p. K. ANOKHIN 197 



the cerebral cortex but also under an efferent excitation of the peripheral 

 apparatus of the sense organs (Granit, Dell, Livingston). Owing 

 to the rapid alternation of this efferent stream from one analyser to 

 another the afferent synthesis stage precedmg the very conditioned 

 reaction is considerably enriched by afferent impulses, something that 

 determines a finer and more adequate (for the given conditions) formation 

 of effector processes of the conditioned reflex. 



Naturally, after the stage oi elaboration of the conditioned reaction this 

 primary period of the multifarious efferent influences on the sense organs, 

 increasing the excitability of the latter, is in large measure eliminated, 

 owing to which the apparatus of the very conditioned reflex are simplified 

 during the stage of its complete automation (see Fig. 4). 



Electrophysiological studies of the orienting and investigatory reaction 

 have shown that it is able continuously to maintain a high level of excita- 

 tion in the cerebral cortex and at the same time maintain in an active 

 state the newly formed temporary bonds (Anokhin, 1957; Karazina, 

 1957). Recently Professor Lindsley published a remarkable paper in wliich 

 direct stimulation of the brain stem reticular formation demonstrated the 

 tremendous role played by the reticular formation in the discriminative 

 function of the cerebral cortex for rhythmic flashes of light (Lindsley, 

 1958). 



Thus we believe it completely proved that the power basis for the all- 

 rouiui synthesis of the iiiiiiieroiis external and internal, situational and trio(^er 

 afferent influences on the cerebral cortex is the ascendino oenerali::ed actiration 

 of the brain stem reticular formation. 



The role of the reticular formation in refining afferent analysis also 

 manifests itself in the fact that at this moment an alternate increase in the 

 excitability of various receptor structures at the periphery takes place 

 (Granit, 1957; Dell, 1957; Snyakin, 1958). 



All told this makes it absolutely necessary, in analysing conditioned 

 reflex adaptations, to set apart an independent stage of afferent synthesis. 



The significance of this stage consists first of all in the fact that before its 

 completion the flow of effector excitations to the functioning organs 

 cannot be formed. The composition of these effector excitations and, 

 consequently, the nature of the adaptive act itself are directly dependent 

 on the way in which this stage of the afferent synthesis is completed. 



At this point I must emphasize that the decisive role of the afferent 

 function, as a 'creative' function of the cerebral cortex, was repeatecily 

 indicated by Pavlov (Pavlov, 1928). The proof of this decisive role of the 

 afferent function o{ the cerebral cortex is. in our opinion, the afferent 



