Effect of prenatal ethanol exposure on response to abrupt reward reduction

The purpose of this study was to examine the effects of prenatal ethanol exposure on an appetitively-motivated behavioral task (consummatory negative contrast) that involves quantification of an animal's response to an abrupt, unexpected reduction in reward (sucrose solutions). Pregnant Long-Evans rats received isocaloric liquid diets containing either 35% or 0% ethanol-derived calories on days 6-20 of gestation. A pair-feeding procedure was employed, and a lab chow control group also was included. Adult male offspring from these three prenatal treatment groups were used for behavioral testing. Results indicated all groups exhibited suppressed responding subsequent to reward reduction. This effect gradually diminished in all prenatal treatment groups over several test sessions. While there was a numerical tendency for ethanol-exposed offspring to exhibit a smaller initial contrast effect (less response inhibition) and recover to control levels at a faster rate than the sucrose and lab chow control groups, this effect was not statistically significant. Thus, prenatal ethanol exposure does not appear to greatly influence the response to abrupt, partial reward reduction in adult rat offspring.