Microanalysis and Macroanalysis of High-Frequency Oscillations in the Human Brain

High-frequency oscillations (HFOs) greater than 40 Hz are thought to underlie several physiological functions of the normal brain (Buzsaki and Draguhn 2004) but are also a characteristic feature of the epileptic brain and may, for example, play a causal role in the initiation of focal epileptic seizure (Köhling et al. 2000; Traub et al. 2001; Bragin et al. 1999, 2002a; Grenier et al. 2003) or in epileptogenesis (Bragin et al. 2004; Khalilov et al. 2005). Thus it is important to determine the differences as well as the common basic underlying mechanisms involved in the production of such normal and pathological activities (Le Van Quyen et al. 2006).