THE GREAT AFFERENT SYSTEMS 315 



conducts impulses from specialized sense organs in the semicircular canals, sac- 

 cule and utricle, which are stimulated by movements and changes in posture 

 of the head. 



Neuron I. From the bipolar cells of the vestibular ganglion (of Scarpa), 

 located within the internal auditory meatus, peripheral processes run to the 

 maculae of the utricle and saccule and to the cristae of the semicircular canals. 

 The central processes are directed through the vestibular nerve toward the 

 floor of the fourth ventricle and divide into ascending and descending branches. 

 While the descending and many of the ascending branches terminate in the 

 vestibular nuclei, many other ascending branches pass without interruption to 

 end in the cerebellar cortex and particularly in that of the vermis (Fig. 136). 



Neuron II. Some of the cells situated in the vestibular nuclei send their 

 axons, along with the ascending branches mentioned above in the vestibulo- 

 cerebellar tract, to the cortex of the vermis, and to a less extent to the cortex 

 of the cerebellar hemispheres also. 



