[Morphogenesis of the brain of rats developing under conditions of weightlessness]

Macroscopic and light microscopic examinations of the brain of 18-day fetuses, and neonate 15-, 30- and 100- day rats whose embryonic development from day 13 to day 18 occurred in space flight on Cosmos-1514 did not reveal any changes in the brain structures of the fetuses or pups of the three ages. However, the brain of the 18-day fetuses that developed in flight showed signs of insufficient tissue oxygenation, trends toward delayed cell migration in the cortex and delayed differentiation of neurosecretory cells of the hypothalamic supraoptic nuclei. The cell differentiation rate returned to normal during continued embryogenesis after flight at 1 g.