IS THERE CHAOS IN THE BRAIN

For some years there has been a controversy about whether brain state variables such as EEG or neuronal spike trains exhibit chaotic behavio ur. Wright & Liley claim that the local dynamics measured by spike tra ins or local field potentials exhibit chaotic behaviour, but global me asures like EEG should be governed by linear dynamics. We propose a di fferent scheme. Based on simulation studies and various experiments, w e suggest that the pointwise dimension of EEG time series may provide some valuable information about underlying neuronal generators.