Interaction foci, information synthesis, and mental activity.

The cerebral organization of mental activity is based on neural integration, specialization of functions, and the combination of rigid and flexible connections. These principles are embodied in dynamic structures, interaction foci that are detectable in the cortex during intellectual activity by means of the intracortical interaction mapping technique. Interaction foci comprise centers of cortical connections. A focus consists of neuronal groups connected by rigid connections, based on structural changes in the synapses. Each of the groups has its own frequency characteristics and is connected by flexible connections constructed on the principle of iso-lability, with neural elements at the periphery which are isorhythmic to it. The construction of interaction focus supports the synthesis of information arriving from sense organs and centers of motivations, and extractable from memory. Information synthesis underlies mental functions, the cerebral basis for which includes a rigid nucleus and a system of peripheral connections, the configuration of which may vary, thus controlling the uniqueness of a given mental experience. The principle of specialization of functions is manifested in the fact that the topography of interaction foci varies for different mental acts. In the case of perception the projection cortex is the integration center; in the case of thinking, the associative zones of the cortex are the integrative center. Imaginal thinking is primarily associated with the parietotemporal, and abstract thinking with the frontal, divisions of the cortex. Evidently, the two principle functions of consciousness are also spatially separated: integration of the "Self", which includes the volitional principle, and communication.(ABSTRACT TRUNCATED AT 250 WORDS)