System changes in the cortical electrical activity and their role in integrative processes in the brain (a synergic approach)

: In the paper, the general theory of systems is applied to a description of the spatio-temporal organization of the summary cortical potentials, synergetic approach is applied for the insight into the functioning of their system changes. This made it possible to consider the human and animal cortical potentials recorded under different experimental conditions from the single viewpoint. The system organization of cortical potentials in multiple derivations was revealed by comparison of momentary topograms (a sequence of momentary values of cortical potentials in all recording points). This technique enables simultaneous estimation of the spatial and temporal characteristics. In the analyzed data array, the independent changes in different types of subsystems of spatial relations between the momentary potential values were found. These subsystems possess both the spatial and temporal characteristics. Parameters of such coexisting dynamic subsystems widely distributed over the cortex present information about the different indices of the system spatio-temporal organization of cortical potentials (STPO), however, only the ratio between the reflected processes is related with the functional features of cortical activity. The brain state and specificity of performance is to a greater extent determined by a reorganization of the topogram relief. The described relatively stable global system relations of cortical potentials during the organism adaptation to the environment principally change under conditions of goal-directed or voluntary activity. In parallel with the increasing role of developing short-term STPO variations, it was found that each stage of performance is characterized by the dominant topogram reliefs. Such reliefs probably present the "order parameters". They can determine spatial characteristics of the new self-organizing in transition periods dynamic systems of cortical potentials, which are related with the forming new functional states of the cortex. It was demonstrated that the functional possibilities of the brain cortex are determined both the dynamics of topogram reliefs and competing or cooperative interaction of the cortical STPO subsystems. The obtained evidence suggest that in parallel with the regional processes closer related with the projection areas of the brain cortex, a global spatio-temporal organization of cortical activity widely distributed over the cortex forms. The role of this organization of the cortical potentials in the integrative brain activity and expedient human and animal behavior is discussed on the basis of the authors' experimental and literature data.