210 CENTRAL NERVOUS SYSTEM 



1. Connections with the Cord. The cerebellospinal tract 

 passes from the cord, through the restiform body, to the cere- 

 bellum, carrying impulses derived from terminations in muscles 

 and tendons. It is still an undecided point whether impulses 

 from the posterior columns may pass from the nuclei gracilis 

 and cuneatus to the cerebellum. Ascending fibers arising in 

 the reticular formation of the medulla and olivary nucleus 

 pass to the cerebellum by way of the inferior peduncles, and 

 probably, on the other hand, make connections with the sen- 

 sory tracts of the cord or sensory nuclei of the medulla. Gowers' 

 tract or the fasciculus anterolateralis superficialis also passes 

 to the cerebellum via the superior peduncle; like Flechsig's 

 tract, carrying impulses of deep sensibility. 



2. Connections with the Vestibular Nerve. This nerve arises 

 in the semicircular canals, utriculus, and sacculus, and ends in the 

 pons in several nuclei (Deiters', Bechterew's) and in the nuclei 

 fastigii of the cerebellum. From Deiters' nucleus the vestib- 

 ulospinal tract arises, passes to the cord, where it makes con- 

 nections with motor neurons. Bechterew's nucleus gives rise 

 to fibers which, passing with the medial longitudinal bundle, 

 make connections with the motor nuclei of cranial nerves. 

 The sensory nuclei of the vagus, trigeminal, and auditory nerves, 

 and. primary end stations of the optic nerves, are said to send 

 afferent paths to the cerebellum. 



3. Connections with the Cerebral Cortex. Fibers arising in 

 the motor area of the cerebrum or anterior to this descend in 

 the internal capsule and cerebral peduncles to the gray matter 

 in the pons. A second set of neurons continues the path across 

 the midline, and passing by way of the middle peduncles 

 reaches the cerebellar cortex. A second connection with the 

 cerebrum is made by fibers from the dentate nucleus, which, 

 passing via the brachium conjunctivum, reaches the red nucleus 

 and the thalamus. The latter are continued to the cerebrum. 

 From the red nucleus, on the other hand, impulses may pass 

 via the rubrospinal tract to motor centres in the cord. 



The Cerebrum. One of the recognized methods for the study 

 of the functions of the central nervous system is that of extir- 

 pating definite portions and noting the effects. The cerebrum 

 in many classes of animals has been dealt with in this way. 

 In the frog, complete removal of the cerebral hemispheres 



