28 BRAINS OF RATS AND MEN 



apparatus will be put in action or inhibited from 

 action. And since the higher animals have very many 

 of these elementary reflex mechanisms, the determi- 

 nation of which of them will be activated in some 

 particular situation may be a very intricate matter. 

 The intricacy (and efficiency) of the process increases 

 with the improvement of the apparatus for registering 

 effects of past experience and incorporating these 

 organic memories into the functional complex so that 

 we act in response to present stimuli in the Hght of 

 past experience (Elliot Smith, 1919^). 



This last seems to be pre-eminently a cortical 

 function in higher animals, yet we have little evidence 

 of it in animals like rats with a simpler grade of 

 cortical organization. We are therefore much puzzled 

 about what the rat's cortex actually does. 



As will appear in the course of the subsequent 

 discussion, the cerebral cortex has many other func- 

 tions besides acting as an arbiter of conduct by 

 "deciding" which of many anatomically possible 

 lower neuromotor systems will be activated in a given 

 situation, that is, by controlling intentionally directed 

 behavior. One of these many functions is to activate 

 or reinforce some particular lower reflex circuits that 

 may already be in process and at the same time to 

 depress or inhibit other reflex circuits that interfere 

 with those which are reinforced. It is, in fact, not 

 improbable that this reciprocal reinforcement and 

 inhibition is an important factor in all cortical control 



