Long-term alterations in the maternal behavior of neonatally undernourished rats.

The effect of early food and sensory deprivation on the maternal responsiveness of female rats was investigated. Animals that were neonatally undernourished by daily mother-litter separation (involving both food and sensory deprivation) showed significant deficits in maternal care, consisting of a reduction in nest rating, nursing time, and retrieving responses. Moreover, they exhibited exaggerated grooming and circling movements in comparison with the controls. Dams neonatally undernourished by the nipple-ligation of their mothers (a method that minimizes sensory deprivation) displayed less alterations in maternal behavior, and no significant differences in grooming and circling from the controls. The data suggest that nest rating, nursing time, and retrieving latency are closely related to food restriction, while the frequency of grooming and circling behavior are primarily associated with sensory deprivation. These results support the view that environmental influences related to food intake and sensory stimulation, interacting at critical stages of brain development, are essential for the maturation of adult behavioral patterns.