Perception and the Conditioned Reflex, pp. 282-294, by Yevgeny Sokolov. Translated by S.W. Waydenfield. R. Worters and A.D.B. Clarke, Eds. Pergammon Press/MacMillan Co.: New York, 1963. Reproduced without permission solely for scholarly purposes.

	2. The Orienting Reflex and its Components   283-285

	3. Selective Extinction of the Orienting Reflex   285-286

4. A Neuronal Model of the Stimulus    286-288

	5. The Filtering Properties of the Neuronal Model  288-289

	6. The Scheme of the Orienting Reflex    289-291

7. The Neuronal Model of the Stimulus and the Conditioned Reflex         291-294

	[Best when read with an ear for relevance to prejudice and discrimination]

	A Neuronal Model of the Stimulus and the Orienting Reflex
	1. Questions in the Objective Study of Sensory Integration
	An important problem in central nervous system research is that of "sensory integration" (Adrian, 1947)--the synthesis of elementary stimuli into a system which, when interpreted, determines the reaction of the organism.
	"Gestalt" psychologists have demonstrated the importance of the relationships between the various elements in perception (Koffka, 1935). As, however, they limited their research to the description of subjective phenomena, it was impossible for them to discover the intrinsic mechanisms in this phenomenon. Pavlov's doctrine on conditioned reflexes made it possible to develop objecive methods of examination for the processes of sensory -analysis and synthesis, based on the elaboration of differentiated conditioned reflexes to simple and compound stimuli. Thus, Ivanov-Smolenskii (1927) has shown that a system of elementary stimuli constitutes a specific stimulus to which, as a single whole, a conditioned reflex can be elaborated. The conditioned reflex method opened up a wide field for the objective study of analyser activity in a variety of animal species (Voronin, 1953, 1957). It should be noted that the investigation of sensory integration by means of conditioned
	reflexes was based on preliminary, often prolonged, elaboration of differentiated reactions with the result that the true limits of afferent analysis and synthesis were often masked.
	The ability of the organism to differentiate external stimuli can, however, manifest itself by the development of an orienting reaction on change of stimulus even before the elaboration of differentiation, as well as in the form  of differential conditioned reactions. Pavlov wrote: ". . . there is an essential difference between the recognition by the nervous system of a difference between external agents generally and the differentiation of these agents by means of conditioned reflexes. The former is revealed by the stimulatory process in the form of an orienting reaction, an investigatory reflex, which only secondarily has an inhibiting or disinhibiting effect on conditioned reflexes. The latter is expressed by the development of an inhibitory process
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	which is the result, so to speak, of a struggle between stimulation and in-
	hibition" (Pavlov, 1947, p. 116).
	Use of the orienting reaction, without requiring the elaboration of differentiated conditioned reflexes, makes it possible to exclude complicating factors and more directly to study the ability of the nervous system to synthesize and analyse stimuli acting on it.