FUNCTIONAL INTERRELATION OF CEREBRAL 



CORTEX WITH BASAL GANGLIA 



AND CEREBELLUM* 



HAR\ Ev GUSHING oncc good-natuiedly accused Herbert Evans of being "pi- 

 tuitary minded," and I believe that there was a prompt rejoinder from 

 Doctor Evans to the effect that Gushing liad lately transferred his "minded- 

 ness" as well as his affections to the hypothalamus. Had it been a three-cor- 

 nered exchange, one might have suggested that these two seats of Cartesian 

 turmoil are connected by silken threads of functional integration. In my 

 mind's eye I can see Herbert racing around the sella turcica, peeping over the 

 posterior clinoid or looking menacingly up through the diaphragm— only to 

 meet the penetrating gaze of a diminutive Harvey Gushing seated securely on 

 the floor of the third ventricle and exclaiming: "What, Herbert, more frac- 

 tions? Stop it— I'll stir up one of them from here, and create a case of diabetes 

 that even Jack Peters cannot control." 



What other excuse can I offer for presenting the nervous system to Herbert 

 Evans on his birthday? I fear he may not like it— but even so, he surely will 

 be pleased by the thought that he and Gushing are still playing hide-and-seek 

 with one another above and around the sella. And what game on the part of 

 two men ever proved more richly rewarding to us all? 



In selecting for discussion the broad theme of the physiological relation be- 

 tween the two great extrapyramidal systems, (i) the cortico-strio-nigral, and 

 (ii) the cortico-ponto-cerebellar, I am aware that I am taking liberties with 

 one of the classical concepts of clinical neurology, for in common parlance 

 the "extrapyramidal" system begins with the basal ganglia and ends some- 

 where in the spinal cord through the reticulo- and rubro-spinal projections. 

 From the physiological standpoint, this is an indefensible concept, since in 

 higher animals all subcortical motor nuclei, including the cerebellum, are 

 under the direct control of the cerebral cortex, and it is impossible in a func- 

 tional analysis to divorce the subcortical from the cortical centers of motor 



integration. 



The Gortico-strio-nigral System 



One may take for granted a knowledge of the principal subcortical nuclei of 

 the extrapyramidal system: the neostriatum (caudate and putamen) discharg- 

 ing through the paleostriatum or globus pallidus, which in turn discharges 

 by the ansa lenticularis to substantia nigra and other tegmental nuclei. In 

 early embryological history, the paleostriatum and its motor projections were 

 the principal motor pathways from the forebrain, but with the development 

 of the cerebral cortex, the striate bodies became dominated by direct and in- 

 * Modified from an address to the Philadelphia Neurological Society, read March 28, 1941. 



1:203] 



