For example, the N variant (in later work also referred to as LVEEG) is characterized by the absence of alpha-rhythm, even in the eyes closed condition. Since alpha-rhythm is the most prominent form of oscillatory activity in most of the individual EEG recordings, this variant is readily recognizable by the naked eye, however, it can be objectively quantified using such measures as percent-time alpha (alpha-index) or alpha-band power. Family studies of these EEG variants conducted in different samples, one of them including large pedigrees (Anokhin et al., 1992; Vogel, 1970a), showed that familial transmission of some of these EEG variants, most notably, the LVEEG, is consistent with a simple Mendelian mode of inheritance, with about 50% of the offspring of a LVEEG carrier showing this EEG pattern and a clear segregation of the offspring into two categories, one with the LVEEG and the other showing varying degree of alpha-activity, with the distribution of quantitative alpha measures similar to that in the general population. Importantly, Vogel et al. have demonstrated modest but significant differences between these genetically transmitted EEG variants with respect to cognitive performance, emotional reactivity and personality(Vogel et al., 1979a; Vogel et al., 1979b).
