162 THE CEREBRUM. 



fibers to the quadrigeminal bodies, the substantia nigra and the 

 lentiform nucleus, its chief termination is in the lateral nucleus 

 of the thalamus. It is sensory. It conducts tactile, pain and 

 temperature impressions. 



Brachium Conjunctivum. (Superior cerebellar peduncle). 

 The brachium conjunct! vum forms a ridge on the surface near 

 the median line of the isthmus, which ends above at the inferior 

 quadrigeminal colliculus (Fig. 44). The lateral fillet winds 

 inward over its upper extremity. It is joined to its -fellow by a 

 sheet of white matter, the superior medullary velum. The fibers 

 of the brachia conjunctiva bend ventrally beneath the inferior 

 colliculus of the corpora quadrigemina and, for the most part, 

 decussate anterior to the cerebral aqueduct, through the median 

 raphe (Fig. 48). These crossed fibers with the few uncrossed 

 run forward toward the inferior surface of the thalamus, where 

 they inclose the red nucleus, and help to form the stratum dorsale 

 of the hypothalamic region (Forel). Many of the fibers terminate 

 in the red nucleus and from it others rise and proceed forward 

 to the thalamus. Though most of the brachium conjunctivum 

 rises in the cerebellum and forms a segment of an indirect sensory 

 tract, it also contains efferent fibers which rise in the red nucleus. 



Rubro-spinal tract (Crossed Descending Tract of the Red 

 Nucleus). Formed by axones of the red nucleus, it immediately 

 crosses through the ventral tegmental decussation (foreli) and 

 proceeds lateral ward to the lateral fillet (Fig. 47). In the lower 

 part of the mid-brain, it is imbedded in the medial part of that 

 fillet. The rubro-spinal tract runs through the medulla and 

 descends in the spinal cord to the lumbar region, where it ends in 

 the center of the gray crescent. 



Olivary Fasciculus. The olivary bundle is a loose "strand of 

 fibers traversing the reticular formation lateral to the medial 

 longitudinal bundle, in the upper part of the mid-brain; in the 

 lower region of the mid-brain, it runs closer to the median line 

 and is mingled with the fibers of the brachium conjunctivum as 

 they are about to enter the decussation. The olivary bundle 

 probably rises in the lentiform nucleus and ends in the olivary 

 nucleus of the medulla. 



