“…The activity is seen in the continuous irregular firing of action potentials at the microscopic level, in fluctuating dendritic potentials at the mesoscopic level, and in spatiotemporal fluctuations in blood flow at the macroscopic level, which indirectly reflect the insatiable demands of brains for energy. It is commonly regarded as chaos, but it is not deterministic chaos (Rapp, 1993), because those systems are stationary, autonomous and noise-free, whereas brains are noisy, time-varying, open systems generating stochastic chaos (Freeman, 2000;Freeman, Kozma, & Werbos, 2001;Kozma, Puljic, Balister, Bollabás, & Freeman, 2005). It is also regarded as noise and removed by time-locked averaging to extract event-related potentials, on the assumption that the stimulus-or response-related activity is superimposed on the background activity.…”