Different frequency bands in EROs have been attributed to underlie various task-specific cognitive processes. Event-related delta activity is generated by cortico-cortical interactions (Devrim et al., 1999), and is a product of the distributed network system of the brain (Basar Eroglu et al., 1992, Basar, 1999a, b) involved in mediating attention and task demand, signal detection and decision making (Basar-Eroglu, Basar, 1992, Basar, 1999a, b, Basar et al., 2001, Schurmann et al., 2001). On the other hand, event-related theta oscillations are related to cortico-hippocampal (Basar, 1999b, Miller, 1991) or fronto-limbic interactions (Karakas et al., 2000), and are associated with a complex set of cognitive processes including alertness, arousal or readiness (Basar, 1999b), episodic encoding and retrieval processes (Klimesch, 1999, Klimesch et al., 1997a, Klimesch et al., 1996a, Klimesch et al., 1997c, Klimesch et al., 2001, Klimesch et al., 1994), selective attention and short-term memory (Basar-Eroglu, Basar, 1992, Demiralp and Basar, 1992, Karakas, 1997, Klimesch, 1999), error processing (Luu et al., 2003, Luu et al., 2004, Trujillo and Allen, 2007), reward processing (Cohen et al., 2007, Gehring and Willoughby, 2004, Kamarajan et
