Biological Underpinnings of Socio-emotional Regulation in Preterm Infants and Healthy Controls

The methylation status of target genes (BDNF, SLC6A4, OXTR, NR3C1, Piezo1, Piezo2, TRPV1 andTRPM8) will be investigated. Saliva sample will be collected for PT and FT. Genomic DNA will be extracted from aliquots of 0. 4 ml of each saliva sample with the Oragene OG575 (DNA Genotek) and stored at -20°C. Aliquots of 250 ng of each DNA will be edited for methylation analysis with the EZ DNA Methylation Lightning kit (Zymo Research). Amplification of samples and their preparation for NGS sequencing will be performed. Samples will be sequenced on NextSeq 500 (Illumina). Individual processed sequences (PE reads) will be independently aligned to reference sequences using a parallel Smith-Waterman algorithm. Only reads that consistently align to the same reference sequence will be retained. At each CpG site in each analyzed sequence, the frequencies of the four bases will be evaluated.

Both PT and FT infants will have their EEG signal recorded during mother-baby interaction according to a modified version of the Still Face paradigm; the EEG signal will be recorded by means of the medical system eego mylab (AntNeuro), using special headphones equipped with 32 electrodes and suitable to acquire the EEG signal since early childhood. After spectral analysis of the EEG signal, the difference in signal strength in the alpha band recorded by two homologous electrodes (or electrode clusters) (i.e. right alpha - left alpha) will be calculated to obtain the FAA index. Because the alpha frequency band is associated with cortical inhibitory activity, a lower asymmetry reflects less left hemisphere activation than right hemisphere activation. The analysis of EEG data will be performed in MatLab environment using the eeglab software and algorithms developed ad hoc.