Nonlinear forecasting measurements of the human EEG during evoked emotions

Forecasting ability applied to a single EEG time sequence may quantify loss of memory of past brain states. This fundamental property of complex dynamical systems could prove to be an important measure of current brain states. The present study examined nonlinear forecasting (or nonlinear predictability) estimates of the scalp-recorded EEG in 76 healthy volunteers in response to emotionally charged (negative, positive and control neutral) video-clip stimuli. EEG was recorded from 18 sites (10-20 system). The obtained results indicate that the negative emotional impact led to a more predictable EEG dynamics, compared with neutral or positive emotional video content, and this effect was restricted to the posterior cerebral sites. The studied signatures of EEG dynamics succeed also in specific discrimination between effects of positive and negative film categories: significantly more predictable dynamics over posterior cerebral sites in response to negative film category was accompanied by enhanced predictability in answer to positive film category over frontocortical loci. It is concluded that these findings suggest the association of basic cortical nonlinear mechanisms with the specific physiological processes of emotional processing.