Induced Synchronization of the Alpha Rhythm During the Pauses Between Visual Stimuli with Different Levels of Cognitive Set Plasticity

Abstract

Studies in healthy adults (n = 35) using a model of a set to recognition of an angry facial expression showed that increases in loading on working memory by extending the duration of the time interval between the target (a facial image) and trigger (a spot of light) stimuli to 16 sec did not lead to any significant slowing of the switching from the old set to the new. Differences were seen between the group of subjects in whom set switching was accompanied by distorted perception of the emotional facial expression and the “no errors” group in the extents of the induced synchronization of the α rhythm during the interstimulus period. Synchronization was more marked in this latter group. The dynamics of changes in the α rhythm showed that selective attention was modulated during sequential cognitive acts, this being apparent at the bioelectrical level as changes in the extent of induced synchronization/desynchronization of α-range potentials. The proposed “inhibitory control” mechanism provides flexibility for cognitive processes by suppressing the influences of irrelevant factors on cortical processes during interstimulus pauses. We believe that this “protective” mechanism can explain the minor effect of increased loading on working memory in the present studies.