Since the discovery of the EEG by Hans Berger in the early part of the last century (Berger 1929) oscillatory brain activity and its potential relationship with a range of behavioural variables has been a dominant theme in neuroscience research. In the 50–60 years following inception of the EEG, the main focus of research on brain oscillations was, unsurprisingly, the classical alpha (α) (8–13 Hz) rhythm. This rhythm, the first EEG oscillation to be documented, is concentrated at occipital sites, reflecting its origins in the visual system, and is most pronounced during periods of relaxed wakefulness (Berger 1929; Adrian and Matthews, 1934; Adrian and Yamagiwa 1935; Hughes and Crunelli 2005). Because the α rhythm is particularly evident when the eyes are closed, it has been widely considered to represent a simple idling of the visual cortex. However, its expression is not exclusively restricted to the eyes-closed condition (Mulholland 1965) and an extremely large body of psychophysical literature spanning several decades has shown that α activity is inseparably linked to a host of perceptual and cognitive phenomena (Lindsley 1952; Lansing 1957;
