SEC. 6. SOME OTHER ASPECTS OF THE FUNC- 

 TIONS OF THE BRAIN. 



512. It is difficult to say anything definite concerning the 

 transmission of sensory impulses and the development of sensa- 

 tions ; it is still more difficult to say anything definite, beyond 

 what has been already incidentally said, concerning the parts 

 played in the work of the brain by the various aggregations of 

 grey matter and tracts of fibres forming the middle part of the 

 brain. Neither experiment nor clinical study has as yet afforded 

 any clear or sure leading. 



Let us first speak of the cerebellum. 



The connections of this body with the rest of the nervous 

 system are strikingly manifold. By the inferior peduncle, the 

 fibres of which end largely in the nucleus dentatus, it has an 

 uncrossed grip on afferent structures of the spinal cord and 

 bulb ; by the cerebellar tract it is connected through the vesicu- 

 lar cylinder with the posterior roots of spinal nerves of the same 

 side ; it has a like connection with the cuneate and gracile 

 nuclei of the same side, and fibres from the eighth (vestibular) 

 nerve, as well probably as from other afferent cranial nerves 

 of the same side, pass into the peduncle. The same inferior 

 peduncle has a crossed connection with the lower olive of the 

 other side, but this is probably efferent in nature, and there are 

 probably other efferent connections. By its middle peduncle, 

 the fibres of which are especially connected with the superficial 

 grey matter, the cerebellum has large connections with the 

 opposite side of the pons and, through the relay of the cells 

 forming the grey matter of the pons, with fibres passing from 

 the frontal and temporo-occipital regions (possibly from scattered 

 elements of the parietal region) of the cerebral cortex to the 

 pons. Thus each lateral half of the cerebellum has wide crossed 

 connections with the opposite half of the cerebrum. Whether 

 these connections are afferent, that is leading from the cere- 

 bellum to the cerebral cortex, or vice versa, or have both char- 

 acters, it is difficult to say. Besides this the superior peduncle, 



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