These oscillatory responses have served as useful endophenotypes for measuring and deconstructing neurocognitive dysfunctions related to a variety of complex behavioral disorders, including alcohol dependence [Jones et al., 2004, 2006b; Porjesz et al., 2005; Padmanabhapillai et al., 2006a,b; Rangaswamy et al., 2007]. The Collaborative Study on the Genetics of Alcoholism (COGA) has investigated event-related oscillatory responses in families densely affected with alcoholism, finding significant reductions in evoked theta and delta ERO amplitudes among affected subjects while processing target stimuli [Jones et al., 2006b]. Studies examining high-risk children of alcoholics for the same paradigm have revealed similar reductions in theta and delta band ERO amplitudes compared to normal children (ages 14-17 years) [Rangaswamy et al., 2007], indicating that the deficits antecede the development of alcoholism and represent a strong trait marker. Family-based linkage analysis and candidate gene association studies of ERO responses have identified several chromosome regions and genetic variants that underpin these neuroelectrical activities and contribute to the risk of alcohol dependence. Most notably, significant genetic linkage was reported on chromosome 7q31-34, with association detected between positional candidate CHRM2, muscarinic
