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 cholinergic receptor 2, and frontal theta EROs underlying the P300 ERP to target stimuli during a visual oddball task [Jones et al., 2004, 2006a]. In addition, several SNPs in GRM8 (metabotropic glutamate receptor type 8), another candidate gene located under the same linkage peak, are associated with theta EROs to target stimuli at frontal, central and parietal regions [Chen et al., 2009]. Both of these receptor genes have also been implicated in the development of alcoholism [Wang et al., 2004; Chen et al., 2009], underscoring the utility of EROs as endophenotypes in relation to psychiatric pathologies.
