[Formation of neocortex in rats after prenatal hypoxia].

Exposure of pregnant rats to the atmosphere containing 7.56% of oxygen for one hour was found to cause the disturbances in the nerve system development in their offspring. The exposure to acute hypoxia at days 13 or 16 of embryonic development induced an attenuation and underdevelopment of brain cortical layers, disturbances in cell orientation and differentiation, i.e. caused the modifications of basic histogenetic processes that were active during this period, including proliferation, migration and differentiation, thus resulting in the changes of structural characteristics of neocortical layers. The effect of hypoxia during the later fetal period--at day 19 of embryonic development, when cell proliferation in the brain ceases while the processes of differentiation are enhanced,--is less damaging. The cortical layers formed in experimental animals are not significantly different from those in control rats, however the death of individual neurons and gliocytes takes place.