Functional organization of different brain areas during convergent and divergent thinking: an EEG investigation

This study examined the task-related changes in EEG patterns during the experimental condition of convergent and divergent thinking in 36 healthy male subjects. EEG was recorded from 16 sites (10/20 system). After FFT a power was calculated for all 16 loci, and a coherence was estimated for all 120 electrode pairs in six frequency bands (4-30 Hz). Different patterns of the significant changes for the obtained EEG parameters were found during the two thinking types. When compared with the rest, both mental experiences produced the significant desynchronization of alpha 1,2 rhythms. At the same time, the convergent thinking induced coherence increases in the theta 1 band that were more caudal and right-sided, whereas divergent thinking showed mainly amplitude decreases in the caudal regions of the cortex in theta 1,2 bands and the massive increases of a amplitude and coherence in the beta 2 indicating a close interaction between both hemispheres. Distinct task-related discrepancies of EEG pattern in the beta 2 band between the subjects divided into groups of good and bad performers of divergent thinking are also found. Good performance is related to die special organization of the cerebral areas in the beta 2 band: (i) increased functional connectivity of central-parietal areas of both hemispheres; and (ii) greater ipsilateral connections between the cortex regions of the right hemisphere. (C) 2000 Elsevier Science B.V. All rights reserved.