The age variation in adolescents and young adults of genotypic effects on theta band event-related oscillations (EROs) was determined by the assessment of developmental trajectories of theta band (4–7 Hz) EROs by non-parametric regression in a sample of 2140 adolescents and young adults ages 12 to 25 from the COGA prospective study, a multisite collaboration designed to study the genetics of alcoholism (Begleiter et al., 1995). The theta band EROs occurring in the P3 response, important indicators of neurocognitive function, were elicited during the evaluation of task-relevant target stimuli in visual and auditory oddball tasks from 9 electrode locations. These tasks call upon attentional and working memory resources. The developmental trajectories of the EROs have large sex differences; scalp location and task modality (visual or auditory) differences within males and females were small compared to sex differences. Associations between the theta EROs and genotypic variants of 21 single nucleotide polymorphisms (SNPs) from cholinergic genes CHRM2, CHRNA3, CHRNA5, CHRNA6, CHRNB1, CHRNB3, and CHRNB4, measured by effect sizes of genotypic covariates in the regression analysis, were found to vary with age, sex,
