Two groups of periadolescent children (age 10-14 yrs) were recruited as described previously [48-52]. Both groups were recruited from the community and individual informed consent was obtained from one biological parent or legal guardian. Participants were excluded if they were taking any prescribed medication or had any major medical or psychiatric/developmental disorder. Records from 31 of the participants were still available on readable media and were used in the present analyses. Baseline EEG and ERP responses to auditory stimuli in these individuals have been reported previously [48-49]. Data in the present report included only ERO responses, for comparison to the young adult participants.
