Hippocampal maturation in the precocial murid rodent Acomys cahirinus.

Growth rates in the dentate gyrus and hippocampus proper of the precocial murid Acomys cahirinus were examined by measuring age-related changes in laminar volume in 0-, 10-, 20-, and 60-day postpartum animals. A biphasic course of maturation was observed in both structures, with rapid expansion occurring in the first 10 postnatal days and more gradual growth thereafter. This pattern of growth resembles those reported for newborn altricial murids such as the laboratory mouse and rat. However, due to the large differences in the length of gestation between Acomys and the rat and mouse, quite different patterns emerge when the species are compared on the basis of postconception age, indicating that rates of neural maturation are not the same in altricial and precocial murids .