EEG spectral power and coherence analysis in healthy full-term neonates

Continuous, bipolar EEG recording was performed in nineteen healthy full-terms during quiet sleep (Q), REM sleep (R) and wakefulness (W). Spectral power was calculated for the bilateral fronto-central (FC), centro-parietal (CP), parieto-occipital (PO) and temporal (TT) derivations. Coherence was determined for the interhemispheric biFC, biCP, biPO and biTT locations, as well as for the left and right intrahemispheric FC-PO and TT-PO combinations. Power was highest in Q in the CP derivations at 0.4-12/s. Generally, power was higher in Q than in R. In most derivations, Q and R power ran parallel. W power behaviour was different. Up to 8/s, power in W was intermediate between Q and R power. From 10/s, it became highest, particularly in the TT and FC derivations. PO power was low. Highest coherence values occurred in the lowest frequencies. Up to 8/s, biFC, biCP and biPO interhemispheric coherences were highest in R and usually lowest during Q. In the alpha-beta range, highest coherences occurred during Q and lowest during R or W, without much variance between stages. BiPO coherences were remarkably high during all stages. BiTT and intrahemispheric coherences were low and less consistent. These data suggest high synchronization of theta-delta activity between biPO regions, particularly during R. We hypothesize active common generators of neonatal theta-delta activity in the posterior regions, indicating less autonomy and more interdependent behaviour of these areas especially during R.