244 PHYSIOLOGY OF CENTRAL NERVOUS SYSTEM. 



paths described above. There arises, however, the question 

 whether or not there is a localization of function in the cere- 

 bellum, that is, whether definite parts of the cerebellar cortex 

 are in specific relations with separate muscles or groups of 

 muscles. The possibility of a localization of function was 

 suggested years ago by experiments made by Ferrier, in which 

 electrical stimulation of the cortex gave definite movements 

 of the head, limbs, and especially of the eyes, the movements 

 varying somewhat according to the part stimulated. These 

 results were not wholly confirmed by later observers. Horsley 

 and Clarke* state that such strong stimuli are required to obtain 

 a decisive effect from the cortex of the cerebellum that it ma} 7 be 

 questioned whether in positive cases the result is due to excita- 

 tion of the cortex itself or to an escape of stimulus to the under- 

 lying nuclei. Direct stimulation of the dentate nucleus gave 

 them conjugate movements of the two eyes. These indications 



Fig. 105. Schema of dog's cerebellum to show Bolk's nomenclature for the lobes and 

 sulci. Dorsal view : La, lobus anterior (this lobe is separated from the larger posterior lobe 

 by the deep primary fissure, Spr) ; Ls, Ipbulus simplex ; Lans, lobulus ansiformis ; Lp, 

 lobulus paramedianus ; Lmp, lobulus medianus posterior ; Fv, formatis vermicularis (pars 

 tonsillaris) ; C 1 , crus primum ; C 2 , crus secundum ; Spr, sulcus primarius ; Sp, sulcus 

 paramedianus ; Si, sulcus intercruralis. (After van Rynberk.) 



of a localization have been strengthened by the results of com- 

 parative anatomy, and especially by the effects of ablation of 

 definite parts of the cortex. Earlier experimenters, using the 

 method of ablation, obtained quite negative results from the 

 standpoint of localization, but this seems to have been due to 

 the fact that a faulty anatomical schema was used; a whole hemi- 

 sphere, or the entire vermiform lobe, etc., was removed. Later 

 experimenters f have adopted the newer anatomical schemata; 



* Horsley and Clark, "Brain," 28, 13, 1905. 



fVan Rynberk, "General Review in Ergebnisse der Physiologic, " 7, 

 653, 1908, and 12, 533, 1912. 



