In the present study periadolescent humans were found to have significantly lower synchrony than adults as indexed by PLI levels in a range of frequencies over all electrode sites. Periadolescent humans also had significantly lower PDLI levels (FZ-PZ) than adults in all frequency ranges. Previous studies have evaluated PLI values over development in human participants. Lower evoked gamma power and PLI in children as compared to adults, has been previously reported using a simple visual choice-reaction task [116]. Additionally, Yordanova and colleagues [104] found that in 13-16 yr olds that gamma band response in parietal but not frontal areas were enhanced by active attending to the side of a motor target more than in 9-12 yr olds. These data suggest that gamma band responses may mature over the course of early adolescence. Changes in alpha responses over development have also been reported previously. In one study, young adults were found to have significantly lower amplitude and stronger phase-locking than children in the 6-11 yr age range [101]. More recently Muller and colleagues [40] have demonstrated that age differences in phase
