Acute alcohol intoxication disrupts brightness but not olfactory conditioning in preweanling rats

The present experiments tested the effect of acute alcohol administration on Pavlovian conditioning of 21-day-old rats using conditioned stimuli of two different sensory modalities--olfaction, an early developing sensory capacity functional at birth, and vision, a later developing sensory system not becoming functional until approximately 15 days of age. Conditioning and testing were conducted between 30 and 60 min following gastric infusion with either physiological saline or a mildly intoxicating alcohol dose (1.5 g/kg body weight). Brain alcohol levels were observed to remain at a peak and stable concentration during this period (Experiment 1). Alcohol impaired acquisition or expression of conditioned aversions to a visual cue paired with footshock when presented either as a single-element conditioned stimulus or as part of an odor/visual compound stimulus (Experiment 2), but it had no discernible effect on conditioned aversions to an olfactory stimulus that had similarly been paired with footshock (Experiments 2 and 3). The results suggest that alcohol may impair some aspects of learning but spare others, depending perhaps on the particular sensory modality to be conditioned.