Reacquisition, reinstatement and renewal of a conditioned taste aversion in preweanling rats

REVILLO DAMIÁN; CASTELLÓ STEFANÍA; PAGLINI GABRIELA; ARIAS CARLOS

Dev Psychobiol

New York, Interscience Publishers.

Año: 2014 vol. 56 p. 713 - 725

1098-2302

Reacquisition, reinstatement and renewal of a conditioned taste aversion in preweanling rats. 2013. Revillo, D. A. a, Castello, S. a, Paglini, G. a and Arias, C. Dev Psychobiol. Aceptado, 26 de abril de 2013. ABSTRACT: Pavlovian or experimental extinction is defined as a reduction of the conditioned response (CR) as a consequence of repeated and non-reinforced presentations of the conditioned stimulus (CS). This phenomenon has been explained through two non-exclusive associative hypotheses. One of them proposes that the CS-unconditioned stimulus (US) association is weakened during extinction, while the second one explains extinction by the formation of a new inhibitory association between the CS and the US (CS-noUS) which competes with the excitatory one acquired at conditioning (CS-US). Research supporting this second hypothesis is based on the demonstration that the CR can be recovered after extinction, for example, if the US is presented before testing (reinstatement) or if the subject is evaluated in a context different than the one used during extinction (renewal). However, after extinction of a conditioned fear response in preweanling rats, renewal and reinstatement treatments have failed to recover the CR, suggesting that extinction of a fear response during this ontogenetic period may involve erasure of the CS-US association. The goal of the present study was to explore whether this conclusion can be extended to the extinction of a conditioned taste aversion. This goal was achieved by evaluating infant rats after acquisition and extinction of a conditioned taste aversion in three different procedures (reacquisition, Experiment 1; ABA renewal, Experiment 2; reinstatement, Experiment 3). The results of these experiments are consistent with the idea that extinction of a taste aversive memory during infancy involves relearning about the relationship between the CS and the US, with the initial CS-US association remaining relatively intact. Extinction of a taste aversive memory and a fear memory may involve different biological mechanisms during infancy. The conclusion that the only psychological mechanism for extinction