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At healthy people (n = 35) on model of the cognitive set on an angry face is shown: introduction of positive and negative coordinated stimuli Go/NoGo in the inter-stimuli interval can change considerably the top-down positive and negative influences of prefrontal cortex on the cortical areas participating in a visual perception and by that to influence plasticity of the set. The cortical topography of the top-down influences in response to NoGo is determined by local changes of power of fluctuations of potentials in alpha rhythm range. Changes of spatial synchronization of alpha potentials occurs only in their low-frequency range, depending on the level of plasticity of the set. At its rigid forms coherent communications between prefrontal and other cortical zones it is obviously more expressed in the left hemisphere. Apparently at rigid forms of cognitive activity left-side cortical activation with more essential involvement of speech, semantic functions, plays the compensating role.

During the experiments, healthy subjects (n = 35) completed Go/NoGo task with a set towards the recognition of negative face expression; the visual stimuli were set in the middle of a 16-second-long interval between target (face) and triggering stimuli. The local changes in low-frequency alpha-oscillations in response to stimuli (desynchronization after a positive Go stimulus and synchronization after an inhibitory NoGo stimulus) take place in posterior frontal and anterior temporal lobes of the left hemisphere, i.e., in cortical areas directly involved in speech processes. In subjects with flexible set towards recognition, we observed synchronization of alpha-rhythm after inhibitory NoGo stimulus; in subjects with more stable set, this did not occur. Thus, we obtained new experimental data confirming that induced synchronization of alpha-oscillations reflects the enhancement of descending inhibitory control of the prefrontal cortex.