Response perseveration in rats exposed to alcohol prenatally

Pregnant female rats consumed liquid diets containing either 35, 17, or 0% of the total calories as ethanol. Offspring of these females were tested for spontaneous alternation at 21 days of age and for reversal learning in a T-maze shock-escape paradigm at 20--21 days of age. In the spontaneous alternation test, rats exposed to alcohol prenatally took more trials than controls to enter the goal compartment opposite to that initially entered. In the T-maze escape study, alcohol-exposed offspring made more mistakes prior to criteron and more mistakes per trial than controls when the previously incorrect goal was made safe during reversal learning. In both studies linear dose-response functions were found. Furthermore, there was a significant tendency for the within-group variabitliy to increase as the level of prenatal exposure increased, perhaps indicating that the incidence as well as the severity of behavioral dysfunction was dose dependent. The results are interpreted in terms of a delay in the development of a central inhibitory system.