CEREBELLUM, PONS, AND MEDULLA. 



221 



3. Connections with the Cortex of the Cerebrum. The cerebellar 

 cortex is connected with the cerebral cortex by the large system 

 known as the cortico-ponto-cerebellar tract (see Fig. 76, A). The 

 fibers of this tract arise in the motor area of the cerebrum or in 

 the frontal cortex anterior to the motor area, descend in the internal 



Fig. 98. Diagram to indicate a possible descending path from cerebrum to cord in ad- 

 dition to the pyramidal system, the secondary or cerebellar motor path (Van Gehuchten). 

 The path is indirect and comprises the following units : 1. The cortico-ponto-cerebellar 

 path, represented as arising in the motor area of the cerebrum and passing down with the 

 pyramidal system to end in the pons, thence continued through the middle peduncles to the 

 cerebellar cortex of opposite side. 2. The path from the cerebellar cortex to the dentate 

 nucleus. 3. The path from the dentate nucleus to the red nucleus passing by way of the 

 superior peduncles. 4. The path from the red nucleus to the motor cells of the spinal cord 

 (rubro-spinal tract). 



capsule and crus cerebri, and end in the gray matter of the pons. 

 Thence new axons continue the path across the mid-line and to 

 the cerebellar cortex by way of the middle peduncle. The tract 

 would seem to convey efferent impulses from the cerebral cortex 

 (motor region) of one side to the cerebellar cortex of the opposite 

 side. A second possible connection with the cerebrum is made 



