Chaos is defined as extreme (exponential) sensitivity to initial conditions. Phenomenologically it is sometimes difficult to distinguish chaos from randomness, especially at the Heisenberg level where the underlying drivers become truly random. Nevertheless chaos has a distinct and precise mathematical formulation. Measuring ChaosHow do you determine when a system is in a chaotic state ? One way is to do it theoretically, using Lyapunov exponents. However for this we must know and understand the network structure in advance, and it would be a whole lot more convenient to be able to put an electrode in the brain and just watch for a while. Such asymptotic tests do exist, like the 0-1 chaos test, but there are pretty stringent conditions under which the results can be reasonably evaluated. Tests like this are good for quick hit-or-miss guesstimates, but rigorous study probably requires a better treatment.Next: Phase Transitions |