Prenatal ethanol exposure can result in social deficits in humans and animals, including altered social interaction and poor communication. Rats exposed to ethanol prenatally show reduced play fighting, and a combination of prenatal ethanol exposure and neonatal whisker clipping further reduces play fighting compared with ethanol exposure alone. In this study, we explored whether expression of hedonic ultrasonic vocalizations (USVs) correlated with the number of playful attacks by ethanol-exposed rats, rats subjected to postnatal sensory deprivation by whisker clipping or both compared to control animals. In normally developing rats, hedonic USVs precede such interactions and correlate with the number of play interactions exhibited in dyads. Pregnant Long-Evans rats were fed an ethanol-containing liquid diet or a control diet. After birth, male and female pups from each litter were randomly assigned to the whisker-clipped or non-whisker-clipped condition. Animals underwent a social interaction test with a normally developing play partner during early or late-adolescence. USVs were recorded during play. Prenatal ethanol exposure reduced both play and hedonic USVs in early adolescence compared to control rats and persistently reduced social play. Interestingly, ethanol exposure, whisker clipping and the combination abolished the significant correlation between hedonic USVs and social play detected in control rats in early adolescence. This relationship remained disrupted in late adolescence only in rats subjected to both prenatal ethanol and whisker clipping. Thus, both insults more persistently disrupted the relationship between social communication and social play.
Keywords: USV; fetal alcohol spectrum disorder; rat; sensory impoverishment; social behavior.