Conditional reflex theory and motivational behavior.

Motivational behavior is explained in the light of reflex theory by reference to: (i) Pavlov's concept of nerve center as an assembly of structures messing the same function, (ii) Sherrington's and Magnus' ideas about the hierarchical structure of the nervous system, (iii) author's notion about the multistage arc of the unconditioned reflex, i.e., an arc with many branches in its central path, each passing through the main integrative levels of the central nervous system, (iv) experimental facts of this laboratory and particularly concerning bidirectional conditioned connections. It is assumed that motivational behavior elicited by endogenous and exogenous factors through hereditary mechanisms may be regarded as a manifestation of complex inborn reflexes, in which the main branch is located in the limbic system. The cortical branch makes it possible to elaborate particular conditioned reflexes. Physiological mechanisms of so-called purposive movements in motivational behavior is regarded as the activity of backward conditioned connections, leading from the unconditioned reflex centers to the centers controlling motor effectors.