CHAPTEE LI 



FUNCTIONS OF THE CEREBELLUM 



IN past times there have been several views held as to the functions 

 of the cerebellum. One of the oldest of these was the idea that the 

 cerebellum was associated with the function of generation ; another 

 view, first promulgated by WilUs, was that the cerebellum contained 

 the centres which regulate the functions of organic life ; this arose 

 from the circumstance that diseases of the cerebellum are often 

 associated with nausea and vomiting; it is a familiar fact that in 

 displacements of equilibrium such as occur on board ship in a rough 

 sea, or in the disease called Meniere's disease, sickness is a frequent 

 result; it appears from this that the cerebellum does receive 

 certain impulses from the viscera. The third and last of these 

 older theories was that the cerebellum was the centre for sensation. 

 This arose from the fact that certain of the afferent channels of the 

 spinal cord were traced into the cerebellum. The impulses that travel 

 along these, however, though afferent, are not truly sensory, and their 

 reception in the cerebellum is not associated with consciousness. 



The true function of the cerebellum was first pointed out by 

 Flourens, who showed that the cerebellum is the great centre for the 

 coordination of muscular movement, and especially for that variety 

 of coordination which is called equilibration that is, the harmonious 

 adjustment of the working of the muscles which maintain the body 

 in a position of equilibrium. 



It must not be supposed from this that the cerebellum is the sole 

 centre for coordination. We have already seen that all the machinery 

 necessary for carrying out very complicated locomotive movements 

 is present in the spinal cord. The higher centres set this machinery 

 going, and the work of arranging what muscles are to act, and in 

 what order, is carried out by the whole of the grey matter from the 

 corpora striata to the end of the spinal cord, including such out- 

 growths as the corpora quadrigemina and cerebellum. An instance 

 of a complex coordinated movement is seen in what we learnt to call 

 in the last chapter conjugate deviation of head and eyes. The higher 

 cortical centre gives the general word of command to turn the head 



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