[Evaluation of evoked potential or event-related potential mapping]

Strategies for the evaluation of EP and ERP maps are discussed. Spatial interpolation is presented. The reference does not change the landscape but the wave shapes, the baselines change the landscape but not the wave shapes. Electric strength of the map is assessed using Global Field Power, whereby non-ambivalent component latencies can be established. Map landscapes are compared using Global Dissimilarity. Maps are classified using extracted landscape descriptors: locations of minimal and maximal potential, locations of the centroids of the positive and negative map area, reduction to a three-dimensional model dipole source. Adaptive segmentation into echoes of stable landscape (functional microstates) based on landscape descriptors is discussed. Diagnostic and physiological-functional interpretation of the results ought to be distinguished.