This work was supported by a CIHR operating grant (MOP-102624) to Q. Y. We thank Dr Carolyn Harley for helpful discussions throughout the study, Dr. Qinlong Hou, Amin Shakhawat, and Andrea Darby-King for technical support.

Se utilizan ratas Sprague Dawley (Charles River) crías de ambos sexos. Las camadas son sacrificados a 12 en PD1 (siendo nacimiento PD0). Las presas se mantienen en un 12 horas de luz / oscuridad ciclo con acceso ad libitum a alimento y agua. Procedimientos experimentales han sido aprobados por el Comité de Cuidado de Animales Institucional de la Universidad Memorial. Plug 1. Nariz Construcción NOTA:. Este procedimiento fue adaptado y modificado a partir de Cummings et al (1997) 35. <ol><li> Aquire tubo de polietileno-20 y 3-0 hilo de sutura de seda. </li><li> Corte un pequeño trozo de polietileno de 20 tubos de aproximadamente 0,8 mm. </li><li> Hilo de sutura de seda a través del tubo dispuesto de tal manera que no hay hilo en cada lado de la sección de tubo. </li><li> En un extremo de la rosca exterior del tapón, un nudo en el hilo. </li><li> Tire de la sección del tubo por encima del nudo en el hilo. El nudo debe presentar dentro de la tubería.</li><li> Recorte ambos extremos de la rosca tal que ~ 2 mm de hilo sobresale de un extremo de la tubería (véase la Figura 1A). </li></ol> 2. Naris Oclusión antes de Capacitación <ol><li> Retire cachorro de presa y colocar en un plato seguro cubierto con ropa de cama regular. </li><li> Utilice una aplicación de punta de algodón para secarse un gel anestésico local 2% Xylocaine, en los INIA a ser ocluido. </li><li> Deje que el cachorro para descansar en el plato para ~ 3 min. </li><li> Mantenga el cachorro con suavidad pero firmemente en la mano no dominante. </li><li> Con la mano dominante, recoger una nariguera y aplique el mismo gel anestésico local alrededor de la punta de la que el hilo no sobresale. Esto actuar tanto como un anestésico para cualquier dolores menores asociados con la inserción del tapón y actuará como un lubricante dentro de la fosa nasal. NOTA: El efecto de xilocaína comienza en un par de minutos y dura 20-30 min. Los cachorros en general muestran buena tolerancia para la inserción del tapón después de la aplicación de la jalea xilocaína (mÍNIMOS luchando y vocalización). </li><li> Inserte con cuidado el tapón de la nariz manteniendo al cachorro firmemente y lentamente girar el enchufe con las pulsaciones muy suaves hasta que el enchufe esté bien conectado y sólo el hilo 2 mm sobresale de la fosa nasal (véase la Figura 1B). No debe haber sangrado de cualquiera de fosa nasal durante este proceso. Los cachorros con hemorragia durante la inserción del tapón nariz se excluyen y se devuelven a las represas </li><li> Permitir que el animal descanse en este plato durante 5 min con el fin de habituar al enchufe. </li><li> Retire el cachorro del plato habituación y comenzar el paradigma de condicionamiento 24. </li></ol><img alt="Figura 1" fo:content-width="5in" src="/files/ftp_upload/51808/51808fig1highres.jpg" width="500" /> Figura 1. Construcción de un tapón de nariz. A) Esquema que muestra las etapas de hacer un tapón de nariz. Un hilo pasa a través de un tubo de polietileno; se hace un nudo y Pulconducido en el centro de la tubería para bloquearlo; dos extremos se cortan con un residuo de 2 mm en un extremo de la tubería. B) Vista frontal y lateral de una rata con un enchufe de la nariz en una fosa nasal. 3. perfumado Preparación de cama <ol><li> El uso de guantes nuevos y en una campana de extracción para evitar la contaminación de olores, coloque 500 ml de ropa de cama de viruta de madera en una bolsa de plástico. </li><li> Utilice una jeringa para extraer hasta 0,3 ml de extracto de menta, y rociar este sobre la ropa de cama en la bolsa de plástico. </li><li> Ate la bolsa para cerrarla, agitar la bolsa con fuerza, y deje que la ropa de cama para descansar en la bolsa durante 5 min. </li><li> Coloque la ropa de cama perfumada en una caja transparente, poco profunda, acrílico formación (20 x 20 x 5 cm 3, Figura 2A) descubierto en una campana de extracción durante 5 minutos antes de su uso. Una vez preparada la ropa de cama, deseche estos guantes, y no permita que estos guantes entren en contacto con los animales. </li><li> Coloque la ropa de cama sin perfume en una caja de plástico transparente idéntica, y enAsegúrese de que no entre en contacto con la ropa de cama perfumada o guantes utilizados. </li></ol> 4. Olor acondicionado Paradigm (ver foto en la Figura 2A) Los cachorros son sometidos ya sea una sola sesión de condicionamiento, el PD 6, o múltiples sesiones de prueba (una sesión por día, PD 3-6). <ol><li> Coloque el cachorro habituado en cama perfumada. Para el control de olores sólo (O / S -) crías, deje estos cachorros en la ropa durante 10 minutos, a continuación, vaya al paso 4.5. Para experimental golpe olor + (O / S +) cachorros, siguen los siguientes pasos de esta sección. </li><li> Carrera al cachorro durante 30 segundos utilizando un pincel pequeño. Use movimientos circulares rápidos principalmente en torno a la región posterior del cachorro. </li><li> Deje que el cachorro para descansar durante 30 segundos. </li><li> Repita los pasos 4.2 y 4.3 para un total de 10 minutos (es decir, 10 parejas de caricias + olor). </li><li> Retire las crías de la caja acondicionado, quitar el tapón de la nariz y devolver el cachorro a la presa. </li></ol> &lt;p class = &quot;jove_title&quot;&gt; 5. Lateralizado Olor Preferencia Testing (ver foto en la Figura 2B) Pruebas se produce en varios puntos de tiempo (por ejemplo, 24 o 48 h) después de la última sesión de entrenamiento. La prueba se llevó a cabo en una cámara de acero inoxidable de prueba (30 x 20 x 18 cm 3), que se coloca en la parte superior de dos cajas de formación (caja de formación se describe en 3.4), separadas por una zona neutral 2 cm. Una caja de capacitación contiene la ropa de cama con olor a menta, mientras que la otra caja contiene ropa de cama limpia, sin olor. El suelo de la cámara de pruebas es una rejilla de metal, que luego es cubierto por una hoja extraíble de malla de plástico (Figura 2B). <ol><li> Preparar una menta y una cama sin perfume según la Sección 3, y colocar cada caja en lados opuestos de la cámara de pruebas, 2 cm. Coloque la malla de plástico en el suelo metálico de la red de la cámara de prueba. </li><li> Retire el cachorro de la presa y colocar una gota firma de grasa de silicona inodora en los INIAque se ocluye durante el entrenamiento. Volver a aplicar la grasa durante todo el primer procedimiento de prueba según sea necesario. NOTA: oclusión INIA aleatoria durante el entrenamiento y las pruebas pueden ser consideradas para evitar sesgos. </li><li> Coloque las crías en la zona neutral de la cámara de prueba. </li><li> Deje que el cachorro para explorar la cámara durante 1 min, registrando el tiempo que el cachorro pasó más de los dos lados de la cámara (es decir, más de la hierbabuena o ropa de cama neutra perfumada). </li><li> Deje que el cachorro para descansar durante 1 min en una cámara de retención de plástico cubierto. </li><li> Repetir los pasos 5.2 y 5.3 para un total de 10 min (es decir, 5 ensayos de prueba separadas por 5 ensayos de descanso) de conmutación de la orientación inicial de la cría en la cámara con el fin de controlar para las preferencias de dirección. </li><li> Inmediatamente después de la prueba, limpie la grasa de la fosa nasal. </li><li> Inserte un noseplug polietileno en la fosa nasal opuesta según la sección 2 y que el animal pueda descansar durante 10 minutos. </li><li> Pruebe el cachorro una vez más como en<html> 5.3 -5.6, quitar el tapón, y regresar al cachorro a la presa. Retire y limpie la malla de plástico de la cámara de pruebas con etanol al 95% y deje que el líquido se evapore. Coloque la malla de vuelta antes de probar la próxima cachorro. NOTA: La aplicación de grasa de silicona en la primera oclusión fosa nasal durante la prueba evita el riesgo de sangrado y el estrés asociado con la inserción del tapón nariz. </li></ol><img alt="Figura 2" fo:content-width="5in" src="/files/ftp_upload/51808/51808fig2highres.jpg" width="500" /> Figura formación preferencia 2. olor temprana y pruebas. A) la formación de olores Early preferencia usando olor + acariciando paradigma. B) Dos elección olor pruebas de preferencia con ropa de cama de menta en un lado, el control de las camas sin aroma en el lado opuesto. Una zona neutral 2 cm se coloca en el medio. 6. Prueba de la eficacia de los sistemas Naris Oclusión nt &quot;&gt; Este experimento se realiza para determinar si sola oclusión INIA conduce a la activación lateralizado del sistema olfativo. <ol><li> Realizar oclusiones naris unilaterales en PD 6 o 7 cachorros como se describe en la sección 2. </li><li> Después de ~ 5 min habituación, coloque el cachorro en un recipiente de plástico cubierto y lo exponga a 30 l de aceite de menta puro empapadas en un pedazo de tejido durante 10 minutos. </li><li> Inmediatamente después de la exposición de menta olor, el cachorro inyectar por vía intraperitoneal (ip) con hidrato de cloral (400 mg / kg) como anestésico general, o pentobarbital, (150 mg / kg). </li><li> Una vez anestesiados completamente (que no muestran respuesta a la cola o pellizco pie), transcardially perfundir el cachorro con soluciones frías de solución salina (0,9%) para ~ 1 min, seguido de paraformaldehído (4%, disuelto en solución tampón 0,1 M de fosfato, PBS ). </li><li> Después de 10 minutos de perfusión de paraformaldehído, recoger el cerebro y lo coloca en paraformaldehído la noche a 4 ° C, y luego transfer el cerebro a una solución de sacarosa (20% en PBS) durante 24 h más. </li><li> Cortar rodajas de cerebro coronal a 30 micras de espesor con un criostato. Recoger OB y PC rodajas y montar en portaobjetos recubiertos de gelatina, seguido por tinción inmunohistoquímica para el anticuerpo estándar pCREB 21,25,30. </li></ol> 7. Prueba de la reversibilidad de Soltero Naris Oclusión Este experimento prueba si el efecto de bloqueo es reversible a las 24 h después de la extracción del tapón de la nariz. <ol><li> Realizar oclusiones naris unilaterales en PD 6 o 7 cachorros como se describe en la sección 2. </li><li> Después de 15 min (equivalente a la duración de la oclusión fosa nasal durante el entrenamiento - 5 habituación + 10 min de entrenamiento min), retire el tapón de la nariz, y devolver el cachorro a la presa. </li><li> 24 horas más tarde, exponer al cachorro al olor de menta en un recipiente de plástico cubierto durante 10 minutos como se describe en el apartado 6.2. </li><li> Siga mismos pasos en sectaiones 6.3 a 6.6. </li></ol>

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W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=What+a+nostril+knows:+olfactory+nerve-evoked+AMPA+responses+increase+while+NMDA+responses+decrease+at+24-h+post-training+for+lateralized+odor+preference+memory+in+neonate+rat.">What a nostril knows: olfactory nerve-evoked AMPA responses increase while NMDA responses decrease at 24-h post-training for lateralized odor preference memory in neonate rat.</a> Learn Mem. 19, 50-53 (2012).</li><li>Schwob, J. E., Price, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+development+of+axonal+connections+in+the+central+olfactory+system+of+rats.">The development of axonal connections in the central olfactory system of rats.</a> J Comp Neurol. 223, 177-202 (1984).</li><li>Kucharski, D., Hall, W. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+routes+to+early+memories.">New routes to early memories.</a> Science. 238, 786-788 (1987).</li><li>Kucharski, D., Johanson, I. B., Hall, W. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Unilateral+olfactory+conditioning+in+6-day-old+rat+pups.">Unilateral olfactory conditioning in 6-day-old rat pups.</a> Behav Neural Biol. 46, 472-490 (1986).</li><li>Cummings, D. M., Henning, H. E., Brunjes, P. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Olfactory+bulb+recovery+after+early+sensory+deprivation.">Olfactory bulb recovery after early sensory deprivation.</a> J Neurosci. 17, 7433-7440 (1997).</li><li>Kucharski, D., Hall, W. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Developmental+change+in+the+access+to+olfactory+memories.">Developmental change in the access to olfactory memories.</a> Behav Neurosci. 102, 340-348 (1988).</li><li>Brunjes, P. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Unilateral+odor+deprivation:+time+course+of+changes+in+laminar+volume.">Unilateral odor deprivation: time course of changes in laminar volume.</a> Brain Res Bull. 14, 233-237 (1985).</li><li>Kass, M. D., Pottackal, J., Turkel, D. J., McGann, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Changes+in+the+neural+representation+of+odorants+after+olfactory+deprivation+in+the+adult+mouse+olfactory+bulb.">Changes in the neural representation of odorants after olfactory deprivation in the adult mouse olfactory bulb.</a> Chem Senses. 38, 77-89 (2013).</li><li>Kim, H. H., Puche, A. C., Margolis, F. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Odorant+deprivation+reversibly+modulates+transsynaptic+changes+in+the+NR2B-mediated+CREB+pathway+in+mouse+piriform+cortex.">Odorant deprivation reversibly modulates transsynaptic changes in the NR2B-mediated CREB pathway in mouse piriform cortex.</a> J Neurosci. 26, 9548-9559 (2006).</li><li>Korol, D. L., Brunjes, P. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+changes+in+2-deoxyglucose+uptake+and+amino+acid+incorporation+following+unilateral+odor+deprivation:+a+laminar+analysis.">Rapid changes in 2-deoxyglucose uptake and amino acid incorporation following unilateral odor deprivation: a laminar analysis.</a> Brain Res Dev Brain Res. 52, 75-84 (1990).</li><li>Leung, C. H., Wilson, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trans-neuronal+regulation+of+cortical+apoptosis+in+the+adult+rat+olfactory+system.">Trans-neuronal regulation of cortical apoptosis in the adult rat olfactory system.</a> Brain Res. 984, 182-188 (2003).</li></ol>

The authors have nothing to disclose.

El modelo de aprendizaje del olor y la memoria lateralizado en crías de rata dentro de una ventana de tiempo crítica fue establecida por primera vez por Hall y colegas. En una serie de estudios 33,34,36, demostraron que una memoria preferencia olor podría ser lateralizado por el olor de la leche + emparejamientos a una fosa nasal en PD 6 en crías de rata. Memoria Preferencia era robusta cuando la misma fosa nasal estaba abierto durante el entrenamiento y las pruebas, pero no se observa cuando la fosa nasa...

El olfato es la modalidad sensorial primaria en los roedores, sin la cual no sería capaz de navegar con éxito o sobrevivir en su medio ambiente. Es especialmente importante para los cachorros recién nacidos, los cuales no pueden ver, ni oír, durante la primera semana posterior al parto, para usar el olfato para localizar a su madre para alimentar a 1. Como resultado, las crías de ratas neonatales pueden estar condicionados a preferir los olores con manipulaciones experimentales sencillos. Una variedad de estímulos se han utilizado como estímulo incondicionado (UCS) para inducir respuestas condicionadas a nuevos olores (estímulo condicionado, CS) en los recién nacidos, incluyendo el medio ambiente de anidación 2,3, la succión de la leche 4-6, acariciando o estimulación táctil de 7 12, pellizcar la cola 13, saliva materna 13, pie de choque leve 14-18, y la estimulación cerebral intracraneal 19. El presente estudio emplea un paradigma de preferencia olor principios bien establecido en el que un olor, en este caso, menta, is combinado con estimulación táctil con el fin de producir una preferencia por de menta 24 horas más tarde 10,11,20. Estos recuerdos olores dependen de circuitos olfativa intacta, incluyendo principalmente los bulbos olfatorios (OB) 21-23 y la corteza piriforme anterior (APC) 24,25. Las investigaciones experimentales de principios del aprendizaje olor preferencia han profundizado y ampliado nuestra comprensión de las bases moleculares y fisiológicas de una memoria de los mamíferos. Este modelo de mamífero tiene varias ventajas en el estudio de los mecanismos de la memoria. En primer lugar, se han identificado las fuentes neuronales de la señal de UCS. Diversos estímulos como se mencionó anteriormente estimulan locus coeruleus la liberación de norepinefrina 26, que a su vez activa múltiples receptores adrenérgicos en el OB y apc, causando efectos celulares y fisiológicos que apoyan el aprendizaje 22,27,28. En segundo lugar, los mecanismos de memoria de apoyo tienen lugar en las estructuras neurales laminares bien definidos. Elsimplicidad del circuito olfatorio en ratas recién nacidas ofrece a los investigadores un marco ideal con el que descubrir los intrincados procesos relacionados con la plasticidad sináptica. Las neuronas sensoriales olfativas (OSN) en el proyecto epitelio olfativo Onto mitrales / células pelo insertado en el OB y estas células mitrales / pelo insertado en el proyecto a su vez ipsilateralmente a corteza piriforme (PC) a través del tracto olfatorio lateral (LOT), entre otras estructuras 29. Tanto las sinapsis OSN en el OB 30,31 y el 24,25 LOT sinapsis en APC han sido identificados como lugares críticos para cambios sinápticos que apoyan el aprendizaje y la memoria. En tercer lugar, en una edad temprana en ratas, insumos olfativas pueden fácilmente ser lateralizado. Cada PCa tiene acceso a la información bilateral olor a través de la comisura anterior una vez que esta sustancia blanca está completamente formado en postnatal día 12 (PD12) 32. Antes de la EP 12, entrada de olor puede ser aislado a ipisilateral OB y APC a través de un solo orificio nasal oclusión 24,25,31,33,34 &lt;/ Sup&gt;. Soltero INIA oclusión permite la formación de la memoria el olor de la fosa nasal abierta, y evita que el mismo recuerdo de los INIA ocluidos antes de PD 12 33. Memoria Olor está aislado en el hemisferio ipsilateral incluyendo tanto OB y APC. Por lo tanto, cada una cría de rata puede ser su propio control para el aprendizaje y que sustenta la fisiología. En el presente estudio, se introduce el protocolo de aprendizaje preferencia olor temprana lateralizado. Este método sirve como una poderosa herramienta para el estudio de los mecanismos neuronales que sustentan el aprendizaje de olores, proporcionando un control intra-animales 24,25,31, lo que reduce tanto el número de animales necesarios y la variación general. Naris oclusión es reversible en que el tapón de grasa o la nariz puede ser aplicado y retirado con un mínimo de estrés o daño al animal. Aquí, en primer lugar, se describen los procedimientos detallados de formación preferencia olor temprana y pruebas, con un enfoque en el protocolo lateralizado usando solo oclusión fosa nasal con un nne enchufe. Entonces resultados se presentan para demostrar la eficacia de la oclusión sola fosa nasal en el aislamiento de entrada de olor y producir olor lateralizado memoria. Por último, se analizan los potenciales de la utilización de este modelo de aprendizaje lateralizado para estudiar los cambios fisiológicos en el sistema olfativo que ambos generan el aprendizaje y la memoria soporte para expresiones.

<table border="0" cellpadding="0" cellspacing="0" width="580">
	<tbody>
		<tr height="50">
			<td height="50" style="height:50px;width:149px;">Polythylene 20 tubing</td>
			<td style="width:123px;">Intramedic</td>
			<td style="width:103px;">427406</td>
			<td style="width:205px;">Non radiopaque, Non toxic</td>
		</tr>
		<tr height="50">
			<td height="50" style="height:50px;width:149px;">3-0 silk suture thread</td>
			<td style="width:123px;">Syneture</td>
			<td style="width:103px;">Sofsilk</td>
			<td style="width:205px;">Non absorbant&#160;</td>
		</tr>
		<tr height="50">
			<td height="50" style="height:50px;width:149px;">Silicone grease</td>
			<td style="width:123px;">Warner Instrument</td>
			<td style="width:103px;">64-0378</td>
			<td style="width:205px;">Odorless</td>
		</tr>
		<tr height="50">
			<td height="50" style="height:50px;width:149px;">2% xylocaine gel</td>
			<td style="width:123px;">AstraZeneca</td>
			<td style="width:103px;">Prod. No 061</td>
			<td style="width:205px;">Lidocaine hydrochloride jelly,&#160; purchased at local pharmacy</td>
		</tr>
		<tr height="50">
			<td height="50" style="height:50px;width:149px;">Paint brush</td>
			<td style="width:123px;">Dynasty</td>
			<td style="width:103px;">206R</td>
			<td style="width:205px;">Similar size/other brands work too</td>
		</tr>
		<tr height="50">
			<td height="50" style="height:50px;width:149px;">Peppermint extract</td>
			<td style="width:123px;">Sigma-Aldrich</td>
			<td style="width:103px;">W284807</td>
			<td style="width:205px;">Other brand should be okay too</td>
		</tr>
		<tr height="171">
			<td height="171" style="height:171px;width:149px;">Training box</td>
			<td style="width:123px;">Custom-made</td>
			<td style="width:103px;">N/A</td>
			<td style="width:205px;">Acrylic box (20x20x5cm3), see Figure 2A. Parameters and material for the box are not critical and can be modified. Material used should be odorless and does not absorb odors</td>
		</tr>
		<tr height="182">
			<td height="182" style="height:182px;width:149px;">Testing chamber</td>
			<td style="width:123px;">Custom-made</td>
			<td style="width:103px;">N/A</td>
			<td style="width:205px;">Stainless steel (30x20x18cm3), see Figure 2B. Parameters and material for the chamber are not critical and can be modified. For example, an acrylic chamber instead of a stainless steel one can be used</td>
		</tr>
		<tr height="50">
			<td height="50" style="height:50px;width:149px;">pCREB antibody</td>
			<td style="width:123px;">Cell Signaling</td>
			<td style="width:103px;">9198</td>
			<td style="width:205px;">Ser 133 (87G3) Rabbit mAb</td>
		</tr>
		<tr height="50">
			<td height="50" style="height:50px;width:149px;">Chloral hydrate</td>
			<td style="width:123px;">Sigma-Aldrich</td>
			<td style="width:103px;">C8383</td>
			<td style="width:205px;">N/A</td>
		</tr>
		<tr height="50">
			<td height="50" style="height:50px;width:149px;">Paraformaldehype</td>
			<td style="width:123px;">Sigma-Aldrich</td>
			<td style="width:103px;">P6148</td>
			<td style="width:205px;">N/A</td>
		</tr>
		<tr height="50">
			<td height="50" style="height:50px;width:149px;">Sucrose</td>
			<td style="width:123px;">Sigma-Aldrich</td>
			<td style="width:103px;">S9378</td>
			<td style="width:205px;">N/A</td>
		</tr>
	</tbody>
</table>

a lateralized odor learning model in neonatal rats for dissecting neural circuitry underpinning memory formation

Rat pups during a critical postnatal period (&#8804; 10 days) readily form a preference for an odor that is associated with stimuli mimicking maternal care. Such a preference memory can last from hours, to days, even life-long, depending on training parameters. Early odor preference learning provides us with a model in which the critical changes for a natural form of learning occur in the olfactory circuitry. An additional feature that makes it a powerful tool for the analysis of memory processes is that early odor preference learning can be lateralized via single naris occlusion within the critical period. This is due to the lack of mature anterior commissural connections of the olfactory hemispheres at this early age. This work outlines behavioral protocols for lateralized odor learning using nose plugs. Acute, reversible naris occlusion minimizes tissue and neuronal damages associated with long-term occlusion and more aggressive methods such as cauterization. The lateralized odor learning model permits within-animal comparison, therefore greatly reducing variance compared to between-animal designs. This method has been used successfully to probe the circuit changes in the olfactory system produced by training. Future directions include exploring molecular underpinnings of odor memory using this lateralized learning model; and correlating physiological change with memory strength and durations.

En este artículo revisamos algunos de los resultados previamente establecidos 24 para demostrar la eficacia de la oclusión INIA en el aislamiento de la entrada de olores y aprender a un hemisferio, y la reversibilidad de este método. Soltero oclusión fosa nasal durante el entrenamiento olor preferencia temprana conduce a una memoria olfativa lateralizado 24. La memoria se limita a la fosa nasal para sustitución (Figura 3). Cuando los cachorros son ...

Watch this Scientific Journal Video about A Lateralized Odor Learning Model in Neonatal Rats for Dissecting Neural Circuitry Underpinning Memory Formation at JoVE.com

A Lateralized Odor Learning Model in Neonatal Rats for Dissecting Neural Circuitry Underpinning Memory Formation

This protocol introduces lateralized early odor preference learning in rats using acute single naris occlusion. Lateralized learning permits the examination of behavioral outcomes and underpinning biological mechanisms within the same animals, reducing variance induced by between-animal designs. This protocol can be used to investigate molecular mechanisms underpinning early odor learning.

Un Modelo de Aprendizaje lateralizado de Olor en ratas recién nacidas para disecar Formación Neural Circuito Recalces Memoria

Rat pups during a critical postnatal period (&#8804; 10 days) readily form a preference for an odor that is associated with stimuli mimicking maternal ...

a-lateralized-odor-learning-model-neonatal-rats-for-dissecting-neural

Research

JoVE Journal

Neuroscience

8.9K vistas.  Faculty of Medicine, Memorial University. This protocol introduces lateralized early odor preference learning in rats using acute single naris occlusion. Lateralized learning permits the examination of behavioral outcomes and underpinning biological mechanisms within the same animals, reducing variance induced by between-animal designs. This protocol can be used to investigate molecular mechanisms underpinning early odor learning.

Video: A Lateralized Odor Learning Model in Neonatal Rats for Dissecting Neural Circuitry Underpinning Memory Formation

C. elegans Positive Butanone Learning, Short-term, and Long-term Associative Memory Assays

The memory of experiences and learned information is critical for organisms to make choices that aid their survival. C. elegans navigates its environment through neuron-specific detection of food and chemical odors1, 2, and can associate nutritive states with chemical odors3, temperature4, and the pathogenicity of a food source5.
Here, we describe assays of C. elegans associative learning and short- and long-term associative memory. We modified an aversive olfactory learning paradigm6 to instead produce a positive response; the assay involves starving ~400 worms, then feeding the worms in the presence of the AWC neuron-sensed volatile chemoattractant butanone at a concentration that elicits a low chemotactic index (similar to Toroyama et al.7). A standard population chemotaxis assay1 tests the worms' attraction to the odorant immediately or minutes to hours after conditioning.
After conditioning, wild-type animals' chemotaxis to butanone increases ~0.6 Chemotaxis Index units, its "Learning Index". Associative learning is dependent on the presence of both food and butanone during training. Pairing food and butanone for a single conditioning period ("massed training") produces short-term associative memory that lasts ~2 hours. Multiple conditioning periods with rest periods between ("spaced training") yields long-term associative memory (&lt;40 hours), and is dependent on the cAMP Response Element Binding protein (CREB),6 a transcription factor required for long-term memory across species.8
Our protocol also includes image analysis methods for quick and accurate determination of chemotaxis indices. High-contrast images of animals on chemotaxis assay plates are captured and analyzed by worm counting software in MatLab. The software corrects for uneven background using a morphological tophat transformation.9 Otsu's method is then used to determine a threshold to separate worms from the background.10 Very small particles are removed automatically and larger non-worm regions (plate edges or agar punches) are removed by manual selection. The software then estimates the size of single worm by ignoring regions that are above a specified maximum size and taking the median size of the remaining regions. The number of worms is then estimated by dividing the total area identified as occupied by worms by the estimated size of a single worm.
We have found that learning and short- and long-term memory can be distinguished, and that these processes share similar key molecules with higher organisms.6,8 Our assays can quickly test novel candidate genes or molecules that affect learning and short- or long-term memory in C. elegans that are relevant across species.

C. elegans Positive Butanone Learning, Short-term, and Long-term Associative Memory Assays

Here we describe methods to test C. elegans associative learning and short- and long-term associative memory. These population assays employ the worms abilities to chemotax toward volatile odorants, and form positive associations upon pairing food with the chemoattractant butanone. Increasing the number of conditioning periods induces long-term memory.

C. elegans de aprendizaje positivo butanona, a corto plazo y largo plazo Ensayos de la memoria asociativa

The memory of experiences and learned information is critical for organisms to make choices that aid their survival. C. elegans navigates its environment ...

Investigación

Neurociencias

Assaying Locomotor, Learning, and Memory Deficits in Drosophila Models of Neurodegeneration

Advances in genetic methods have enabled the study of genes involved in human neurodegenerative diseases using Drosophila as a model system1. Most of these diseases, including Alzheimer's, Parkinson's and Huntington's disease are characterized by age-dependent deterioration in learning and memory functions and movement coordination2. Here we use behavioral assays, including the negative geotaxis assay3 and the aversive phototaxic suppression assay (APS assay)4,5, to show that some of the behavior characteristics associated with human neurodegeneration can be recapitulated in flies. In the negative geotaxis assay, the natural tendency of flies to move against gravity when agitated is utilized to study genes or conditions that may hinder locomotor capacities. In the APS assay, the learning and memory functions are tested in positively-phototactic flies trained to associate light with aversive bitter taste and hence avoid this otherwise natural tendency to move toward light. Testing these trained flies 6 hours post-training is used to assess memory functions. Using these assays, the contribution of any genetic or environmental factors toward developing neurodegeneration can be easily studied in flies.

Assaying Locomotor, Learning, and Memory Deficits in Drosophila Models of Neurodegeneration

Behavior assays for measuring locomotor functions, learning, and memory abilities in Drosophila.

Locomotor ensayo, aprendizaje, memoria y déficit en Drosophila Los modelos de neurodegeneración

Advances in genetic methods have enabled the study of genes involved in human neurodegenerative diseases using Drosophila as a model system1. Most of ...

Morris Water Maze Test for Learning and Memory Deficits in Alzheimer&#39;s Disease Model Mice

The Morris Water Maze (MWM) was first established by neuroscientist Richard G. Morris in 1981 in order to test hippocampal-dependent learning, including acquisition of spatial memoryand long-term spatial memory 1. The MWM is a relatively simple procedure typically consisting of six day trials, the main advantage being the differentiation between the spatial (hidden-platform) and non-spatial (visible platform) conditions 2-4. In addition, the MWM testing environment reduces odor trail interference 5. This has led the task to be used extensively in the study of the neurobiology and neuropharmacology of spatial learning and memory. The MWM plays an important role in the validation of rodent models for neurocognitive disorders such as Alzheimer&#x2019;s Disease 6, 7. In this protocol we discussed the typical procedure of MWM for testing learning and memory and data analysis commonly used in Alzheimer&#x2019;s disease transgenic model mice.

Morris Water Maze Test for Learning and Memory Deficits in Alzheimer&#039;s Disease Model Mice

The Morris Water Maze is a behavioral task to test hippocampal-dependent learning and memory. It has been widely used in the study of neurobiology, neuropharmacology and neurocognitive disorders in rodent models.

Agua Morris laberinto de prueba para los déficits de aprendizaje y memoria en ratones de Alzheimer modelo de enfermedad

The Morris Water Maze (MWM) was first established by neuroscientist Richard G. Morris in 1981 in order to test hippocampal-dependent learning, including ...

Optical Recording of Suprathreshold Neural Activity with Single-cell and Single-spike Resolution

Signaling of information in the vertebrate central nervous system is often carried by populations of neurons rather than individual neurons. Also propagation of suprathreshold spiking activity involves populations of neurons. Empirical studies addressing cortical function directly thus require recordings from populations of neurons with high resolution. Here we describe an optical method and a deconvolution algorithm to record neural activity from up to 100 neurons with single-cell and single-spike resolution. This method relies on detection of the transient increases in intracellular somatic calcium concentration associated with suprathreshold electrical spikes (action potentials) in cortical neurons. High temporal resolution of the optical recordings is achieved by a fast random-access scanning technique using acousto-optical deflectors (AODs)1. Two-photon excitation of the calcium-sensitive dye results in high spatial resolution in opaque brain tissue2. Reconstruction of spikes from the fluorescence calcium recordings is achieved by a maximum-likelihood method. Simultaneous electrophysiological and optical recordings indicate that our method reliably detects spikes (&gt;97% spike detection efficiency), has a low rate of false positive spike detection (&lt; 0.003 spikes/sec), and a high temporal precision (about 3 msec) 3. This optical method of spike detection can be used to record neural activity in vitro and in anesthetized animals in vivo3,4.

Understanding the function of the vertebrate central nervous system requires recordings from many neurons because cortical function arises on the level of populations of neurons. Here we describe an optical method to record suprathreshold neural activity with single-cell and single-spike resolution, dithered random-access scanning. This method records somatic fluorescence calcium signals from up to 100 neurons with high temporal resolution. A maximum-likelihood algorithm deconvolves the underlying suprathreshold neural activity from the somatic fluorescence calcium signals. This method reliably detects spikes with high detection efficiency and a low rate of false positives and can be used to study neural populations in vitro and in vivo.

Grabación óptica de la actividad neural suprathreshold con la resolución de una sola célula y único punta-

Signaling of information in the vertebrate central nervous system is often carried by populations of neurons rather than individual neurons. Also ...

Viral Tracing of Genetically Defined Neural Circuitry

Classical methods for studying neuronal circuits are fairly low throughput. Transsynaptic viruses, particularly the pseudorabies (PRV) and rabies virus (RABV), and more recently vesicular stomatitis virus (VSV), for studying circuitry, is becoming increasingly popular. These higher throughput methods use viruses that transmit between neurons in either the anterograde or retrograde direction.
Recently, a modified RABV for monosynaptic retrograde tracing was developed. (Figure 1A). In this method, the glycoprotein (G) gene is deleted from the viral genome, and resupplied only in targeted neurons. Infection specificity is achieved by substituting a chimeric G, composed of the extracellular domain of the ASLV-A glycoprotein and the cytoplasmic domain of the RABV-G (A/RG), for the normal RABV-G1. This chimeric G specifically infects cells expressing the TVA receptor1. The gene encoding TVA can been delivered by various methods2-8. Following RABV-G infection of a TVA-expressing neuron, the RABV can transmit to other, synaptically connected neurons in a retrograde direction by nature of its own G which was co-delivered with the TVA receptor. This technique labels a relatively large number of inputs (5-10%)2 onto a defined cell type, providing a sampling of all of the inputs onto a defined starter cell type.
We recently modified this technique to use VSV as a transsynaptic tracer9. VSV has several advantages, including the rapidity of gene expression. Here we detail a new viral tracing system using VSV useful for probing microcircuitry with increased resolution. While the original published strategies by Wickersham et al.4 and Beier et al.9 permit labeling of any neurons that project onto initially-infected TVA-expressing-cells, here VSV was engineered to transmit only to TVA-expressing cells (Figure 1B). The virus is first pseudotyped with RABV-G to permit infection of neurons downstream of TVA-expressing neurons. After infecting this first population of cells, the virus released can only infect TVA-expressing cells. Because the transsynaptic viral spread is limited to TVA-expressing cells, presence of absence of connectivity from defined cell types can be explored with high resolution. An experimental flow chart of these experiments is shown in Figure 2. Here we show a model circuit, that of direction-selectivity in the mouse retina. We examine the connectivity of starburst amacrine cells (SACs) to retinal ganglion cells (RGCs).

A method of tracing synaptically connected neurons is described. We use TVA specificity of an upstream cell to probe whether a cell population of interest receives synaptic input from genetically defined cell types.

Trazado de Circuitos Viral genéticamente definidos Neural

Classical methods for studying neuronal circuits are fairly low throughput. Transsynaptic viruses, particularly the pseudorabies (PRV) and rabies virus ...

In vivo Optogenetic Stimulation of the Rodent Central Nervous System

The ability to probe defined neural circuits in awake, freely-moving animals with cell-type specificity, spatial precision, and high temporal resolution has been a long sought tool for neuroscientists in the systems-level search for the neural circuitry governing complex behavioral states. Optogenetics is a cutting-edge tool that is revolutionizing the field of neuroscience and represents one of the first systematic approaches to enable causal testing regarding the relation between neural signaling events and behavior. By combining optical and genetic approaches, neural signaling can be bi-directionally controlled through expression of light-sensitive ion channels (opsins) in mammalian cells. The current protocol describes delivery of specific wavelengths of light to opsin-expressing cells in deep brain structures of awake, freely-moving rodents for neural circuit modulation. Theoretical principles of light transmission as an experimental consideration are discussed in the context of performing in vivo optogenetic stimulation. The protocol details the design and construction of both simple and complex laser configurations and describes tethering strategies to permit simultaneous stimulation of multiple animals for high-throughput behavioral testing.

In vivo Optogenetic Stimulation of the Rodent Central Nervous System

Optogenetics has become a powerful tool for use in behavioral neuroscience experiments. This protocol offers a step-by-step guide to the design and set-up of laser systems, and provides a full protocol for carrying out multiple and simultaneous in vivo optogenetic stimulations compatible with most rodent behavioral testing paradigms.

In vivo optogenético la estimulación del sistema nervioso central de roedores

The ability to probe defined neural circuits in awake, freely-moving animals with cell-type specificity, spatial precision, and high temporal resolution ...

Assessing Spatial Learning and Memory in Small Squamate Reptiles

Clinical research has leveraged a variety of paradigms to assess cognitive decline, commonly targeting spatial learning and memory abilities. However, interest in the cognitive processes of nonmodel species, typically within an ecological context, has also become an emerging field of study. In particular, interest in the cognitive processes in reptiles is growing although experimental studies on reptilian cognition are sparse. The few reptilian studies that have experimentally tested for spatial learning and memory have used rodent paradigms modified for use in reptiles. However, ecologically important aspects of the physiology and behavior of this taxonomic group must be taken into account when testing for spatially based cognition. Here, we describe modifications of the dry land Barnes maze and associated testing protocol that can improve performance when probing for spatial learning and memory ability in small squamate reptiles. The described paradigm and procedures were successfully used with male side-blotched lizards (Uta stansburiana), demonstrating that spatial learning and memory can be assessed in this taxonomic group with an ecologically relevant apparatus and protocol.

This paper describes a modification of the Barnes maze, a standard rodent paradigm used to assess spatial memory and learning, for use in small squamate reptiles.

La evaluación del aprendizaje espacial y la memoria en pequeños reptiles escamosos

Clinical research has leveraged a variety of paradigms to assess cognitive decline, commonly targeting spatial learning and memory abilities. However, ...

Recording EEG in Freely Moving Neonatal Rats Using a Novel Method

EEG is a useful method to detect electrical activity in the brain. Moreover, it is a widely used diagnostic tool for various neurological conditions, such as epilepsy and neurodegenerative disorders. However, it is technically difficult to obtain EEG recordings in neonates as it requires specialized handling and great care. Here, we present a novel method to record EEG in neonatal rat pups (P8-P15). We designed a simple and reliable electrode using computer pin loci; it can be easily implanted into the skull of a rat pup to record high-quality EEG signals in the normal and epileptic brain. Pups were given an intraperitoneal (i.p.) injection of the neurotoxin kainic acid (KA) to induce epileptic seizures. The surgical implantation performed in this procedure is less expensive than other EEG procedures for neonates. This method allows one to record high-quality and stable EEG signals for more than 1 week. Furthermore, this procedure can also be applied to adult rats and mice to study epilepsy or other neurological disorders.

Here, we introduce a novel technique designed to record electroencephalography (EEG) in freely moving neonatal epileptic pups and describe its procedures, features, and applications. This method allows one to record EEG for more than 1 week.

Grabación de EEG en Ratas Neonatales que se mueven libremente usando un método nuevo

EEG is a useful method to detect electrical activity in the brain. Moreover, it is a widely used diagnostic tool for various neurological conditions, such ...

Drosophila Courtship Conditioning As a Measure of Learning and Memory

Many insights into the molecular mechanisms underlying learning and memory have been elucidated through the use of simple behavioral assays in model organisms such as the fruit fly, Drosophila melanogaster. Drosophila is useful for understanding the basic neurobiology underlying cognitive deficits resulting from mutations in genes associated with human cognitive disorders, such as intellectual disability (ID) and autism. This work describes a methodology for testing learning and memory using a classic paradigm in Drosophila known as courtship conditioning. Male flies court females using a distinct pattern of easily recognizable behaviors. Premated females are not receptive to mating and will reject the male&#39;s copulation attempts. In response to this rejection, male flies reduce their courtship behavior. This learned reduction in courtship behavior is measured over time, serving as an indicator of learning and memory. The basic numerical output of this assay is the courtship index (CI), which is defined as the percentage of time that a male spends courting during a 10 min interval. The learning index (LI) is the relative reduction of CI in flies that have been exposed to a premated female compared to na&#239;ve flies with no previous social encounters. For the statistical comparison of LIs between genotypes, a randomization test with bootstrapping is used. To illustrate how the assay can be used to address the role of a gene relating to learning and memory, the pan-neuronal knockdown of Dihydroxyacetone phosphate acyltransferase (Dhap-at) was characterized here. The human ortholog of Dhap-at, glyceronephosphate O-acyltransferase (GNPT), is involved in rhizomelic chondrodysplasia punctata type 2, an autosomal-recessive syndrome characterized by severe ID. Using the courtship conditioning assay, it was determined that Dhap-at is required for long-term memory, but not for short-term memory. This result serves as a basis for further investigation of the underlying molecular mechanisms.

Drosophila Courtship Conditioning As a Measure of Learning and Memory

This protocol describes a Drosophila learning and memory assay called courtship conditioning. This classic assay is based on a reduction of male courtship behavior after sexual rejection by a non-receptive premated female. This natural form of behavioral plasticity can be used to test learning, short-term memory, and long-term memory.

Drosophila condicionamiento del corte como una medida de aprendizaje y memoria

Many insights into the molecular mechanisms underlying learning and memory have been elucidated through the use of simple behavioral assays in model ...

In Vitro Wedge Slice Preparation for Mimicking In Vivo Neuronal Circuit Connectivity

In vitro slice electrophysiology techniques measure single-cell activity with precise electrical and temporal resolution. Brain slices must be relatively thin to properly visualize and access neurons for patch-clamping or imaging, and in vitro examination of brain circuitry is limited to only what is physically present in the acute slice. To maintain the benefits of in vitro slice experimentation while preserving a larger portion of presynaptic nuclei, we developed a novel slice preparation. This &#8220;wedge slice&#8221; was designed for patch-clamp electrophysiology recordings to characterize the diverse monaural, sound-driven inputs to medial olivocochlear (MOC) neurons in the brainstem. These neurons receive their primary afferent excitatory and inhibitory inputs from neurons activated by stimuli in the contralateral ear and corresponding cochlear nucleus (CN). An asymmetrical brain slice was designed which is thickest in the rostro-caudal domain at the lateral edge of one hemisphere and then thins towards the lateral edge of the opposite hemisphere. This slice contains, on the thick side, the auditory nerve root conveying information about auditory stimuli to the brain, the intrinsic CN circuitry, and both the disynaptic excitatory and trisynaptic inhibitory afferent pathways that converge on contralateral MOC neurons. Recording is performed from MOC neurons on the thin side of the slice, where they are visualized using DIC optics for typical patch-clamp experiments. Direct stimulation of the auditory nerve is performed as it enters the auditory brainstem, allowing for intrinsic CN circuit activity and synaptic plasticity to occur at synapses upstream of MOC neurons. With this technique, one can mimic in vivo circuit activation as closely as possible within the slice. This wedge slice preparation is applicable to other brain circuits where circuit analyses would benefit from preservation of upstream connectivity and long-range inputs, in combination with the technical advantages of in vitro slice physiology.

Integration of diverse synaptic inputs to neurons is best measured in a preparation that preserves all pre-synaptic nuclei for natural timing and circuit plasticity, but brain slices typically sever many connections. We developed a modified brain slice to mimic in vivo circuit activity while maintaining in vitro experimentation capability.

In Vitro Wedge Slice Preparación para imitar la conectividad del circuito neuronal In Vivo

In vitro slice electrophysiology techniques measure single-cell activity with precise electrical and temporal resolution. Brain slices must be relatively ...