p.223 no simple sensory impulses ordinarily reach the cortex, but only nervous impulses arising from lower correlation centers, where complex reflex combinations of various sensory systems are possible... The optic impulses reach the cortex most nearly pure, i.e., with less subcortical associational relation with other sensory systems

 

p.228-229 From these anatomical considerations it follows that no simple sensory impulse can, under ordinary circumstances, reach the cerebral cortex without first begin influenced by subcortical association centers, within which complex reflex combinations may be effected and various automatisms set off in accordance with their preformed structure... It is shown by the lower vertebrates which lack the cerebral cortex that these subcortical mechanisms are adequate for all of the ordinary simple processes of life... But here, when emergencies arise which involve situations too complex to be resolved by these mechanisms, the animal will pay the inevitable penalty of failure - perhaps the loss of... his life.

 

p.229 In the higher mammals with well developed cortex... Here is a mechanism adapted, not for a limited number of predetermined and immediate responses, but for a much greater range of combination... and a much larger range of possible modes of response to any given set of afferent impressions. By a process of trial and error, perhaps, the elements necessary to effect the adaptive response may be assembled and the problem solved.

 

p.236 From all of these considerations it seems probable that the functions of the higher association centers of the cerebral cortex do not consist of the elaboration of crude sensory data or of any similar elements, but rather of the coordination and integration of highly elaborated subcortical organic circuits which in the aggregate make up the greater part of the reflex and instinctive life of the species.