Functional MRI (fMRI) and electroencephalography (EEG) allow the measurement of brain function and activity. To our knowledge, only one study examined heritability of the functional brain networks using fMRI in the younger population (van den Heuvel et al. 2013. Connectivity density is defined as the total number of brain connections, and cortical network efficiency is assessed by the temporal dependency of neuronal activation patterns of anatomically separated brain regions. Independent of the connectivity density, heritability of the global cortical network efficiency was moderate (42%) at 12 years of age (van den Heuvel et al. 2013), and higher (60%) in adults (Fornito et al. 2011).
