Dynamic neurophysiological correlates of mental processes.

The study of neurophysiological correlates of states and activity has revealed different mechanisms of the brain. Infraslow physiological processes (ISPP) as well as impulse activity of neurons and neuronal populations (NIA) were recorded during the performance of psychological and other trials by the subject. Subjects were neurological patients diagnosed and treated with implanted electrodes. We found correlates of mental activity to be reproducible (stable) in some brain areas and variable in others, which confirmed our concept that mental activity is maintained by cortical-subcortical functional system with links of different degrees of rigidity. One of the ISPP types, omega-potential, was shown to reflect quantitatively the state of the brain areas. We have described NIA rearrangements accompanying mental operations and revealed the complimentary character of various NIA rearrangements. Extremely promising in the investigation of neurophysiological correlates of mental processes, is the study of the relationship of local and distributed rearrangements in various neurophysiological processes, as well as combination of averaging with the study of correlates of single mental acts. Stability, combined with the dynamic character of rearrangements of physiological processes in the brain, seems to be its fundamental property responsible for informational capacity of the brain and adaptational ability of the organism.