This research was supported by the National Institute of Mental Health MH 086960-01A1 (Christa K. McIntyre).

The authors have no competing interests or conflicts.

Nós apresentamos aqui um protocolo que é usado para facilitar a extinção do medo condicionado durante uma única sessão de exposição a estímulos condicionados 19 e modular a plasticidade na via entre o córtex infralimbic ea amígdala basolateral que podem mediar a aprendizagem extinção 20. Um passo crucial para o sucesso deste protocolo é a entrega dos VNS durante o treinamento de extinção. Portanto, um cuidado especial deve ser dada para a construção dos eléctrodos de punho e a co...

Medo condicionado clássico fornece um modelo animal amplamente utilizado para estudar a função biológica de perturbações de ansiedade. Durante o condicionamento do medo, um estímulo aversivo (o estímulo não condicionado, EUA, por exemplo, um choque eléctrico na pata) é apresentada em conjunto com um estímulo neutro, tal como um tom e / ou um quadro (o estímulo condicionado; CS). Durante o condicionamento do medo, as associações entre o CS e os EUA são formadas. Eventualmente, a apresentação do CS sozinho induz uma resposta de medo (resposta condicionada; CR). Em extinção medo, o CS é apresentada repetidamente na ausência de os EUA, fazendo com que o CR a diminuir gradualmente 1. Assim, a extinção do medo condicionado é um processo ativo em que as respostas comportamentais medo de estímulos neutros são atenuados quando já não prever resultados aversivos. Extinção de respostas condicionadas requer a consolidação de novas memórias que competem com as associações aprendidas. Uma característica dos transtornos de ansiedade é impaextinção Ired 2-4. Assim, a extinção do medo condicionado em modelos animais serve como um paradigma importante tanto para a aprendizagem inibidor e como um modelo de terapia comportamental para transtornos de ansiedade humanos 5,6. Porque existe uma estreita correspondência entre o medo ea ansiedade humana, pensa-se que estes estudos podem fornecer insights sobre a natureza biológica de distúrbios relacionados com a ansiedade como o transtorno de estresse pós-traumático e ajudará a desenvolver estratégias para tratá-los. Um objetivo importante da pesquisa pré-clínica é ajudar aprendizagem extinção e para induzir plasticidade alvejado em circuitos de extinção para consolidar a aprendizagem extinção. Estimulação do nervo vago (VNS) é uma abordagem neuroprosthetic minimamente invasivo que pode ser usado para fornecer modulação temporal e específico do circuito apertado de áreas do cérebro e sinapses envolvidos em uma tarefa contínua. Uma série de estudos recentes do grupo de Michael Kilgard na Universidade do Texas em Dallas temmostraram que o emparelhamento VNS com estímulos sensoriais ou motoras discretas (por exemplo, um tom ou um puxão alavanca) é altamente eficaz na promoção da plasticidade cortical para tratar o zumbido 7, ou para superar os défices motores após acidente vascular cerebral 8-10. Além disso, não contingente VNS que ocorre dentro de um intervalo de tempo curto depois de saber semelhante promove plasticidade cortical e melhora a consolidação da memória em ratos e em seres humanos 11-13. Considerando o papel do nervo vago na via parassimpático, não é surpreendente que possa participar na modulação da plasticidade sináptica e memórias. Altamente eventos emocionais tendem a produzir memórias mais fortes do que as memórias não-emocionais. Isto é provavelmente devido à influência dos hormônios do estresse sobre a consolidação da memória. Pós-treino administração da adrenalina hormônio do estresse aumenta a consolidação da memória em animais humanos e não-humanos, mas a adrenalina não atravessar a barreira sangue-cérebro-barreira 14, 15 </sup&gt;. Portanto, a liberação de adrenalina induzida por estresse deve impactar o cérebro indirectamente para melhorar a consolidação da memória. Fortes evidências sugerem que o nervo vago pode ser o elo entre a adrenalina circulante eo cérebro. Miyashita e Williams 16 acharam que a administração sistêmica da adrenalina aumentou disparo do nervo vago, e aumento dos níveis de norepinefrina na amígdala 17. A administração sistémica de adrenalina não melhora a consolidação da memória quando os receptores β-adrenérgicos são bloqueados na amígdala 18 sugerindo que o nervo vago desempenha um papel importante no caminho que se transforma experiências emocionalmente carregadas em memórias de longo prazo. Assim, o emparelhamento com VNS treinamento tem o potencial de melhorar as mudanças do cérebro que suportam a consolidação da memória e exposição a estímulos condicionados, na ausência de reforço aumenta a consolidação da aprendizagem extinção em ratos 19,20. Aqui descreve-se a utilização de um VNSsa ferramenta para promover a plasticidade cortical e facilitar a extinção de uma resposta de medo condicionada.

<table><tbody><tr><td>Alcohol</td><td></td><td></td><td></td></tr><tr><td>Atropine</td><td>Fisher</td><td>A0132-5G</td><td></td></tr><tr><td>Betadine</td><td>Henry Schein</td><td>69066950</td><td></td></tr><tr><td>Hydrogen peroxide&amp;nbsp;</td><td>CVS</td><td>209478</td><td></td></tr><tr><td>Ketamine</td><td>Henry Schein&amp;nbsp;</td><td>1129300</td><td></td></tr><tr><td>Marcaine</td><td>Henry Schein</td><td>6312615</td><td></td></tr><tr><td>Mineral Oil</td><td>CVS</td><td>152355</td><td></td></tr><tr><td>Neosporin</td><td>CVS</td><td>629451</td><td></td></tr><tr><td>Oxygen</td><td>Home Depot</td><td>304179</td><td></td></tr><tr><td>Pennicillin</td><td>Fisher</td><td>PENNA-10MU</td><td></td></tr><tr><td>Propane</td><td>Home Depot</td><td>304182</td><td></td></tr><tr><td>Xylazine</td><td>Henry Schein</td><td>4019308</td><td></td></tr><tr><td>Tools</td><td></td><td></td><td></td></tr><tr><td>Jewelery Torch</td><td>Smith Equipment</td><td>23-1001D</td><td></td></tr><tr><td>Sewing Needle</td><td>Walgreens</td><td>441831</td><td></td></tr><tr><td>#5 Forceps (2)</td><td>Fine Science Tools</td><td>11254-20</td><td></td></tr><tr><td>Soldering Iron</td><td>Home Depot&amp;nbsp;</td><td>203525863</td><td></td></tr><tr><td>AmScope SM-4TX-144A 3.5X-45X Circuit Board Boom Stereo Microscope + 144 LED</td><td>AmScope</td><td>SM-4TX-144A</td><td></td></tr><tr><td>Helping Hands</td><td>A-M Systems&amp;nbsp;</td><td>726200</td><td></td></tr><tr><td>Scalpel Blade Holder</td><td>Fine Science Tools</td><td>10003-12</td><td></td></tr><tr><td>Metal File</td><td>Home Depot</td><td>6601</td><td></td></tr><tr><td>Ruler</td><td>Home Deopt</td><td>202035324</td><td></td></tr><tr><td>Curved Hemostats&amp;nbsp;</td><td>Fine Science Tools</td><td>130009-12</td><td></td></tr><tr><td>Fine Scissors</td><td>Fine Science Tools</td><td>14058-09</td><td></td></tr><tr><td>Spatula</td><td>Fine Science Tools</td><td></td><td></td></tr><tr><td>Small Screwdriver</td><td>Home Depot</td><td>646507</td><td></td></tr><tr><td>Magnetic Fixator Retraction System</td><td>Fine Science Tools</td><td>18200-04, 18200-01, 18200-05</td><td></td></tr><tr><td>Heating Pad</td><td>Walgreens</td><td>30294</td><td></td></tr><tr><td>Clippers</td><td>Walgreens</td><td>277966</td><td></td></tr><tr><td>Sharpie</td><td>Staples</td><td>125328</td><td></td></tr><tr><td>Ring Forceps</td><td>Fine Science Tools</td><td>11103-09</td><td></td></tr><tr><td>Custom Micropipette Glass Tools (J shape and Straight) - Borosilicate glass</td><td>Sutter Instrument</td><td>B150-110-10</td><td></td></tr><tr><td>Adson Forceps</td><td>Fine Science Tools</td><td>11006-12</td><td></td></tr><tr><td>Cuffs</td><td></td><td></td><td></td></tr><tr><td>Tubing</td><td>Braintree Scientific Inc</td><td>MRE-065</td><td></td></tr><tr><td>Platinum Iridium Wire</td><td>Medwire</td><td>10IR9/49T</td><td></td></tr><tr><td>Gold Pins</td><td>Mill-Max</td><td>1001-0-15-15-30-27-04-0</td><td></td></tr><tr><td>Suture Thread</td><td>Henry Schein</td><td>100-5797</td><td></td></tr><tr><td>22 G needles</td><td>Fisher&amp;nbsp;</td><td>14-815-525</td><td></td></tr><tr><td>Paper Tape</td><td>Fisher&amp;nbsp;</td><td>03-411-602</td><td></td></tr><tr><td>Solder</td><td>Home Depot</td><td>327793</td><td></td></tr><tr><td>Flux&amp;nbsp;</td><td>Home Depot</td><td>300142</td><td></td></tr><tr><td>Scalpel Blade, 10 or 15</td><td>Stoelting</td><td>52173-10</td><td></td></tr><tr><td>Silastic Laboratory Tubing .51 mm ID x .94 mm OD</td><td>Fisher&amp;nbsp;</td><td>508-002</td><td></td></tr><tr><td>Headcaps</td><td></td><td></td><td></td></tr><tr><td>Connector Pieces (male)</td><td>Omnetics Connector Corporation</td><td>A25001-004</td><td></td></tr><tr><td>Headcap pieces (female)</td><td>Omnetics Connector Corporation</td><td>A24001-004</td><td></td></tr><tr><td>Teets Dental Acrylic, Liquid and Powder</td><td>A-M Systems</td><td>525000, 526000</td><td></td></tr><tr><td>26 Gauge Solid Copper Wire</td><td>Staples</td><td>1016882 &amp;nbsp;</td><td></td></tr><tr><td>Surgery</td><td></td><td></td><td></td></tr><tr><td>Bone Screws</td><td>Stoelting+CB33:C61</td><td>51457</td><td></td></tr><tr><td>Scalpel Blades, 10 or 15</td><td>Stoelting</td><td>52173-10</td><td></td></tr><tr><td>1 ml syringes</td><td>Fisher</td><td>14-826-261</td><td></td></tr><tr><td>22 G Needles</td><td>Fisher&amp;nbsp;</td><td>14-815-525</td><td></td></tr><tr><td>27 G Needles</td><td>Fisher</td><td>14-826-48</td><td></td></tr><tr><td>2&quot; x 2&quot; Gauze</td><td>Fisher</td><td>22-362-178</td><td></td></tr><tr><td>Swabs</td><td>Fisher</td><td>19-120-472</td><td></td></tr><tr><td>Puppy Pads</td><td>PetCo</td><td>1310747</td><td></td></tr><tr><td>Kim Wipes</td><td>Fisher</td><td>06-666-A</td><td></td></tr><tr><td>Chamber and Behavioral Setting&amp;nbsp;</td><td></td><td></td><td></td></tr><tr><td>Husky Metal Front Base Cabinet (30WX19DX34H)</td><td>Home Depot</td><td>100607961</td><td></td></tr><tr><td>Quiet Barrier&amp;shy; HD Soundproofing Material (Sheet) (PSA)</td><td>soundproofcow.com</td><td>10203041</td><td></td></tr><tr><td>Convoluted Acoustic Foam Panel</td><td>soundproofcow.com</td><td>10432400</td><td></td></tr><tr><td>Isolated Pulse Stimulator Model 2100</td><td>A-M Systems</td><td>720000</td><td></td></tr><tr><td>Digital Camera - Logitech Webcam C210</td><td>Logitech</td><td>B003LVZO88</td><td></td></tr><tr><td>MatLab</td><td>Mathworks.com</td><td></td><td></td></tr><tr><td>Sinometer 10 MHz Single Channel Oscilloscope</td><td>Sinometer</td><td>CQ5010C</td><td></td></tr><tr><td>OxyLED T-01 DIY Stick-on Anywhere 4-LED Touch Tap Light</td><td>OXYLED</td><td>B00GD8OKY0</td><td></td></tr><tr><td>5k ohm potentiomter</td><td>Alpha Electronics</td><td>B00CTWDHIO</td><td></td></tr><tr><td>Extech 407730 40-to-130-Decibel Digital Sound Level Meter</td><td>Extech Instruments</td><td>B000EWY67W</td><td></td></tr><tr><td>DSCK-C Dual Output, scrambled shocker</td><td>Kinder Scientific Co</td><td></td><td></td></tr></tbody></table>

vagus nerve stimulation as a tool to induce plasticity in pathways relevant for extinction learning

Extinction describes the process of attenuating behavioral responses to neutral stimuli when they no longer provide the reinforcement that has been maintaining the behavior. There is close correspondence between fear and human anxiety, and therefore studies of extinction learning might provide insight into the biological nature of anxiety-related disorders such as post-traumatic stress disorder, and they might help to develop strategies to treat them. Preclinical research aims to aid extinction learning and to induce targeted plasticity in extinction circuits to consolidate the newly formed memory. Vagus nerve stimulation (VNS) is a powerful approach that provides tight temporal and circuit-specific release of neurotransmitters, resulting in modulation of neuronal networks engaged in an ongoing task. VNS enhances memory consolidation in both rats and humans, and pairing VNS with exposure to conditioned cues enhances the consolidation of extinction learning in rats. Here, we provide a detailed protocol for the preparation of custom-made parts and the surgical procedures required for VNS in rats. Using this protocol we show how VNS can facilitate the extinction of conditioned fear responses in an auditory fear conditioning task. In addition, we provide evidence that VNS modulates synaptic plasticity in the pathway between the infralimbic (IL) medial prefrontal cortex and the basolateral complex of the amygdala (BLA), which is involved in the expression and modulation of extinction memory.

Esta secção ilustra exemplos de resultados que podem ser obtidos através da utilização de VNS em combinação com a aprendizagem extinção para reduzir a expressão da resposta de medo condicionado em ratos. Para Dias 1 e 2 (Auditivo Medo Condicionado), os ratos foram treinados em uma tarefa auditiva medo condicionado em choques nas patas que foram pareados com um tom. No Dia 3 (Pré-Tratamento de teste), tons foram apresentados na ausência de choques nas patas para medir os níveis de congelamento e inferir aqui...

Watch this Scientific Journal Video about Vagus Nerve Stimulation as a Tool to Induce Plasticity in Pathways Relevant for Extinction Learning at JoVE.com

Vagus Nerve Stimulation as a Tool to Induce Plasticity in Pathways Relevant for Extinction Learning

Estimulação do nervo vago (VNS) emergiu como uma ferramenta para induzir plasticidade sináptica alvejado na parte frontal do cérebro para modificar uma série de comportamentos. Este protocolo descreve como implementar VNS para facilitar a consolidação da memória de extinção do medo.

Estimulação do nervo vago como uma ferramenta para induzir plasticidade em Pathways relevantes para a Aprendizagem Extinção

Extinction describes the process of attenuating behavioral responses to neutral stimuli when they no longer provide the reinforcement that has been ...

vagus-nerve-stimulation-as-tool-to-induce-plasticity-pathways

Research

JoVE Journal

Behavior

23.3K visualizações.  The University of Texas at Dallas.  Estimulação do nervo vago (VNS) emergiu como uma ferramenta para induzir plasticidade sináptica alvejado na parte frontal do cérebro para modificar uma série de comportamentos. Este protocolo descreve como implementar VNS para facilitar a consolidação da memória de extinção do medo. 

Vídeo: Vagus Nerve Stimulation as a Tool to Induce Plasticity in Pathways Relevant for Extinction Learning

Long-term Potentiation of Perforant Pathway-dentate Gyrus Synapse in Freely Behaving Mice

Studies of long-term potentiation of synaptic efficacy, an activity-dependent synaptic phenomenon having properties that make it attractive as a potential cellular mechanism underlying learning and information storage, have long been used to elucidate the physiology of various neuronal circuits in the hippocampus, amygdala, and other limbic and cortical structures. With this in mind, transgenic mouse models of neurological diseases represent useful platforms to conduct long-term&#160;potentiation (LTP) studies to develop a greater understanding of the role of genes in normal and abnormal synaptic communication in neuronal networks involved in learning, emotion and information processing. This article describes methodologies for reliably inducing LTP in the freely behaving mouse. These methodologies can be used in studies of transgenic and knockout freely&#160;behaving mouse models of neurodegenerative diseases.

Transgenic and knockout mouse models of neurological diseases are useful for studying the role of genes in normal and abnormal neurophysiology. This article describes methodologies which can be used to study long-term potentiation, a cellular mechanism which may underlie learning and memory, in transgenic and knockout freely&#160;behaving mouse models of neuropathology.

Potenciação de longo prazo da Via Perfurante-giro denteado Synapse em Livremente Comportando Ratos

Studies of long-term potentiation of synaptic efficacy, an activity-dependent synaptic phenomenon having properties that make it attractive as a potential ...

Comportamento

A Method for Remotely Silencing Neural Activity in Rodents During Discrete Phases of Learning

This protocol describes how to temporarily and remotely silence neuronal activity in discrete brain regions while animals are engaged in learning and memory tasks. The approach combines pharmacogenetics (Designer-Receptors-Exclusively-Activated-by-Designer-Drugs) with a behavioral paradigm (sensory preconditioning) that is designed to distinguish between different forms of learning. Specifically, viral-mediated delivery is used to express a genetically modified inhibitory G-protein coupled receptor (the Designer Receptor) into a discrete brain region in the rodent. Three weeks later, when designer receptor expression levels are high, a pharmacological agent (the Designer Drug) is administered systemically 30 min prior to a specific behavioral session. The drug has affinity for the designer receptor and thus results in inhibition of neurons that express the designer receptor, but is otherwise biologically inert. The brain region remains silenced for 2-5 hr (depending on the dose and route of administration). Upon completion of the behavioral paradigm, brain tissue is assessed for correct placement and receptor expression. This approach is particularly useful for determining the contribution of individual brain regions to specific components of behavior and can be used across any number of behavioral paradigms.

This protocol describes how to temporarily and remotely silence neuronal activity in discrete brain regions while rats are engaged in learning and memory tasks. The approach combines pharmacogenetics (Designer-Receptors-Exclusively-Activated-by-Designer-Drugs) with a behavioral paradigm (sensory preconditioning) that is designed to distinguish between different components of learning.

Um método para a atividade neural remotamente Silenciando em Roedores Durante fases distintas de Aprendizagem

This protocol describes how to temporarily and remotely silence neuronal activity in discrete brain regions while animals are engaged in learning and ...

Extinction Training During the Reconsolidation Window Prevents Recovery of Fear

Fear is maladaptive when it persists long after circumstances have become safe. It is therefore crucial to develop an approach that persistently prevents the return of fear. Pavlovian fear-conditioning paradigms are commonly employed to create a controlled, novel fear association in the laboratory. After pairing an innocuous stimulus (conditioned stimulus, CS) with an aversive outcome (unconditioned stimulus, US) we can elicit a fear response (conditioned response, or CR) by presenting just the stimulus alone1,2 . Once fear is acquired, it can be diminished using extinction training, whereby the conditioned stimulus is repeatedly presented without the aversive outcome until fear is no longer expressed3. This inhibitory learning creates a new, safe representation for the CS, which competes for expression with the original fear memory4. Although extinction is effective at inhibiting fear, it is not permanent. Fear can spontaneously recover with the passage of time. Exposure to stress or returning to the context of initial learning can also cause fear to resurface3,4.
Our protocol addresses the transient nature of extinction by targeting the reconsolidation window to modify emotional memory in a more permanent manner. Ample evidence suggests that reactivating a consolidated memory returns it to a labile state, during which the memory is again susceptible to interference5-9. This window of opportunity appears to open shortly after reactivation and close approximately 6hrs later5,11,16, although this may vary depending on the strength and age of the memory15. By allowing new information to incorporate into the original memory trace, this memory may be updated as it reconsolidates10,11. Studies involving non-human animals have successfully blocked the expression of fear memory by introducing pharmacological manipulations within the reconsolidation window, however, most agents used are either toxic to humans or show equivocal effects when used in human studies12-14. Our protocol addresses these challenges by offering an effective, yet non-invasive, behavioral manipulation that is safe for humans.
By prompting fear memory retrieval prior to extinction, we essentially trigger the reconsolidation process, allowing new safety information (i.e., extinction) to be incorporated while the fear memory is still susceptible to interference. A recent study employing this behavioral manipulation in rats has successfully blocked fear memory using these temporal parameters11. Additional studies in humans have demonstrated that introducing new information after the retrieval of previously consolidated motor16, episodic17, or declarative18 memories leads to interference with the original memory trace14. We outline below a novel protocol used to block fear recovery in humans.

Conditioned fear can be diminished through an inhibitory process called extinction, but can resurface under conditions such as the passage of time or exposure to stress. Our protocol presents a novel way of preventing fear recovery by introducing extinction during the reconsolidation window (the re-storage phase of a reactivated memory).

Formação extinção durante a janela de reconsolidação impede a recuperação do Medo

Fear is maladaptive when it persists long after circumstances have become safe. It is therefore crucial to develop an approach that persistently prevents ...

Neurociência

Stress-Enhanced Fear Learning, a Robust Rodent Model of Post-Traumatic Stress Disorder

Fear behaviors are important for survival, but disproportionately high levels of fear can increase the vulnerability for developing psychiatric disorders such as post-traumatic stress disorder (PTSD). To understand the biological mechanisms of fear dysregulation in PTSD, it is important to start with a valid animal model of the disorder. This protocol describes the methodology required to conduct stress-enhanced fear learning (SEFL) experiments, a preclinical model of PTSD, in both rats and mice. SEFL was developed to recapitulate critical aspects of PTSD, including long-term sensitization of fear learning caused by an acute stressor. SEFL uses aspects of Pavlovian fear conditioning but produces a distinct and robust sensitized fear response far greater than normal conditional fear responses. The trauma procedure involves placing a rodent in a conditioning chamber and administering 15 unsignaled shocks randomly distributed over 90 minutes (for rat experiments; for mouse experiments, 10 unsignaled shocks randomly distributed over 60 minutes are used). On day 2, rodents are placed in a novel conditioning context where they receive a single shock; then, on day 3 they are placed back in the same context as on day 2 and tested for changes in freezing levels. Rodents that previously received the trauma display enhanced levels of freezing on the test day compared to those that received no shocks on the first day. Thus, with this model, a single highly stressful experience (the trauma) produces extreme fear of the stimuli associated with the traumatic event.

Here we describe the detailed methodology required to conduct stress-enhanced fear learning (SEFL) experiments, a preclinical model of post-traumatic stress disorder, in both rats and mice. The model utilizes aspects of Pavlovian fear conditioning and freezing as an index of enhanced fear in rodents.

Aprendizagem avançada stress medo, um modelo robusto de roedor do transtorno de estresse pós-traumático

Fear behaviors are important for survival, but disproportionately high levels of fear can increase the vulnerability for developing psychiatric disorders ...

Ex Vivo Optogenetic Dissection of Fear Circuits in Brain Slices

Optogenetic approaches are now widely used to study the function of neural populations and circuits by combining targeted expression of light-activated proteins and subsequent manipulation of neural activity by light. Channelrhodopsins (ChRs) are light-gated cation-channels and when fused to a fluorescent protein their expression allows for visualization and concurrent activation of specific cell types and their axonal projections in defined areas of the brain. Via stereotactic injection of viral vectors, ChR fusion proteins can be constitutively or conditionally expressed in specific cells of a defined brain region, and their axonal projections can subsequently be studied anatomically and functionally via ex vivo optogenetic activation in brain slices. This is of particular importance when aiming to understand synaptic properties of connections that could not be addressed with conventional electrical stimulation approaches, or in identifying novel afferent and efferent connectivity that was previously poorly understood. Here, a few examples illustrate how this technique can be applied to investigate these questions to elucidating fear-related circuits in the amygdala. The amygdala is a key region for acquisition and expression of fear, and storage of fear and emotional memories. Many lines of evidence suggest that the medial prefrontal cortex (mPFC) participates in different aspects of fear acquisition and extinction, but its precise connectivity with the amygdala is just starting to be understood. First, it is shown how ex vivo optogenetic activation can be used to study aspects of synaptic communication between mPFC afferents and target cells in the basolateral amygdala (BLA). Furthermore, it is illustrated how this ex vivo optogenetic approach can be applied to assess novel connectivity patterns using a group of GABAergic neurons in the amygdala, the paracapsular intercalated cell cluster (mpITC), as an example.

Ex Vivo Optogenetic Dissection of Fear Circuits in Brain Slices

Optogenetic approaches are widely used to manipulate neural activity and assess the consequences for brain function. Here, a technique is outlined that&#160;upon in vivo expression of the optical activator Channelrhodopsin, allows for ex vivo analysis of synaptic properties of specific long range and local neural connections in fear-related circuits.

Ex Vivo optogenética Dissection de Circuitos medo no cérebro Slices

Optogenetic approaches are now widely used to study the function of neural populations and circuits by combining targeted expression of light-activated ...

Assessment of Long-term Depression Induction in Adult Cerebellar Slices

Synaptic plasticity provides a mechanism for learning and memory. For cerebellar motor learning, long-term depression (LTD) of synaptic transmissions from parallel fibers (PF) to Purkinje cells (PC) is considered the basis for motor learning, and deficiencies of both LTD and motor learning are observed in various gene-manipulated animals. Common motor learning sets, such as adaptation of the optokinetic reflex (OKR), the vestibular-ocular reflex (VOR), and rotarod test were used for evaluation of motor learning ability. However, results obtained from the GluA2-carboxy terminus modified knock-in mice demonstrated normal adaptation of the VOR and the OKR, despite lacking PF-LTD. In that report, induction of LTD was only attempted using one type of stimulation protocol at room temperature. Thus, conditions to induce cerebellar LTD were explored in the same knock-in mutants using various protocols at near physiological temperature. Finally, we found stimulation protocols, by which LTD could be induced in these gene-manipulated mice. In this study, a set of protocols are proposed to evaluate LTD-induction, which will more accurately allow examination of the causal relationship between LTD and motor learning. In conclusion, experimental conditions are crucial when evaluating LTD in gene-manipulated mice.

In some gene-manipulated animals, using a single protocol may fail to induce LTD in cerebellar Purkinje cells, and there may be a discrepancy between LTD and motor learning. Multiple protocols are necessary to assess LTD-induction in gene-manipulated animals. Standard protocols are shown.

Avaliação da indução de depressão em longo prazo em fatias Cerebelares adultas

Synaptic plasticity provides a mechanism for learning and memory. For cerebellar motor learning, long-term depression (LTD) of synaptic transmissions from ...

Vagus Nerve Stimulation As an Adjunctive Neurostimulation Tool in Treatment-resistant Depression

Vagus nerve stimulation (VNS) is an approved neurostimulation therapy. The purpose of the method is to treat patients with therapy-resistant depression (TRD). VNS exhibits antidepressive and stabilizing effects. This method is particularly useful as a long-term treatment, in which up to two-thirds of patients respond. The vagus nerve stimulator is positioned on the left vagus nerve during a surgical procedure and is activated telemetrically by a wand connected to a handheld computerized device. The treating physician can perform various adjustments of the vagus nerve stimulator during in-office visits (e.g., by modifying stimulation intensity or stimulation frequency) to achieve maximum therapeutic effects with low side effects. Set-up of the device usually takes several months. Typical side effects include wound infection, temporary salivation, coughing, paralysis of the vocal cords, bradycardia, or even asystole. The patient can stop the VNS by placing a magnet over the generator. The current protocol describes delivery of the specific stimulation tool and methods for adjusting the tuning parameters to achieve the best remission rates in patients with TRD.

Vagus nerve stimulation (VNS) has been shown to be effective as an adjunct treatment for treatment-resistant depression (TRD). VNS leads to antidepressive and antisuicidal effects and quality of life improvements. This protocol offers a step-by-step guide to managing and adjusting a vagus nerve stimulator for efficient treatment of TRD.

Estimulação do nervo vago como uma ferramenta de neuroestimulação adjuvante na depressão tratamento-resistente

Vagus nerve stimulation (VNS) is an approved neurostimulation therapy. The purpose of the method is to treat patients with therapy-resistant depression ...

Medicina

Preparation of Peripheral Nerve Stimulation Electrodes for Chronic Implantation in Rats

Peripheral nerve cuff electrodes have long been used in the neurosciences and related fields for stimulation of, for example, vagus or sciatic nerves. Several recent studies have demonstrated the effectiveness of chronic VNS in enhancing central nervous system plasticity to improve motor rehabilitation, extinction learning, and sensory discrimination. Construction of chronically implantable devices for use in such studies is challenging due to rats&#8217; small size, and typical protocols require extensive training of personnel and time-consuming microfabrication methods. Alternatively, commercially available implantable cuff electrodes can be purchased at a significantly higher cost. In this protocol, we present a simple, low-cost method for construction of small, chronically implantable peripheral nerve cuff electrodes for use in rats. We validate the short and long-term reliability of our cuff electrodes by demonstrating that VNS in ketamine/xylazine anesthetized rats produces decreases in breathing rate consistent with activation of the Hering-Breuer reflex, both at the time of implantation and up to 10 weeks after device implantation. We further demonstrate the suitability of the cuff electrodes for use in chronic stimulation studies by pairing VNS with skilled lever press performance to induce motor cortical map plasticity.

Existing approaches for constructing chronically implantable peripheral nerve cuff electrodes for use in small rodents often require specialized equipment and/or highly trained personnel. In this protocol we demonstrate a simple, low-cost approach for fabricating chronically implantable cuff electrodes, and demonstrate their effectiveness for vagus nerve stimulation (VNS) in rats.

Preparação de Eletrodos de Estimulação Nervosa Periférica para Implantação Crônica em Ratos

Peripheral nerve cuff electrodes have long been used in the neurosciences and related fields for stimulation of, for example, vagus or sciatic nerves. ...

Using Optogenetics to Reverse Neuroplasticity and Inhibit Cocaine Seeking in Rats

This protocol demonstrates the steps needed to use optogenetic tools to reverse cocaine-induced plasticity at thalamo-amygdala circuits to reduce subsequent cocaine seeking behaviors in the rat. In our research, we had found that when rats self-administer intravenous cocaine paired with an audiovisual cue, synapses formed at inputs from the medial geniculate nucleus of the thalamus (MGN) onto principal neurons of the lateral amygdala (LA) become stronger as the cue-cocaine association is learned. We hypothesized that reversal of the cocaine-induced plasticity at these synapses would reduce cue-motivated cocaine seeking behavior. In order to accomplish this type of neuromodulation in vivo, we wanted to induce synaptic long-term depression (LTD), which decreases the strength of MGN-LA synapses. To this end, we used optogenetics, which allows neuromodulation of brain circuits using light. The excitatory opsin oChiEF was expressed on presynaptic MGN terminals in the LA by infusing an AAV containing oChiEF into the MGN. Optical fibers were then implanted in the LA and 473 nm laser light was pulsed at a frequency of 1 Hz for 15 minutes to induce LTD and reverse cocaine induced plasticity. This manipulation produces a long-lasting reduction in the ability of cues associated with cocaine to induce drug seeking actions.

The methods described here outline a procedure used to optogenetically reverse cocaine-induced plasticity in a behaviorally-relevant circuit in rats. Sustained low-frequency optical stimulation of thalamo-amygdala synapses induces long-term depression (LTD). In vivo optogenetically-induced LTD in cocaine-experienced rats resulted in the subsequent attenuation of cue-motivated drug seeking.

Usando a optogenética para reverter a neuroplasticidade e inibir a busca de cocaína em ratos

This protocol demonstrates the steps needed to use optogenetic tools to reverse cocaine-induced plasticity at thalamo-amygdala circuits to reduce ...

VNS abdominal para tratamento de condições inflamatórias em modelos de ratos

Implantation Surgery for Abdominal Vagus Nerve Stimulation and Recording Studies in Awake Rats

Abdominal vagus nerve stimulation (VNS) can be applied to the subdiaphragmatic branch of the vagus nerve of rats. Due to its anatomical location, it does not have any respiratory and cardiac off-target effects commonly associated with cervical VNS. The lack of respiratory and cardiac off-target effects means that the intensity of stimulation does not need to be lowered to reduce side effects commonly experienced during cervical VNS. Few recent studies demonstrate the anti-inflammatory effects of abdominal VNS in rat models of inflammatory bowel disease, rheumatoid arthritis, and glycemia reduction in a rat model of type 2 diabetes. Rat is a great model to explore the potential of this technology because of the well-established anatomy of the vagus nerve, the large size of the nerve that allows easy handling, and the availability of many disease models. Here, we describe the methods for cleaning and sterilizing the abdominal VNS electrode array and surgical protocol in rats. We also describe the technology required for confirmation of suprathreshold stimulation by recording evoked compound action potentials. Abdominal VNS has the potential to offer selective, effective treatment for a variety of conditions, including inflammatory diseases, and the application is expected to expand similarly to cervical VNS.

Autor em destaque: explorando VNS abdominal para condições inflamatórias

The present protocol describes the surgical technique for implanting an electrode array onto the abdominal vagus nerve in rats, along with methods for chronic electrophysiology testing and stimulation using the implanted device.

Cirurgia de Implante para Estimulação do Nervo Vago Abdominal e Estudos de Gravação em Ratos Acordados

Abdominal vagus nerve stimulation (VNS) can be applied to the subdiaphragmatic branch of the vagus nerve of rats. Due to its anatomical location, it does ...