CHANGES IN HUMAN CEEEBELLUM WITH AGE 



31 



I have pointed out that the vermis is ahead of the lateral lobes 

 of the cerebellum in its early development. This agrees well 

 with the supposition that the vermis is concerned with bilateral 

 movements of the trunk and limbs. The vermis is older phylo- 

 genetically than the lateral lobes, and this further suggests that 

 it is the center for the control of the more primitive coordinations 

 of the neuromuscular system. 



2 4 6 8 10 12 14 16 18 20 MONTHS 24 



Chart 8 A composite based on charts 1, 4, and 5. The uppermost graph — 

 solid line — gives the changes in the thickness of the molecular layer in n. Ordi- 

 nate values at the left. The next below — broken line — gives the weight of the 

 cerebellum in grams. Ordinate values to the right. The next below — solid line 

 — gives the percentage weight of the cerebellum. Ordinate values entered above 

 eighteen months. The lowest graph — broken line — gives the number of rows of 

 cells in the external granule layer. Ordinate values entered above ten months. 

 The grouping of these graphs permits a comparison of several growth changes 

 occurring simultaneously during the first twenty-four months of life. 



In that case the earlier development of the vermis agrees 

 well with the fact that the child is able to control many move- 

 ments of the trunk and limbs before he is able to walk. 



In general the head and arm musculature is under control 

 for some months before the child can walk, and this, I think, 

 can be correlated with the earlier disappearance of the external 

 granule cells in the anterior part of the cerebellum. 



THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 32, NO. 1 



