Neuronal oscillations are a ubiquitous phenomenon observed in multiple cortical and subcortical areas across a wide range of species [1]. Neuronal oscillations are often generated in neuronal networks that in uence each other via excitatory and inhibitory connections. As a result, neurons are rhythmically stimulated and inhibited [2]. Neuronal oscillations have been described on several levels, ranging from single cells to cell assemblies of several thousand neurons. Accordingly, several methods exist to measure neuronal oscillations. On the level of single cells or small cell assemblies neuronal oscillations can be measured invasively by single cell or multi-unit recordings. If thousands of neurons oscillate synchronously, the resulting signal might be strong enough to be recorded non-invasively outside the skull using electroencephalography (EEG) and magnetoencephalography (MEG) [3,4].Using EEG, the first to observe such rhythmic fluctuations non-invasively in the living human brain was Hans Berger [5]. In his seminal work, he first described rhythmic patterns in the EEG in the 8-12 Hz range; the famous alpha waves.Since then, investigators have revealed a wide range of oscillatory activity in several di erent frequency bands ranging from slow (0.1 Hz) to ultra-fast (~ 500 Hz) oscillations [4].Neuronal oscillations can be found in local neuronal groups, but oscillations have also been suggested as a mechanism for long-range communication between neuronal groups. Long-range communication is a process in which one area transfers certain characteristics of its current functional state to another area [6] or in which spatially distinct cortical areas are bound to one functional network [7]. In general, high frequencies are believed to re ect neuronal activity over small spatial regions and short temporal windows, while low frequencies are believed to modulate activity over large spatial regions and long temporal windows [8,9]. These relations between spatial and temporal patterns allow brain processes to be carried out simultaneously at multiple spatial and temporal scales [10][11][12].Neuronal oscillations have been classified in mainly five distinct frequency bands: delta (1.5-4 Hz), theta (5-7 Hz), alpha (8-12 Hz), beta (13-29 Hz) and gamma . Within the same neuronal network each frequency band is usually associated with di erent cognitive states [13] or sensory, motor and cognitive processes [14][15][16][17][18][19][20]. Delta oscillations are often seen during deep sleep, but recently they have also been linked to cognitive functions such as motivational and reward processes [21][22][23].Theta-band is often associated with working memory [24,25], while alpha oscillations have been suggested to re ect cortical idling states [26]. In recent years however, the role of alpha oscillations has also been linked to active inhibition [27] as well as cortical excitability [28][29][30]. Oscillations in the beta-band have been more characteristically related to sensorimotor functions [31,32], whilst gamma oscillations ha...