Legnani, M. | bioRxiv Science

bioRxiv2026

Maturation of Sleep EEG Complexity in Preterm Newborns: Insights from Lempel-Ziv and Joint Lempel-Ziv Analyses

The development of the sleep-wake cycle reflects the progressive structural and functional maturation of the brain. However, the organization of neural dynamics during prematurity remains incompletely understood. In this study, we analyzed the EEG from 54 polysomnographic recordings obtained from 39 preterm infants, grouped according to postmenstrual age (PMA) into three categories: 30-31, 32-33 and 34-35 weeks. Lempel-Ziv Complexity (LZC) and Joint Lempel-Ziv Complexity (JLZC) of the electroencephalogram (EEG) were analyzed during active sleep (AS), quiet sleep (QS), and indeterminate sleep (IS). LZC computed from the raw, unfiltered recordings were significantly higher during QS than during AS and increased with PMA during AS. To further refine the analysis, LZC was also evaluated separately in the low-frequency (1-15.5 Hz) and high-frequency (16-30 Hz) EEG bands. In the low-frequency band, LZC was consistently higher during QS than during AS, an effect that was most pronounced in more immature groups. Furthermore, LZC increased with maturation particularly during AS. Sleep-state comparisons of LZC in the high-frequency EEG band also revealed higher values during QS than during AS across all PMA groups. Moreover, in contrast to the low-frequency band, LZC progressively decreased with advancing PMA both in AS and QS, suggesting that the neural mechanisms underlying low- and high-frequency EEG activity follow distinct maturational trajectories. Interestingly, larger LZC in the temporal cortex and interhemispheric differences were detected in the 32-33 PMA group. On the other hand, JLZC analysis revealed greater joint spatiotemporal dynamics across EEG channels during QS than during AS, with consistently higher JLZC values in temporal regions and lower in occipital regions. Together, these findings show that these complexity metrics distinguishes sleep states and captures maturational changes in EEG activity in preterm infants. These results provide novel insights into early brain development and suggest potential quantitative biomarkers of neonatal brain maturation.

neuroscience↗

bioRxiv2020

GMO LABELING IN FOOD PRODUCTS IN MONTEVIDEO, URUGUAY

Montevideo establishes the mandatory labeling of foods containing genetically modified material through the Departmental Decree No. 36.554, positioning Uruguay within the 65 countries that have incorporated this type of regulation. The Food Regulation Service, in its role of sanitary police, and through its Laboratory of Bromatology, in agreement with the Food Molecular Traceability Laboratory (Faculty of Sciences, University of the Republic), carried out the analysis of 206 products made with ingredients derived from corn and/or soybean, during the 2015-2017 period, within the framework of compliance with the aforementioned Decree. The strategy used consisted of the application of molecular techniques (Real Time PCR), for the detection of common sequences present in the transgenic events of soybean and corn, and the subsequent quantification of the content of GM material, in relation to an established labeling threshold of 1%. As a result of this study, it was found that 36.9% of the analyzed foods presented sequences derived from genetically modified plant organisms (GMOs); and in 95% of the cases, its content exceeded the threshold established for its labeling. This study, constitutes the first approach to the knowledge of different transgenic elements distribution in food commercialized in Montevideo. These results provide valuable information to both the consumer, for decision making about the food to be consumed, and also for the official control organizations, which must enforce the regulations. This type of work has demonstrated, once again, the importance of the interrelation between academy and state agencies, in the generation of knowledge and in the implementation of new analytical methodologies, as well as in the training of qualified human resources and in the compliance with current regulations.

molecular biology↗