LOCALIZATION OF LEARNING PROCESS 217 



(Lashley, 1922) that the cortex may participate in 

 these reactions in general and apart from any specific 

 local differentiation. 



It is probable that in the simplest cases both the 

 local and the unlocalized cortical participation are 

 fundamentally manifestations of reinforcement, facil- 

 itation, or activation of the thalamic apparatus, with 

 inhibitory (or pseudo-inhibitory) and other factors 

 not clearly brought out in the experiments here under 

 consideration. 



In other animals some simple forms of learning by 

 trial-and-error are clearly exclusively subcortical func- 

 tions and some of these may be so in normal rats. In 

 some of the cases where the cortex has been shown to 

 participate it is quite possible that the physiological 

 modification of nervous pathways correlated with the 

 acquisition of the new behavior pattern and the proc- 

 ess of learning considered as a structural change in the 

 organization or **set" of the nervous connections are 

 essentially thalamic. In this case, the learned activity 

 as a behavior pattern is not neurologically a cortical 

 pattern at all but a thalamic pattern, and the essen- 

 tial part played by the cortex is of a quite different 

 sort. 



Lashley (1922, p. 64) considers the possibility that 

 the habits which he has investigated are learned whol- 

 ly at subcortical levels, and he very properly rejects 

 it. The cortex does participate, in some of the cases 

 at least. But even so, the specific local mechanism 



