ABA, AAB and ABC renewal in taste aversion learning

Context renewal is identified when the conditioned response (CR) elicited by an extinguished conditioned stimulus (CS) reappears as a result of changing the contextual cues during the test. Two experiments were designed for testing contextual renewal in a conditioned taste aversion preparation. Experiment 1 assessed ABA and AAB context renewal, whereas Experiment 2 assessed ABA, AAB and ABC context renewal. The procedure of both experiments included three successive phases: acquisition, extinction and testing. The acquisition phase involved one pairing of sucrose flavor with a lithium chloride (LiCl) injection in Context A for all groups of rats. The groups were exposed to the sucrose flavor alone during the extinction phase, for the groups AAB and AAA extinction was carried out in Context A, whereas groups ABA and ABC were extinguished in Context B. Testing was done in context A for the groups ABA and AAA, whereas group AAB was tested in context B; lastly, the ABC group was tested in Context C. Results showed ABA, AAB and ABC renewal of conditioned taste aversion. The results are interpreted and discussed in relation to Bouton’s (1994) retrieval of information model(AU)

Modulación contextual en la extinción: recuperación de una aversión condicionada al sabor en un tercer contexto / Modulação contextual na extinção: recuperação de uma aversão condicionada ao sabor em um terceiro contexto / Contextual modulation of extinction: recovery of taste-aversion conditioning in a third context

Este experimento se diseñó para evaluar la renovación ABC con un procedimiento de condicionamiento de aversión al sabor (CAS) en tres fases: adquisición, extinción y prueba. Durante la adquisición, 15 ratas Wistar, asignadas a los grupos ABC y ABB, tuvieron acceso a una solución con sacarosa y posteriormente recibieron una inyección de cloruro de litio (liCl) en el Contexto A. En la extinción, ambos grupos bebieron la solución con sacarosa sin la administración del liCl en el Contexto B. En la prueba, los grupos tuvieron acceso a la solución con sacarosa sin administrarles liCl en el contexto de extinción para el grupo ABB, y en un tercer contexto para el grupo ABC. Los resultados mostraron la recuperación de la aversión condicionada al sabor únicamente en el grupo ABC.

This experiment was designed to evaluate ABC renewal in a conditioned taste aversion (CTA) procedure consisting of three phases: acquisition, extinction and test. During the acquisition phase, 15 Wistar rats assigned to groups ABC and ABB had access to a sucrose solution, after which they were injected with lithium chloride (liCl) in Context A. In the extinction phase, both groups of rats had access to the sucrose solution in Context B, but no liCl was administered. Finally, during the test, group ABB received sucrose solution without liCl in the extinction context, while group ABC was tested in a third context. Results showed renewal of conditioned taste aversion only in the ABC group.

Este experimento foi elaborado para avaliar a renovação ABC com um procedimento de condicionamento de aversão ao sabor (CAS) em três fases: aquisição, extinção e prova. Durante a aquisição, 15 ratos Wistar, designados aos grupos ABC e ABB, tiveram acesso a uma solução com sacarose e posteriormente receberam uma injeção de cloreto de lítio (liCl) em Contexto a. Na extinção, ambos grupos beberam a solução com sacarose sem a administração do liCl em Contexto B. Na prova, os grupos tiveram acesso à solução com sacarose sem administrar-lhes liCl num contexto de extinção para o grupo ABB, e num terceiro contexto para o grupo ABC. Os resultados mostraram a recuperação da aversão condicionada ao sabor unicamente no grupo ABC.

Effects of Scopolamine on Conditioning of Lever Pressing / Efectos de la escopolamina en el condicionamiento de presiones a la palanca

The aim of this work was to determine the effects of scopolamine, a cholinergic antagonist, on the conditioning of an instrumental response and the contextual conditioning of this response. Five groups of rats were trained to lever-press on a Variable Interval 30 s schedule in context A. Scopolamine was administered 15 min before each conditioning session to AB 0.01 mg/kg, AB 0.10 mg/kg and AB 1.00 mg/kg groups. The AA Saline and AB Saline groups received saline injections. Contextual conditioning of the lever-pressing response was assessed in one extinction session. The AA group received this extinction session in the conditioning context (A), while the AB groups received this session in a different context (B). Results showed that scopolamine impaired the conditioning of the lever-pressing response but no effects on contextual conditioning were found.

El propósito de este trabajo fue determinar los efectos de la escopolamina, un antagonista colinérgico, sobre el condicionamiento de una respuesta instrumental así como sobre el condicionamiento contextual de esta respuesta. Se entrenó a cinco grupos de ratas a presionar una palanca bajo un programa de Intervalo Variable 30 s en el contexto A. 15 min antes de cada sesión de condicionamiento se administró escopolamina en dosis de 0.01, 0.10 y 1.00 mg/kg a grupos diferentes en el contexto A, mientras dos grupos de ratas recibieron solución salina en el contexto A. El condicionamiento contextual de la respuesta de palanqueo se evaluó en una sesión de extinción en el contexto A o en un contexto B diferente. Los resultados mostraron que la escopolamina obstaculizó el condicionamiento de la respuesta de presionar la palanca pero no se encontraron efectos sobre el condicionamiento contextual.

Efecto de la duración de la extinción en la reinstauración selectiva de respuestas instrumentales en función de diferentes consecuencias / Effect of extinction duration on outcome-selective reinstatement of instrumental responses

Se diseñaron dos experimentos para evaluar la reinstauración selectiva de respuestas instrumentales asociadas a consecuencias diferentes (Experimento 1), y el efecto del número de sesiones de extinción en dicha reinstauración (Experimento 2). En el Experimento 1 se entrenó a dos grupos de ratas en tres fases. En la primera fase se condujeron dos sesiones diarias, en una la respuesta (R) 1 se asoció con la consecuencia (C) 1 y en la otra la R2 se asoció con la C2 para el Grupo Diferente, y para el Grupo Común se empleó la misma consecuencia para entrenar ambas respuestas. Posteriormente, en extinción, se descontinuó la entrega de las consecuencias. Finalmente, en la prueba se re-expuso a los sujetos a una de las consecuencias empleadas en la primera fase. En el Experimento 2 se empleó un procedimiento similar al del experimento previo, se entrenaron tres grupos (i.e. Común, Diferente C1 y Diferente C2) en cuatro fases secuenciales: Adquisición de R1, Adquisición de R2, Extinción y Prueba. En la fase de prueba se expuso a los grupos a alguna de las consecuencias empleadas durante el entrenamiento, después de 5 ó 10 sesiones de extinción. Los resultados mostraron reinstauración selectiva de respuestas en función de la consecuencia en ambos experimentos, aunque el Experimento 2 mostró reinstauración selectiva sólo cuando la prueba se realizó después de 5 sesiones de extinción, pero no cuando se emplearon 10 sesiones. Se discuten los resultados en términos de las propiedades que adquieren las consecuencias como estímulo discriminativo(AU)

Two-experiments were designed to analyze outcome-selective instrumental reinstatement (Experiment 1) and the effect of extinction on this sort of reinstatement (Experiment 2). In Experiment 1 two groups of rats were trained in three phases. In the first phase two-daily sessions were conducted. For the Different Group Response (R) 1 was reinforced with the (O) Outcome 1 in one of these sessions, and in the other session R2 was reinforced with the O2, while for the Same Group both responses were reinforced with the same outcome. In the extinction phase, outcomes were discontinued while both responses were available. Finally, in the test phase groups were re-exposed to one of the outcomes used in the first phase. In Experiment 2 a similar procedure to that described for Experiment 1 was used, three groups of rats (i.e. Same, Different O1 and Different O2) were trained in four sequential phases: Acquisition of R1, Acquisition of R2, Extinction and Test. In the test phase all groups were exposed to one of the outcomes used in either Acquisition phases, after 5 or 10 extinction sessions. Findings showed selective outcome reinstatement in both experiments, although Experiment 2 showed selective reinstatement only after 5 extinction sessions, but not after 10 extinction sessions. Results are discussed in terms of the properties of discriminative stimulus of the reinstatement outcome(AU)