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The goals of the present study were to characterize the effects of prenatal exposure to moderate levels of ethanol on adult social behavior, and to evaluate fetal-ethanol-related effects on dendritic morphology, structural plasticity and activity-related immediate early gene (IEG) expression in the agranular insular (AID) and prelimbic (Cg3) regions of frontal cortex. Baseline fetal-ethanol-related alterations in social behavior were limited to reductions in social investigation in males. Repeated experience with novel cage-mates resulted in comparable increases in wrestling and social investigation among saccharin-and ethanol-exposed females, whereas social behavioral effects among males were more evident in ethanol-exposed animals. Male ethanol-exposed rats also displayed profound increases in wrestling when social interaction was motivated by 24 hours of isolation. Baseline decreases in dendritic length and spine density in AID were observed in ethanolexposed rats that were always housed with the same cage-mate. Modest experience-related decreases in dendritic length and spine density in AID were observed in saccharin-exposed rats housed with various cage-mates. In contrast, fetal-ethanol-exposed rats displayed experience-related increases in dendritic length in AID, and no experience-related changes in spine density. The only effect observed in Cg3 was a baseline increase in basilar dendritic length among male ethanol-exposed rats. Robust increases in activity-related IEG expression in AID (c-fos and Arc) and Cg3 (c-fos) were observed following social interaction in saccharin-exposed rats, however, activity-related increases in IEG expression were not observed in fetal-ethanol-exposed rats in either region. The results indicate that deficits in social behavior are among the long-lasting behavioral consequences of moderate ethanol exposure during brain development, and implicate AID, and to a lesser degree Cg3, in fetal-ethanolrelated social behavior abnormalities.

Previous work from our laboratory has demonstrated that rats display a preference for directional responding over true place navigation in the Morris water task. The present study evaluated the range of situations in which this preference is observed and attempted to identify methods that favor navigation to the precise location of the escape platform in the room. A preference for directional responding over place navigation was observed in a wide range of procedures that included providing extensive training (Experiment 1), providing only platform placement experience in the absence of active swim training (Experiment 2), training navigation to multiple platform locations in a moving platform variant of the task (Experiment 3), and explicitly training navigation to a precise location in the room, versus navigation in a particular direction, regardless of the pool's position in the room (Experiments 4 -5). A modest preference for navigation to the precise spatial location of the platform was observed when the pool wall was virtually eliminated as a source of control by filling it to the top with water (Experiment 6).

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