Genetic Influence on ERP Slow Wave Measures of Working Memory

Individual differences in the variance of event-related potential (ERP) slow wave (SW) mea-sures were examined. SW was recorded at prefrontal and parietal sites during memory and sen-sory trials of a delayed-response task in 391 adolescent twin pairs. Familial resemblance was identified and there was a strong suggestion of genetic influence. A common genetic factor influencing memory and sensory SW was identified at the prefrontal site (accounting for an estimated 35%–37 % of the reliable variance) and at the parietal site (51%–52 % of the reliable variance). Remaining reliable variance was influenced by unique environmental factors. Mea-surement error accounted for 24 % to 30 % of the total variance of each variable. The results show genetic independence for recording site, but not trial type, and suggest that the genetic factors identified relate more directly to brain structures, as defined by the cognitive functions they support, than to the cognitive networks that link them. KEY WORDS: Working memory; event-related potentials; slow wave; reliability; twin study; adolescents. 1996) and ERPs elicited in a working memory task have been shown to vary with intellectual ability (Gevins and Smith, 2000). However, no previous genetic studies hav