44 K. S. LASHLEY 



Examples ranging from cerebral mass function in the rat's 

 discrimination of brightness to the very complex conditions 

 of aphasia in polyglots, who lose merely the 'spirit' of a 

 language, all point to the same conclusion. The thing which 

 is localized is, in the majority of cases, the ability to relate 

 any reactions in certain specific ways, rather than a relation 

 between specific reactions. That is, modes of thinking or 

 reacting rather than specific thoughts or reactions are elimi- 

 nated by cerebral lesions. A sensory pattern projected on 

 the cortex must shift from place to place with movements of 

 the stimulus over the sensory surface and yet may retain its 

 capacity to elicit a constant reaction; it must therefore act 

 as a whole and not by isolated connections of single cortical 

 cells with lower motor levels. Once a cortical system of inte- 

 gration is established for one sensory-motor coordination, 

 other sensory-motor combinations seem capable of fitting 

 spontaneously into the schema, even though diiferent afferent 

 and efferent neurons are involved (e.g., the conformation of 

 new word combinations to the habitual grammatical form). 

 The situation seems best described by saying that when a 

 final common path is sensitized to a given cortical pattern, it 

 will respond to that pattern no matter in what part of the 

 cortex it occurs. The significant feature of the cortical pat- 

 tern is the ratio between its parts, and not the particular 

 neurons excited. 



There are many points in common between the behavior 

 data cited above and the direct physiological data obtained 

 in the present experiment. The former point to a cerebral 

 mechanism which, although spacially extended, behaves as a 

 unit and within which dynamic relations or stresses are more 

 important than particulate neuron connections. The physio- 

 logical work indicates a cerebral area which behaves as a unit 

 whose parts are equivalent in function, capable of summated 

 action and independent of particulate cortical association 

 paths. The analogy is so close as to suggest that in the 

 operative experiments we have really isolated a mechanism 

 which underlies the more complex adaptive reactions: that 



