Chunk #56 — 3. Impact of spatial scale on CSD implementations — 3.3. Empirical considerations for planar (two-dimensional) scalp-recorded EEG — 3.3.2. CSD as a conservative description of neural current generators
a CSD topography does not. Conversely, an equivalent dipole may be used to simplify a field potential topography even when it does not accurately represent the neuroanatomical generators that produce it. As sharply concluded by Fishman et al. (2001a), intracranial data “render untenable the often used assumption that auditory cortical organization can be elucidated by modeling auditory cortical activity as a single dipole generator situated within the superior temporal gyrus.” In contrast, a CSD topography can accurately describe the pattern of radial currents impinging on the skull from an ensemble of generators, even though their number and locations remain unknown. For these reasons, the sink/source CSD pairs representing N1 may be considered to be essential constraints on the flow of radial currents corresponding to these dipoles.
