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A M Ivanitskii

Publications and source records attributed to A M Ivanitskii.

6 recordsLinked to original sources
PubMedDate not supplied

Information synthesis in key parts of the cerebral cortex as the basis of subjective experience.

This paper discusses a number of principles of the organization of cerebral processes underlying subjective experiences. The concept developed here suggests that these experiences arise as a result of the synthesis of different types of information, this synthesis occurring in various parts of the cortex which have key roles in this mental function. The synthesis is made using information arriving from the external environment, information extracted from memory, and information arriving from motivational centers. The concept is based on studies of the cerebral mechanisms of perception and thought. Experiences are demonstrated to arise as a result of the synthesis, by neurons in the projectional cortex, of data describing the physical and informational properties of a stimulus; the mechanism of the synthesis is a circular movement of excitation from the projectional to the associative regions of the cortex, then to the hippocampus and motivational centers, with return of excitation to the projectional cortex. It is also demonstrated that the process of thought involves convergence of cortical connections on defined centers, which are called interaction foci. Different thought operations are associated with their own specific interaction focus topographies: in imaginative thinking, foci are located in the temporo-parietal cortex, while abstract thinking foci in the frontal cortex. It is suggested that information arriving by means of neural connections is compared and synthesized in interaction foci, and that this provides the basis for decision-making. The final part of this paper addresses the functional importance of mental phenomena and their possible effects on cerebral processes.

Cerebral Cortex↗
PubMedDate not supplied

Studies of cortical interactions over short periods of time during the search for verbal associations.

Interactions between cortical areas were studied during the search for verbal associations and reading of words. The functional anatomy and the sequence of involvement of cortical areas during the solution of these tasks have been described previously, in studies using positron emission tomography and multichannel recordings of evoked potentials combined with identification of the locations of dipole sources [8, 9, 19, 25]. Cortical interactions reflected in terms of the synchronization of EEG rhythms were studied by developing a method based on correlating curve wavelets, which allows the moments at which this synchronization occurs to be identified over short periods of time comparable with the speeds of individual thought operations (up to 100 msec). Three main stages were identified in the search for associations. During the first 200 msec after stimulus presentation, cortical connections were seen between the right and left frontal areas; at 200-500 msec, there were connections between the frontal and the temporal-parietal areas; finally, at 450-700 sec, there were connections between the left temporal and the right frontal-central-temporal areas. These results are in good agreement with data obtained previously using other methods and supplement them with mapping data on cortical connections. A number of differences in the mechanisms of information processing during the search for associations and reading were also identified.

Adolescent↗