There are many changes related to brain development during adolescence that may affect theta ERO power. On the neuronal level, there is a decrease in gray matter density and cortical thickness in adolescence, as well as increases in white matter, reflecting synaptic pruning and myelination (Sowell et al., 2004; Toga et al., 2006). On the structural/anatomical level, trajectories of brain volumes of different regions and tissue types, as well as other features of cortical anatomy, exhibit curvilinear properties which vary between regions (Lenroot et al., 2007; Shaw et al., 2008; Giedd et al., 2010; Raznahan et al., 2011a; Sullivan et al., 2011) and between sexes (Lenroot and Giedd, 2010; Lenroot et al., 2007; Peper et al., 2011; Koolschijn and Crone, 2013), as determined by magnetic resonance imaging (MRI) of subjects between the ages of 8 and 20. Sex differences are also present in functional MRI studies of the development of task-related brain activity in adolescents and young adults in a number of different tasks (Rubia et al., 2006; Christakou et al., 2009; Rubia et al., 2010, 2013; Rubia, 2013). Brain
