannula implantation and microinjections of viral constructs.

גישה סטריאו-טיאו-טסטרואקטיבית מסתגלת לטכניקות רב-תכליתיות במדעי המוח

Stereotactic surgery is an essential tool in the modern neuroscience lab. However, the ability to precisely and accurately target difficult-to-reach brain ...

Stereotaxic Intracranial Delivery of Chemicals, Proteins or Viral Vectors to Study Parkinson's Disease

Parkinson's disease (PD) is a progressive disorder traditionally defined by resting tremor and akinesia, primarily due to loss of dopaminergic neurons in the substantia nigra. Affected brain areas display intraneuronal fibrillar inclusions consisting mainly of alpha-synuclein (asyn) proteins. No animal model thus far has recapitulated all characteristics of this disease. Here, we describe the use of stereotaxic injection to deliver chemicals, proteins, or viral vectors intracranially in order to mimic various aspects of PD. These methods are well-established and widely used throughout the PD field. Stereotaxic injections are incredibly flexible; they can be adjusted in concentration, age of animal used for injection, brain area targeted and in animal species used. Combinations of substances allow for rapid variations to assess treatments or alter severity of the pathology or behavioral deficits. By injecting toxins into the brain, we can mimic inflammation and/or a severe loss of dopaminergic neurons resulting in substantial motor phenotypes. Viral vectors can be used to transduce cells to mimic genetic or mechanistic aspects. Preformed fibrillar asyn injections best recapitulate the progressive phenotype over an extended period of time. Once these methods are established, it can be economical to generate a new model compared to creating a new transgenic line. However, this method is labor intensive as it requires 30 minutes to four hours per animal depending on the model used. Each animal will have a slightly different targeting and therefore create a diverse cohort which on one hand can be challenging to interpret results from; on the other hand, help mimic a more realistic diversity found in patients. Mistargeted animals can be identified using behavioral or imaging readouts, or only after being sacrificed leading to smallercohort size after the study has already been concluded. Overall, this method is a rudimentary but effective way to assess a diverse set of PD aspects.

We describe how to successfully inject solutions into specific brain areas of rodents using a stereotaxic frame. This survival surgery is a well-established method used to mimic various aspects of Parkinson's disease.

Parkinson's disease (PD) is a progressive disorder traditionally defined by resting tremor and akinesia, primarily due to loss of dopaminergic neurons in ...

אופטימיזציה של דיוק מיקרו-הזרקה סטריאוטקסית בעכברים

Preliminary Validation of Stereotaxic Injection Coordinates via Cryosectioning

Stereotaxic injection of a specific brain region constitutes a fundamental experimental technique in basic neuroscience. Researchers commonly base their choice of stereotaxic injection parameters on mouse brain atlases or published materials that employed various populations/ages of mice and different stereotaxic equipment, necessitating further validation of the stereotaxic coordinate parameters. The efficacy of calcium imaging, chemogenetic, and optogenetic manipulations relies on the precise expression of reporter genes within the region of interest, often requiring several weeks of effort. Thus, it is a time-consuming task if the coordinates of the target brain region are not verified in advance. Using an appropriate dye instead of a virus and implementing cryosectioning, researchers can observe the injection site immediately following dye administration. This facilitates timely adjustments to coordinate parameters in cases where discrepancies exist between the actual injection site and the theoretical position. Such adjustments significantly enhance the accuracy of viral expression within the target region in subsequent experiments.

מחבר זרקור: האצת מחקר ליקויים קוגניטיביים בעכברים באמצעות הזרקה סטריאוטקסית וצבעים חסכוניים

The present protocol describes a practical strategy to expedite the verification step of stereotaxic injection coordinates before conducting viral tracing using dyes and frozen sections.

אימות ראשוני של קואורדינטות הזרקה סטריאוטקסיות באמצעות קריוסקציה

Stereotaxic injection of a specific brain region constitutes a fundamental experimental technique in basic neuroscience. Researchers commonly base their ...