Intrauterine Development of Sleep States

The fetal sheep is an important model of human pregnancy. The time-course of brain development is similar to the human situation. We aimed to investigate functional brain maturation in regard to the development of sleep states by examination of developmental changes of the electrocorticogram (ECoG) in utero. We recorded the ECoG of five chronically instrumented fetal sheep continuously between 105 and 139 days gestation (dGA, term 150 dGA). Three to five artifact-free 10min ECoG-epochs from NREM and REM sleep, respectively, were analyzed every third day using linear (power spectral analysis) and non-linear metho…