236 



PHYSIOLOGY OF CENTRAL NERVOUS SYSTEM. 



cord (vestibulospinal), which end in the motor centers for the spinal 

 nerves. In how far the vestibular nuclei may make afferent con- 

 nections with the cerebellum is undecided, but it seems probable 



Fig. 104. Diagram to indicate a possible descending path from cerebrum to cord in ad- 

 dition to the pyramidal system, namely, the secondary or cerebellar motor path (Van 

 Gehuchten). The path is indirect and comprises trie following units: 1. The cortico- 

 ponto-cerebellar path, represented as arising in tne motor area of the cerebrum and passing 

 down with the pyramidal system to end in the pons, thence continued through the middle 

 peduncles to the cerebellar cortex of opposite side. 2. The path from the cerebellar cortex 

 to the dentate nucleus. 3. The path from the dentate nucleus to the red nucleus passing 

 by way of the superior peduncles, brachium conjunctivum. 4. The path from the red 

 nucleus to the motor cells of the spinal cord (rubro-spinal tract). 



that such tracts exist, in view of the fact that destruction of the 

 semicircular canals and severe lesions of the cerebellum cause motor 

 disturbances that are strikingly similar. 



3. Connections with Other Sensory Nuclei. In addition to the 

 special sensory connections just described, it is stated by various 

 neurologists that the sensory nuclei of the vagus, the trigeminal 

 and the auditory nerves, send afferent paths into the cerebellum, 

 and that similar paths extend from the primary end stations 

 of the optic fibers.* 



* See Edinger, "Brain," 29, 483, 1906. 



