Interaction-induced reduction in differential maternal responsiveness: an effect of cue-reduction or behavior?

Litters from donor mothers received differential treatments (handling or shocking) and were then placed in wire-mesh baskets affixed to the cage tops of test mothers. Pup-produced cues from donor litters elicited different patterns of maternal behavior from test mothers that interacted with their own litters. In addition to these differences in maternal behavior, cues from the donor litters elicited a differential pattern of pituitary-adrenal activity. Shocked pups elicited larger corticosterone elevations than handled pups. These data suggest that the elimination of differential pituitary-adrenal responsiveness evidenced when mothers interact directly with pups subseuqent to pup treatment resllts from the termination of pup-produced cues that normally accompany active mother-infant interactions.