NONLINEAR DYNAMICAL COUPLING BETWEEN DIFFERENT BRAIN-AREAS DURING EVOKED EMOTIONS - AN EEG INVESTIGATION

This study examined changes in the non-linear dynamical coupling betwe en different brain areas in response to emotionally valenced (i.e. neu tral, affective positive and negative) film stimuli in 76 healthy volu nteers. EEG was recorded from 18 sites (10-20 system). A new dynamical measure, mutual dimension (D-m) was applied to the EEG. The D-m was c alculated between each electrode paired to all other electrodes. The r esults were compared to coherence measures. Differential patterns of s ignificant changes of D-m estimates were found in the two emotional co nditions. When compared to the neutral viewing condition, the emotiona lly negative experience provoked significant decreases of short- and l ong-distance ipsi- and contralateral D-m estimates that were more left -sided (with a 'center of gravity' of D-m decrease at the F7 site), wh ereas the emotionally positive experience showed a pattern of symmetri cally distributed ipsi- and contralateral increases of D-m estimates o ver central and posterior cortical regions (with 'main processing node s' of D-m increases at T5 and T6 sites). It is concluded that estimate s of the mutual dimension are sensitive to subtle aspects of emotional processing, not accessible by linear (i.e. coherence) analyses. (C) 1 998 Elsevier Science B.V. All rights reserved.