52 Anatomy of the Nervous System 



Fuse has described in some detail for the rat and other types caudal 

 and oral ventro-medial cell groups of the. spinal V root lying between the 

 latter and the superior olive, and a few small cell groups ventral to the 

 motor V nucleus (Pis. IX., XL). 



The medulla oblongata Is furthermore traversed by 

 numerous pathways connecting higher and lower regions of 

 the brain. Some of these — the secondary sensory tracts — ■ 

 have already been considered. Among the ascending path- 

 ways, there are to be noted in addition to these the restiform 

 body (corpus resiiforme) or inferior cerebellar peduncle and the 

 ventral spino- cerebellar tract which forms a large part of the 

 composite tract of Gowers. The former is the direct con- 

 tinuation of the dorsal spino-cerebellar tract of the spinal 

 cord, to which are added various elements originating in the 

 medulla oblongata. It forms a conspicuous, compact bundle 

 in the dorso-lateral corner of the sections (oval area), where it 

 can be followed up into the cerebellum (Pis. IX. -XL). The 

 ventral spino-cerebellar tract lies superficially in the ventro- 

 lateral region, where it is not clearly marked off from the 

 surrounding tissue (PI. VHI.). In the upper part of the 

 oblongata, anterior to the trigeminal nuclei, it may be seen 

 to turn dorsally and pass to a position dorsal to the brachium 

 conjunctivum (vide infra), with which it then runs back into 

 the cerebellum (PI. XI.). As it passes dorsally, it appears in 

 the form of numerous small bundles which may easily be 

 confused with the lateral lemniscus, as this tract runs in a 

 similar direction immediately medial to it. 



There may also be included in this group the brachium 

 conjunctivum, or superior cerebellar peduncle, which traverses 

 the uppermost part of the hindbrain in passing from the 

 cerebellum into the midbrain. It is a rather large bundle 

 situated laterally, at each side of the ventricle, and having a 

 dorso-ventrally flattened form. It passes in an antero-ventral 

 direction into the midbrain, becoming decreasingly compact 

 as it does so (Pis. XL, XII.). 



