We show that a simple non-linear system of ordinary differential equations
may possess a time varying attractor dimension. This indicates that it is
infeasible to characterize EEG and MEG time series with a single time global
dimension. We suggest another measure for the description of non-stationary
attractors.Comment: 13 Postscript pages, 12 Postscript figures (figures 3b and 4 by
request from Y. Ashkenazy: [email protected]