conscious awareness, recognition memory and episodic retrieval (Gevins et al. 1998; Klimesch et al. 2001; Klimesch et al. 1994). Theta oscillations have been implicated in sensorimotor integration (Bland & Oddie 2001; O'Keefe & Recce 1993), evaluating loss and gain (Kamarajan et al. 2008) and several processes associated with memory (Jacobs et al. 2006; Klimesch et al. 2008; Vertes 2005). Theta rhythm plays a role in information processing using an attentional double-gating mechanism, “filtering-in” signals for effective registration and encoding of selected information and “filtering-out” interfering inputs (Vinogradova 1995). Brain oscillations have been shown to be stable, highly heritable (van Beijsterveldt & Boomsma 1994; van Beijsterveldt et al. 1996), and to be reliable endophenotypes that reflect a shared liability between alcoholism and related disorders (Porjesz et al. 2005). Power estimates of oscillations are more heritable than event-related potential (ERP) components, giving them a slight edge as endophenotypes (de Geus 2010).
