Este trabajo es apoyado por una beca de la Universidad de Baylor Research Council y de una beca de investigación de la Fundación para la Epilepsia.

Los ratones usados ​​en el experimento siguiente se generaron y se alojaron en la Universidad de Baylor en una temperatura ambiente de 22 ° C, con una luz de 14 horas y 10 horas de oscuridad (20:00-06:00 h) ciclo diurno. Los ratones se les dio acceso ad libitum a comida y agua. Todos los procedimientos a los ratones estaban en el cumplimiento de los Institutos Nacionales de Salud para el Cuidado y Uso de Animales de Laboratorio y el protocolo de los animales fue aprobado por la Universidad de Baylor Cuidado de Animales y el empleo Comisión. Visión de conjunto La traza acondicionado tarea temor se basa en los procedimientos descritos por Wiltgen y colegas 9. 1. Preparación de Equipo La cámara de aparato de acondicionamiento de miedo (26 cm x 22 cm x 18 cm) se compone de dos partes que son de acrílico, dos lados que son metal, y un fondo suelo de rejilla que se utiliza para entregar un choque leve pie. La cámara de pruebas es la casad en una cámara de sonido atenuado. La cámara también es estanca a la luz para evitar que la luz fuera de influir en el software de detección de movimiento. <ol><li> Calibre los niveles de impacto, los niveles de luz, y los niveles de intensidad sonora de la cámara de prueba. Medir el nivel de fondo de la cámara de prueba. El ruido de fondo en esta cámara es de 65 dB. Utilice un medidor de sonido para medir este nivel. El medidor se debe establecer en 70 dB, establece en C, y para la detección de establecer lento. <ol><li> Calibre el nivel de impacto de 0,5 mA. Utilice un dispositivo de ajuste externo para calibrar correctamente el nivel de impacto (véase la Tabla de Materiales). La medición interna del generador de descargas no es exacta. El generador de descargas administra un choque revueltos, que no se puede medir con precisión mediante un medidor de amplificador estándar. </li><li> Coloque un cable en una de las barras de la rejilla y colocar el otro cable de 3 o 4 bares terminado. Utilice el generador de descargas para administrar el shock. Ajuste el nivel de impacto hasta que se alcance el nivel correcto. Haga esto por each temer cámara de acondicionamiento. </li><li> Cierre la puerta de la cámara cuando se mide el nivel de luz de la cámara. Calibre el nivel de luz de aproximadamente 1,0. Este es un número específico para el software freezeframe utilizado en este experimento. Un medidor de luz externa se lee esto como 2 lux. El nivel de luz puede ajustarse moviendo la ubicación de la luz de la casa o ajustando el condensador de la lente. Asegúrese de apretar los tornillos de ajuste de la lente después del ajuste. </li><li> Calibre el nivel de decibeles de sonido de 85 dB. Utilice un medidor de decibelios externa dentro de la jaula de pruebas para calibrar el nivel de decibeles (ver Tabla de Materiales). El sonido se presenta será un tono de 2700 Hz. Nota: Si el uso de ratones mayores de 6 meses de edad, puede ser mejor utilizar ruido blanco ya que los ratones de edad avanzada pueden tener déficits auditivos. </li></ol></li><li> Después de que el aparato está listo tomar los sujetos a una sala de espera separada. Nota: No albergar el ratón en la habitación con la sala de pruebas. </li><li> ª de la etiquetae la cola de los ratones a los que se pondrán a prueba con el fin de la prueba. Lo mejor es reducir la manipulación excesiva antes de la prueba. Alternativamente, las colas pueden ser etiquetados el día antes del experimento para reducir el manejo de estrés. Después de que los ratones han sido etiquetados les permite aclimatarse al ambiente durante 30 min. Tener jaulas limpias adicional para alojar a los ratones una vez finalizada la prueba. </li></ol> 2. Traza Acondicionado Día 1 <ol><li> Retire cada ratón de la jaula y colocarlos en jaulas individuales para el transporte a la cámara de acondicionamiento miedo. Utilice ropa de cama limpia para cada jaula. Coloque una nota adhesiva en la caja de transferencia para mantener el orden de los ratones prueba correcta. Nota: Si los ratones son alojados individualmente, entonces pueden ser transportados en sus jaulas. </li><li> Coloque el ratón en la cámara de pruebas y cierre la puerta. Inicie el programa de software. </li><li> En el día de entrenamiento, permiten a los ratones para explorar la cámara durante 3 min. Entonces, el programa presenta un segundo tono de 20 (85 dB, 2700 Hz) to el animal. Después de un período de seguimiento de 20 seg un choque suave (2 seg, 0,5 mA) se administra al animal. </li><li> Registre la reacción del sujeto para confirmar que recibieron los estímulos aversivos viendo el video. Un intervalo entre ensayos de 200 seg separa los ensayos de condicionamiento 5. Cada prueba consiste en un tono de 20 segundos seguida de un retraso de 20 segundos luego un shock. </li><li> Una vez finalizada la prueba que el animal pueda permanecer en la cámara de ensayo durante 1 minuto antes de sacarla de la jaula de la prueba. </li><li> Colocar el animal en la jaula de transferencia y devolverlo a su jaula. Si hay otros ratones en su jaula y luego albergar individualmente el ratón hasta que todos los ratones de prueba completa. Esto reducirá la tensión a la otra ratones que no han sido probados. Una solución alternativa sería para albergar por separado todos los ratones una semana antes de la prueba para reducir la influencia de la eliminación continua de los ratones de una jaula. </li><li> Limpie la cámara de pruebas con isopropanol al 30% después de each animales se prueba. </li><li> Repetir los pasos 2.2 a 2.7 para todos los ratones en la cohorte de pruebas. </li><li> Volver a todos los ratones a su habitación después de la última colonia del ratón en la cohorte ha sido probado. </li></ol> 3. Traza el condicionamiento del miedo Día 2: Pruebas de memoria de seguimiento <ol><li> Las pruebas de memoria de seguimiento tendrá lugar el día 2. En este protocolo hay 3 presentaciones de tono. Coloque el ratón en un nuevo contexto para la prueba de rastreo acondicionado. </li><li> Preparar el software para ejecutar un programa con un período de línea de base 2 min seguido de tres presentaciones de tono 20 seg. No sa 220 sec ITI entre cada presentación tono. </li><li> Para la nueva condición de contexto, colocar insertos de acrílico transparente en el suelo de la cámara para alterar la forma, la textura, y el color de la cámara de acondicionamiento. </li><li> Cambie el olor en la cámara mediante la colocación de extracto de vainilla en un barco bajo el peso de inserción baja. </li><li> Limpie la cámara con etanol al 70% en lugar del 30% de isopropanol. Nota: Esto ayudará apara crear un nuevo contexto. </li><li> Traiga a los ratones a la sala de espera y volver a etiquetar sus colas para probar si es necesario. </li><li> Preparar las jaulas de transferencia de contexto novedosos mediante la sustitución de la ropa de cama con papel triturado. Nota: Esto le ayudará en la creación de un nuevo contexto. </li><li> Coloque el ratón en la cámara de prueba, se iniciará el programa. Limpiar la cámara con etanol al 70% después de que se complete la prueba. </li><li> Volver a los ratones a su jaula después de que se completó la traza acondicionado. Volver a todos los ratones a su habitación colonia cuando todos los ratones han sido probados. </li></ol> 4. Traza el condicionamiento del miedo Día 3: Pruebas de memoria contextual <ol><li> En el tercer día se lleva a cabo el condicionamiento contextual. Preparar el software para ejecutar un programa para grabar el comportamiento de congelación durante 8 min. </li><li> Limpie la cámara con isopropanol al 30% antes de la prueba y después de las pruebas de cada ratón. El contexto debe ser idéntica a la del día 1. Las jaulas de transferencia deben ser el mismo que en el día 1. </li><li&gt; Traer los ratones a la sala de espera y la etiqueta de la cola para la prueba. </li><li> Coloque cada ratón en la cámara de pruebas se iniciará el programa. Limpie la cámara con isopropanol al 30% después de finalizar la prueba. </li><li> Volver a todos los ratones a su habitación colonia cuando esté terminado. </li></ol>

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Los autores no tienen nada que revelar.

Se han realizado varios estudios que han aclarado el circuito neural que subyace traza el condicionamiento del miedo. Se cree Trazar el condicionamiento del miedo de involucrar a la CA1 del hipocampo 12-14. También hay evidencia de que la corteza prefrontal medial (mPFC) desempeña un papel importante en la traza de ojos parpadean acondicionado 15, y el córtex prefrontal medial se ha encontrado a participar en traza el condicionamiento del miedo. Un estudio encontró que las neuronas mPFC proporc...

En el condicionamiento del miedo un estímulo neutro (NS) está emparejado con un estímulo aversivo incondicionado (EE.UU.). El NS es normalmente un tono y se convierte en un estímulo condicionado (EC) a través de apareamientos repetidos con los EE.UU.. El CS puede entonces provocar una respuesta condicionada (RC), tales como la congelación, en ausencia de la aversivo EE.UU.. Un protocolo acondicionado temor comúnmente utilizado es el retraso acondicionado. En este protocolo la aparición de la SN y los EE.UU. es contigua o con algún solapamiento en la presentación del estímulo. A pesar de que demora el condicionamiento del miedo es uno de los tipos más comunes de temporal acondicionado asociativo, hay varios otros tipos de arreglos temporales acondicionado asociativa: acondicionamiento simultánea, acondicionamiento de espaldas, y traza acondicionado 1. En traza el condicionamiento del miedo hay un intervalo de estímulo libre entre la SN y los EE.UU. de varios segundos que resulta en un período de &quot;rastro&quot;. Varios estudios han reportado déficits en traza el condicionamiento del miedo cuando lesiones neurotóxicas se producen en las estructuras que la entrada en el hipocampo 2-5 o cuando los agentes farmacológicos se utilizan para bloquear la función del receptor en el hipocampo. Lesión a los resultados del hipocampo en los déficits en rastro acondicionador y acondicionador contextual, pero no perjudica demora el condicionamiento del miedo 8. Hay varias ventajas a usar traza el condicionamiento del miedo. El protocolo acondicionado temor se puede lograr en un período de prueba de tres días de la memoria y permite hipocampo-dependiente que no es espacialmente dependiente. Traza el condicionamiento del miedo puede ser utilizado como una prueba complementaria para el laberinto de Morris agua, nuevo test de reconocimiento de objetos, u otras pruebas de laberinto en la investigación de la memoria dependiente del hipocampo.

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trace fear conditioning in mice

En este experimento se presenta una técnica para medir el aprendizaje y la memoria. En el protocolo acondicionado rastrear el miedo que se presenta aquí hay cinco emparejamientos entre un estímulo neutro y un estímulo incondicionado. Hay un período de 20 segundos traza que separa cada ensayo acondicionado. En la siguiente congelación día se mide durante la presentación del estímulo condicionado (EC) y el periodo de rastreo. En el tercer día hay una prueba de 8 min para medir la memoria contextual. Los resultados representativos son de los ratones que fueron presentados con el estímulo incondicionado aversivo (shock) en comparación con los ratones que recibieron las presentaciones de tono sin el estímulo incondicionado. Traza el condicionamiento del miedo se ha utilizado con éxito para detectar los déficits de aprendizaje y memoria y mejoras sutiles en los ratones que no se encuentran con otros métodos de condicionamiento del miedo. Este tipo de condicionamiento del miedo se cree que es dependiente de las conexiones entre la corteza medial prefrontal y el hipocampo. Una controversia actual es si se cree que este método es-amígdala independiente. Por lo tanto, es necesaria otra prueba acondicionado miedo para examinar los efectos de aprendizaje y memoria de la amígdala-dependientes, como a través del retardo condicionamiento del miedo.

Para obtener resultados representativos se presentan datos de C57BL/6J ratones adultos control que recibieron los emparejamientos de estímulo neutro con el estímulo no condicionado (condición shock) en comparación con los ratones que recibieron el estímulo neutro, pero no recibieron el estímulo incondicionado (sin condiciones de choque). Es importante ejecutar esta condición cuando el ajuste inicial de esta prueba de comportamiento para determinar si el protocolo se ha realizado correctamente. <p class="jove_...

Watch this Scientific Journal Video about Trace Fear Conditioning in Mice at JoVE.com

Trace Fear Conditioning in Mice

En el siguiente experimento se describe un protocolo para rastrear el miedo acondicionado en ratones. Este tipo de memoria asociativa incluye un período de seguimiento que separa el estímulo neutro y el estímulo no condicionado.

Traza el condicionamiento del miedo en ratones

In this experiment we present a technique to measure learning and memory. In the trace fear conditioning protocol presented here there are five pairings ...

Research

JoVE Journal

Behavior

32.6K vistas.  Baylor University.  En el siguiente experimento se describe un protocolo para rastrear el miedo acondicionado en ratones. Este tipo de memoria asociativa incluye un período de seguimiento que separa el estímulo neutro y el estímulo no condicionado. 

Video: Trace Fear Conditioning in Mice

Contextual and Cued Fear Conditioning Test Using a Video Analyzing System in Mice

The contextual and cued fear conditioning test is one of the behavioral tests that assesses the ability of mice to learn and remember an association between environmental cues and aversive experiences. In this test, mice are placed into a conditioning chamber and are given parings of a conditioned stimulus (an auditory cue) and an aversive unconditioned stimulus (an electric footshock). After a delay time, the mice are exposed to the same conditioning chamber and a differently shaped chamber with presentation of the auditory cue. Freezing behavior during the test is measured as an index of fear memory. To analyze the behavior automatically, we have developed a video analyzing system using the ImageFZ application software program, which is available as a free download at http://www.mouse-phenotype.org/. Here, to show the details of our protocol, we demonstrate our procedure for the contextual and cued fear conditioning test in C57BL/6J mice using the ImageFZ system. In addition, we validated our protocol and the video analyzing system performance by comparing freezing time measured by the ImageFZ system or a photobeam-based computer measurement system with that scored by a human observer. As shown in our representative results, the data obtained by ImageFZ were similar to those analyzed by a human observer, indicating that the behavioral analysis using the ImageFZ system is highly reliable. The present movie article provides detailed information regarding the test procedures and will promote understanding of the experimental situation.

This article presents a protocol for a contextual and cued fear conditioning test using a video analyzing system to assess fear learning and memory in mice.

Contextuales y complementada el condicionamiento del miedo de prueba utilizando un sistema de análisis de vídeo en ratones

The contextual and cued fear conditioning test is one of the behavioral tests that assesses the ability of mice to learn and remember an association ...

Investigación

Comportamiento

Disrupting Reconsolidation of Fear Memory in Humans by a Noradrenergic &#946;-Blocker

The basic design used in our human fear-conditioning studies on disrupting reconsolidation includes testing over different phases across three consecutive days. On day 1 - the fear acquisition phase, healthy participants are exposed to a series of picture presentations. One picture stimulus (CS1+) is repeatedly paired with an aversive electric stimulus (US), resulting in the acquisition of a fear association, whereas another picture stimulus (CS2-) is never followed by an US. On day 2 - the memory reactivation phase, the participants are re-exposed to the conditioned stimulus without the US (CS1-), which typically triggers a conditioned fear response. After the memory reactivation we administer an oral dose of 40 mg of propranolol HCl, a &#946;-adrenergic receptor antagonist that indirectly targets the protein synthesis required for reconsolidation by inhibiting the noradrenaline-stimulated CREB phosphorylation. On day 3 - the test phase, the participants are again exposed to the unreinforced conditioned stimuli (CS1- and CS2-) in order to measure the fear-reducing effect of the manipulation. This retention test is followed by an extinction procedure and the presentation of situational triggers to test for the return of fear. Potentiation of the eye blink startle reflex is measured as an index for conditioned fear responding. Declarative knowledge of the fear association is measured through online US expectancy ratings during each CS presentation. In contrast to extinction learning, disrupting reconsolidation targets the original fear memory thereby preventing the return of fear. Although the clinical applications are still in their infancy, disrupting reconsolidation of fear memory seems to be a promising new technique with the prospect to persistently dampen the expression of fear memory in patients suffering from anxiety disorders and other psychiatric disorders.

Disrupting Reconsolidation of Fear Memory in Humans by a Noradrenergic &amp;#946;-Blocker

Disrupting reconsolidation is a promising approach to dampen the behavioral expression of fear memory in patients with anxiety disorders or posttraumatic stress disorder. In a series of human fear conditioning studies we showed that disrupting reconsolidation by the noradrenergic &#946;-blocker propranolol is very effective in erasing conditioned fear responding.

La interrupción de reconsolidación de la memoria del miedo en los seres humanos por un noradrenérgico β-bloqueador

The basic design used in our human fear-conditioning studies on disrupting reconsolidation includes testing over different phases across three consecutive ...

Protocol for Studying Extinction of Conditioned Fear in Naturally Cycling Female Rats

Extinction of conditioned fear has been extensively studied in male rodents. Recently, there have been an increasing number of studies indicating that neural mechanisms for certain behavioral tasks and response behaviors are different in females and males. Using females in research studies can represent a challenge because of the variation of gonadal hormones during their estrous cycle. This protocol describes well-established procedures that are useful in investigating the role of estrogen in fear extinction memory consolidation in female rats. Phase of the estrous cycle and exogenous estrogen administration prior to extinction training can influence extinction recall 24 hr later. The vaginal swabbing technique for estrous phase identification described here aids the examination and manipulation of naturally cycling gonadal hormones. The use of this basic rodent model may further delineate the mechanisms by which estrogen can modulate fear extinction memory in females.

Gonadal hormones such as estrogen modulate memory formation in a number of experimental paradigms including fear extinction memory. This protocol describes a set of methods for investigating the influence of gonadal hormones specifically during extinction in naturally cycling females, including estrous cycle monitoring and exogenous estrogen administration.

Protocolo para el Estudio de la extinción del miedo condicionado en ratas hembras Naturalmente Ciclismo

Extinction of conditioned fear has been extensively studied in male rodents. Recently, there have been an increasing number of studies indicating that ...

Quantifying Social Motivation in Mice Using Operant Conditioning

In this protocol, social motivation is measured in mice through a pair of operant conditioning paradigms. To conduct the experiments, two-chambered shuttle boxes were equipped with two operant levers (left and right) and a food receptacle in one chamber, which was then divided from the second chamber by an automated guillotine door covered by a wire grid. Different stimulus mice, rotated across testing days, served as a social stimulus behind the wire grid, and were only visible following the opening of the guillotine door. Test mice were trained to lever press in order to open the door and gain access to the stimulus partner for 15 sec. The number of lever presses required to obtain the social reward progressively increased on a fixed schedule of 3. Testing sessions ended after test mice stopped lever pressing for 5 consecutive minutes. The last reinforced ratio or breakpoint can be used as a quantitative measure of social motivation. For the second paradigm, test mice were trained to discriminate between left and right lever presses in order to obtain either a food reward or the social reward. Mice were rewarded for every 3 presses of each respective lever. The number of food and social rewards can be compared as a measurement of the value placed upon each reward. The ratio of each reward type can also be compared between mouse strains and the change in this ratio can be monitored within testing sessions to measure satiation with a given reward type. Both of these operant conditioning paradigms are highly useful for the quantification of social motivation in mouse models of autism and other disorders of social behavior.

This article describes a new protocol for the quantitative measurement of social motivation in mice using operant conditioning for a social reward. The protocol is useful for the measurement of social motivation in mouse models of autism and other disorders of social behavior.

La cuantificación de la motivación social en ratones utilizando Condicionamiento operante

In this protocol, social motivation is measured in mice through a pair of operant conditioning paradigms. To conduct the experiments, two-chambered ...

Whisker-signaled Eyeblink Classical Conditioning in Head-fixed Mice

Eyeblink conditioning is a common paradigm for investigating the neural mechanisms underlying learning and memory. To better utilize the extensive repertoire of scientific techniques available to study learning and memory at the cellular level, it is ideal to have a stable cranial platform. Because mice do not readily tolerate restraint, they are usually trained while moving about freely in a chamber. Conditioned stimulus (CS) and unconditioned stimulus (US) information are delivered and eyeblink responses recorded via a tether connected to the mouse's head. In the head-fixed apparatus presented here, mice are allowed to run as they desire while their heads are secured to facilitate experimentation. Reliable conditioning of the eyeblink response is obtained with this training apparatus, which allows for the delivery of whisker stimulation as the CS, a periorbital electrical shock as the US, and analysis of electromyographic (EMG) activity from the eyelid to detect blink responses.

The preparation presented here for whisker-signaled eyeblink conditioning in head-fixed mice precisely stimulates specific whiskers while allowing mice to ambulate on a cylindrical treadmill. A whisker stimulation conditioned stimulus (CS) paired with a periorbital shock unconditioned stimulus (US) results in reliable associative learning on this apparatus.

Eyeblink Condicionamiento clásico bigote-señalado en la cabeza de ratones fijo

Eyeblink conditioning is a common paradigm for investigating the neural mechanisms underlying learning and memory. To better utilize the extensive ...

Reducing State Anxiety Using Working Memory Maintenance

The purpose of this protocol is to explain how to examine the relationship between working memory processes and anxiety by combining the Sternberg Working Memory (WM) and the threat of shock paradigms. In the Sternberg WM paradigm, subjects are required to maintain a series of letters in the WM for a brief interval and respond by identifying whether the position of a given letter in the series matches a numerical prompt. In the threat of shock paradigm, subjects are exposed to alternating blocks where they are either at risk of receiving unpredictable presentations of a mild electric shock or are safe from the shock. Anxiety is probed throughout the safe and threat blocks using the acoustic startle reflex, which is potentiated under threat (Anxiety-Potentiated Startle (APS)). By conducting the Sternberg WM paradigm during the threat of shock and probing the startle response during either the WM maintenance interval or the intertrial interval, it is possible to determine the effect of WM maintenance on APS.

This protocol demonstrates how to measure anxiety-potentiated startle during the Sternberg Working Memory paradigm.

Reducción de la ansiedad estatal mediante el mantenimiento de la memoria de trabajo

The purpose of this protocol is to explain how to examine the relationship between working memory processes and anxiety by combining the Sternberg Working ...

Classical Short-Delay Eyeblink Conditioning in One-Year-Old Children

Classical eyeblink conditioning (EBC) refers to the learned association between a conditioned stimulus (an auditory tone) and an unconditioned stimulus (a puff of air to the cornea). Eyeblink conditioning is often used experimentally to detect abnormalities in cerebellar-dependent learning and memory that underlies this type of associative learning. While experiments in adults and older children are relatively simple to administer using commercial equipment, eyeblink conditioning in infants is more challenging due to their poor compliance, which makes correct positioning of the equipment difficult. To achieve conditioning in one-year-old infants, a custom-made or an adapted commercial system can be used to deliver the air puff to the infant's cornea. The main challenge lies in successfully detecting and classifying the behavioral responses. We report that automated blink detection methods are unreliable in this population, and that conditioning experiments should be analyzed using frame-by-frame analysis of supplementary video camera recordings. This method can be applied to study developmental changes in eyeblink conditioning and to examine whether this paradigm can detect children with neurological disorders.

This protocol describes an eyeblink conditioning paradigm appropriate for experiments with one-year-old infants. Commercial or custom-made equipment can be used to deliver the stimuli, and data collection and analysis should be performed on the video recordings.

Clásico corto retardo Eyeblink acondicionado en niños menores de un año

Classical eyeblink conditioning (EBC) refers to the learned association between a conditioned stimulus (an auditory tone) and an unconditioned stimulus (a ...

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.

Miedo estrés mayor aprendizaje, un modelo de roedor robusto del trastorno por estrés postraumático

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

Visual Classical Conditioning in Wood Ants

Several species of insects have become model systems for studying learning and memory formation. Although many studies focus on freely moving animals, studies implementing classical conditioning paradigms with harnessed insects have been important for investigating the exact cues that individuals learn and the neural mechanisms underlying learning and memory formation. Here we present a protocol for evoking visual associative learning in wood ants through classical conditioning. In this paradigm, ants are harnessed and presented with a visual cue (a blue cardboard), the conditional stimulus (CS), paired with an appetitive sugar reward, the unconditional stimulus (US). Ants perform a Maxilla-Labium Extension Reflex (MaLER), the unconditional response (UR), which can be used as a readout for learning. Training consists of 10 trials, separated by a 5-minute intertrial interval (ITI). Ants are also tested for memory retention 10 minutes or 1 hour after training. This protocol has the potential to allow researchers to analyze, in a precise and controlled manner, the details of visual memory formation and the neural basis of learning and memory formation in wood ants.

We present a protocol for the classical conditioning of harnessed ants that permits researchers to study visual learning and memory formation at a level of analysis not possible with freely moving individuals.

Visual condicionamiento clásico en madera hormigas

Several species of insects have become model systems for studying learning and memory formation. Although many studies focus on freely moving animals, ...

Fear Incubation Using an Extended Fear-Conditioning Protocol for Rats

Emotional memory has been primarily studied with fear-conditioning paradigms. Fear conditioning is a form of learning through which individuals learn the relationships between aversive events and otherwise neutral stimuli. The most-widely utilized procedures for studying emotional memories entail fear conditioning in rats. In these tasks, the unconditioned stimulus (US) is a footshock presented once or several times across single or several sessions, and the conditioned response (CR) is freezing. In a version of these procedures, called cued fear conditioning, a tone (conditioned stimulus, CS) is paired with footshocks (US) during the training phase. During the first test, animals are exposed to the same context in which training took place, and freezing responses are tested in the absence of footshocks and tones (i.e., a context test). During the second test, freezing is measured when the context is changed (e.g., by manipulating the smell and walls of the experimental chamber) and the tone is presented in the absence of footshocks (i.e., a cue test). Most cued fear conditioning procedures entail few tone-shock pairings (e.g., 1-3 trials in a single session). There is a growing interest in less common versions involving an extensive number of pairings (i.e., overtraining) related to the long-lasting effect called fear incubation (i.e., fear responses increase over time without further exposure to aversive events or conditioned stimuli). Extended fear-conditioning tasks have been key to the understanding of fear incubation&#8217;s behavioral and neurobiological aspects, including its relationship with other psychological phenomena (e.g., post-traumatic stress disorder). Here, we describe an extended fear-conditioning protocol that produces overtraining and fear incubation in rats. This protocol entails a single training session with 25 tone-shock pairings (i.e., overtraining) and a comparison of conditioned freezing responses during context and cue tests 48 h (short-term) and 6 weeks (long-term) after training.

We describe an extended fear-conditioning protocol that produces overtraining and fear incubation in rats. This protocol entails a single training session with 25 tone-shock pairings (i.e., overtraining) and a comparison of conditioned freezing responses during context and cue tests 48 h (short-term) and 6 weeks (long-term) after training.

La incubación del miedo utilizando un protocolo de acondicionamiento del miedo extendido para ratas

Emotional memory has been primarily studied with fear-conditioning paradigms. Fear conditioning is a form of learning through which individuals learn the ...