The organization of classical and instrumental conditional reactions

This paper makes a theoretical analysis of the process of formation of neural associations among sensory changes produced in the brain by environmental stimuli; it also analyzes the origin of classical and instrumental conditional reactions. It has been proposed that sensory traces of stimuli “intermingle,” forming patterns of associations in “polymodal” structures of the brain. The sensory traces of stronger stimulus dominate over the sensory traces of weaker stimulus in the pattern. An activation of a pattern of associations by any of the stimuli involved releases a reaction typical of the stronger stimulus (called a reinforcing or unconditional stimulus) before the latter is presented. That type of reaction, called classical conditional reaction, is dispensable; it is one of post-reinforcement origin and therefore, is not represented in the pattern of associations. When a physiological act, such as a definite movement (e.g., pressing a bar) must precede the obtaining of the reinforcing stimulus, this physiological act, called an instrumental conditional reaction, is also evoked each time the pattern of associations has been activated. The instrumental conditional reaction is indispensable and, because of its pre-reinforcement origin, belongs, through its sensory feedback, to the pattern of associations.