Several studies have demonstrated that P3 responses are primarily the outcome of theta and delta oscillations elicited during cognitive processing of stimuli (Basar-Eroglu et al., 1992; Yordanova and Kolev, 1996; Basar, 1999; Karakas et al., 2000a, b), with delta oscillations more concentrated in the posterior region, while theta is more centered in the frontocentral region (Karakas et al., 2000b) (Fig. 23.1). ERO changes in chronic alcoholics reveal a neuronal state with altered excitability. This has also been suggested by some transcranial magnetic stimulation (TMS) studies (Conte et al., 2008; Muralidharan et al., 2008).
