Pontosubicular neuronal necrosis is characterized by neuronal karyorrhexis, showing a peculiar distribution. In infants delivered at more than 29 gestational weeks (GW), neuronal karyorrhexis is restricted to the pons and subiculum, while in very premature infants (delivered at less than 28 GW), neurons in other brain regions, such as the inferior olivary nucleus, cerebellum, basal ganglia, thalamus and cerebral cortex, are also involved. Thus, karyorrhexis is more widely distributed in the more immature brain, implicating neuronal maturation as one of the pathogenetic factors relevant to this type of neuronal cell death.