Effect of Estrogen Treatment on the Performance of Habitual Behavior in Intact Female Rats

Abstract: Previous studies have shown that female rats develop habitual behavior faster than males do. However, ovariectomized females show goal-directed behavior when given cyclic estradiol (E2) during acquisition training to a level that usually results in habitual behavior in intact females. This study was a pilot study designed to examine whether E2 treatment 15 hours before testing for habit in extensively trained, intact, female rats will also return them to goal-directed behavior. The results of this study showed that E2 did not significantly push females back into goal-directed behavior, possibly due to over-training. There was, however, a significant interaction effect between the females given E2 and vehicle prior to testing. This implies that estradiol had some diminishing effect on the strength of the habitual behavior, and thus works to increase sensitivity to devaluation in female rats. Future research following this experiment could have important implications in addiction, fear expression, obsessive compulsive disorder, and other psychopathologies that involve mal-adaptive habits.