Changes in the Spatial Synchronization of Oscillations of Cortical Potentials in the α Range after Conditioning Go/No-Go Stimuli

Studies in healthy subjects ( n = 35) using a model based on a cognitive set to an angry facial expression showed that use of positive and inhibitory Go/No-Go stimuli during the interstimulus period can produce marked changes in the top-down inhibitory influences of the prefrontal cortex on cortical areas involved in visual recognition, thus influencing set plasticity. The cortical topography of top-down influences in response to No-Go stimuli was determined in terms of local changes in the power of oscillations in potentials in the α range. Changes in spatial synchronization of α oscillations occurred only in the low-frequency range and depended on the level of set plasticity. In rigid forms of the set, coherence connections between the prefrontal cortex and other cortical zones were clearly more marked in the left hemisphere. In rigid forms of cognitive activity, left-hemisphere activation, with greater involvement of the speech and semantic functions, appears to play a compensatory role.