characteristic electrical pattern (signature) in its waveform (timing), these properties may be obscured by the overlap in time and space from simultaneous activity within multiple neuronal regions and networks. Moreover, since electrical measurements are potential differences (i.e., voltages), the resulting ambiguity may be further exacerbated when the voltage measured at one electrode contact actually originates from activity near the “indifferent” recording reference (i.e., the ubiquitous reference problem; e.g., Kayser and Tenke, 2010; Luck, 2005; Nunez and Srinivasan, 2006a; Wolpaw and Wood, 1982; Yao, 2001). In view of the desirability of a common set of methods, models and analysis strategies capable of spanning from intracranial investigations of neuronal activity within narrowly-defined regions of cortical tissue to macroscopic, grossly-sampled electrical activity at the scalp, an examination of the impact of these measurement scales on the recorded EEG is of considerable importance.
