CORRELATION BETWEEN SPATIAL SYNCHRONIZATION AND HUMAN EEG RHYTHMS

1. The study of changes in cross-correlation between potentials from different cortical zones of the human brain during activation associated with intellectual concentration showed that the level of synchronization is in most cases increased. This applies in particular to distant regions of the cortex and it leads to flattening of the gradient of synchronization which exist at rest. During intellectual concentration a stabilization of relations takes place between fluctuations in the degree of synchronization of potentials, as expressed by strengthening of the tendency toward unidirectional shifts in the coefficients of cross-correlation between different cortical regions. 2. Investigation of changes in the spectral characteristics of the EEG of different cortical areas of the left hemisphere led to the conclusion that the changes taking place are parallel: enhancement of low-frequency components (delta-theta-rhythm) and a decrease in the spectral power of the alpha-rhythm. The energy of beta-activity showed no significant change in a state of mental concentration. 3. Enhancement of low-frequency activity during intellectual concentration is accompanied by an increase in the degree of synchronization of fluctuations in its energy. The opposite tendency is observed with respect to the alpha-rhythm, probably because of mechanisms limiting the spread of this type of activity over the cortex.