When Mothers Go Wrong: Likely Neural Undercurrents Related to Poor Parenting

The mammalian model of survival begins with puzzling-out a simple but stark truth: Life must learn to care for life. We have described the experiences involved in changing from nulliparous female to mother, from unresponsive to committed. The transition taking place in the nervous system that underpins the shift from largely self-centered organism to other-focused car-egiver is accompanied by an assortment of effects ranging from basic gene expression changes, to modifications of neuronal complexity and activity, to wholesale shifts in the size of specific brain structures. In total, the female changes in ways both subtle and striking, and for one simple reason: reducing the cost:benefit ratio required for successful rearing of young. The system, however, is imperfect. Here we attempt to reconcile the ultimate goals of life and evolution, the manifest reshaping of the female mammal's brain in service to her young, with its incomplete or faulty development. That is, things go wrong; mothers can be apathetic, abusive, or worse. How might the inherent adaptation that, on average, directs the formation of the maternal brain, and which in turn, governs the set of behaviors required for successful reproduction and gene passage, fail to adequately express itself? Susan Smith drives her car and two young boys into a lake in South Carolina, killing the children. Andrea Yates drowns five children, one after the other, in her family's bathtub. These cold and heinous acts are doubly shocking because of the per-petrators' relationship to the victims: the children's mothers. How, we ask, can that most hard-wired of mammalian behaviors – in fact, the very word " mammal " derives from the act of caring – go awry? Why and in what ways do mothers vary in their degree of maternal motivation/care? The simple answer is, nothing is perfect. Things go wrong, sometimes terribly so. From the standpoint of the brain's regulation of maternal behavior, however, which of the factors that normally order maternal responsiveness might malfunc-tion? The fosB gene is a good place to start. Brown et al. (1996) established a regulatory role for the fosB gene in the display of mouse maternal behavior. A knockout of fosB gene activity, including preoptic area (POA) expression, led to a significant reduction in what the authors refer to as " nurturing, " wherein a lack of maternal responsiveness affected offspring survival, in the absence of observed deficits in basic hypothalamic activity, pregnancy, cognition, or olfaction. …