All assessments include measures of brain activity. Although most MTFS research on EEG and event-related brain potentials (ERPs) has been conducted using a 5-channel system, we employ 64-channel EEG recording in the ES study. We use the same “rotated heads” visual oddball task (Begleiter et al., 1984) used in the previous MTFS cohorts to elicit ERPs. We and others have demonstrated that amplitude of the P300 wave is reduced in individuals with disorders in the externalizing spectrum as well as those at risk for such disorders (Iacono et al., 2002b; Porjesz et al., 2005). P3AR also predicts the subsequent development of substance use disorders (Carlson et al., 2004; Habeych et al., 2005; Iacono et al., 2002b). Because certain aspects of spontaneous and task-related EEG oscillations may also prove valuable as endophenotypes for substance use disorders (Gilmore et al., in press; Porjesz et al., 2005) and are associated with ADHD (Barry et al., 2003), we also extract event-related oscillations (EROs) from our ERP data and examine the spectral components extracted from our recordings of spontaneous EEG.
