Topographic independent component analysis

In ordinary independent component analysis, the components are assumed to b e completely independent, and they do not necessarily have any meaningful o rder relationships. In practice, however, the estimated "independent" compo nents are often not at all independent. We propose that this residual depen dence structure could be used to define a topographic order for the compone nts. In particular, a distance between two components could be defined usin g their higher-order correlations, and this distance could be used to creat e a topographic representation. Thus, we obtain a linear decomposition into approximately independent components, where the dependence of two componen ts is approximated by the proximity of the components in the topographic re presentation.