Relationship between maternal aggression and maternal care in the rat

✍ Scribed by Jay S. Rosenblatt; Elizabeth M. Factor; Anne D. Mayer

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 926 KB
• Volume: 20
• Category: Article
• ISSN: 0096-140X
• DOI: 10.1002/1098-2337(1994)20:3<243::aid-ab2480200311>3.0.co;2-l

✦ Synopsis

Aggression among female rats is almost entirely confined to the period of late pregnancy and lactation. Behaviorally it is similar to the aggression of males including piloerection and lateral attacks, but it differs in its function. Unlike male aggression which serves to establish a social hierarchy and a territory, i.e., is compefitive, maternal aggression is protective, i.e., it serves to prevent predation of the mother's offspring. In this respect it is closely related temporally and causally to maternal care; if the offspring are removed maternal aggression wanes almost immediately-its function no longer exists! Studies on aggression by mothers, among rats, from the authors' laboratory are reviewed and comparisons made with maternal care. As noted, maternal aggression and maternal care are closely related during the cycle of maternal behavior and they share a similar hormonal basis and possibly the effect of uterine stimulation, but maternal care requires prolactin and the decline of progesterone while maternal aggression appears independent of pituitary hormones and does not require a decline in progesterone. Maternal aggression like maternal care appears to be organized into a hormonal phase, during pregnancy, parturition, and for about a week postpartum and a nonhormonal phase thereafter. Bilateral radiofrequency lesions of the lateral midbrain peripeduncular nucleus (PPN) produce deficits in maternal aggression if made on lactation day 7 (L7), but not earlier, without producing significant deficits in maternal behavior. Experiments showed that the PPN does not mediate hormonally stimulated maternal aggression; it appears to mediate only nonhormonally stimulated maternal aggression. Studies on the role of pregnancy hormones on long-term retention of maternal aggression and the role of olfaction in maternal aggression are also reviewed.