Latent inhibition and facilitation of conditioned taste aversion in infant rats

GAZTAÑAGA, M; ARIAS, C.; CHOTRO, M. G.

Jaen

Congreso; Sociedad Española de Psicología comparada/International society for comparative psychology; 2012

Sociedad Española de Psicología comparada/International society for comparative psychology

In adults, stimulus preexposure generally induces latent inhibition effect. Early in ontogeny this effect is rarely found and facilitation of conditioning is rather seen. The effects of stimulus preexposure on conditioned taste aversion were investigated in 2-week-old rats. On postnatal day 13 pups received 0, 1 or 3 preexposure trials to saccharin. After this, all pups received the conditioned stimulus saccharin followed by the unconditioned stimulus: saline, or a 0.15M LiCl dose, or a 0.30M LiCl dose. On PD14, the same conditioning procedures were repeated and saccharin intake was registered. On PD15 saccharin consumption was again tested. After 1 conditioning trial, without preexposure only the strong US induced taste aversion, while with preexposure the aversion was observed with both doses. Three preexposure trials reduced taste aversion observed with the highest dose. After 2 conditioning trials all conditioned groups showed taste aversion. Stimulus preexposure can either facilitate conditioning or induce latent inhibition in infant rats depending on the amount of stimulus preexposure, the intensity of the US, and the number of conditioning trials. This early learning is not generalized to other tastes. (MEC PSI2011-24231 and Basque Government IT-276-07)