E. A. ASRATYAN IO7 



conditions of combined action ot both stimuli a weak above-threshold 

 excitation evoked by a weak electric current becomes considerably intensi- 

 fied, etc. Finally, it must be noted that according to these findings, the 

 phenomena described above and the determining factors observed in the 

 formation of conditioned reflexes are not connected to any appreciable 

 degree with typology, age or other features of the experimental animals; 

 it follows that they belong to the category of basic phenomena and 

 determining factors which are characteristic of the conditioned reflex 

 activity of higher parts ot the central nervous system. 



How are all these fmdings to be interpreted and generalized? 



Experimental psychologists, neurophysiologists and animal trainers have 

 for long known a number of facts which prove the formation of a tw^o- 

 way nervous connection and have provided a basis for the formulation of 

 corresponding theories on this question (Goltz, 1884; Bekhtercv, 1887; 

 Ebbinghaus, 1911-13; Kahsher, 1912-14, Savich, 1918; Zeliony, 1929; 

 Beritov, 1932; Konorsky and Miller, 1936; Narbutovich and Podkopayev, 

 1936; Rosenthal, 1936; Petrova, 1941; Kupalov, 1948; Fiodorov, 1952; 

 Voronin, 1952, and others). In this connection special mention must be 

 made of the theories of Pavlov (1949) concerning double (or two-way) 

 conditioned connections, advanced by him in recent years and based on 

 original facts brought to light in his laboratories. Pavlov stated that 'when 

 two nervous points are connected, or associated, the nervous processes 

 developing between them proceed in both directions'.^ At that time, 

 however the founder of the theory of conditioned reflexes was of the 

 opinion that the important question of two-way conditioned connection 

 was still not sufficiently elaborated, experimentally or theoretically, and 

 that it required further investigation. It appears to us that the facts recently 

 obtained in our laboratory increase to some degree our knowledge of this 

 problem. They reveal new aspects of direct and reverse connections, and, 

 in particular, new aspects of the role played in this process by the physio- 

 logical strength of the stimuli and by the sequence of their combination. 



All these facts, in addition to the previously known data of other investi- 

 gators, lead to the assumption that the formation of a double (or two-way) 

 conditioned comiection is not a limited phenomenon peculiar only to a 

 certain group of conditioned reflexes, but is widespread, if not universal 

 for this class of reflexes. This creates, so to speak, a structural basis tor a 

 two-way tunctional connection and for a circular conditioned reflex 

 interaction between the comiected nervous points, approximately in the 



1 1. P. Pavlov, Complete Works, 1949, vol. Ill, p. 452. 



