Chaos and chronos in the human brain: a tribute to Franz Halberg.

In order to understand the significance of brain signals, chaotic dynamics of the EEG were analyzed during parabolic flight. Chaotic and other measures of brain waves and eye movements change their characteristics as a function of a host of relatively slow components, such as an about-monthly cycle and early in human ontogeny, starting in gestation. Structural and functional redundancy, yet with diversity in space and time, may serve for adjustment to changes in the environment of the species and thus of the individual. With increasing age, with the accumulation of structured information, the order-to-noise ratio increases, suggesting that for a while during growth, the making of order out of chaos may define the course of development in time.