Cortical ODI increase accompanies FC increase after early music intervention
PRETERM BIRTH
To better evaluate the microstructural modifications underlying the observed cortical FC increase following the early music intervention, we have complemented our FBA with a NODDI analysis, applied specifically to those cortical regions where we observed a significant effect of the music intervention.In all the evaluated cortical regions exhibiting a significantly superior FC longitudinal increase from the 33rd week GA to term-equivalent age, we also found a significant longitudinal ODI increase, in line with previous results using NODDI to evaluate early cortical maturation (ODI relates to the degree of incoherence of fiber orientations, which has been linked to an increased dendritic arborisation and consequent geometrical complexification in cortical GM (The cortical ODI increase is in line with the increase in cortical FC, since it supports that a higher number of dendritic branches are present when the cross-sectional plan is evaluated; as well as with the parallel FD decrease, given that the complex cortical microstructure may reduce FD, which is a directional-dependent metric.Our results further support the hypothesis that the early music intervention, by enriching the auditory environment of preterm infants during a critical period of cortical activity-dependent plasticity, might modify the establishment and remodelling of the incoming thalamo-cortical connections and enhance cortical maturation, due to an increase in cortical dendritic arborisation and complexity, in regions known to be structurally impaired by preterm birth and related to the behavior and socio-emotional difficulties observed later in this population (