Fig. 1.

Proportion of dams exhibiting preference for each chamber or lacking a chamber preference (a) and mean times spent in each chamber (b) of the three-chambered conditioned place preference (CPP) apparatus during the preconditioning baseline session, before assigning dams to different stimulus-chamber assignment groups. Both graphs include data from both postpartum groups. Proportions of dams placed into each preference category differed significantly from each other; only times in the left and center chambers differed significantly (number sign); both P<0.05