Locomotor activity was used as a measure of overall activity and exploratory behavior in a novel environment. Reduced exploration was an index of anxiety-like behavior (Crawley, 1999). The open field chamber (40 cm × 40 cm × 30 cm, VersaMax system, AccuScan Instruments) was crossed by a grid of photobeams to detect motion. Mice were tested for one hour in the open field chamber. Measures of distance traveled, rearing movements, and time spent in the center were taken.
