82 LABORATORY OUTLINE OF NEUROLOGY 



7. Structure and Connections of the Cerebellum 



96. The cerebellar peduncles. There are three of these pe- 

 duncles: the superior (brachium conjunctivum), the middle 

 (brachium pontis), and the inferior (corpus restiforme). 



(a) Gross Structure. The cerebellar peduncles have been sev- 

 ered in both the human and the sheep's brain (Section 49). 

 Examine their cut surfaces on the dorsal aspect of the medulla 

 oblongata (for the sheep see Fig. 11). With the orange- wood 

 stick separate the fibers of the three peduncles from each other 

 on the cut surface and continue the separation of the superior, 

 and middle peduncles for ] cm. or less in a downward direction. 



On the left half of the sheep's brain expose the inferior 

 peduncle, or restiform body, by the removal of the cochlear 

 nuclei^ (cf. Section 81) and tease out its fibers from their cut 

 ends downward along the dorso-lateral border of the medulla 

 oblongata. They cross the fibers of the spinal V tract super- 

 ficially from their dorsal to their ventral border and continue 

 into the cord as the dorsal spino-cerebellar tract of Flechsig 

 (see Fig. 12). 



The fibers of the middle peduncle, or brachium pontis, of the 

 left side were partially dissected when studying the cochlear 

 nuclei (Section 81). Their dissection may now be completed. 



The superior peduncle, or brachium conjunctivum, can now 

 be dissected further to its decussation in the cerebral peduncle 

 under the colliculus superior. 



For the dissection of the human cerebellar peduncles, see 

 Sections 103-105. 



(b) Microscopic study of the cerebellar peduncles. In the 

 microscopic sections locate the inferior cerebellar peduncle 

 (corpus restiforme) immediately below its connection with 

 the cerebellum. Following it downward it will be found to 

 receive fibers from the vestibular nucleus (see Section 83) and 

 the inferior olive of the opposite side (olivo-cerebellar tract; 

 see Herrick ('18), Figs. 72 and 87). 



Some of its fibers can also be followed downward into the 

 spinal cord, where they are known as the dorsal spino-cerebellar 

 tract (fasciculus cerebello-spinalis of Flechsig in the B NA list). 

 For the courses of this dorsal spino-cerebellar tract (of Flech- 

 sig) and of the ventral spino-cerebellar tract (of Gowers) in 



