198 



BRAIN MECHANISMS AND LEARNING 



synthesis stage which, as wc shall sec below, determines all the subsequent 

 stages in the formation of the behaviour of man and animals. 



Fig. 4 

 General scheme illustrating the role of the orienting-investigatory 

 reaction in the formation of the conditioned reaction, i.e. in the 

 establishment of the chain of afferent traces from the stimulus to 

 the acceptor of action. 



A. At each stage of the animal's movement towards the 

 reinforcing factor the orientmg-investigatory reaction contributes 

 to the production of return afferentation. 



B. Final form of bonds. The conditioned signal aids in the almost 

 instant spread of excitations along the afferent traces fixed in the 

 past by means of the orienting-investigatory reaction. 



2. SPECIFIC ACTIVATING EFFECT ON THE CEREBRAL CORTEX AND PROCESSES 

 OF AFFERENT SYNTHESIS 



The specific activating function of the brain stem reticular formation 

 plays a special part in the processes of afferent synthesis (Anokhin, 1958). 



