THE MAMMALIAN NERVOUS SYSTEM 



87 



revealed a rather obscure type of functional localization within 

 the cerebellum which bears no simple relation to the anatom- 

 ical subdivisions as defined in the B N A tables. 



Broadly speaking, there are centers within the cerebellar 

 cortex for muscular coordination and tonic control of the more 

 cephalic parts of the body in the dorsal and rostral parts of the 

 cerebellum. Centers for the similar control of the more caudal 

 muscular complexes extend around the caudal margin of the 

 cerebellum to the inferior surface. Centers for bilaterally 

 coordinated movements of paired groups of muscles are me- 



Folium vermis 

 Declive monticuli 



Culmen monticuli 



Lobulus centralis 



Velum medullare 

 anterius 



Lingula 



Tuber vermis 



Pyramis 



^"LJLHj Uvula 



Nodulus 



Tela chorioidea 

 ventriculi quarti 



FIG. 15. A sagittal section through the vermis of the human cerebel- 

 lum. The B N A names of the parts are given and also the functional 

 localization as determined by Bolk, Rynberk, and others. The areas of 

 the head and neck extend lateralward as indicated on Fig. 13. The area 

 for control of movements of the trunk is limited to the inferior vermis. 

 The area for the limbs in the tuber vermis is for the control of coordinated 

 movements of both members of a pair, while the arm and leg areas shown 

 in Figs. 13 and 14 control the separate movements of these limbs. 



dian and unpaired. The centers for the motor control of each 

 limb separately lie laterally on the corresponding side of the 

 cerebellum. 



The general arrangement of these functional regions is shown 

 in Figs. 13, 14, 15 and 16, though many details are still ob- 

 scure. In particular, it has not been possible to separate the 

 arm areas from the leg areas in man; but experimental studies 

 on other mammals suggest that the leg area lies inferior to the 

 arm area, as indicated in Fig. 14. 



The preceding account of localization of function is based 

 on the studies of Bolk and Van Rynberk. More recently 



