Normal and Pathological States of the Cerebral Hemispheres27
The central phenomenon in the activity of the cerebral hemispheres is the conditioned reflex. The idea of reflex in physiology, the gift of Descartes’ genius, is, of course, a purely natural-science idea. Conditioned reflexes are formed to all manner of agents in nature, for which the given animal has receptor apparatus, and with all unconditioned reflexes. Their biological significance is enormous, since only because of them can the most precise and finest equilibrium be established between the complex organism and its environment. Both, the process of excitation and the process of inhibition move through the cerebral cortex, at first irradiating rather far from the initial point and then concentrating in it. During concentration these processes are very subtly localised, owing to which the entire cortex is transformed into a vast mosaic of closely following each other stimulated and inhibited points. The chapter furnishes new data of the studies of experimental pathology of higher nervous activity conducted in Pavlov’s laboratories.