seen before) involves interactions between widely separated brain regions (e.g., frontal and parietal lobes [figure 1]). Higher cognitive processing involves slow synchronization in the theta or delta frequency range (Lubar 1997). Thus, faster frequencies represent synchronization of groups of neurons in more local areas, whereas slower frequencies are involved in synchronization over longer distances in the brain (von Stein and Sarnthein 2000; Kopell et al. 2000).
