Electrical stimulation of dorsal, but not ventral hippocampus reduces behavioral defense in the elevated plus maze and shock-probe burying test in rats.

Recent evidence indicates that the hippocampus contributes to the control of defensive behaviors in rodents. Here, electrical stimulation (1s, 60 Hz) of the rat dorsal hippocampus inhibited defense in the elevated plus maze (increased open arm exploration) and shock-probe burying test (reduced burying duration), while ventral hippocampal stimulation had no effects. Thus, the dorsal hippocampus may play an important role in modulating a range of defensive strategies.

Maternal care is similar for rat pups subjected to birth hypoxia and for controls.

The rat model of global anoxia during cesarean section birth has been used extensively to investigate effects of birth hypoxia on central nervous system function. This study tested whether differential maternal care mediates central nervous system alterations in this model. Maternal care of mixed litters of pups born vaginally, by cesarean section or by cesarean section with anoxia, was assessed. Frequency and duration of licking and grooming by dams were similar for all birth groups. No group differences were observed in order of retrieval, when pups were displaced from the nest. The results indicate that altered central nervous system function in anoxic animals in this model are not due to differential maternal care, but may be mediated by other mechanisms such as direct hypoxic insult to neurons.