A LONGDITUDINAL STUDY OF MOTHER-YOUNG INTERACTION IN THE RAT: THE EFFECTS OF INFANTILE STIMULATION, DIURNAL RHYTHMS, AND PUP MATURATION

Rat litters had either pups and mother handled (LH), mother only handled (MH), or were left undisturbed (NH), in two sessions per day from birth to weaning. They were observed throughout this period. Recordings were made hourly, and also at 3 minute intervals for an hour before and an hour after each treatment. Diurnal rhythms and maturational changes were catalogued. Treatment interacted with these factors; overall it had deleterious consequences for the quality of maternal care as measured by nursing behaviour, nest building, and the quality of the pup environment. Some changes, notably in nest building, were specific to LH, but generally LH and MH showed similar trends with more marked effects in MH. As adult open-field testing showed LH offspring to ambulate significantly more than MH or NH no clear support is found for maternal mediation of infantile stimulation.