Context and tone conditioning are selectively impaired by ethanol in the preweanling rat: Effects of dose and time of administration

Depending on dose and task requirements, ethanol can have either a facilitative or an impairing influence on learning. Some explanations for this dichotomy have considered ethanol's suppression of behavioral variability and processing of incidental stimuli (e.g., context). The present study examined the effect of ethanol on context and conditioned stimulus (CS) learning in the preweanling rat. To assess state-dependent effects, a drug dissociation design was used. Learning to both context and CS were analyzed within each dose of ethanol (0, 1.2, 1.6, or 2.0 g/kg) and a trend analysis was conducted to determine dose-response relationships as a function of train-test state. The 1.2 g/kg dose of ethanol did not affect conditioning to either the context or the CS. A 1.6 g/kg dose tended to disrupt context, but not CS, conditioning. The influence of 2.0 g/kg ethanol depended on train-test conditions. Ethanol administration prior to training resulted in the stronger impairment of CS learning while context conditioning was most disrupted if ethanol was given only prior to testing. The results suggest that ethanol selectively attenuates processing of stimuli, possibly dependent on relative saliency at the time of testing.