VITAL RESERVES 317 



ular past experiences — this does seem to be in man- 

 kind a typically cortical sort of nervous action. 



On this view of the mechanics of cortical function 

 we see that to the non-specific cortical reserves of the 

 rat there are added immensely more significant re- 

 serves in the human association centers. These re- 

 serves are manifested in several forms. 



First, every mnemonic vestige, every engram, is 

 represented by a complex web of interrelated neurons, 

 each with a certain potential energy while in the rest- 

 ing condition. When reactivated in recall (say by a 

 sensory stimulus) the reserve energy of this mnemonic 

 complex is released and is available both to co-op- 

 erate with the reactivating sensory excitation in de- 

 termining the nature of the response and also to in- 

 tensify that response and inhibit or neutralize all 

 other responses. Obviously, in these specific memory 

 vestiges or engrams we have a sort of cortical re- 

 serves quite different from the non-specific reserves of 

 the cerebellum and other more primitive nervous 

 apparatus. 



In the second place, the cortex contains innumer- 

 able nervous elements with short axons (type II 

 neurons, see p. 91) which seem structurally not well 

 adapted to participate in the more extensive associa- 

 tional patterns of the usual memory vestiges but are 

 so situated as to be able to function in a non-specific 

 way by discharging their reserve energy locally into 

 any associational system that at the moment may be 



