EEG showed low heritability (11–27%) of frontal asymmetry in 9 to 10-year old children (Gao et al. 2009), similar to that in adults (Coan and Allen 2003; Anokhin et al. 2006; Smit et al. 2008). In contrast, EEG alpha power was highly heritable (70–85%) in children (Gao et al. 2009; van Baal et al. 2001), and in older adolescents and adults (van Baal et al. 1996). EEG alpha power scores increased from 9 to 10 years of age (Gao et al. 2009) and from 15 to 17 years of age (McGuire KA 1998), despite these narrow age ranges. Although these studies involved small sample sizes, the findings suggest that heritability of global functional brain connectivity increases during brain development, while heritability of the architecture and maturation in the frontal cortex is relatively stable across the age range.
