Changes in the spatial organization of cortical electrical activity during increasing working memory load

Analysis of EEG coherence performed in 60 healthy adult subjects revealed some changes in the spatial organization of cortical electrical activity produced by complication of the context of cognitive performance (increasing the working memory load). Changes in the degree of coherence of cortical potentials within the local areas were observed already at the stage of the "operative readiness" immediately after the instruction, i.e., representation of the cognitive task sequence in the explicit working memory. The observed changes were different in the anterior (decrease in the degree of coherence) and posterior (increase in coherence) areas of the cortex. Context-related increase in the local coherence was more pronounced in the temporal, parietal, and occipital areas of the left hemisphere than in the right hemisphere.